Voltage and reactive power monitoring and control device, computer program for the same, and voltage and reactive power monitoring and control method

Abstract

To provide a voltage and reactive power monitoring and control device that calculates the voltage of an upper power system, ensuring sufficient adjustment reserve capacity for the lower power system even when the state quantities related to the power of the lower power system fluctuate significantly.SOLUTION: A voltage and reactive power monitoring and control device 1 includes an input unit 11 where state quantities related to electrical quantities and control status of the power system 9 are input and an operation unit 12 that selects a tap position satisfying the margin from among multiple taps of a transformer placed in the lower-level system 92 on the basis of the margin indicating the number of taps outputting a voltage higher than the selected tap position and the number of taps outputting a lower voltage and calculates the target voltage of the upper system 91 as control information on the basis of the state quantities input to the input unit 11, assuming the tap is at the selected tap position, by having the lower system 92 independently controlled.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present embodiment relates to a voltage and reactive power monitoring and control device, a computer program for the voltage and reactive power monitoring and control device, and a voltage and reactive power monitoring and control method for maintaining the stability of a power system and supplying electric power stably. [Background technology]

[0002] Depending on the load state of a power system, both reactive power and voltage change. Power systems are stabilized by adjusting the voltage and reactive power. Voltage and reactive power monitoring and control devices that stabilize power systems by adjusting the voltage and reactive power are known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-18748 Summary of the Invention [Problem to be solved by the invention]

[0004] Electric power systems are composed of systems with multiple voltage classes. Electric power systems are mainly composed of upper systems such as 500kV systems and 275kV systems, and lower systems of 154kV or lower. Generally, voltage and reactive power monitoring and control devices are installed separately for the upper and lower systems. The upper and lower systems are controlled separately by the voltage and reactive power monitoring and control devices.

[0005] In the upper system, the bus voltage is monitored by a voltage and reactive power monitoring and control device installed in the upper system, and the phase modifying equipment, transformer taps, generator voltage, etc. connected to the system are controlled. In the lower system, the bus voltage is monitored by a voltage and reactive power monitoring and control device installed in the lower system, and the phase modifying equipment, transformer taps, generator voltage, etc. connected to the system are controlled.

[0006] The control by the voltage and reactive power monitoring and control device of the upper system is performed independently of the control of the lower system, and the upper system is controlled based on state quantities such as the power supply in the upper system and the power consumption in the load.

[0007] In recent years, renewable energy power generation devices such as solar power generation devices and wind power generation devices are increasingly being connected to downstream power systems. The output of these renewable energy power generation devices fluctuates significantly. As a result, the impact of output fluctuations from renewable energy power generation devices on the power system is becoming greater.

[0008] The control of the voltage and reactive power monitoring and control device of the lower system is carried out independently from the control of the upper system. The lower system is controlled based on state quantities such as the power supply and power consumption of the load in the lower system. Generally, in the lower system, when the voltage drops due to an increase in load, the voltage is controlled to be higher, close to the operational limit voltage, while ensuring a margin for reactive power adjustment. Accordingly, the taps of the transformers in the lower system are controlled.

[0009] This can lead to the tap position in the lower system being biased towards the upper or lower limit. When a renewable energy power generation device is connected to the lower system, the output fluctuates greatly. When the tap position is biased towards the upper or lower limit, there is not enough room for adjustment, making it difficult to perform appropriate power control.

[0010] When a renewable energy power generation device is connected to a lower-level system, the output fluctuates greatly, so voltage control by tap changing is frequently performed. Therefore, if the control of the upper-level system is performed independently of the control of the lower-level system, it is difficult to perform appropriate power control.

[0011] In view of the above problems, the present embodiment aims to provide a voltage and reactive power monitoring and control device that calculates the voltage of a higher-level system, while ensuring sufficient adjustment margin in the lower-level system even when the state quantities related to the power of the lower-level system fluctuate greatly. [Means for solving the problem]

[0012] The voltage and reactive power monitoring and control device of this embodiment has the following features. (1) In a power system having a lower system that is independently controlled and an upper system that supplies power to the lower system, the voltage and reactive power monitoring and control device calculates control information related to system control of the upper system. (2) The voltage and reactive power monitoring and control device has an input unit to which state quantities relating to the electrical quantities and control states of the power system are input. (3) The voltage and reactive power monitoring and control device has a calculation unit that selects a tap position from among multiple taps of a transformer arranged in the lower system that satisfies the margin based on a margin indicating the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage, and calculates a target voltage of the upper system as the control information based on the state quantity input to the input unit, assuming that the tap is at the selected tap position by independently controlling the lower system. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the configuration of a system using a voltage and reactive power monitoring and control device according to a first embodiment; [Figure 2] FIG. 1 is a diagram showing a program flow of the voltage and reactive power monitoring and control device according to the first embodiment. [Figure 3] FIG. 10 is a diagram showing the configuration of a system using a voltage and reactive power monitoring and control device according to a second embodiment. [Figure 4] FIG. 10 is a diagram showing the configuration of a system using a voltage and reactive power monitoring and control device according to a third embodiment. [Figure 5] FIG. 10 is a diagram showing a program flow of the voltage and reactive power monitoring and control device according to the third embodiment. [Figure 6] FIG. 10 is a diagram showing the configuration of a system using a voltage and reactive power monitoring and control device according to a fourth embodiment. [Figure 7] FIG. 10 is a diagram showing the configuration of a system using a voltage and reactive power monitoring and control device according to a fifth embodiment. [Figure 8] FIG. 13 is a diagram showing the configuration of a system using a voltage and reactive power monitoring and control device according to a sixth embodiment. [Figure 9] FIG. 13 is a diagram showing the configuration of a system using a voltage and reactive power monitoring and control device according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] [1. First embodiment] [1-1.Configuration] [1-1-1. Overall structure] 1 is an overall diagram showing the configuration of a system using a voltage and reactive power monitoring and control device 1 according to a first embodiment. In this embodiment, when there are multiple devices or components with the same configuration, they are described using the same number, and when describing each individual device or component with the same configuration, they are distinguished by adding an alphabetic suffix to the common number. The voltage and reactive power monitoring and control device 1 is sometimes called a VQC device.

[0015] As an example, this system has a voltage and reactive power monitoring and control device 1, a control device 5, and a power system 9. The power system 9 is composed of an upper system 91 and a lower system 92. A system adjustment device 6 and a state quantity detection device 7 are arranged in the power system 9. In addition, an information transmission device 8a is arranged on the power system 9 side, and an information transmission device 8b is arranged on the voltage and reactive power monitoring and control device 1 side.

[0016] The upper system 91 is composed of a high-voltage system such as 500 kV or 275 kV. The lower system 92 is composed of a system of 154 kV or less. The lower system 92 is connected to the upper system 91, and power is supplied from the upper system 91 to the lower system 92. The number of lower systems 92 connected to the upper system 91 is not limited to one. Multiple lower systems 92 may be connected to one upper system 91.

[0017] The lower system 92 transforms the power supplied from the upper system 91 using a transformer (not shown) to generate supply power. The transformer has multiple taps that change the ratio between the primary and secondary voltages. The transformer taps are switched by an on-load tap changer.

[0018] A system adjustment device 6a is connected to the upper system 91, and a system adjustment device 6b is connected to the lower system 92. The system adjustment device 6a adjusts the voltage and reactive power of the upper system 91. The system adjustment device 6a is controlled by the control device 5. The system adjustment device 6b adjusts the voltage and reactive power of the lower system 92. The system adjustment device 6b is controlled by a control device (not shown in the figure) that controls the lower system 92. The lower system 92 is controlled independently of the upper system 91.

[0019] The system adjustment device 6a is controlled by the control device 5, and adjusts the amount of reactive power generated by the generators connected to the upper system 91, and switches on and off power capacitors and switches on and off shunt reactors, thereby adjusting the voltage and reactive power of the upper system 91. The system adjustment device 6b is controlled by a control device (not shown in the figure) that controls the lower system 92, and changes taps of the transformers of the lower system 92, adjusts the power generation devices connected to the lower system, and switches on and off power capacitors and switches on and off shunt reactors, thereby adjusting the voltage and reactive power of the lower system 92. The power generation devices connected to the lower system may be renewable energy power generation devices.

[0020] A state quantity detection device 7 is installed in the power system 9. The state quantity detection device 7 is connected to a higher-level system 91, a lower-level system 92, and a system adjustment device 6a. The state quantity detection device 7 is composed of a measuring device that measures electrical quantities including active power, reactive power, voltage, current, etc., and a state detection device that detects the state of the system adjustment device 6.

[0021] The state quantity detection device 7 detects electrical quantities including active power, reactive power, voltage, and current of the upper system 91, and electrical quantities including active power, reactive power, voltage, and current of the lower system 92. The state quantity detection device 7 also detects the amount of reactive power generated by the system adjustment device 6a in the upper system 91, and the state of control including the closing and opening of power capacitors and the closing and opening of shunt reactors.

[0022] The state quantity detection device 7 transmits the state quantities as system information to the information transmission device 8. The state quantities are the electrical quantities of the upper system 91 and the lower system 92 detected by the state quantity detection device 7 and the states related to the control by the system adjustment device 6a. The information transmission device 8 is composed of a communication device that transmits and receives information via a wired or wireless dedicated line, a telephone line, an internet line, or the like. The information transmission device 8a is located on the power system 9 side, and the information transmission device 8b is located on the voltage and reactive power monitoring and control device 1 side.

[0023] The information transmission device 8a transmits the system information received from the state quantity detection device 7 to the information transmission device 8b. The information transmission device 8b transmits the system information received from the information transmission device 8a to the voltage and reactive power monitoring and control device 1.

[0024] [1-1-2. Configuration of voltage and reactive power monitoring and control device 1] The voltage and reactive power monitoring and control device 1 is a device that calculates control information related to system control of an upper system 91 in a power system 9 that has a lower system 92 that is independently system-controlled and an upper system 91 that supplies power to the lower system 92. The voltage and reactive power monitoring and control device 1 may be a power system control amount calculation device that calculates the control amount of the power system 9, or may be a power system control support device that supports the control of the power system 9.

[0025] The voltage and reactive power monitoring and control device 1 receives state quantities of the upper system 91 through system information, and calculates a target voltage of the upper system 91 as control information based on the state quantities. The target voltage of the upper system 91 calculated as control information is a voltage at which the tap of the transformer arranged in the lower system 92, when independently controlled, is at a tap position with a predetermined margin relative to the upper and lower limits of the tap. The target voltage may be the center value of the target voltage, or may include the upper and lower limit voltage values ​​of the target voltage in addition to the center value of the target voltage.

[0026] The voltage and reactive power monitoring and control device 1 is configured with a computer or the like. The voltage and reactive power monitoring and control device 1 has an input unit 11, a calculation unit 12, a memory unit 13, and an output unit 14. The processing by the input unit 11 may be called an input step or an input procedure, the processing by the calculation unit 12 may be called a calculation step or a calculation procedure, the processing by the memory unit 13 may be called a memory step or a memory procedure, and the processing by the output unit 14 may be called an output step or an output procedure.

[0027] The input unit 11 is configured with a transmitting / receiving circuit, an external memory connection circuit, or an operation device such as a keyboard, a mouse, a touch panel, etc. The input unit 11 is connected to the calculation unit 12. Information related to the power system 9 is input to the input unit 11.

[0028] The input unit 11 includes a system information input unit 111 , an upper-level constraint information setting unit 112 , and a lower-level constraint information setting unit 113 .

[0029] The system information input unit 111 receives the electric quantity and state detected by the state quantity detection device 7 from the information transmission device 8b as system information.

[0030] The system information may be received from the information transmission device 8b by a transmitting / receiving circuit of the system information input unit 111, or the system information stored in an external memory may be received by an external memory connection circuit. Also, the system information may be input by an operation device arranged in the system information input unit 111, such as a keyboard, a mouse, or a touch panel.

[0031] The system information includes, as state quantities, information on electrical quantities related to the active power, reactive power, voltage, and current of the upper system 91, and information on electrical quantities related to the active power, reactive power, voltage, and current of the lower system 92.

