Power distribution network state estimation system, power distribution network state estimation device, power distribution network state estimation method, and program

Abstract

The power distribution network state estimation system includes a measurement value acquisition unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; a voltage drop calculation unit that calculates a value indicating a voltage drop from the first switch to the second switch using the measurement value of the power flow; a correlation calculation unit that calculates a time correlation between a value obtained by subtracting the measurement value of the first connection end voltage from the measurement value of the voltage at the first switch and the value indicating the voltage drop, and calculates a time correlation between a value obtained by subtracting the measurement value of the second connection end voltage from the measurement value of the voltage at the first switch and the value indicating the voltage drop; and a determination unit that estimates which of the first connection end and the second connection end is connected to the first distribution line based on at least these time correlations.

Description

[Technical field]

[0001] The present disclosure relates to a power distribution network state estimation system, a power distribution network state estimation device, a power distribution network state estimation method, and a program. [Background technology]

[0002] Among the switches installed in the power distribution network, there are sensor-equipped switches that are equipped with sensors that measure voltage and power flow (active power and reactive power). The voltage and power flow measured by these sensors are used for voltage control to maintain appropriate voltages at each point in the power distribution network.

[0003] Furthermore, Patent Document 1 discloses a connection phase estimation method for estimating a connection phase between a first distribution line and a second distribution line based on a correlation value of line currents in a distribution network in which a set of first distribution lines branches into a plurality of sets of second distribution lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-151089 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a system that collects voltages at both ends of a sensor-equipped switch, the connection direction of the switch may be set incorrectly. The connection phase estimation method described in Patent Document 1 has the problem that it can estimate the connection phase but cannot estimate the connection direction of the switch.

[0006] The present disclosure has been made in consideration of the above circumstances, and provides a power distribution network state estimation system, a power distribution network state estimation device, a power distribution network state estimation method, and a program that are capable of estimating the connection direction of a sensor-equipped switch. [Means for solving the problem]

[0007] This disclosure has been made to solve the above-mentioned problems, and one aspect of the disclosure includes a measurement value acquisition unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch, and a voltage drop calculation unit that calculates a value indicating a first voltage drop from the first switch to the second switch using the measurement value of the power flow. a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting a measured value of the first connection end voltage from the measured value of the voltage and a value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting a measured value of the second connection end voltage from the measured value of the voltage and the value indicating the first voltage drop, and a determination unit that estimates which of the first connection end and the second connection end is connected to the first distribution line based on at least the first time correlation and the second time correlation.

[0008] Another aspect of the present disclosure is the above-mentioned power distribution network state estimation system, wherein the measured value of the power flow includes active power and reactive power at the first switch, and the voltage drop calculation unit calculates, as a value indicating the first voltage drop, a sum of a value obtained by multiplying a preset value indicating the resistance of the first distribution line by the active power and a value obtained by multiplying a preset value indicating the reactance of the first distribution line by the reactive power.

[0009] Another aspect of the present disclosure is the above-mentioned power distribution network state estimation system, further comprising a display unit that displays a message notifying a user of the inconsistency when the determination unit determines that the estimation result of the connection end connected to the first power distribution line does not match the pre-stored connection relationship of the second switch with the first power distribution line.

[0010] Another aspect of the present disclosure is the above-mentioned power distribution network state estimation system, wherein the measurement value acquisition unit acquires measurement values ​​of a voltage and a power flow at a third switch installed on a second distribution line to which the other end of the second switch is connected, the voltage drop calculation unit calculates a value indicating a second voltage drop from the third switch to the second switch using the measurement value of the power flow at the third switch, the correlation calculation unit calculates a third time correlation between a value obtained by subtracting a measurement value of the first connection end voltage from the measurement value of the voltage at the third switch and the value indicating the second voltage drop, and calculates a fourth time correlation between a value obtained by subtracting a measurement value of the second connection end voltage from the measurement value of the voltage at the third switch and the value indicating the second voltage drop, and the determination unit estimates which of the first connection end and the second connection end is connected to the first distribution line based at least on the first time correlation, the second time correlation, the third time correlation, and the fourth time correlation.

