Merging Unit

Abstract

This will help curb the increase in equipment associated with the digitalization of substations. [Solution] A merging unit 24 that takes in electrical signals including the amount of electricity and information about the main unit of a substation, wherein the merging unit is connected to a first time source and a second time source which has higher accuracy than the first time source, and comprises an A / D conversion unit 242 which converts the amount of electricity into a digital signal in synchronization with a sampling signal synchronized with the second time source, an arithmetic processing unit 244 which receives information from the A / D conversion unit and generates event information which adds time information synchronized with the first time source to the information about the main unit and / or the internal log information of the merging unit, and a transmission and reception circuit 245 which outputs event information and information about the amount of electricity.

Description

Technical Field

[0001] The present invention relates to a merging unit.

Background Art

[0002] In recent years, the consideration of digitalizing substations has been rapidly progressing. The digitalization of substations may aim to reduce cable and its laying construction costs. For example, the control cables from main equipment in a substation such as a Gas Insulated Switchgear (hereinafter, GIS) to the protection and control devices in the control panel room are replaced from conventional metal wires to digital transmission using optical cables. At that time, for a conventional protection and control system, a "Merging Unit (hereinafter, MU)" for replacing an electrical signal with a digital signal is additionally required. However, from the perspective of cost reduction, the cost increase due to the addition of the above MU becomes an issue.

[0003] Patent Document 1 describes a merging unit that processes analog signals acquired from a power system and outputs digital data indicating the state of the power system.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A substation performs protection and control based on information sent as an electrical signal from main equipment such as GIS. The information transmitted from the main equipment includes analog information such as electrical quantities of voltage and current, and digital information such as information representing the on / off state of the switchgear (hereinafter, 30S) and fault information of the main equipment (hereinafter, 30F).

[0006] This information is input as electrical signals from the main unit to the MU in the digital substation. The voltage and current quantities are converted from analog signals to digital signals within the MU and transmitted via the process bus to the Intelligent Electronic Device (IED). Meanwhile, the 30S and 30F information is input to the MU as digital input signals, and the MU adds time information along with its internal log information before transmitting it via the process bus, IED, and station bus to the Supervisory Control and Data Acquisition (SCADA) and the power dispatch center.

[0007] Furthermore, the IED performs protection calculations internally based on the voltage and current quantities captured by the MU, thereby protecting the power system. In this process, the IED sends a tripping command as a digital signal to the MU, and the MU then outputs a tripping command as an electrical signal to the main unit based on that signal.

[0008] As mentioned above, digital substations use digital signals, requiring the installation of a Music Unit (MU) that converts between electrical and digital signals. Therefore, the number of devices increases compared to conventional substation systems. However, due to market demands for cost reduction, the number of devices must be kept to a minimum.

[0009] Therefore, especially when the MU is directly connected to the station bus and has control functions, it is conceivable to implement both protection and control functions for the same circuit in a single MU. However, in the case of such an MU, the following time synchronization problems arise.

[0010] Because high-precision time synchronization is required for protection functions, the electrical quantity information acquired by the MU needs to be synchronized with a time source compliant with the Precise Time Protocol (PTP). On the other hand, in control functions, when sending the 30S and 30F from the main unit to the SCADA and the power dispatch center, there is a need to confirm events using a single time reference, and this needs to be synchronized with the time distributed from the power dispatch center to the substations. This time may comply with the Simple Network Time Protocol (SNTP) or Network Time Protocol (NTP) protocol, which has lower synchronization accuracy than PTP and cannot be used for protection functions.

[0011] For the reasons described above, even if the input / output master is a single unit, it is necessary to have both a MU that synchronizes with time information compliant with PTP and a MU that synchronizes with time information compliant with SNTP or NTP, which presents a challenge that increases the required number of MUs.