[0032] The system information also includes, as state quantities, information on the state of control including the adjustment of the reactive power generation amount of the upper system 91 by the system adjustment device 6a, the closing and opening of the power capacitor, and the closing and opening of the shunt reactor.

[0033] The system information input to the system information input unit 111 is transmitted to the calculation unit 12. The system information may also be stored in the storage unit 13.

[0034] The upper-level constraint information setting unit 112 receives upper-level constraint information relating to the operation of the upper-level system 91 .

[0035] The higher-level constraint information may be input by an operation device arranged in the higher-level constraint information setting unit 112, such as a keyboard, a mouse, or a touch panel, or the higher-level constraint information set and stored in an external device may be received by a transmitting / receiving circuit or an external memory connection circuit of the higher-level constraint information setting unit 112.

[0036] The upper-level constraint information includes information on the upper voltage limit, the lower voltage limit, and the dead band width for the target voltage of the upper-level system 91. The upper-level constraint information may also include the target voltage of the upper-level system.

[0037] The upper and lower voltage limits are the upper and lower voltage limits relative to the target voltage of the monitored bus in the higher-level system 91. The dead band width is a voltage close to the target voltage that does not require abrupt voltage switching. The dead band width refers to a voltage range of, for example, ±2% relative to the target voltage.

[0038] The upper-level constraint information input to the upper-level constraint information setting unit 112 is transmitted to the calculation unit 12. The upper-level constraint information may be stored in the storage unit 13.

[0039] The lower level constraint information setting unit 113 receives lower level constraint information relating to the operation of the lower level system 92 .

[0040] The lower-level constraint information may be input by an operating device arranged in the lower-level constraint information setting unit 113, such as a keyboard, mouse, or touch panel, or the lower-level constraint information set and stored in an external device may be received by a transmitting / receiving circuit or an external memory connection circuit of the lower-level constraint information setting unit 113.

[0041] The lower-level constraint information includes information on the upper and lower voltage limits of the lower-level system 92 .

[0042] The lower-level constraint information includes upper and lower voltage limit values ​​for the lower-level system operational limit voltage when the tap of the lower-level system monitoring point of the lower-level system 92 connected to the monitored bus of the upper-level system 91 is set to the middle position (neutral), and upper and lower voltage limit values ​​for the target voltage of the lower-level system. The lower-level constraint information may also include the target voltage of the lower-level system.

[0043] The lower-level constraint information input to the lower-level constraint information setting unit 113 is transmitted to the calculation unit 12. The lower-level constraint information may also be stored in the storage unit 13.

[0044] The calculation unit 12 is configured by a calculation processing unit in a computer or a software module. The calculation unit 12 is connected to the input unit 11, the storage unit 13, and the output unit 14. The calculation unit 12 controls the input unit 11, the storage unit 13, and the output unit 14.

[0045] The calculation unit 12 has a voltage calculation unit 121. The voltage calculation unit 121 creates control information for the upper system 91 based on the system information received from the system information input unit 111, the upper constraint information received from the upper constraint information setting unit 112, and the lower constraint information received from the lower constraint information setting unit 113. The voltage calculation unit 121 calculates a target voltage for the upper system 91 as the control information.

[0046] The target voltage of the upper system 91 calculated as control information is a voltage value at which the tap of the transformer arranged in the lower system 92, when controlled independently, will be at a tap position with a predetermined margin relative to the upper and lower limits of the tap.

[0047] The target voltage of the upper system 91 calculated as control information is stored in the storage unit 13 and transmitted to the output unit 14.

[0048] The storage unit 13 is configured with a storage medium such as a semiconductor memory or a hard disk. The storage unit 13 is connected to the calculation unit 12. The calculation unit 12 controls the writing and reading of data into and from the storage unit 13. The storage unit 13 has a voltage data storage unit 131.

[0049] The voltage data storage unit 131 stores, as control information, the target voltage of the upper system 91 calculated by the voltage calculation unit 121 of the calculation unit 12. The storage unit 13 may store the system information input to the system information input unit 111, the upper constraint information input to the upper constraint information setting unit 112, and the lower constraint information input to the lower constraint information setting unit 113.

[0050] The output unit 14 is composed of a transmission circuit, a display device such as a liquid crystal display, a printing device such as a printer, an external memory connection circuit, etc. The output unit 14 is connected to the calculation unit 12. The output unit 14 outputs the target voltage of the upper system 91 calculated by the voltage calculation unit 121 of the calculation unit 12 as control information. The output unit 14 outputs the target voltage of the upper system 91 as electronic data, a display, or a printout. The output unit 14 transmits the target voltage value to the control device 5.

[0051] [1-1-3. Configuration of the control device 5] The control device 5 is a device that outputs a control command for system control of the upper system 91 to the system adjustment device 6a based on the state quantity related to the system information detected by the state quantity detection device 7 and the target voltage of the upper system 91 as control information calculated by the voltage and reactive power monitoring and control device 1.

[0052] The control device 5 is configured by a computer including control devices, etc. The control device 5 has a system information input unit 51, a control amount calculation unit 52, and a control command output unit 53.

[0053] The system information input unit 51 is configured with a transmitting / receiving circuit, an external memory connection circuit, or an operation device such as a touch panel or a switch. The system information input unit 51 is connected to the control amount calculation unit 52. System information regarding the power system 9 is input to the system information input unit 51.

[0054] The system information input unit 51 receives, as system information, the state quantities detected by the state quantity detection device 7. The system information includes, as state quantities, information on the electrical quantities of the upper system 91 and the lower system 92, and information on the state related to the control of the upper system 91.

[0055] The system information may be received from the state quantity detection device 7 by a transmitting / receiving circuit of the system information input unit 51, or the system information stored in an external memory may be received by an external memory connection circuit.

[0056] The system information includes, as state quantities, information on electrical quantities including active power, reactive power, voltage, and current of the upper system 91 and information on electrical quantities including active power, reactive power, voltage, and current of the lower system 92.

[0057] The system information also includes, as state quantities, information on the control state including the reactive power generation amount of the upper system 91 by the system adjustment device 6a, the closing and opening of the power capacitor, and the closing and opening of the shunt reactor.

[0058] The system information input to the system information input unit 51 is transmitted to the control amount calculation unit 52 .

[0059] The control amount calculation unit 52 is configured by an arithmetic processing unit in a computer or a software module. The control amount calculation unit 52 is connected to the system information input unit 51 and the control command output unit 53.

[0060] The control amount calculation unit 52 receives system information from the system information input unit 51 and a target voltage of the upper system 91 as control information from the voltage and reactive power monitoring and control device 1. The control amount calculation unit 52 creates a control command based on the system information received from the system information input unit 51 and the target voltage of the upper system 91 as control information received from the voltage and reactive power monitoring and control device 1.

[0061] The control command is a command for controlling the upper system 91 by the system adjustment device 6a, including at least one of the reactive power generation amount of the upper system 91, the opening and closing of a power capacitor, and the opening and closing of a shunt reactor.

[0062] The control command output unit 53 is configured by a transmission circuit etc. The control command output unit 53 may have a display device such as a liquid crystal display, a printing device such as a printer, an external memory connection circuit etc. The control command output unit 53 is connected to the control amount calculation unit 52.

[0063] The control command output unit 53 transmits the control command created by the control amount calculation unit 52 to the system adjustment device 6a. As described above, the control command is a command related to the control of the upper system 91 by the system adjustment device 6a, including the reactive power generation amount of the upper system 91, the opening and closing of power capacitors, and the opening and closing of shunt reactors.

[0064] The system adjustment device 6a receives a control command from the control command output unit 53 and adjusts the upper system 91. As a result, the voltage and reactive power of the upper system 91 are adjusted.

[0065] The above is the configuration of the system using the voltage and reactive power monitoring and control device 1.

[0066] [1-2. Effect] Next, an outline of the operation of the voltage and reactive power monitoring and control device 1 of this embodiment will be described with reference to Figures 1 and 2. Figure 2 is a diagram showing the flow of a program for the voltage and reactive power monitoring and control device 1.

[0067] The voltage and reactive power monitoring and control device 1 calculates control information related to system control of the upper system 91 in a power system 9 having a lower system 92 that is independently system-controlled and an upper system 91 that supplies power to the lower system 92.

[0068] The voltage and reactive power monitoring and control device 1 receives system information of the upper system 91 via the system information input unit 111 of the input unit 11, and calculates the target voltage of the upper system 91 as control information via the voltage calculation unit 121 of the calculation unit 12 based on the state quantities related to the received system information.

[0069] The voltage and reactive power monitoring and control device 1 calculates the target voltage of the upper system 91 as control information based on the state quantity input to the input unit 11, assuming that the taps of a transformer having multiple taps arranged in the lower system 92 are selected by independently controlling the system so that the number of taps outputting a high voltage and the number of taps outputting a low voltage are set to tap positions with a predetermined margin relative to the selected tap positions. The target voltage may be the center value of the target voltage, or may include an upper voltage limit value and a lower voltage limit value of the target voltage in addition to the center value of the target voltage.

[0070] The calculation unit 12 calculates the target voltage of the upper system 91 as control information, assuming that the taps of a transformer having multiple taps arranged in the lower system 92 are selected by independent system control to tap positions where the number of taps outputting a higher voltage than the selected tap position and the number of taps outputting a lower voltage are approximately equal.

[0071] The transformer arranged in the lower system 92 has a plurality of taps, for example, 27 stages, 23 stages, 17 stages, etc. If the arranged transformer has, for example, 23 stages, the calculation unit 12 assumes that the 12th stage, which is the tap in the middle position, is selected, and calculates the target voltage of the upper system 91. The tap in the middle position is sometimes called a "neutral."

[0072] In the voltage and reactive power monitoring and control device 1, upper-level constraint information including information on the upper voltage limit value, lower voltage limit value, and voltage dead band width of the upper-level system 91 is set in the upper-level constraint information setting unit 112 of the input unit 11, and a target voltage of the upper-level system 91 that satisfies the set upper-level constraint information is calculated as control information by the voltage calculation unit 121 of the calculation unit 12.

[0073] In the voltage and reactive power monitoring and control device 1, lower-level constraint information including information on the upper and lower voltage limits of the lower-level system 92 is set in the lower-level constraint information setting unit 113 of the input unit 11, and the target voltage of the upper-level system 91 that satisfies the set lower-level constraint information is calculated as control information by the voltage calculation unit 121 of the calculation unit 12.

[0074] The operation of the voltage and reactive power monitoring and control device 1 is realized by a computer program shown in Fig. 2. The computer program shown in Fig. 2 is stored in the calculation unit 12 of the voltage and reactive power monitoring and control device 1.

[0075] (Step S01: Receive system information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 controls the input unit 11 to receive system information. The system information input unit 111 of the input unit 11 receives, as system information, the state quantities related to the upper system 91, the lower system 92, and the system adjustment device 6a, detected by the state quantity detection device 7, via the information transmission devices 8a and 8b.

[0076] The system information includes, as state quantities, information on the quantities of electricity related to the active power, reactive power, voltage, and current of the upper system 91, and the quantities of electricity related to the active power, reactive power, voltage, and current of the lower system 92.

[0077] The system information also includes, as state quantities, information on the state of control by the system adjustment device 6a, including the amount of reactive power generated in the upper system 91, the closing and opening of power capacitors, and the closing and opening of shunt reactors. The system information input to the system information input unit 111 is transmitted to the calculation unit 12. The system information may also be stored in the storage unit 13.

[0078] (Step S02: Receive upper level constraint information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 controls the input unit 11 to receive upper-level constraint information. The upper-level constraint information is input to an upper-level constraint information setting unit 112 of the input unit 11. The upper-level constraint information includes information on an upper voltage limit value and a lower voltage limit value for the upper-level system operational limit voltage, as well as an upper voltage limit value and a lower voltage limit value for the target voltage of the upper-level system 91, and a dead band width for the target voltage. The upper-level constraint information may also include the target voltage of the upper-level system 91.

[0079] The upper and lower voltage limits are those of the monitored bus bar in the higher-level system 91. The dead band width is a voltage close to the target voltage that does not require switching due to sudden voltage fluctuations. The dead band width refers to a voltage range of, for example, ±2% of the target voltage.