[0011] Another aspect of the present disclosure includes a measurement value acquisition unit that acquires a measurement value of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch, the measurement value of the power flow being used to calculate a value indicating a first voltage drop from the first switch to the second switch, and a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting a measured value of the first connection end voltage from the measured value of the voltage and a value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting a measured value of the second connection end voltage from the measured value of the voltage and the value indicating the first voltage drop, and a determination unit that estimates which of the first connection end and the second connection end is connected to the first distribution line based on at least the first time correlation and the second time correlation.

[0012] Another aspect of the present disclosure is a method for estimating a state of a power distribution network, comprising the steps of: acquiring measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; calculating a value indicating a first voltage drop from the first switch to the second switch using the measurement values ​​of the power flow; calculating a first time correlation between a value obtained by subtracting the measurement value of the first connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop, and calculating a second time correlation between a value obtained by subtracting the measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop; and estimating, based at least on the first time correlation and the second time correlation, which of the first connection end and the second connection end is connected to the first distribution line.

[0013] Another aspect of the present disclosure is a program for causing a computer to function as: a measurement value acquisition unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; a voltage drop calculation unit that calculates a value indicating a first voltage drop from the first switch to the second switch using the power flow measurement value; a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting the measurement value of the first connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting the measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop; and a determination unit that estimates which of the first connection end and the second connection end is connected to the first distribution line based at least on the first time correlation and the second time correlation. Effect of the Invention

[0014] According to this disclosure, a power distribution network state estimation system, a power distribution network state estimation device, a power distribution network state estimation method, and a program can estimate the connection direction of a sensor-equipped switch. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic block diagram illustrating the connections of an electric power grid state estimation system 10 according to an embodiment of the present disclosure. [Diagram 2] 1 is a schematic block diagram showing a configuration of a power distribution network state estimation system 10 in the embodiment. [Diagram 3] 11 is a graph showing a display example (part 1) of the display unit 15 in the embodiment. [Figure 4] 11 is a graph showing a second display example of the display unit 15 in the embodiment. [Diagram 5] 4 is a flowchart illustrating an example of the operation of the power distribution network state estimation system 10 in the embodiment. [Figure 6] 13 is a flowchart illustrating an example of the operation of the power distribution network state estimation system 10 in a modified example of the embodiment. [Figure 7] FIG. 2 is an explanatory diagram illustrating a hardware configuration of each device according to the embodiment and a modification example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic block diagram showing a connection relationship of a power distribution network state estimation system 10 according to an embodiment of the present disclosure. The power distribution network state estimation system 10 is a system that estimates the state of a power distribution network. The power distribution network state estimation system 10 may be configured as one device (power distribution network state estimation device). The state of the power distribution network estimated by the power distribution network state estimation system 10 includes the connection direction of the switch Sc, but may also include voltages, currents, and the like at each point of the power distribution network. The voltage centralized control system 20 performs voltage control to keep the voltage at each point of the power distribution network at an appropriate level based on the state of the power distribution network estimated by the power distribution network state estimation system 10. The measurement value collection system 30 collects measurement values ​​of sensors arranged in the power distribution network, including sensors provided in the switches Sa, Sb, and Sc.

[0017] Each of the power distribution grid state estimation system 10, the centralized voltage control system 20, and the measurement value collection system 30 may be realized by one or more computers reading and executing a program. Each of the power distribution grid state estimation system 10, the centralized voltage control system 20, and the measurement value collection system 30 may be configured as one device, or may be configured as multiple devices connected via a network or the like.

[0018] The switch Sa (first switch) is a switch with a sensor arranged on a distribution line Fa (first distribution line) constituting a power distribution network. The distribution line Fa is connected to a transformer Ta via the switch Sa. The load center La is the load center of the distribution line Fa. The switch Sa is normally closed in order to supply power from the transformer Ta to the distribution line Fa. The switch Sb (third switch) is a switch with a sensor arranged on a distribution line Fb (second distribution line) constituting a power distribution network. The distribution line Fb is connected to a transformer Tb via the switch Sb. The load center Lb is the load center of the distribution line Fb. The switch Sb is normally closed in order to supply power from the transformer Tb to the distribution line Fb.