[0012] Therefore, the present invention has been made in view of the above problems, and its purpose is to provide a technology that suppresses the increase in equipment associated with the digitalization of substations. [Means for solving the problem]

[0013] Therefore, the present invention has been made in view of the above problems, and provides a merging unit for acquiring electrical signals including the amount of electricity of a main unit of a substation and information about the main unit, wherein the merging unit is connected to a first time source and a second time source which has higher accuracy than the first time source, and comprises: a conversion unit which converts the amount of electricity into a digital signal in synchronization with a sampling signal synchronized with the second time source; a calculation unit which receives information from the conversion unit and generates event information which adds time information synchronized with the first time source to the information of the main unit and / or the internal log information of the merging unit; and a transmission unit which outputs the event information and the information of the amount of electricity. [Effects of the Invention]

[0014] According to the present invention, an increase in equipment associated with digitalization of a substation is suppressed.

Brief Description of the Drawings

[0015] [Figure 1] Functional block diagram showing an example of a digital substation system according to Example 1. [Figure 2] Functional block diagram showing an example of a merging unit according to Example 1. [Figure 3] Functional block diagram showing an example of a digital substation system according to Example 2. [Figure 4] Functional block diagram showing an example of a digital substation system according to Example 3. [Figure 5] Functional block diagram showing an example of a digital substation system according to Example 4.

Modes for Carrying Out the Invention

[0016] Hereinafter, several examples will be described with reference to the drawings.

Examples

[0017] FIG. 1 is a functional block diagram showing an example of a digital substation system according to Example 1.

[0018] The digital substation system 10 includes a power supply command station 11 as an example of a "superior system", a power supply network 12, and a substation 20.

[0019] The power supply command station 11 has a first time source. The time information of the first time source conforms to the SNTP or NTP protocol. The first time source can be considered as a clock in a server conforming to the SNTP or NTP protocol.

[0020] The power supply network 12 communicatively connects the power supply command station 11 and a gateway device 22 of the substation 20 described later.

[0021] The substation 20 includes a SCADA (Supervisory Control And Data Acquisition) 21, a gateway device 22, an intelligent electronic device (hereinafter referred to as IED) 23, a merging unit (hereinafter referred to as MU) 24, a main apparatus 25, and a second time source 26.

[0022] The SCADA 21, the gateway device 22, the IED 23, and the MU 24 are communicatively connected to each other via a station bus 31. The IED 23, the MU 24, and the second time source 26 are communicatively connected to each other via a process bus 33.

[0023] The SCADA 21 monitors and controls each device of the digital substation system 10. The gateway device 22 communicatively connects the power supply network 12 and the communication network within the substation 20. The IED 23 performs protection calculations for the main apparatus 25.

[0024] The MU 24 is connected to the first time source and the second time source 26. The MU 24 captures an electrical signal including the electrical quantity of the main apparatus 25 and the information of the main apparatus 25, and converts the electrical quantity into a digital signal.

[0025] The main apparatus 25 is communicatively connected to the MU 24 via a metal cable 32. The main apparatus 25 may include, for example, a gas-insulated switchgear as an example of a "switching device" that disconnects or connects the power system of the substation 20.

[0026] The second time source 26 has time information with higher accuracy than the first time source of the power supply command center 11. The second time source 26 complies with the PTP protocol.

[0027] Next, the operation of the digital substation system 10 will be described.

[0028] The MU 24 captures information representing the state of the main apparatus 25 (analog information such as electrical quantities of voltage and current, information 30S representing on / off states, and digital information such as fault information 30F) via the metal cable 32.

[0029] The MU24 transmits the information it has received from the main unit 25 to the SCADA 21 via the communication channel 31 for display, and also transmits it to the power dispatch center 11 via the gateway device 22 and the power supply network 12. In order to display the information received by the MU24 based on a unified time within the substation 20, regardless of the receiving equipment, the power dispatch center 11 distributes time information from a first time source to the substation 20, and the MU24 synchronizes with the received first time source. This time information from the first time source may conform to the SNTP or NTP protocol.

[0030] Meanwhile, MU24 transmits electrical quantity information to IED23 via communication channel 33, and performs protection calculations within IED23 based on this information. Because this protection calculation requires accurate acquisition of electrical quantity, all IED23 and MU24 involved in protection must be synchronized with time information distributed from a second time source 26 connected to the process bus. The time information from this second time source 26 conforms to PTP and is transmitted and received with synchronization accuracy suitable for protection.

[0031] Figure 2 is a functional block diagram showing an example of a merging unit according to Example 1.