[0080] The upper-level constraint information input to the upper-level constraint information setting unit 112 is transmitted to the calculation unit 12. The upper-level constraint information may be stored in the storage unit 13.

[0081] The higher-level constraint information may be input by an operation device arranged in the higher-level constraint information setting unit 112, such as a keyboard, a mouse, or a touch panel, or the higher-level constraint information set and stored in an external device may be received by a transmitting / receiving circuit or an external memory connection circuit of the higher-level constraint information setting unit 112.

[0082] (Step S03: Receive lower-level constraint information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 controls the input unit 11 to receive lower-level constraint information. The lower-level constraint information is input to the lower-level constraint information setting unit 113 of the input unit 11. The lower-level constraint information includes information on the upper and lower voltage limits of the lower system 92.

[0083] The lower-level constraint information includes an upper voltage limit value and a lower voltage limit value for the lower-level system operational limit voltage when the tap of the lower-level system monitoring point of the lower-level system 92 connected to the monitored bus of the upper-level system 91 is set to the middle position (neutral), and an upper voltage limit value and a lower voltage limit value for the target voltage of the lower-level system 92. The lower-level constraint information may also include the target voltage of the lower-level system 92.

[0084] The lower-level constraint information input to the lower-level constraint information setting unit 113 is transmitted to the calculation unit 12. The lower-level constraint information may also be stored in the storage unit 13.

[0085] The lower-level constraint information may be input by an operating device arranged in the lower-level constraint information setting unit 113, such as a keyboard, mouse, or touch panel, or the lower-level constraint information set and stored in an external device may be received by a transmitting / receiving circuit or an external memory connection circuit of the lower-level constraint information setting unit 113.

[0086] (Step S04: Calculate the target voltage of the upper system 91) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 calculates a target voltage of the upper system 91. The target voltage of the upper system 91 is calculated by a voltage calculation unit 121 of the calculation unit 12. The target voltage includes a central value of the target voltage, an upper voltage limit value, and a lower voltage limit value of the target voltage.

[0087] The voltage calculation unit 121 calculates the target voltage of the upper system 91 based on the system information received in step S01. As described above, the system information is information about the state quantities of the upper system 91, the lower system 92, and the system adjustment device 6a detected by the state quantity detection device 7.

[0088] The voltage calculation unit 121 calculates the target voltage of the upper system 91, assuming that the taps of a transformer having multiple taps arranged in the lower system 92 are selected by independent system control so that the number of taps that output a high voltage and the number of taps that output a low voltage are set to tap positions with a predetermined margin for the selected tap positions.

[0089] The voltage calculation unit 121 calculates the target voltage of the upper system 91, assuming that the taps of a transformer having multiple taps arranged in the lower system 92 are selected by independent system control to tap positions where the number of taps outputting a higher voltage than the selected tap position and the number of taps outputting a lower voltage are approximately equal. The voltage calculation unit 121 calculates the target voltage of the upper system 91, assuming that the tap at the tap position located midway among the multiple taps is selected.

[0090] If the transformer arranged in the lower system 92 has, for example, 23 stages, the voltage calculation unit 121 assumes that the 12th stage, which is the tap at the middle position, is selected. The tap at the middle position is sometimes called a "neutral."

[0091] Furthermore, the voltage calculation unit 121 calculates the upper and lower voltage limits of the target voltage based on the dead zone width included in the higher-level constraint information. The voltage calculation unit 121 sets the upper limit of the dead zone width as the upper voltage limit of the target voltage, and the lower limit of the dead zone width as the lower voltage limit of the target voltage.

[0092] (Step S05: Determine whether the target voltage satisfies the lower-level constraint information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 determines whether the target voltage calculated in step S04 satisfies the lower-order constraint information. The determination whether the target voltage satisfies the lower-order constraint information is made by the voltage calculation unit 121 of the calculation unit 12. If it is not determined that the target voltage satisfies the lower-order constraint information (NO in step S05), the program proceeds to step S06. If it is determined that the target voltage satisfies the lower-order constraint information (YES in step S05), the program proceeds to step S07.

[0093] (Step S06: Calculate a target voltage that satisfies the lower-level constraint information) If it is not determined in step S05 that the calculated target voltage satisfies the lower-order constraint information, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 calculates a target voltage of the upper system 91 that satisfies the lower-order constraint information. The target voltage that satisfies the lower-order constraint information is calculated by the voltage calculation unit 121 of the calculation unit 12.

[0094] The voltage calculation unit 121 corrects the target voltage calculated in step S04 to a target voltage that satisfies the lower-level constraint information input from the lower-level constraint information setting unit 113. The voltage calculation unit 121 corrects the target voltage to a target voltage that satisfies the upper and lower voltage limits of the lower system 92, which are information included in the lower-level constraint information, and sets the target voltage as a new target voltage for the upper system 91. The voltage calculation unit 121 may set a voltage that is, for example, ±2% of the target voltage for the lower system 92 included in the lower-level constraint information as the new target voltage.

[0095] (Step S07: Determine whether the target voltage satisfies the upper-level constraint information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 determines whether the target voltage determined in step S04 or the target voltage corrected in step S06 satisfies the upper-level constraint information. The determination of whether the target voltage satisfies the upper-level constraint information is made by the voltage calculation unit 121 of the calculation unit 12. If it is not determined that the target voltage satisfies the upper-level constraint information (NO in step S07), the program proceeds to step S08. If it is determined that the target voltage satisfies the upper-level constraint information (YES in step S07), the program proceeds to step S09.

[0096] (Step S08: Calculate a target voltage that satisfies the upper-level constraint information) If it is not determined that the target voltage calculated in step S04 or the target voltage corrected in step S06 satisfies the upper-level constraint information, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 calculates a target voltage of the upper system 91 that satisfies the upper-level constraint information. The target voltage that satisfies the upper-level constraint information is calculated by the voltage calculation unit 121 of the calculation unit 12.

[0097] The voltage calculation unit 121 corrects the target voltage calculated in step S04 or the target voltage corrected in step S06 to a target voltage that satisfies the higher-level constraint information input from the higher-level constraint information setting unit 112. The voltage calculation unit 121 corrects the target voltage to a target voltage that satisfies the upper voltage limit value, lower voltage limit value, and dead band width in voltage of the higher-level system 91, which is information included in the higher-level constraint information, and sets the corrected target voltage as a new target voltage for the higher-level system 91.

[0098] The voltage calculation unit 121 sets a voltage within the range between the upper voltage limit value and the lower voltage limit value of the upper system 91 according to the upper constraint information as a new target voltage of the upper system 91.

[0099] (Step S09: Store the target voltage) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 stores the target voltage calculated in step S04 or the target voltage corrected in step S06 or step S08 in the voltage data storage unit 131 of the storage unit 13. Of the target voltage calculated in step S04 or the target voltage corrected in step S06 or step S08, the target voltage newly calculated after correction is stored in the voltage data storage unit 131 of the storage unit 13. The central value of the target voltage, the upper voltage limit value of the target voltage, and the lower voltage limit value are stored in the voltage data storage unit 131 of the storage unit 13 as target voltages.

[0100] (Step S10: Output control information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 causes the output unit 14 to output, as control information, the target voltage relative to the central value of the target voltage, the upper voltage limit value of the target voltage, and the lower voltage limit value.

[0101] The operation of the voltage and reactive power monitoring and control device 1 has been described above.

[0102] The control information output from the output unit 14 of the voltage and reactive power monitoring and control device 1 is transmitted to the control device 5.

[0103] The control device 5 outputs a control command for system control to the system adjustment device 6a of the upper system 91 based on the electrical quantity and state included in the system information related to the state quantity detected by the state quantity detection device 7, and the control information calculated by the voltage and reactive power monitoring control device 1.

[0104] The system information input unit 51 of the control device 5 receives the state quantities detected by the state quantity detection device 7 and related to the upper system 91, the lower system 92, and the system adjustment device 6a as system information.

[0105] The system information includes, as state quantities, information on electrical quantities including active power, reactive power, voltage, and current of the upper system 91, and information on electrical quantities including active power, reactive power, voltage, and current of the lower system 92. The system information also includes, as state quantities, information on the amount of reactive power generated by the system adjustment device 6a in the upper system 91, and the state of control including the closing and opening of power capacitors and the closing and opening of shunt reactors. The system information input to the system information input unit 51 is transmitted to the control quantity calculation unit 52.

[0106] The control variable calculation unit 52 of the control device 5 receives system information from the system information input unit 51 and control information from the voltage and reactive power monitoring and control device 1. The control information includes information related to the central value of the target voltage of the higher-level system 91, the upper voltage limit value of the target voltage, and the lower voltage limit value of the target voltage. The control variable calculation unit 52 creates a control command based on the system information received from the system information input unit 51 and the target voltage of the higher-level system 91 as control information received from the voltage and reactive power monitoring and control device 1.

[0107] The control commands are commands related to the control of the upper system 91 by the system adjustment device 6a, including the reactive power generation amount of the upper system 91, the closing and opening of power capacitors, and the closing and opening of shunt reactors. The control amount calculation unit 52 calculates the reactive power generation amount, the amount related to the closing and opening of power capacitors, and the amount related to the closing and opening of shunt reactors, which are control amounts related to the control commands to the system adjustment device 6a. The system adjustment device 6a adjusts the reactive power, thereby controlling the voltage of the upper system 91.

[0108] Increasing the input of power capacitors in the upper system 91 increases reactive power, and the voltage of the upper system 91 rises. Increasing the input of shunt reactors in the upper system 91 decreases reactive power, and the voltage of the upper system 91 falls. On the other hand, opening power capacitors in the upper system 91 decreases reactive power, and the voltage of the upper system 91 falls. Opening shunt reactors in the upper system 91 increases reactive power, and the voltage of the upper system 91 rises. The control amount calculation unit 52 calculates the amount of reactive power generated, the amount required for inputting and opening power capacitors, and the amount required for inputting and opening shunt reactors, and outputs the results as control commands.

[0109] The control command output unit 53 of the control device 5 transmits the control command created by the control amount calculation unit 52 to the grid adjustment device 6a.

[0110] The system adjustment device 6a receives a control command from the control command output unit 53 and controls the upper system 91. The system adjustment device 6a adjusts the reactive power of the upper system 91 based on the reactive power generation amount related to the control command, the amount related to the closing and opening of power capacitors, and the amount related to the closing and opening of shunt reactors, and as a result, the voltage of the upper system 91 is adjusted.

[0111] The above is the operation of the system using the voltage and reactive power monitoring and control device 1 according to this embodiment.

[0112] [1-3.Effects] (1) According to this embodiment, the voltage and reactive power monitoring and control device 1 calculates control information related to system control of the upper system 91 in the power system 9, which has a lower system 92 that is independently system-controlled and an upper system 91 that supplies power to the lower system 92. The voltage and reactive power monitoring and control device 1 includes an input unit 11 to which state quantities related to the electrical quantities and control state of the power system 9 are input, and a calculation unit 12 that selects a tap position from among multiple taps of a transformer arranged in the lower system 92 that satisfies the margin based on a margin indicating the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage, and calculates a target voltage of the upper system 91 as control information based on the state quantities input to the input unit 11, assuming that the tap is at the selected tap position due to the lower system 92 being independently system-controlled. Therefore, it is possible to provide a voltage and reactive power monitoring and control device 1 that calculates a target voltage of the upper system 91 that ensures sufficient adjustment margin of the lower system 92 even when the state quantities related to the power of the lower system 92 fluctuate significantly. The target voltage may be a central value of the target voltage, or may include an upper voltage limit and a lower voltage limit of the target voltage in addition to the central value of the target voltage.

[0113] The calculation unit 12 calculates the voltage of the upper system 91 such that the tap of the transformer arranged in the lower system 92 is at a tap position that satisfies the margin, thereby ensuring a margin for adjusting the voltage up and down of the lower system 92. As a result, even if the output power of the renewable energy power generation device arranged in the lower system 92 fluctuates greatly, a sufficient margin for adjusting the voltage of the lower system 92 can be ensured.