[0019] The sensors provided in the switches Sa and Sb measure the voltage and power flow (active power and reactive power) at each switch and supply these measurement values ​​to the measurement value collection system 30. Note that the switches Sa and Sb are normally closed and the voltages at both ends are equal. Therefore, the voltage measurement value measured by the sensor and supplied to the measurement value collection system 30 may be the voltage at either end of the switches Sa and Sb on the transformer Ta, Tb side or the distribution line Fa, Fb side, or may be the voltage at each of the both ends.

[0020] The switch Sc (second switch) is a switch with a sensor arranged such that one end (S end) is connected to the power distribution line Fa and the other end (T end) is connected to the power distribution line Fb. When the switch Sc is closed, a loop is formed between the power distribution line Fa and the power distribution line Fb, so that the switch Sc is normally open. The sensor provided in the switch Sc measures at least the voltages at the S end and the T end, and supplies the measurement values ​​to the measurement value collection system 30. In FIG. 1, the S end is connected to the power distribution line Fa, and the T end is connected to the power distribution line Fb, but this is the setting of the connection direction stored in the power distribution network state estimation system 10. That is, the power distribution network state estimation system 10 is set to recognize that the measurement value acquired from the measurement value collection system 30 as the voltage at the S end is the voltage at the end of the switch Sc on the power distribution line Fa side, and that the measurement value acquired as the voltage at the T end is the voltage at the end of the switch Sc on the power distribution line Fb side. The power distribution grid state estimation system 10 in this embodiment judges whether this setting is correct or not. In addition to consumers, distributed power sources such as solar cells and branch lines may be connected to the distribution lines Fa and Fb.

[0021] 2 is a schematic block diagram showing the configuration of a power distribution network state estimation system 10 according to the present embodiment. The power distribution network state estimation system 10 includes a measurement value acquisition unit 11, a voltage drop calculation unit 12, a correlation calculation unit 13, a determination unit 14, and a display unit 15.

[0022] The measurement value acquiring unit 11 acquires a measurement value of a voltage Va and a power flow (e.g., active power Pa and reactive power Qa) at a switch Sa installed on a power distribution line Fa, a measurement value of a voltage Vs (first connection end voltage) at an S end (first connection end) of a switch Sc having one end connected to the power distribution line Fa, and a measurement value of a voltage Vt (second connection end voltage) at a T end (second connection end) of the switch Sc. These voltage and power flow measurement values ​​may be average values ​​for a predetermined period (e.g., one day) of a predetermined time length (e.g., one minute) at a predetermined time interval (e.g., one minute). Note that the measurement value acquiring unit 11 may acquire these average values ​​calculated from instantaneous values ​​by the measurement value collecting system 30, or the measurement value acquiring unit 11 may calculate them based on instantaneous values ​​acquired from the measurement value collecting system 30.

[0023] The voltage drop calculation unit 12 calculates a value indicating a first voltage drop from the switch Sa to the switch Sc by using the measurement value of the power flow. When the measurement value acquisition unit 11 acquires the measurement values ​​of the active power Pa and the reactive power Qa as the power flow, the voltage drop calculation unit 12 may calculate the sum of a value obtained by multiplying a preset value Ra indicating the resistance of the power distribution line Fa by the active power Pa and a value obtained by multiplying a preset value Xa indicating the reactance of the power distribution line Fa by the reactive power Qa (i.e., PaRa+QaXa) as a value indicating the voltage drop (first voltage drop).

[0024] Ra may be the resistance of a preset length of the distribution line Fa (e.g., from the switch Sa to the load center La, or from the switch Sa to the switch Sc). Xa may be the reactance of a preset length of the distribution line Fa (e.g., from the switch Sa to the load center La, or from the switch Sa to the switch Sc). Note that these preset lengths or the position of the load center La may be constant values ​​or may be values ​​that vary depending on the time.

[0025] The correlation calculation unit 13 calculates a time correlation (first time correlation) between a value obtained by subtracting the measured value of the voltage Vs from the measured value of the voltage Va and a value indicating the voltage drop (first voltage drop) calculated by the voltage drop calculation unit 12. The correlation calculation unit 13 also calculates a time correlation (second time correlation) between a value obtained by subtracting the measured value of the voltage Vt from the measured value of the voltage Va and a value indicating the voltage drop (first voltage drop) calculated by the voltage drop calculation unit 12.