[0032] The MU24 comprises an input conversion unit 241, an A / D conversion unit 242 as an example of a "conversion unit", an integrated circuit unit 243, a communication IF 246 as an example of a "first communication unit", and a communication IF 247 as an example of a "second communication unit".

[0033] The input conversion unit 241 acquires the amount of electricity transmitted as an electrical signal from the main unit 25 and the information 30S and 30F of the main unit 25.

[0034] The A / D conversion unit 242 converts electrical quantities into digital signals in synchronization with a sampling signal synchronized with the second time source 26. That is, the A / D conversion unit 242 converts the electrical quantities from the electrical signals into digital values ​​in synchronization with a sampling signal synchronized with the second time source 26, and then transmits the digital signal containing the converted electrical quantities and the information 30S, 30F of the main unit 25 to the integrated circuit unit 243.

[0035] The integrated circuit unit 243 includes an arithmetic processing unit 244 as an example of an "arithmetic unit" and a transmission / reception circuit 245 as an example of a "transmission unit".

[0036] The arithmetic processing unit 244 receives information from the A / D conversion unit 242 (electrical quantities converted to digital values ​​and information 30S, 30F from the main unit 25). The arithmetic processing unit 244 generates event information by adding time information synchronized with the first time source to the information 30S, 30F from the main unit 25 and the internal log information of the MU24. The event information is information that adds time information to the information 30S representing the on / off state of the gas-insulated switchgear or fault information 30F. The arithmetic processing unit 244 may be a CPU.

[0037] The transmission / reception circuit 245 outputs event information and electrical quantity information. Specifically, the transmission / reception circuit 245 outputs event information with time information synchronized with the first time source, and outputs the electrical quantity contained in the digital signal synchronized with the second time source 26. Furthermore, the transmission / reception circuit 245 is connected to the IED 23 via the communication IF 247 and the process bus 33, and the IED 23 performs protection calculations using the electrical quantity information output from the transmission / reception circuit 245. The transmission / reception circuit 245 may be a circuit built on an FPGA circuit.

[0038] The communication IF 246 communicates with the transmission / reception circuit 245 and the first time source via the station bus 31.

[0039] The communication IF247 connects the transmission / reception circuit 245 and the second time source 26 via the process bus 33.

[0040] Next, we will explain how the MU24 works.

[0041] The arithmetic processing unit 244 instructs the transmission / reception circuit 245 to transmit electrical quantity information and event information to the station bus 31 via communication IF 246 and to the process bus 33 via communication IF 247, respectively. At this time, the A / D conversion unit 242 converts the electrical quantity into a digital signal based on a sampling signal synchronized with the second time source 26 in accordance with PTP, and the transmission / reception circuit 245 outputs the digital signal into which the electrical quantity has been converted. Furthermore, the arithmetic processing unit 244 generates event information by adding time information synchronized with the first time source in accordance with SNTP or NTP, and outputs the generated event information. These electrical quantity and event information converted into digital signals are received by higher-level devices such as SCADA 21 and IED 23.

[0042] In this configuration, the MU24, which receives electrical signals including the amount of electricity from the substation's main unit 25 and information 30S,30F from the main unit 25, is connected to a first time source and a second time source 26 which has higher accuracy than the first time source, and comprises an A / D conversion unit 242, an arithmetic processing unit 244, and a transmission / reception circuit 245. The A / D conversion unit 242 converts the amount of electricity into a digital signal in synchronization with a sampling signal synchronized with the second time source 26. The arithmetic processing unit 244 receives information from the A / D conversion unit 242 and generates event information by adding time information synchronized with the first time source to the information 30S,30F from the main unit 25 and the internal log information of the MU24. The transmission / reception circuit 245 outputs the event information and information on the amount of electricity.

[0043] This allows the MU24 to synchronize with two time zones, enabling a single MU24 to implement both "event information transmission synchronized with the first time source" and "input / output functions for protection synchronized with the second time source 26." As a result, the number of MU24s required in the digital substation 10 can be reduced. On the other hand, if this configuration is not applied, it is necessary to provide an MU synchronized with the first time source and an MU synchronized with the second time source 26, thus requiring two MUs to implement the functions described above. [Examples]

[0044] The following describes an example in which a part of substation 202, as shown in Example 1, has been modified.