[0114] (2) According to this embodiment, the margin for selecting tap positions by the calculation unit 12 of the voltage and reactive power monitoring and control device 1 is approximately equal to the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage. Therefore, it is possible to calculate the voltage of the upper system 91 so as to ensure sufficient adjustment margin of the lower system 92 in both cases of controlling the voltage of the lower system 92 to increase and decrease it.

[0115] (3) According to this embodiment, the input unit 11 of the voltage and reactive power monitoring and control device 1 has a higher-level constraint information setting unit 112 that sets higher-level constraint information including information on the upper voltage limit value, lower voltage limit value, and dead band width indicating the upper and lower limits for the target voltage of the higher-level system 91. The calculation unit 12 calculates the target voltage of the higher-level system 91 as control information based on the higher-level constraint information set in the higher-level constraint information setting unit 112. Therefore, a more appropriate voltage for controlling the higher-level system 91 can be calculated as the target voltage of the higher-level system 91.

[0116] (4) According to this embodiment, the input unit 11 of the voltage and reactive power monitoring and control device 1 has a lower-level constraint information setting unit 113 that sets lower-level constraint information including information about the upper and lower voltage limits of the lower-level system 92. The calculation unit 12 calculates the target voltage of the upper-level system 91 as control information based on the lower-level constraint information set in the lower-level constraint information setting unit 113. Therefore, when the lower-level system 92 is controlled independently, it is possible to calculate the target voltage of the upper-level system 91 such that the voltage of the lower-level system 92 becomes a more appropriate voltage.

[0117] [2. Second Embodiment] [2-1. Composition and Function] The voltage and reactive power monitoring and control device 1 according to the second embodiment will be described with reference to Fig. 3. The input unit 11 of the voltage and reactive power monitoring and control device 1 according to the first embodiment has a lower-level constraint information setting unit 113, but instead, the input unit 11 of the voltage and reactive power monitoring and control device 1 according to the second embodiment has a lower-level system assumption information setting unit 114. The voltage and reactive power monitoring and control device 1 according to the second embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in that it does not have the lower-level constraint information setting unit 113 but has the lower-level system assumption information setting unit 114.

[0118] Other configurations of the voltage and reactive power monitoring and control device 1 according to the second embodiment are the same as the configuration of the voltage and reactive power monitoring and control device 1 according to the first embodiment shown in Fig. 1. The same components as those of the voltage and reactive power monitoring and control device 1 according to the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0119] In the voltage and reactive power monitoring and control device 1 according to the second embodiment, the lower system assumption information setting unit 114 of the input unit 11 receives input of arbitrary margins for the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage, and the calculation unit 12 calculates the target voltage of the upper system 91 as control information, assuming that the taps of the lower system 92 are selected by being independently controlled by the system to the tap position based on the arbitrary margins input to the input unit 11.

[0120] The lower-level system assumption information setting unit 114 receives input of lower-level constraint information that assumes the operation of the lower-level system 92 .

[0121] The lower-level constraint information may be input by an operating device arranged in the lower-level system assumption information setting unit 114, such as a keyboard, a mouse, or a touch panel, or the lower-level constraint information set and stored in an external device may be received by a transmitting / receiving circuit or an external memory connection circuit of the lower-level system assumption information setting unit 114.

[0122] The lower-level constraint information includes information on the upper and lower voltage limits of the lower-level system 92, as well as information on the tap positions of a transformer having multiple taps arranged in the lower-level system 92.

[0123] The lower-level constraint information includes information about tap positions of transformers arranged in the lower-level system 92, which are selected based on the assumed future power demand and power supply of the lower-level system 92. In the lower-level constraint information, an arbitrary tap position is selected.

[0124] The tap position selected in the lower-level constraint information is not limited to the tap at the middle position among the taps of the transformer. Any tap position is selected depending on the expected future power demand and power supply. For example, if it is expected that the voltage of the lower-level system 92 will increase in the future, a tap position on the higher voltage side than the middle position is selected to ensure a lower margin. If it is expected that the voltage of the lower-level system 92 will decrease in the future, a tap position on the lower voltage side than the middle position is selected to ensure a higher margin.

[0125] Preferably, the tap position on the voltage side lower than the selected intermediate position has a predetermined margin with respect to the lower limit of the plurality of tap positions, and the tap position on the voltage side higher than the selected intermediate position has a predetermined margin with respect to the upper limit of the plurality of tap positions.

[0126] For example, if the number of transformers installed is 23, the sixth tap from the bottom is selected as the tap position on the low voltage side, and the sixth tap from the top is selected as the tap position on the high voltage side.

[0127] In the above, the lower-level constraint information includes information about the selected tap position, but it may also include information indicating the margin from the upper limit and the margin from the lower limit for the tap position. For example, if the installed transformer has 23 stages and it is preferable to select a tap position on the voltage side higher than the intermediate position, the margin is set to 6 stages from the upper limit and 16 stages from the lower limit. If it is preferable to select a tap position on the voltage side lower than the intermediate position, the margin is set to 6 stages from the lower limit and 16 stages from the upper limit.

[0128] The tap positions are selected according to the expected future power demand and power supply. For example, if it is expected that power demand will increase during the daytime in the future and the voltage of the downstream system 92 will drop, downstream constraint information indicating a tap position on the voltage side lower than the intermediate position is input to the downstream system assumption information setting unit 114. Furthermore, if it is expected that the amount of power supply by renewable energy power generation devices will increase during the daytime in the future and the voltage of the downstream system 92 will rise, downstream constraint information indicating a tap position on the voltage side higher than the intermediate position is input to the downstream system assumption information setting unit 114.

[0129] For example, if it is expected that power demand will decrease in the future during the night and that the voltage of the downstream system 92 will increase, downstream constraint information indicating a tap position on the voltage side higher than the intermediate position is input to the downstream system assumption information setting unit 114. Furthermore, if it is expected that the amount of power supply by the renewable energy power generation device will decrease in the future during the night and that the voltage of the downstream system 92 will decrease, downstream constraint information indicating a tap position on the voltage side lower than the intermediate position is input to the downstream system assumption information setting unit 114.

[0130] The tap position may be selected based on the difference between the power demand of the customer and the amount of power supplied by the renewable energy power generation device.

[0131] The voltage calculation unit 121 of the calculation unit 12 assumes that the tap of a transformer having multiple taps arranged in the lower system 92 is at the tap position indicated by the lower system constraint information input to the lower system assumption information setting unit 114, and calculates the target voltage of the upper system 91 as control information based on the state quantities input to the input unit 11.

[0132] The voltage calculation unit 121 of the calculation unit 12 may calculate the target voltage of the upper system 91 as control information based on the state quantities input to the input unit 11, assuming that the taps of a transformer having multiple taps arranged in the lower system 92 are at tap positions that satisfy the margins from the upper limit and the lower limit indicated by the lower system constraint information input to the lower system assumption information setting unit 114.

[0133] A computer program for the voltage and reactive power monitoring and control device 1 according to the second embodiment will be described. The voltage and reactive power monitoring and control device 1 according to the second embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in the processing of steps S03 and S04 in the computer program shown in Fig. 2.

[0134] (Step S01, Step S02) As in the first embodiment, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 receives system information in step S01 and receives upper-level constraint information in step S02. The system information and upper-level constraint information may be stored in the storage unit 13.

[0135] (Step S03: Receive lower-level constraint information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 controls the lower system assumption information setting unit 114 of the input unit 11 to receive lower system constraint information including information on the upper and lower voltage limits of the lower system 92 as well as information on the tap positions of the transformers arranged in the lower system 92.

[0136] In the lower-level constraint information, an arbitrary tap position is selected according to the expected future power demand and power supply. As the arbitrary tap position, a tap position on the higher voltage side or a tap position on the lower voltage side of the intermediate position is selected.

[0137] The lower-level constraint information is not limited to information about the selected tap position, and may include information indicating the margin of the tap position from the upper limit and the margin of the tap position from the lower limit. The tap position may be selected based on the difference between the power demand of the consumer and the power supply amount of the renewable energy power generation device.

[0138] The lower-level constraint information input to the lower-level system assumption information setting unit 114 is transmitted to the calculation unit 12. The lower-level constraint information may also be stored in the storage unit 13.

[0139] (Step S04: Calculate the target voltage of the upper system 91) The voltage calculation unit 121 of the calculation unit 12 calculates a target voltage for the upper system 91 based on the system information received in step S01 and based on information about the tap position included in the lower constraint information received in step S03, or information indicating the margin from the upper limit and the margin from the lower limit regarding the tap position. The target voltage includes a central value of the target voltage, and an upper voltage limit and a lower voltage limit of the target voltage.

[0140] The voltage calculation unit 121 calculates the target voltage of the upper system 91, assuming that the tap of the transformer arranged in the lower system 92 is at a tap position included in the lower constraint information. Alternatively, the voltage calculation unit 121 calculates the target voltage of the upper system 91, assuming that the tap of the transformer arranged in the lower system 92 is at a tap position that satisfies the margin from the upper limit and the margin from the lower limit included in the lower constraint information.

[0141] Furthermore, the voltage calculation unit 121 calculates the upper and lower voltage limits of the target voltage based on the dead zone width included in the higher-level constraint information. The voltage calculation unit 121 sets the upper limit of the dead zone width as the upper voltage limit of the target voltage, and the lower limit of the dead zone width as the lower voltage limit of the target voltage.

[0142] (Step S05, Step S06) As in the first embodiment, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 determines in step S05 whether the target voltage satisfies the lower-order constraint information, and if it is determined that the target voltage does not satisfy the lower-order constraint information, calculates a target voltage of the upper system 91 that satisfies the lower-order constraint information in step S06. The voltage calculation unit 121 corrects the target voltage calculated in step S04 to a target voltage that satisfies the lower-order constraint information input from the lower-order constraint information setting unit 113.

[0143] (Step S07, Step S08) As in the first embodiment, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 determines in step S07 whether the target voltage satisfies the higher-level constraint information, and if it is determined that the target voltage does not satisfy the higher-level constraint information, calculates a target voltage of the higher-level system 91 that satisfies the higher-level constraint information in step S08. The voltage calculation unit 121 corrects the target voltage calculated in step S04 or step S06 to a target voltage that satisfies the higher-level constraint information input from the higher-level constraint information setting unit 112.

[0144] (Step S09, Step S10) As in the first embodiment, in step S09, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 stores the target voltage calculated in step S04 or the target voltage corrected in step S06 or step S08 in the voltage data storage unit 131 of the storage unit 13. The central value of the target voltage, the upper voltage limit value, and the lower voltage limit value of the target voltage are stored as target voltages in the voltage data storage unit 131 of the storage unit 13. In step S10, the calculation unit 12 causes the output unit 14 to output the target voltage as control information.

[0145] The control device 5 outputs a control command for system control to the system adjustment device 6a of the higher-level system 91 based on the state quantity detected by the state quantity detection device 7 and the control information calculated by the voltage and reactive power monitoring and control device 1.

[0146] The configuration and operation of the voltage and reactive power monitoring and control device 1 according to this embodiment have been described above.

[0147] [2-2. Effects] (1) According to this embodiment, the margin for selecting tap positions by the calculation unit 12 of the voltage and reactive power monitoring and control device 1 is arbitrarily set by the input unit 11, i.e., the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage. Therefore, even when the state quantity related to the power of the lower system 92 fluctuates greatly, it is possible to provide a voltage and reactive power monitoring and control device 1 that calculates a target voltage for the upper system 91 that ensures sufficient adjustment margin for the lower system 92. The target voltage may be a center value of the target voltage, or may include an upper voltage limit value and a lower voltage limit value for the target voltage in addition to the center value of the target voltage.

[0148] An appropriate arbitrary margin is set in the input unit 11 according to the state of the downstream system 92. The calculation unit 12 calculates the voltage of the upstream system 91 based on the arbitrarily set margin. This makes it possible to ensure a sufficient adjustment margin of the downstream system 92 even when the output power of the renewable energy power generation device arranged in the downstream system 92 fluctuates greatly.