[0026] The determination unit 14 estimates which of the S-terminal and the T-terminal is connected to the distribution line Fa, based on at least the first time correlation and the second time correlation calculated by the correlation calculation unit 13. The determination unit 14 estimates that the connection terminal corresponding to the larger of the first time correlation and the second time correlation (the one with higher correlation) is connected to the distribution line Fa. In addition, when making the estimation, other conditions may be used, such as the value of the larger time correlation exceeding a predetermined threshold value. Here, the connection terminal corresponding to the first time correlation is the S-terminal where the voltage Vs used in calculating the first time correlation is measured, and the connection terminal corresponding to the second time correlation is the T-terminal where the voltage Vt used in calculating the second time correlation is measured. In addition, since the switch Sc is usually open, the voltage of the connection terminal of the switch Sc on the distribution line Fa side and the voltage of the connection terminal of the switch Sc on the distribution line Fb side usually do not match, and the time correlation on the distribution line Fa side is generally larger than the time correlation on the distribution line Fb side. The determination unit 14 uses this to make an estimation.

[0027] When the determination unit 14 determines that the estimation result of the connection end connected to the distribution line Fa does not match the connection relationship between the switch Sc and the distribution line Fa that was stored in advance in the distribution grid state estimation system 10, the display unit 15 displays a notification of the mismatch. Based on this display, the operator can correct the connection relationship between the switch Sc and the distribution line Fa that was stored in the distribution grid state estimation system 10 or the like. The notification of the mismatch may be made by text, or may be made by using a graph showing the relationship between the measured voltage value and the calculated voltage drop, a graph showing the correlation, or the like.

[0028] This display may be performed using a display provided in the power distribution grid state estimation system 10, or may be performed using a display provided in another device communicatively connected to the power distribution grid state estimation system 10.

[0029] FIG. 3 is a graph showing a display example (part 1) by the display unit 15 in this embodiment. FIG. 3 is a graph showing the relationship between the measured values ​​of voltages Va, Vs, and Vt and the voltage drop (PaRa+QaXa) calculated by the voltage drop calculation unit 12. In the graph of FIG. 3, the horizontal axis is the length of the distribution line Fa, and the vertical axis is the voltage. On the horizontal axis, Sa indicates the position of the switch Sa, La indicates the position of the load center La, and Sc indicates the position of the switch Sc. The solid line graph is a straight line connecting the voltage Va at the switch Sa and the voltage Vs at the switch Sc. The dashed line graph is a straight line connecting the voltage Va at the switch Sa and the voltage Vt at the switch Sc. The dashed line graph is a line connecting the voltage Va at the switch Sa and the voltage Va-(PaRa+QaXa) at the load center La, and further connecting it to the switch Sc at the same voltage. These values ​​are values ​​at a certain time, and the time may be set by the operator, or may be average values ​​over a predetermined period.

[0030] Voltage Va-(PaRa+QaXa) indicates the voltage at switch Sc based on the calculated voltage drop. If the connection direction of switch Sc stored in power distribution grid state estimation system 10 is correct, this value is expected to be close to voltage Vs. Therefore, by comparing this value with voltages Vs and Vt, an operator can also confirm (estimate) whether or not there is an error in the connection direction (S end, T end) of switch Sc stored in power distribution grid state estimation system 10.

[0031] FIG. 4 is a graph showing a display example (part 2) by the display unit 15 in this embodiment. In FIG. 4, the horizontal axis is PaRa+QaXa, and the vertical axis is Va-Vs. FIG. 4 is a graph plotting points consisting of PaRa+QaXa and Va-Vs at each time. If there is a time correlation between PaRa+QaXa and Va-Vs, a regularity appears in the set of plotted points as shown in FIG. 4, but if there is no time correlation, no regularity appears. By referring to the graph in FIG. 4, the operator can also confirm (estimate) whether there is an error in the connection direction (S end, T end) of the switch Sc stored in the power distribution network state estimation system 10. The display unit 15 may display a graph plotting points consisting of PaRa+QaXa and Va-Vt at each time.

[0032] Fig. 5 is a flowchart for explaining an operation example of the power distribution network state estimation system 10 in this embodiment. Fig. 5 is a flowchart of a determination process of a connection setting of a switch Sc by the power distribution network state estimation system 10. This determination process may be started by an operator's designation, may be started periodically, or may be started when the setting related to the switch Sc is changed.