[0045] Figure 3 is a functional block diagram showing an example of a digital substation system according to Example 2.

[0046] The digital substation system 102 comprises a power dispatch center 11, a power supply network 12, and a substation 202.

[0047] Substation 202 includes SCADA 21, gateway device 22, IED 23, MU 24, main unit 25, and second time source 262.

[0048] The second time source 262 is interconnected with the SCADA 21, gateway device 22, IED 23, and MU 24 via the station bus 31. Specifically, the transmission / reception circuit 245 of the MU 24 is interconnected with the second time source 262 via the station bus 31.

[0049] In this configuration, a single MU24 synchronizes with the time information of both the first time source and the second time source 262. This makes it possible to provide an MU24 that combines event information distribution and input / output for protection. [Examples]

[0050] Figure 4 is a functional block diagram showing an example of a digital substation system according to Embodiment 3.

[0051] The digital substation system 103 comprises a power dispatch center 11, a power supply network 12, and a substation 203.

[0052] SCADA21, gateway device22, and IED23 are interconnected via station bus313. IED23, MU24, and second time source26 are interconnected via process bus33.

[0053] With this configuration, the transmission / reception circuit 245 can output event information synchronized with a first time source and electrical quantity information synchronized with a second time source, which has higher accuracy than the first time source, via the process bus 33.

[0054] Figure 5 is a functional block diagram showing an example of a digital substation system according to Embodiment 4.

[0055] The digital substation system 104 comprises a power dispatch center 11, a power supply network 12, and a substation 204.

[0056] SCADA21, gateway device22, IED23, MU24, and second time source26 are interconnected via process bus33. Specifically, the transmission / reception circuit245 of MU24 is interconnected via process bus33.

[0057] With this configuration, the transmission / reception circuit 245 can output event information synchronized with the first time source and electrical quantity information synchronized with the second time source 26, which has higher accuracy than the first time source, via the process bus 33.

[0058] In the embodiments described above, event information was assumed to include both information from the main unit and internal information from the MU; however, the present invention is equally applicable even if only one of these is used.

[0059] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0060] 20, 202, 203, 204… Substation, 23… Intelligent electronic device, 24… Merging unit, 25… Main unit, 26, 262… Second time source, 242… A / D conversion unit, 244… Arithmetic processing unit, 245… Transmission / reception / reception circuit, 246, 247… Communication IF, 31… Station bus, 33… Process bus

Claims

1. A merging unit that takes in electrical signals including the amount of electricity from the main unit of a substation and information about the main unit, The merging unit is connected to a first time source and a second time source which is more accurate than the first time source. A conversion unit that converts the electrical quantity into a digital signal in synchronization with a sampling signal synchronized with the second time source, A calculation unit that receives information from the conversion unit and generates event information by adding time information synchronized with the first time source to the information of the main unit and / or the internal log information of the merging unit, A merging unit comprising a transmission unit that outputs the event information and the amount of electricity information.

2. The transmission unit is connected via a process bus to an intelligent electronic device that performs protection calculations for the main unit. The intelligent electronic device performs the protection calculation using the information on the electrical quantity. The merging unit according to claim 1.

3. The conversion unit converts the electrical quantity into a digital signal based on a sampling signal synchronized with the second time source in accordance with the PTP protocol. The merging unit according to claim 1.

4. A first communication unit that connects the transmission unit and the first time source via a station bus, The system comprises a second communication unit that communicates the transmission unit and the second time source via a process bus, The merging unit according to claim 1.

5. The time information of the first time source is compliant with the SNTP or NTP protocol. The calculation unit generates the event information by assigning time information synchronized with the first time source in accordance with SNTP or the NTP protocol. The merging unit according to claim 1.

6. The first time source is a clock in a server compliant with the SNTP or NTP protocol, which is communicated to a higher-level system of the station bus via the station bus. The merging unit according to claim 1.

7. The transmission unit is connected to the second time source via a station bus. The merging unit according to claim 1.

8. The main unit includes a switchgear for interrupting or connecting the power system of the substation. The event information is information that is obtained by adding the time information to information indicating the on / off state of the switchgear or the malfunction state of the main unit. The merging unit according to claim 1.

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