[0149] (2) According to this embodiment, an appropriate arbitrary margin is set as the margin for selecting the tap position by the calculation unit 12 of the voltage and reactive power monitoring and control device 1 according to the state of the lower system 92. Therefore, it is possible to calculate the target voltage of the upper system 91 that ensures sufficient adjustment margin of the lower system 92 in both cases of controlling the voltage of the lower system 92 to increase and decrease it.

[0150] The margin is set to an appropriate arbitrary margin depending on the state of the lower system 92. The calculation unit 12 can select a tap position that is not limited to the center but is biased toward the higher voltage side or the lower voltage side. This allows the voltage and reactive power monitoring and control device 1 to calculate a target voltage for the upper system 91 that more appropriately controls the voltage of the lower system 92.

[0151] 3. Third Embodiment [3-1. Composition and Function] The voltage and reactive power monitoring and control device 1 according to the third embodiment will be described with reference to Fig. 4. The voltage and reactive power monitoring and control device 1 according to the third embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in that, in addition to the components of the voltage and reactive power monitoring and control device 1 according to the first embodiment, the calculation unit 12 has an adjustment margin calculation unit 122 and the storage unit 13 has a lower adjustment information storage unit 132.

[0152] Furthermore, the voltage and reactive power monitoring and control device 1 according to the third embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in the system information received by the system information input unit 111 of the input unit 11 and the calculation processing by the voltage calculation unit 121 of the calculation unit 12.

[0153] Other configurations of the voltage and reactive power monitoring and control device 1 according to the third embodiment are the same as the configuration of the voltage and reactive power monitoring and control device 1 according to the first embodiment shown in Fig. 1. The same components as those of the voltage and reactive power monitoring and control device 1 according to the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0154] The input unit 11 of the voltage and reactive power monitoring and control device 1 according to the third embodiment receives the state quantities of the lower system 92, and the calculation unit 12 calculates a margin based on the state quantities of the lower system 92 received by the input unit 11, and calculates the target voltage of the upper system 91 as control information, assuming that a tap is selected at the tap position based on the calculated margin.

[0155] The input unit 11 of the voltage and reactive power monitoring and control device 1 according to the first embodiment receives, via the system information input unit 111, the electrical quantities of the upper system 91, the electrical quantities of the lower system 92, and the state quantities relating to the control state of the upper system 91 by the system adjustment device 6a as system information.

[0156] The input unit 11 of the voltage and reactive power monitoring and control device 1 according to the third embodiment receives, via the system information input unit 111, state quantities related to the state of control of the lower system 92 by the system adjustment device 6b, as system information, in addition to state quantities related to the electrical quantities of the upper system 91, the electrical quantities of the lower system 92, and the state of control of the upper system 91 by the system adjustment device 6a. The system information is information including, as state quantities, the electrical quantities of the upper system 91, the state of control of the upper system 91 by the system adjustment device 6a, the electrical quantities of the lower system 92, and the state of control of the lower system 92 by the system adjustment device 6b.

[0157] In the third embodiment, the state quantity detection device 7 disposed in the power system 9 is connected to the system adjustment device 6b in addition to the upper system 91, the lower system 92, and the system adjustment device 6a. The state quantity detection device 7 detects electrical quantities including active power, reactive power, voltage, and current of the upper system 91, and electrical quantities including active power, reactive power, voltage, and current of the lower system 92.

[0158] The state quantity detection device 7 also detects the state of control by the system adjustment device 6a, including the amount of reactive power generated in the upper system 91, the closing and opening of power capacitors, and the closing and opening of shunt reactors. Furthermore, the state quantity detection device 7 detects the state of control by the system adjustment device 6b, including tap changing of the transformer in the lower system 92, the amount of power generated by the power generation device connected to the lower system, the closing and opening of power capacitors, and the closing and opening of shunt reactors.

[0159] The state quantity detection device 7 transmits the detected electrical quantities and state quantities related to the controlled states as system information to the input unit 11 of the voltage and reactive power monitoring and control device 1 via the information transmission devices 8a and 8b.

[0160] The input unit 11 of the voltage and reactive power monitoring and control device 1 receives system information via the system information input unit 111. The system information includes, as state quantities, information on electrical quantities related to the active power, reactive power, voltage, and current of the upper system 91, and electrical quantities related to the active power, reactive power, voltage, and current of the lower system 92. The system information also includes, as state quantities, information on the reactive power generation amount of the upper system 91 by the system adjustment device 6a, the state of control including the closing and opening of power capacitors and the closing and opening of shunt reactors, tap changing of the transformer of the lower system 92, the amount of power generated by a power generation device connected to the lower system, the state of control including the closing and opening of power capacitors and the closing and opening of shunt reactors.

[0161] The calculation unit 12 extracts information related to the control of the downstream system 92 based on the state quantities included in the system information. The information related to the control of the downstream system 92 is information related to the control state, including tap switching of the transformer of the downstream system 92 by the system adjustment device 6b, the power generation amount of the power generation device connected to the downstream system, the opening and closing of the power capacitor, and the opening and closing of the shunt reactor. The extracted information related to the control of the downstream system 92 is stored in the downstream adjustment information storage unit 132 as downstream adjustment information.

[0162] The adjustment margin calculation unit 122 of the calculation unit 12 calculates the reactive power adjustment margin based on the extracted lower-order adjustment information.

[0163] The reactive power of the downstream system 92 is adjusted by closing and opening power capacitors and closing and opening shunt reactors. The adjustment margin calculation unit 122 calculates the amount of fluctuation in reactive power that can be varied by closing and opening power capacitors and closing and opening shunt reactors, based on the downstream adjustment information. The adjustment margin calculation unit 122 also calculates the amount of fluctuation in reactive power based on the power generation amount of the renewable energy power generation device or the adjustment amount by the downstream system phase modifier, which are included in the downstream adjustment information.

[0164] The adjustment margin calculation unit 122 adds up the amount of fluctuation in reactive power due to the closing and opening of power capacitors and the closing and opening of shunt reactors, the amount of fluctuation in reactive power applied to the renewable energy power generation device, and the amount of fluctuation due to the downstream system phase modifying devices, to calculate the reactive power adjustment margin of the downstream system 92. The reactive power adjustment margin is the amount of fluctuation in reactive power that can be varied in the downstream system 92. The adjustment margin calculation unit 122 stores the calculated reactive power adjustment margin in the downstream adjustment information storage unit 132 of the storage unit 13.

[0165] The voltage calculation unit 121 of the calculation unit 12 selects a tap position of a transformer arranged in the lower system 92 based on the reactive power adjustment margin calculated by the adjustment margin calculation unit 122. The voltage calculation unit 121 of the calculation unit 12 creates control information for the upper system 91 based on the selected tap position, system information received from the system information input unit 111, upper-level constraint information received from the upper-level constraint information setting unit 112, and lower-level constraint information received from the lower-level constraint information setting unit 113. The voltage calculation unit 121 calculates a target voltage for the upper system 91 as the control information.

[0166] The target voltage of the upper system 91 calculated as the control information is a voltage value at which the tap of the transformer arranged in the lower system 92 is at a tap position with a predetermined margin relative to the upper and lower limits of the tap when the system is independently controlled. The target voltage may be the center value of the target voltage, or may include the upper and lower limit voltage values ​​of the target voltage in addition to the center value of the target voltage.

[0167] The tap position selected by the voltage calculation unit 121 is not limited to the tap at the middle position among the taps of the transformer. Any tap position may be selected depending on the expected future power demand and power supply. For example, if it is expected that the voltage of the downstream system 92 will increase in the future, a tap position on the higher voltage side than the middle position is selected. If it is expected that the voltage of the downstream system 92 will decrease in the future, a tap position on the lower voltage side than the middle position is selected.

[0168] Preferably, the tap position on the voltage side lower than the selected intermediate position has a predetermined margin with respect to the lower limit of the plurality of tap positions, and the tap position on the voltage side higher than the selected intermediate position has a predetermined margin with respect to the upper limit of the plurality of tap positions.

[0169] For example, if the number of transformers is 23, the sixth tap from the bottom is selected as the tap position on the low voltage side, and the sixth tap from the top is selected as the tap position on the high voltage side.

[0170] The lower-level constraint information may include information indicating the margin from the upper limit and the margin from the lower limit of the tap position. For example, if the installed transformer has 23 stages and it is preferable to select a tap position on the voltage side higher than the intermediate position, the margin is set to 6 stages from the upper limit and 16 stages from the lower limit. If it is preferable to select a tap position on the voltage side lower than the intermediate position, the margin is set to 6 stages from the lower limit and 16 stages from the upper limit.

[0171] The tap position may be selected according to the expected future power demand and power supply. For example, if it is expected that power demand will increase during the daytime in the future and the voltage of the downstream system 92 will drop, the voltage calculation unit 121 selects a tap position on the voltage side lower than the intermediate position, calculates the target voltage of the upstream system 91, and creates control information. Also, if it is expected that the amount of power supplied by the renewable energy power generation device will increase in the future and the voltage of the downstream system 92 will rise, the voltage calculation unit 121 selects a tap position on the voltage side higher than the intermediate position, calculates the target voltage of the upstream system 91, and creates control information.

[0172] For example, if it is expected that power demand will decrease in the future at night and the voltage of the downstream system 92 will rise, the voltage calculation unit 121 selects a tap position on the voltage side higher than the intermediate position, calculates the target voltage of the upstream system 91, and creates control information. Also, if it is expected that the amount of power supplied by the renewable energy power generation device will decrease in the future and the voltage of the downstream system 92 will drop, the voltage calculation unit 121 selects a tap position on the voltage side lower than the intermediate position, calculates the target voltage of the upstream system 91, and creates control information.

[0173] The tap position may be selected based on the difference between the power demand of the customer and the amount of power supplied by the renewable energy power generation device.

[0174] The voltage calculation unit 121 of the calculation unit 12 assumes that the tap of the transformer arranged in the lower system 92 is at a tap position calculated based on the reactive power adjustment margin, and calculates the target voltage of the upper system 91 as control information based on the state quantities input to the input unit 11.

[0175] The operation of the voltage and reactive power monitoring and control device 1 is realized by a computer program shown in Fig. 5. The computer program shown in Fig. 5 is built into the calculation unit 12 of the voltage and reactive power monitoring and control device 1. The voltage and reactive power monitoring and control device 1 according to the third embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in that it includes processing according to steps S21 to S25.

[0176] (Step S01: Receive system information) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 controls the input unit 11 to receive system information. The system information is received by a system information input unit 111 of the input unit 11. The system information input unit 111 receives the state quantities of the upper system 91, the lower system 92, the system adjustment device 6a, and the system adjustment device 6b detected by the state quantity detection device 7.

[0177] The system information includes, as state quantities, information on the quantities of electricity related to the active power, reactive power, voltage, and current of the upper system 91, and the quantities of electricity related to the active power, reactive power, voltage, and current of the lower system 92.

[0178] The system information also includes, as state quantities, information on the state of control by the system adjustment device 6a, including the amount of reactive power generated in the upper system 91, the closing and opening of power capacitors, and the closing and opening of shunt reactors. Furthermore, the system information also includes, as state quantities, information on the state of control by the system adjustment device 6b, including tap changing of the transformer in the lower system 92, the amount of power generated by the power generation device connected to the lower system, the closing and opening of power capacitors, and the closing and opening of shunt reactors.

[0179] The system information input to the system information input unit 111 is transmitted to the calculation unit 12. The system information may also be stored in the storage unit 13.

[0180] (Step S02, Step S03) The calculation unit 12 of the voltage and reactive power monitoring and control device 1 receives upper-level constraint information in step S02, and receives the upper-level constraint information in step S03. The upper-level constraint information includes information on the upper voltage limit value, the lower voltage limit value, and the dead band width for the target voltage of the upper system 91. The upper-level constraint information may also include the target voltage of the upper system. The lower-level constraint information includes the upper voltage limit value, the lower voltage limit value, and the upper voltage limit value and the lower voltage limit value for the target voltage of the lower system 92. The lower-level constraint information may also include the target voltage of the lower system. The upper-level constraint information and the lower-level constraint information are transmitted to the calculation unit 12. The upper-level constraint information and the lower-level constraint information may also be stored in the storage unit 13.