[0033] First, the measurement value acquisition unit 11 acquires the measurement values ​​(Va, Pa, Qa, Vs, Vt) at the switches Sa and Sc (step Sa1). Next, the voltage drop calculation unit 12 calculates the voltage drop Ca from the switch Sa to the switch Sc based on the power flow (active power Pa, reactive power Qa) at the switch Sa (step Sa2). This voltage drop Ca is, for example, PaRa+QaXa.

[0034] Next, the correlation calculation unit 13 calculates the correlation between the voltage drop Ca calculated in step Sa2 and the measured voltage drop A (step Sa3). The measured voltage drop A is, for example, Va-Vs or Va-Vt. Next, the determination unit 14 determines whether the connection setting of the switch Sc stored in the power distribution network state estimation system 10 is correct or incorrect based on the correlation calculated in step Sa3 (step Sa4). If the determination result in step Sa4 is incorrect (the connection setting is incorrect) (step Sa5-Yes), the display unit 15 notifies the operator that there is an error in the connection setting (step Sa6). On the other hand, if the determination result in step Sa4 is not incorrect (correct) (step Sa5-No), the power distribution network state estimation system 10 ends the determination process of the connection setting of the switch Sc.

[0035] In this way, by using the time correlation between the voltage drop from the switch Sa calculated based on the power flow and the voltage drop from the switch Sa based on the measured voltage value, the power distribution network state estimation system 10 can estimate the connection direction of the sensor-equipped switch Sc.

[0036] <Modification> In the above embodiment, the measurement value of the switch Sa and the measurement value of the switch Sc are used to determine the connection setting of the switch Sc, but in this modified example, the measurement value of the switch Sb may also be used. The measurement value acquisition unit 11, voltage drop calculation unit 12, correlation calculation unit 13, determination unit 14, and display unit 15 in this modified example described below are the same as those in the above embodiment, but also perform processing using the measurement value of the switch Sb. The processing added in this modified example to the above embodiment will be described below.

[0037] The measurement value acquiring unit 11 acquires measurement values ​​of the voltage Vb and the power flow (active power Pb, reactive power Qb) at the switch Sb (third switch) installed on the power distribution line Fb to which the T end (the end considered to be the T end) of the switch Sc is connected. The voltage drop calculating unit 12 calculates a value indicating the voltage drop (second voltage drop) from the switch Sb to the switch Sc using the measurement value of the power flow at the switch Sb.

[0038] The correlation calculation unit 13 calculates a time correlation (third time correlation) between a value obtained by subtracting the measured value of the voltage Vs from the measured value of the voltage Vb at the switch Sb and a value indicating the second voltage drop calculated by the voltage drop calculation unit 12. The correlation calculation unit 13 also calculates a time correlation (fourth time correlation) between a value obtained by subtracting the measured value of the voltage Vt from the measured value of the voltage Vb at the switch Sb and a value indicating the second voltage drop calculated by the voltage drop calculation unit 12.

[0039] The determination unit 14 estimates which of the S-end and the T-end is the connection end connected to the power distribution line Fa based on at least the first time correlation, the second time correlation, the third time correlation, and the fourth time correlation. For example, the determination unit 14 may estimate that the T-end is the connection end connected to the power distribution line Fa when the first time correlation is smaller than the second time correlation or the third time correlation is larger than the fourth time correlation. The determination unit 14 may also estimate that the S-end is the connection end connected to the power distribution line Fa when the first time correlation is larger than the second time correlation or the third time correlation is smaller than the fourth time correlation.

[0040] Furthermore, the determination unit 14 may estimate that the T end is a connection end connected to the power distribution line Fa when the first time correlation is smaller than the second time correlation and the third time correlation is larger than the fourth time correlation. Similarly, the determination unit 14 may estimate that the S end is a connection end connected to the power distribution line Fa when the first time correlation is larger than the second time correlation and the third time correlation is smaller than the fourth time correlation.

[0041] Fig. 6 is a flowchart for explaining an example of the operation of the power distribution network state estimation system 10 in this modified example. Fig. 6 is also a flowchart of the process of determining the connection setting of the switch Sc by the power distribution network state estimation system 10. The start timing of this determination process is the same as in the above-described embodiment.

[0042] First, the measurement value acquisition unit 11 acquires the measurement values ​​(Va, Pa, Qa, Vb, Pb, Qb, Vs, Vt) at the switches Sa, Sb, and Sc (step Sb1). Next, the voltage drop calculation unit 12 calculates the voltage drop Ca from the switch Sa to the switch Sc based on the power flow (Pa, Qa) at the switch Sa (step Sa2). This voltage drop Ca is, for example, PaRa+QaXa. Next, the voltage drop calculation unit 12 calculates the voltage drop Cb from the switch Sb to the switch Sc based on the power flow (Pb, Qb) at the switch Sb (step Sb2). This voltage drop Cb is, for example, PbRb+QbXb.

[0043] Next, the correlation calculation unit 13 calculates the correlation between the voltage drop Ca calculated in step Sa2 and the measured voltage drop A (step Sa3). Next, the correlation calculation unit 13 calculates the correlation between the voltage drop Cb calculated in step Sb2 and the measured voltage drop B (step Sb3). The measured voltage drop B is, for example, Vb-Vs or Vb-Vt. Next, the determination unit 14 determines whether the connection setting of the switch Sc stored in the power distribution network state estimation system 10 is correct or incorrect based on the correlation calculated in steps Sa3 and Sb3 (step Sb4). If the determination result in step Sb4 is incorrect (the connection setting is incorrect) (step Sa5-Yes), the display unit 15 notifies the operator that the connection setting is incorrect (step Sa6). On the other hand, if the determination result in step Sa4 is not incorrect (correct) (step Sa5-No), the power distribution network state estimation system 10 ends the determination process of the connection setting of the switch Sc.

[0044] In this manner, in the modified example, by also using the voltage drop from the switch Sb to the switch Sc, the connection setting of the switch Sc can be determined with even higher accuracy.

[0045] FIG. 7 is an explanatory diagram illustrating the hardware configuration of each device according to the above-described embodiment and modifications. The devices are a power distribution grid state estimation system 10, a voltage centralized control system 20, and a measurement value collection system 30. Each device includes an input / output module I, a storage module M, and a control module P. The input / output module I is realized by including some or all of a communication module H11, a connection module H12, a pointing device H21, a keyboard H22, a display H23, a button H3, a microphone H41, a speaker H42, a camera H51, or a sensor H52. The storage module M is realized by including a drive H7. The storage module M may further be configured by including some or all of a memory H8. The control module P is realized by including a memory H8 and a processor H9. These hardware components are connected to each other so as to be able to communicate with each other via a bus, and are supplied with power from a power source H6.

[0046] The connection module H12 is a digital input / output port such as a USB (Universal Seriul Bus). In the case of a portable device, the pointing device H21, the keyboard H22, and the display H23 are touch panels. The sensor H52 is an acceleration sensor, a gyro sensor, a GPS receiving module, a proximity sensor, or the like. The power source H6 is a power supply unit that supplies electricity required to operate each device. In the case of a portable device, the power source H6 is a battery. The drive H7 is an auxiliary storage medium such as a hard disk drive or a solid state drive. The drive H7 may be a non-volatile memory such as an EEPROM or a flash memory, or a magneto-optical disk drive or a flexible disk drive. In addition, the drive H7 is not limited to being built into each device, but may be an external storage device connected to a connector of the connection module H12. The memory H8 is a main storage medium such as a random access memory. The memory H8 may be a cache memory. The memory H8 stores instructions when the instructions are executed by one or more processors H9. The processor H9 is a CPU (Central Processing Unit). The processor H9 may be a microprocessing unit (MPU) or a graphics processing unit (GPU). The processor H9 reads out programs and various data from the drive H7 via the memory H8 and performs calculations to execute instructions stored in one or more memories H8.

[0047] The input / output module I is used in the power distribution grid state estimation system 10, the centralized voltage control system 20, the measurement value collection system 30, etc. The control module P is used to implement each part of the power distribution grid state estimation system 10, the centralized voltage control system 20, and the measurement value collection system 30. Note that in this specification and the like, the descriptions of the power distribution grid state estimation system 10, the centralized voltage control system 20, and the measurement value collection system 30 may be replaced with the description of the control module P.