[0181] (Step S21: Extract information related to the control of the lower system 92) Step S21 is executed after step S03. The calculation unit 12 extracts information related to the control of the downstream system 92 based on the state quantities included in the system information. The information related to the control of the downstream system 92 is information related to the control state, including tap changing of the transformer of the downstream system 92 by the system adjustment device 6b, the power generation amount of the power generation device connected to the downstream system, the opening and closing of the power capacitor, and the opening and closing of the shunt reactor. The calculation unit 12 extracts the information related to the control of the downstream system 92 and sets it as downstream adjustment information.

[0182] (Step S22: Store information related to the control of the lower system 92) Step S22 is executed after step S21. The calculation unit 12 stores the information relating to the control of the lower system 92 extracted in step S21 in the lower adjustment information storage unit 132 as lower adjustment information.

[0183] (Step S23: Calculate reactive power adjustment margin) Step S23 is executed after step S22. The calculation unit 1 calculates the reactive power adjustment margin based on the extracted lower-level adjustment information using the adjustment margin calculation unit 122. The reactive power adjustment margin is the amount of fluctuation in reactive power that can be varied in the lower-level system 92. The adjustment margin calculation unit 122 adds up the amount of reactive power fluctuation due to the opening and closing of power capacitors and the opening and closing of shunt reactors, calculated based on the lower-level adjustment information, the amount of reactive power fluctuation applied to the renewable energy power generation device, and the amount of fluctuation due to the lower-level system phase modifying device, to calculate the reactive power adjustment margin of the lower-level system 92.

[0184] (Step S24: Store the reactive power adjustment margin) Step S24 is executed after step S23. The calculation unit 12 stores information on the reactive power adjustment margin calculated in step S23 in the lower adjustment information storage unit 132.

[0185] (Step S25: Select the tap position) Step S25 is executed after step S24. The calculation unit 12 selects a tap position using the voltage calculation unit 121. The voltage calculation unit 121 selects a tap position of a transformer arranged in the downstream system 92 based on the reactive power regulation margin calculated by the regulation margin calculation unit 122.

[0186] (Step S04: Calculate the target voltage of the upper system 91) Step S04 is executed after step S25. The voltage calculation unit 121 of the calculation unit 12 calculates the target voltage of the upper system 91, assuming that the tap of the transformer arranged in the lower system 92 is at the tap position selected in step S25.

[0187] Furthermore, the voltage calculation unit 121 calculates the upper and lower voltage limits of the target voltage based on the dead zone width included in the higher-level constraint information. The voltage calculation unit 121 sets the upper limit of the dead zone width as the upper voltage limit of the target voltage, and the lower limit of the dead zone width as the lower voltage limit of the target voltage.

[0188] (Step S05, Step S06) As in the first embodiment, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 determines in step S05 whether the target voltage satisfies the lower-order constraint information, and if it is determined that the target voltage does not satisfy the lower-order constraint information, calculates a target voltage of the upper system 91 that satisfies the lower-order constraint information in step S06. The voltage calculation unit 121 corrects the target voltage calculated in step S04 to a target voltage that satisfies the lower-order constraint information input from the lower-order constraint information setting unit 113.

[0189] (Step S07, Step S08) As in the first embodiment, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 determines in step S07 whether the target voltage satisfies the higher-level constraint information, and if it is determined that the target voltage does not satisfy the higher-level constraint information, calculates a target voltage of the higher-level system 91 that satisfies the higher-level constraint information in step S08. The voltage calculation unit 121 corrects the target voltage calculated in step S04 or step S06 to a target voltage that satisfies the higher-level constraint information input from the higher-level constraint information setting unit 112.

[0190] (Step S09, Step S10) As in the first embodiment, in step S09, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 stores the target voltage calculated in step S04 or the target voltage corrected in step S06 or step S08 in the voltage data storage unit 131 of the storage unit 13. The central value of the target voltage, the upper voltage limit value, and the lower voltage limit value of the target voltage are stored as target voltages in the voltage data storage unit 131 of the storage unit 13. In step S10, the calculation unit 12 causes the output unit 14 to output the target voltage as control information.

[0191] The control device 5 outputs a control command for system control to the system adjustment device 6a of the upper system 91 based on the electrical quantity and state included in the system information related to the state quantity detected by the state quantity detection device 7, and the control information calculated by the voltage and reactive power monitoring control device 1.

[0192] The configuration and operation of the voltage and reactive power monitoring and control device 1 according to this embodiment have been described above.

[0193] [3-2. Effects] (1) According to this embodiment, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 calculates the amount of reactive power fluctuation that can be varied in the downstream system 92 as the reactive power regulation margin based on information related to control of the downstream system 92 included in the state quantity of the power system 9 received by the input unit 11, calculates a tap margin based on the calculated reactive power regulation margin, selects a tap position from among multiple taps of a transformer arranged in the downstream system 92 that satisfies the margin, and calculates a target voltage for the upstream system 91 as control information assuming that the tap is at the selected tap position by independently controlling the downstream system 92. Therefore, it is possible to provide a voltage and reactive power monitoring and control device 1 that calculates a target voltage for the upstream system 91 that ensures sufficient regulation margin for the downstream system 92 even when the state quantity related to the power of the downstream system 92 fluctuates significantly. The target voltage may be a center value of the target voltage, or may include an upper voltage limit value and a lower voltage limit value of the target voltage in addition to the center value of the target voltage.

[0194] The calculation unit 12 calculates the amount of fluctuation in reactive power that can be varied in the downstream system 92 as reactive power adjustment margin, calculates a tap margin based on the calculated reactive power adjustment margin, and further selects a tap position. The calculation unit 12 calculates the voltage of the upstream system 91 based on the selected tap position. As a result, even if the output power of the renewable energy power generation device arranged in the downstream system 92 fluctuates greatly, it is possible to calculate the voltage of the upstream system 91 that sufficiently ensures the adjustment margin of the downstream system 92.

[0195] As a margin, an appropriate tap position is selected according to the state of the lower system 92. The calculation unit 12 selects a tap position that is not limited to the center, but is biased toward the higher voltage side or the lower voltage side. This allows the voltage and reactive power monitoring and control device 1 to accurately calculate the voltage of the upper system 91, which allows for more appropriate control of the voltage of the lower system 92.

[0196] [4. Fourth Embodiment] [4-1. Composition and Function] The voltage and reactive power monitoring and control device 1 according to the fourth embodiment will be described with reference to Fig. 6. The voltage and reactive power monitoring and control device 1 according to the fourth embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in that, in addition to the components of the voltage and reactive power monitoring and control device 1 according to the first embodiment, the calculation unit 12 has a control command creation unit 123 and the storage unit 13 has a control command storage unit 133.

[0197] In the first embodiment, the control device 5 outputs a control command for system control to the system adjustment device 6a of the upper system 91 based on the control information calculated by the voltage and reactive power monitoring and control device 1. The fourth embodiment differs from the first embodiment in that the voltage and reactive power monitoring and control device 1 creates a control command based on the control information and outputs the control command for system control to the system adjustment device 6a of the upper system 91.

[0198] Other configurations of the voltage and reactive power monitoring and control device 1 according to the fourth embodiment are the same as the configuration of the voltage and reactive power monitoring and control device 1 according to the first embodiment shown in Fig. 1. The same components as those of the voltage and reactive power monitoring and control device 1 according to the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0199] The calculation unit 12 of the voltage and reactive power monitoring and control device 1 according to the fourth embodiment is characterized by having a control command creation unit 123 that creates a control command for adjusting the reactive power of the upper system 91 based on the calculated target voltage.

[0200] The control command creation unit 123 of the calculation unit 12 receives control information from the voltage calculation unit 121. The control information includes information on the central value of the target voltage, the upper voltage limit value of the target voltage, and the lower voltage limit value of the target voltage as the target voltage of the higher-level system 91. The control command creation unit 123 creates a control command based on the system information received by the system information input unit 111 and the target voltage of the higher-level system 91 related to the control information.

[0201] The control commands are commands related to the control of the upper system 91 by the system adjustment device 6a, including the reactive power generation amount of the upper system 91, the closing and opening of power capacitors, and the closing and opening of shunt reactors. The control command creation unit 123 calculates the reactive power generation amount, the amount related to the closing and opening of power capacitors, and the amount related to the closing and opening of shunt reactors, which are control variables related to the control commands to the system adjustment device 6a. The system adjustment device 6a adjusts the reactive power, thereby controlling the voltage of the upper system 91.

[0202] Increasing the input of power capacitors in the upper system 91 increases reactive power, and the voltage of the upper system 91 rises. Increasing the input of shunt reactors in the upper system 91 decreases reactive power, and the voltage of the upper system 91 falls. On the other hand, opening power capacitors in the upper system 91 decreases reactive power, and the voltage of the upper system 91 falls. Opening shunt reactors in the upper system 91 increases reactive power, and the voltage of the upper system 91 rises. The control command creation unit 123 calculates the amount of reactive power generated, the amount required for inputting and opening power capacitors, and the amount required for inputting and opening shunt reactors, and generates control commands.

[0203] The control command creation unit 123 of the calculation unit 12 stores the control command in the control command storage unit 133 of the storage unit 13. The calculation unit 12 controls the output unit 14 of the voltage and reactive power monitoring and control device 1, and transmits the control command created by the control command creation unit 123 to the system adjustment device 6a via the information transmission devices 8b and 8a.

[0204] The system adjustment device 6a receives the control command and controls the upper system 91. The system adjustment device 6a adjusts the reactive power of the upper system 91 based on the reactive power generation amount related to the control command, the amount related to the closing and opening of the power capacitor, and the amount related to the closing and opening of the shunt reactor, and as a result, the voltage of the upper system 91 is adjusted.

[0205] The configuration and operation of the voltage and reactive power monitoring and control device 1 according to this embodiment have been described above.

[0206] The control command creation unit 123 of the calculation unit 12 may create a control command based on the control information created in steps S01 to S10 of the first and second embodiments, or may create a control command based on the control information created in steps S04 to S10 including steps S21 to S25 of the third embodiment.

[0207] [4-2.Effects] (1) According to this embodiment, the calculation unit 12 of the voltage and reactive power monitoring and control device 1 has a control command creation unit 123 that creates a control command for adjusting the reactive power of the upper system 91 based on the calculated target voltage. Therefore, the voltage and reactive power monitoring and control device 1 can send a control command to the system adjustment device 6, making the control device 5 unnecessary.

[0208] [5. Fifth Embodiment] [5-1. Composition and Function] The voltage and reactive power monitoring and control device 1 according to the fifth embodiment will be described with reference to Fig. 7. The voltage and reactive power monitoring and control device 1 according to the fifth embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in that, in addition to the components of the voltage and reactive power monitoring and control device 1 according to the first embodiment, the input unit 11 has a past performance data input unit 115, the calculation unit 12 has a power demand simulation unit 124, and the storage unit 13 has a time schedule storage unit 134.

[0209] Other configurations of the voltage and reactive power monitoring and control device 1 according to the fifth embodiment are the same as the configuration of the voltage and reactive power monitoring and control device 1 according to the first embodiment shown in Fig. 1. The same components as those of the voltage and reactive power monitoring and control device 1 according to the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0210] The input unit 11 of the voltage and reactive power monitoring and control device 1 according to the fifth embodiment has a past performance data input unit 115 that receives past performance data relating to the power demand of the power system 9 in the past, and the calculation unit 12 has a power demand simulation unit 124 that predicts the future power demand of the power system 9 based on the past performance data received by the past performance data input unit 115, and is characterized in that a future time schedule for the target voltage of the upper system 91 is created based on the future power demand of the power system 9 predicted by the power demand simulation unit 124.

[0211] The past performance data input unit 115 of the input unit 11 receives as input past performance data relating to the past power demand of the power system 9. The past performance data is data relating to the power demand and power generation amount in the power system 9 for each time period in the past, for example, 5 minutes or 30 minutes. The past performance data is stored in an external storage device or the like. The past performance data input unit 115 receives the past performance data from the external storage device or the like. The external storage device may be a storage unit of the reactive power monitoring and control device.