[0048] The present disclosure may also be embodied as follows. (1) One embodiment of the present disclosure includes a measurement value acquisition unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch, the measurement value of the power flow being used to calculate a value indicating a first voltage drop from the first switch to the second switch, and a voltage drop calculation unit that calculates a value indicating a first voltage drop from the first switch to the second switch using the measurement values ​​of the power flow. a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting a measurement value of the first connection end voltage from the measurement value of the voltage and a value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting a measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop, and a determination unit that estimates which of the first connection end and the second connection end is connected to the first distribution line based on at least the first time correlation and the second time correlation.

[0049] This enables the power distribution network state estimation system to estimate the connection direction of the second switch.

[0050] (2) Another embodiment of the present disclosure is the power distribution network state estimation system described in (1), wherein the measured value of the power flow includes active power and reactive power at the first switch, and the voltage drop calculation unit calculates, as a value indicating the first voltage drop, a sum of a value obtained by multiplying a preset value indicating a resistance of the first distribution line by the active power and a value obtained by multiplying a preset value indicating a reactance of the first distribution line by the reactive power.

[0051] This enables the power distribution network state estimation system to estimate the connection direction of the second switch by using the voltage drop calculated from the active power and reactive power at the first switch.

[0052] (3) Furthermore, another embodiment of the present disclosure is the power distribution network state estimation system described in (1) or (2), further comprising a display unit that displays a message notifying a user of the inconsistency when the determination unit determines that the estimation result of the connection end connected to the first power distribution line does not match the pre-stored connection relationship of the second switch with the first power distribution line.

[0053] Thereby, when the pre-stored connection direction of the second switch does not match the estimation result, the power distribution grid state estimation system can notify that it does not match.

[0054] (4) Another embodiment of the present disclosure is the power distribution network state estimation system according to any one of (1) to (3), wherein the measurement value acquisition unit acquires measurement values ​​of a voltage and a power flow at a third switch installed on a second power distribution line to which the other end of the second switch is connected, the voltage drop calculation unit calculates a value indicating a second voltage drop from the third switch to the second switch using the measurement value of the power flow at the third switch, and the correlation calculation unit calculates a correlation value indicating a second voltage drop from the measurement value of the voltage at the third switch to the previous voltage drop. a third time correlation between a value obtained by subtracting the measured value of the first connection end voltage from a value indicating the second voltage drop; and a fourth time correlation between a value obtained by subtracting the measured value of the second connection end voltage from the measured value of the voltage at the third switch and a value indicating the second voltage drop, and the determination unit estimates which of the first connection end and the second connection end is connected to the first distribution line based at least on the first time correlation, the second time correlation, the third time correlation, and the fourth time correlation.

[0055] This enables the power distribution grid state estimation system to estimate the connection direction of the second switch with greater accuracy than (1).

[0056] (5) Furthermore, another embodiment of the present disclosure includes a measurement value acquisition unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch, the second switch being connected to the first distribution line, a voltage drop calculation unit that calculates a value indicating a first voltage drop from the first switch to the second switch using the measurement value of the power flow, and The power distribution network state estimation device includes: a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting a measurement value of the first connection end voltage from a measurement value and a value indicating the first voltage drop; and a correlation calculation unit that calculates a second time correlation between a value obtained by subtracting a measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop; and a determination unit that estimates which of the first connection end and the second connection end is connected to the first power distribution line based on at least the first time correlation and the second time correlation.

[0057] This allows the power distribution network state estimating device to estimate the connection direction of the second switch.

[0058] (6) Another embodiment of the present disclosure is a method for estimating a state of a power distribution network, comprising the steps of: acquiring measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; calculating a value indicating a first voltage drop from the first switch to the second switch using the measurement values ​​of the power flow; calculating a first time correlation between a value obtained by subtracting the measurement value of the first connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop, and calculating a second time correlation between a value obtained by subtracting the measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop; and estimating, based at least on the first time correlation and the second time correlation, which of the first connection end and the second connection end is connected to the first distribution line.

[0059] This makes it possible for the power distribution network state estimating method to estimate the connection direction of the second switch.