[0212] The power demand simulation unit 124 of the calculation unit 12 simulates the future power demand and power generation amount in the power system 9 based on the past performance data received by the past performance data input unit 115 and the system information received by the system information input unit 111.

[0213] The power demand simulation unit 124 predicts the power demand and power generation amount for each time period, for example, 5 minutes or 30 minutes, up to a certain time in the future, and creates power demand prediction data. The created power demand prediction data may be stored in the storage unit 13.

[0214] The voltage calculation unit 121 of the calculation unit 12 calculates the target voltage center value, upper voltage limit value of the target voltage, and lower voltage limit value of the target voltage as the target voltage of the upper system 91 based on the power demand forecast data created by the power demand simulation unit 124, the upper constraint information input to the upper constraint information setting unit 112, and the lower constraint information input to the lower constraint information setting unit 113.

[0215] Based on the power demand forecast data created by the power demand simulation unit 124, the voltage calculation unit 121 repeatedly executes steps S04 to S08 of the computer program shown in FIG. 2, and calculates the target voltage of the upper system 91 for each time period, for example, 5 minutes or 30 minutes into the future.

[0216] The voltage calculation unit 121 sets the target voltage center value, upper limit voltage value, and lower limit voltage value calculated as the target voltage as control information. The voltage calculation unit 121 may create the control information by steps S01 to S10 of the first and second embodiments, or may create the control information by steps S04 to S10 including steps S21 to S25 of the third embodiment.

[0217] The voltage calculation unit 121 stores a time schedule related to the control information of the higher-level system 91 in the time schedule storage unit 134. The time schedule includes a target voltage of the higher-level system 91 for each future time period, such as a central value of the target voltage, an upper voltage limit value of the target voltage, and a lower voltage limit value of the target voltage. The time schedule is created up to a certain time into the future. For example, a time schedule is created for 24 hours, one week, or one month into the future.

[0218] The calculation unit 12 outputs the target voltage according to the created time schedule as control information from the output unit 14. The control information output from the output unit 14 of the voltage and reactive power monitoring and control device 1 is transmitted to the control device 5. The control information according to a plurality of time periods may be transmitted to the control device 5 all at once, or the control information may be transmitted to the control device 5 individually for each time period.

[0219] The control device 5 outputs a control command for system control to the system adjustment device 6a of the upper system 91 based on the control information related to the time schedule transmitted from the voltage and reactive power monitoring and control device 1. The control command may be created by the calculation unit 12 and output from the voltage and reactive power monitoring and control device 1 as shown in the fourth embodiment. The system adjustment device 6a receives the control command and controls the upper system 91. The system adjustment device 6a adjusts the reactive power of the upper system 91 based on the reactive power generation amount, the amount related to the opening and closing of power capacitors, and the amount related to the opening and closing of shunt reactors, which are related to the control command, and as a result, the voltage of the upper system 91 is adjusted.

[0220] The configuration and operation of the voltage and reactive power monitoring and control device 1 according to this embodiment have been described above.

[0221] [5-2.Effects] (1) According to this embodiment, the input unit 11 of the voltage and reactive power monitoring and control device 1 has a past performance data input unit 115 that receives past performance data related to the past power demand of the power system 9, and the calculation unit 12 has a power demand simulation unit 124 that predicts the future power demand of the power system 9 based on the past performance data received by the past performance data input unit 115. Based on the future power demand of the power system 9 predicted by the power demand simulation unit 124, a future time schedule for the target voltage of the upper system 91 is created. Therefore, it is possible to output control information or a control command based on the past performance data before the control time of the upper system 91 arrives.

[0222] This makes it possible to maintain the voltage of the higher-level system 91 in a more responsive manner to fluctuations. The target voltage may be the center value of the target voltage, or may include an upper voltage limit value and a lower voltage limit value of the target voltage in addition to the center value of the target voltage.

[0223] [6. Sixth Embodiment] [6-1. Composition and Function] The voltage and reactive power monitoring and control device 1 according to the sixth embodiment will be described with reference to Fig. 8. The voltage and reactive power monitoring and control device 1 according to the sixth embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in that, in addition to the components of the voltage and reactive power monitoring and control device 1 according to the first embodiment, the input unit 11 has a prediction data input unit 116, the calculation unit 12 has a power demand simulation unit 124, and the storage unit 13 has a time schedule storage unit 134.

[0224] The rest of the configuration of the voltage and reactive power monitoring and control device 1 according to the sixth embodiment is the same as the configuration of the voltage and reactive power monitoring and control device 1 according to the first embodiment shown in Fig. 1. The same components as those of the voltage and reactive power monitoring and control device 1 according to the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0225] The input unit 11 of the voltage and reactive power monitoring and control device 1 according to the sixth embodiment has a forecast data input unit 116 that receives forecast data relating to weather forecasts for the area where the power system 9 is located, and the calculation unit 12 has a power demand simulation unit 124 that predicts the future power generation amount and power demand of the power system 9 based on the forecast data received by the forecast data input unit 116, and is characterized in that it creates a future time schedule for the target voltage of the upper system 91 based on the future power generation amount and power demand of the power system 9 predicted by the power demand simulation unit 124.

[0226] The forecast data input unit 116 of the input unit 11 receives forecast data relating to weather forecasts for the area where the power grid 9 is located. The forecast data is information relating to forecasts of future weather, including the amount of sunlight, wind speed, temperature, and humidity. The forecast data is stored in an external storage device or the like. The forecast data input unit 116 receives the forecast data from the external storage device or the like.

[0227] The power demand simulation unit 124 of the calculation unit 12 simulates the future power demand and power generation amount in the power system 9 based on the forecast data received by the forecast data input unit 116 and the system information received by the system information input unit 111. The power generation amount includes the amount of power generated by renewable energy power generation devices such as solar power generation devices and wind power generation devices.

[0228] The power demand simulation unit 124 predicts the power demand and power generation amount for each time period, for example, 5 minutes or 30 minutes, up to a certain time in the future, and creates power demand prediction data. The created power demand prediction data may be stored in the storage unit 13.

[0229] The voltage calculation unit 121 of the calculation unit 12 calculates the target voltage center value, upper voltage limit value of the target voltage, and lower voltage limit value of the target voltage as the target voltage of the upper system 91 based on the power demand forecast data created by the power demand simulation unit 124, the upper constraint information input to the upper constraint information setting unit 112, and the lower constraint information input to the lower constraint information setting unit 113.

[0230] The voltage calculation unit 121 repeatedly executes steps S04 to S08 of the computer program shown in FIG. 2 based on the power demand forecast data created by the power demand simulation unit 124, and calculates the target voltage of the upper system 91 for each time period, for example, 5 minutes or 30 minutes into the future.

[0231] The voltage calculation unit 121 sets the target voltage center value, upper limit voltage value, and lower limit voltage value calculated as the target voltage as control information. The voltage calculation unit 121 may create the control information by steps S01 to S10 of the first and second embodiments, or may create the control information by steps S04 to S10 including steps S21 to S25 of the third embodiment.

[0232] The voltage calculation unit 121 stores a time schedule related to the control information of the higher-level system 91 in the time schedule storage unit 134. The time schedule includes a target voltage of the higher-level system 91 for each future time period, such as a central value of the target voltage, an upper voltage limit value of the target voltage, and a lower voltage limit value of the target voltage. The time schedule is created for a certain time into the future. For example, a time schedule is created for 24 hours, one week, or one month into the future.

[0233] The calculation unit 12 outputs the target voltage according to the created time schedule as control information from the output unit 14. The control information output from the output unit 14 of the voltage and reactive power monitoring and control device 1 is transmitted to the control device 5. The control information according to a plurality of time periods may be transmitted to the control device 5 all at once, or the control information may be transmitted to the control device 5 individually for each time period.

[0234] The control device 5 outputs a control command for system control to the system adjustment device 6a of the upper system 91 based on the control information related to the time schedule transmitted from the voltage and reactive power monitoring and control device 1. The control command may be created by the calculation unit 12 and output from the voltage and reactive power monitoring and control device 1 as shown in the fourth embodiment. The system adjustment device 6a receives the control command and controls the upper system 91. The system adjustment device 6a adjusts the reactive power of the upper system 91 based on the reactive power generation amount, the amount related to the opening and closing of power capacitors, and the amount related to the opening and closing of shunt reactors, which are related to the control command, and as a result, the voltage of the upper system 91 is adjusted.

[0235] The configuration and operation of the voltage and reactive power monitoring and control device 1 according to this embodiment have been described above.

[0236] [6-2.Effects] (1) According to this embodiment, the input unit 11 of the voltage and reactive power monitoring and control device 1 has a forecast data input unit 116 that receives forecast data related to weather forecasts for the area where the power system 9 is located, and the calculation unit 12 has a power demand simulation unit 124 that predicts the future power generation amount and power demand of the power system 9 based on the forecast data received by the forecast data input unit 116. Based on the future power generation amount and power demand of the power system 9 predicted by the power demand simulation unit 124, a future time schedule for the target voltage of the upper system 91 is created. Therefore, before the control time of the upper system 91 arrives, control information or a control command based on the weather forecast and the future power generation amount and power demand of the power system 9 can be output.

[0237] This makes it possible to maintain the voltage of the higher-level system 91 in a more responsive manner to fluctuations. The target voltage may be the center value of the target voltage, or may include an upper voltage limit value and a lower voltage limit value of the target voltage in addition to the center value of the target voltage.

[0238] [7. Seventh Embodiment] [7-1. Composition and Function] A voltage and reactive power monitoring and control device 1 according to the seventh embodiment will be described with reference to Fig. 9. The voltage and reactive power monitoring and control device 1 according to the seventh embodiment differs from the voltage and reactive power monitoring and control device 1 according to the first embodiment in that the input unit 11 of the voltage and reactive power monitoring and control device 1 according to the first embodiment has a lower system future information setting unit 117 instead of the lower constraint information setting unit 113, and in that, in addition to the components of the voltage and reactive power monitoring and control device 1 according to the first embodiment, the input unit 11 has a forecast data input unit 116, the calculation unit 12 has a power demand simulation unit 124, and the storage unit 13 has a time schedule storage unit 134.

[0239] Other configurations of the voltage and reactive power monitoring and control device 1 according to the seventh embodiment are the same as the configuration of the voltage and reactive power monitoring and control device 1 according to the first embodiment shown in Fig. 1. The same components as those of the voltage and reactive power monitoring and control device 1 according to the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0240] The input unit 11 of the voltage and reactive power monitoring and control device 1 of the seventh embodiment has a lower-system future information setting unit 117 to which future margins indicating the number of taps that output a higher voltage than the tap position selected in the lower-system 92 and the number of taps that output a lower voltage are input, and a forecast data input unit 116 that receives forecast data related to weather forecasts for the area where the power system 9 is located.The calculation unit 12 has a power demand simulation unit 124 that predicts the future power generation amount and power demand of the power system 9 based on the forecast data received by the forecast data input unit 116, and is characterized in that it selects a tap position based on the margins input to the lower-system future information setting unit 117 and the future power generation amount and power demand of the power system 9 predicted by the power demand simulation unit 124, and creates a future time schedule for the target voltage of the upper-system 91.

[0241] The lower-level system future information setting unit 117 of the input unit 11 receives as input lower-level system future information that assumes future operation of the lower-level system 92 .

[0242] The lower-system future information may be input by an operating device arranged in the lower-system future information setting unit 117, such as a keyboard, mouse, or touch panel, or the lower-system future information set and stored in an external device may be received by a transmitting / receiving circuit or an external memory connection circuit of the lower-system future information setting unit 117.

[0243] The future information on the downstream system includes information on the upper and lower voltage limits of the downstream system 92, as well as information on the future margins regarding the tap positions of a transformer having multiple taps arranged in the downstream system 92. The information on the future margins regarding the tap positions indicates the number of taps that will output a higher voltage than the selected tap position and the number of taps that will output a lower voltage.

[0244] The future margin regarding the tap position may be set as lower-system future information for each time period, such as 5 minutes or 30 minutes, in the future.

[0245] The forecast data input unit 116 of the input unit 11 receives forecast data relating to weather forecasts for the area where the power grid 9 is located. The forecast data is information relating to forecasts of future weather, including the amount of sunlight, wind speed, temperature, and humidity. The forecast data is stored on the weather forecast site of the Japan Meteorological Agency on the Internet, etc. The forecast data input unit 116 receives the forecast data from the site on the Internet, etc.

[0246] The power demand simulation unit 124 of the calculation unit 12 simulates the future power demand and power generation amount in the power system 9 based on the forecast data received by the forecast data input unit 116 and the system information received by the system information input unit 111. The power generation amount includes the amount of power generated by renewable energy power generation devices such as solar power generation devices and wind power generation devices.

[0247] The power demand simulation unit 124 predicts the power demand and power generation amount for each time period, for example, 5 minutes or 30 minutes, up to a certain time in the future, and creates power demand prediction data. The created power demand prediction data may be stored in the storage unit 13.

[0248] The voltage calculation unit 121 of the calculation unit 12 selects the tap position based on the margin included in the lower-system future information input to the lower-system future information setting unit 117 and the future power generation amount and power demand of the power system 9 included in the power demand forecast data created by the power demand simulation unit 124, and calculates the central value of the target voltage, the upper voltage limit value of the target voltage, and the lower voltage limit value of the target voltage as the target voltage of the upper system 91.

[0249] The voltage calculation unit 121 repeatedly executes steps S04 to S08 of the computer program shown in FIG. 2, and calculates the target voltage of the higher-level system 91 for each time period, such as 5 minutes or 30 minutes, in the future.

[0250] The voltage calculation unit 121 sets the target voltage center value, upper limit voltage value, and lower limit voltage value calculated as the target voltage as control information. The voltage calculation unit 121 may create the control information by steps S01 to S10 of the first and second embodiments, or may create the control information by steps S04 to S10 including steps S21 to S25 of the third embodiment.

[0251] The voltage calculation unit 121 stores a time schedule related to the control information of the higher-level system 91 in the time schedule storage unit 134. The time schedule includes a target voltage of the higher-level system 91 for each future time period, such as a central value of the target voltage, an upper voltage limit value of the target voltage, and a lower voltage limit value of the target voltage. The time schedule is created for a certain time into the future. For example, a time schedule is created for 24 hours, one week, or one month into the future.

[0252] The calculation unit 12 outputs the target voltage according to the created time schedule as control information from the output unit 14. The control information output from the output unit 14 of the voltage and reactive power monitoring and control device 1 is transmitted to the control device 5. The control information according to a plurality of time periods may be transmitted to the control device 5 all at once, or the control information may be transmitted to the control device 5 individually for each time period.

[0253] The control device 5 outputs a control command for system control to the system adjustment device 6a of the upper system 91 based on the control information related to the time schedule transmitted from the voltage and reactive power monitoring and control device 1. The control command may be created by the calculation unit 12 and output from the voltage and reactive power monitoring and control device 1 as shown in the fourth embodiment. The system adjustment device 6a receives the control command and controls the upper system 91. The system adjustment device 6a adjusts the reactive power of the upper system 91 based on the reactive power generation amount, the amount related to the opening and closing of power capacitors, and the amount related to the opening and closing of shunt reactors, which are related to the control command, and as a result, the voltage of the upper system 91 is adjusted.

[0254] The configuration and operation of the voltage and reactive power monitoring and control device 1 according to this embodiment have been described above.

[0255] [7-2.Effects] (1) According to this embodiment, the input unit 11 of the voltage and reactive power monitoring and control device 1 includes a downstream system future information setting unit 117 to which future margins indicating the number of taps in the downstream system 92 that will output a higher voltage and the number of taps that will output a lower voltage than the tap position selected in the downstream system 92 are input, and a forecast data input unit 116 that receives forecast data related to weather forecasts for the area where the power system 9 is located. The calculation unit 12 includes a power demand simulation unit 124 that predicts the future power generation amount and power demand of the power system 9 based on the forecast data received by the forecast data input unit 116. The calculation unit 12 selects a tap position based on the margins input to the downstream system future information setting unit 117 and the future power generation amount and power demand of the power system 9 predicted by the power demand simulation unit 124, and creates a future time schedule for the target voltage of the upstream system 91. Therefore, before the control time of the upstream system 91 arrives, it is possible to output control information or control commands based on the future power generation amount and power demand of the power system 9 predicted based on the weather forecast and the input margins.

[0256] This makes it possible to maintain the voltage of the higher-level system 91 in a more responsive manner to fluctuations. The target voltage may be the center value of the target voltage, or may include an upper voltage limit value and a lower voltage limit value of the target voltage in addition to the center value of the target voltage.

[0257] 8. Other Embodiments Although embodiments including modifications have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. The following is an example.

[0258] (1) In the above embodiment, the output unit 14 is controlled by the calculation unit 12 and outputs control information or control commands related to the central value of the target voltage, the upper voltage limit value of the target voltage, and the lower voltage limit value of the target voltage as the target voltage of the higher-level system 91. However, the information output from the output unit 14 is not limited to this. The output unit 14 may be controlled by the calculation unit 12 and output, for example, state quantities of the higher-level system 91, the lower-level system 92, the system adjustment device 6a, and the system adjustment device 6b received by the system information input unit 111, information related to the upper voltage limit value, the lower voltage limit value, and the dead-band width for the target voltage of the higher-level system 91 input to the higher-level constraint information setting unit 112, information related to the upper voltage limit value and the lower voltage limit value of the lower-level system 92 input to the lower-level constraint information setting unit 113, and fault information and operation information of the voltage and reactive power monitoring and control device 1.

[0259] (2) In the above embodiment, the storage unit 13 stores control information or control commands related to the target voltage of the higher-level system 91, such as the central value of the target voltage, the upper limit voltage value of the target voltage, and the lower limit voltage value of the target voltage, but the information stored in the storage unit 13 is not limited to this. The storage unit 13 may also store processing procedures for each unit, arithmetic expressions for processing by each unit, parameters, threshold values, etc. [Explanation of symbols]

[0260] 1. Voltage and reactive power monitoring and control device 11 Input section 111 System information input section 112 Upper level constraint information setting section 113 Lower-level constraint information setting unit 114 Subsystem assumption information setting section 115 Past performance data entry section 116···Prediction data input section 117... Lower system future information setting section 12... Arithmetic section 121 Voltage calculation unit 122...Adjustment surplus calculation section 123 Control command creation unit 124···Power Demand Simulation Section 13...Storage section 131 Voltage data storage unit 132...Lower adjustment information storage unit 133 Control command memory unit 134 Time schedule memory section 14. Output section 5. Control device 51 System information input section 52 Control amount calculation unit 53 Control command output section 6...System adjustment device 7. State quantity detection device 8, 8a, 8b... Information transmission device 9...Power system 91... Upper system 92...subsystem

Claims

1. A voltage and reactive power monitoring and control device for calculating control information related to system control of an upper system in an electric power system having a lower system that is independently controlled and an upper system that supplies power to the lower system, comprising: an input unit to which state quantities relating to the electric quantity and the control state of the power system are input; selecting a tap position that satisfies the margin from among a plurality of taps of a transformer arranged in the lower system based on a margin indicating the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage than the selected tap position; a calculation unit that calculates a target voltage of the upper system as the control information based on the state quantity input to the input unit, assuming that the tap is at the selected tap position by independently controlling the lower system, Voltage and reactive power monitoring and control device.

2. The margin is such that the number of the taps outputting a voltage higher than the selected tap position is equal to the number of the taps outputting a voltage lower than the selected tap position. The voltage and reactive power monitoring and control device according to claim 1 .

3. The margin is set by the input unit as the number of the taps that output a voltage higher than the selected tap position and the number of the taps that output a voltage lower than the selected tap position. The voltage and reactive power monitoring and control device according to claim 1 .

4. the calculation unit calculates, as a reactive power adjustment margin, a fluctuation amount of reactive power that can be varied in the lower system, based on information related to control of the lower system included in the state quantity of the power system received by the input unit; calculating the margin for the tap based on the calculated reactive power adjustment margin, and selecting a tap position that satisfies the margin from among a plurality of taps of a transformer arranged in the lower system; the target voltage of the upper system is calculated as the control information, assuming that the tap is at the selected tap position by independently controlling the lower system; The voltage and reactive power monitoring and control device according to claim 1 .

5. the input unit has a higher-level constraint information setting unit that sets higher-level constraint information including information on a voltage upper limit value, a voltage lower limit value, and a dead-zone width indicating an upper limit and a lower limit for the target voltage of the higher-level system, the calculation unit calculates the target voltage of the higher-level system as the control information based on the higher-level constraint information set by the higher-level constraint information setting unit. The voltage and reactive power monitoring and control device according to any one of claims 1 to 4.

6. the input unit includes a lower-level constraint information setting unit that sets lower-level constraint information including information about an upper voltage limit value and a lower voltage limit value of the lower-level system, the calculation unit calculates the target voltage of the higher-level system as the control information based on the lower-level constraint information set by the lower-level constraint information setting unit. The voltage and reactive power monitoring and control device according to any one of claims 1 to 4.

7. The calculation unit has a control command creation unit that creates a control command related to reactive power adjustment of the higher-level system based on the calculated target voltage. The voltage and reactive power monitoring and control device according to any one of claims 1 to 4.

8. the input unit includes a past performance data input unit that receives past performance data related to past power demands of the power system, the calculation unit includes a power demand simulation unit that predicts future power demand of the power system based on the past performance data received by the past performance data input unit, creating a future time schedule for the target voltage of the upper system based on the future power demand of the power system predicted by the power demand simulation unit; The voltage and reactive power monitoring and control device according to any one of claims 1 to 4.

9. the input unit has a forecast data input unit that receives forecast data related to weather forecasts for an area where the power grid is located, a power demand simulation unit that predicts a future power generation amount and power demand of the power system based on the prediction data received by the calculation unit and the prediction data input unit, creating a future time schedule for the target voltage of the upper system based on the future power generation amount and power demand of the power system predicted by the power demand simulation unit; The voltage and reactive power monitoring and control device according to any one of claims 1 to 4.

10. the input unit is a lower-system future information setting unit to which the margin in the future is input, the margin indicating the number of the taps that output a higher voltage than the tap position selected in the lower-system and the number of the taps that output a lower voltage; a forecast data input unit that receives forecast data relating to weather forecasts for an area where the power system is installed; the calculation unit includes a power demand simulation unit that predicts a future power generation amount and power demand of the power system based on the prediction data received by the prediction data input unit, selecting the tap position based on the margin input to the lower-level system future information setting unit and the amount of power generated and the power demand of the power system in the future predicted by the power demand simulation unit; creating a future time schedule for the target voltage of the higher-level system; The voltage and reactive power monitoring and control device according to any one of claims 1 to 4.

11. On the computer, A computer program for a voltage and reactive power monitoring and control device for calculating control information for system control of an upper system in an electric power system having an independently controlled lower system and an upper system that supplies power to the lower system, comprising: an input step in which state quantities relating to the electrical quantities and control states of the power system are input; selecting a tap position that satisfies the margin from among a plurality of taps of a transformer arranged in the lower system based on a margin indicating the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage than the selected tap position; a calculation unit step of calculating a target voltage of the upper system as the control information based on the state quantity input in the input step, assuming that the tap is at the selected tap position due to the lower system being independently controlled; A computer program for a voltage and reactive power monitoring and control device.

12. 1. A voltage and reactive power monitoring and control method for calculating control information related to system control of an upper system in an electric power system having an independently controlled lower system and an upper system that supplies power to the lower system, comprising: an input step in which state quantities relating to the electrical quantities and control states of the power system are input; selecting a tap position that satisfies the margin from among a plurality of taps of a transformer arranged in the lower system based on a margin indicating the number of taps that output a higher voltage than the selected tap position and the number of taps that output a lower voltage than the selected tap position; and a calculation step of calculating a target voltage of the upper system as the control information based on the state quantity input in the input step, assuming that the tap is at the selected tap position due to the lower system being independently controlled. Voltage and reactive power monitoring and control method.

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