[0060] (7) Furthermore, another embodiment of the present disclosure provides a computer including a measurement value acquisition unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch, the measurement value of the power flow being used to calculate a value indicating a first voltage drop from the first switch to the second switch, the correlation calculation unit calculates a first time correlation between a value obtained by subtracting a measured value of the first connection end voltage from a measured value of the first voltage drop and a value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting a measured value of the second connection end voltage from the measured value of the first voltage drop and a value indicating the first voltage drop; and the program for causing the correlation calculation unit to function as a determination unit that estimates which of the first connection end and the second connection end is connected to the first distribution line based at least on the first time correlation and the second time correlation.

[0061] This allows a computer that reads and executes the program to estimate the connection direction of the second switch.

[0062] 1 and 2 may be recorded on a computer-readable recording medium, and the programs recorded on the recording medium may be read into a computer system and executed to realize the power distribution grid state estimating system 10, the voltage centralized control system 20, and the measurement value collecting system 30. Note that the term "computer system" herein includes hardware such as an OS and peripheral devices.

[0063] In addition, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording medium" also includes those that dynamically hold a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and those that hold a program for a certain period of time, such as volatile memory inside a computer system that serves as a server or client in such cases. Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0064] Although the embodiment of this disclosure has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not depart from the gist of this disclosure. [Explanation of symbols]

[0065] 10 Power distribution grid state estimation system 11 Measurement value acquisition section 12 Voltage drop calculation section 13 Correlation calculation section 14 Judgment section 15 Display 20 Centralized voltage control system 30 Measurement Collection System

Claims

1. a measurement value acquiring unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; a voltage drop calculation unit that calculates a value indicating a first voltage drop from the first switch to the second switch by using the measurement value of the power flow; a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting a measurement value of the first connection end voltage from the measurement value of the voltage and a value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting a measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop; a determination unit that estimates a connection end connected to the first distribution line, out of the first connection end and the second connection end, based on at least the first time correlation and the second time correlation; A power distribution grid state estimation system comprising:

2. The power flow measurement value includes active power and reactive power at the first switch, the voltage drop calculation unit calculates, as the value indicating the first voltage drop, a sum of a value obtained by multiplying a preset value indicating a resistance of the first distribution line by the active power and a value obtained by multiplying a preset value indicating a reactance of the first distribution line by the reactive power; The power grid state estimation system of claim 1 .

3. a display unit that, when the determination unit determines that the estimation result of the connection end connected to the first distribution line does not match a prestored connection relationship of the second switch with the first distribution line, displays a message notifying the user that the estimation result does not match. The power grid state estimation system of claim 1 .

4. the measurement value acquisition unit acquires measurement values ​​of a voltage and a power flow at a third switch installed on a second distribution line to which the other end of the second switch is connected; the voltage drop calculation unit calculates a value indicating a second voltage drop from the third switch to the second switch using a measurement value of a power flow at the third switch; the correlation calculation unit calculates a third time correlation between a value obtained by subtracting the measurement value of the first connection end voltage from the measurement value of the voltage at the third switch and a value indicating the second voltage drop, and calculates a fourth time correlation between a value obtained by subtracting the measurement value of the second connection end voltage from the measurement value of the voltage at the third switch and a value indicating the second voltage drop; the determination unit estimates a connection end connected to the first power distribution line, out of the first connection end and the second connection end, based on at least the first time correlation, the second time correlation, the third time correlation, and the fourth time correlation; The power distribution network state estimation system according to any one of claims 1 to 3.

5. a measurement value acquiring unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; a voltage drop calculation unit that calculates a value indicating a first voltage drop from the first switch to the second switch by using the measurement value of the power flow; a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting a measurement value of the first connection end voltage from the measurement value of the voltage and a value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting a measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop; a determination unit that estimates a connection end connected to the first distribution line, out of the first connection end and the second connection end, based on at least the first time correlation and the second time correlation; A power distribution network state estimating apparatus comprising:

6. acquiring measurement values ​​of voltage and power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; calculating a value indicating a first voltage drop from the first switch to the second switch using the power flow measurement; calculating a first time correlation between a value obtained by subtracting the measured value of the first connection end voltage from the measured value of the voltage and a value indicating the first voltage drop, and calculating a second time correlation between a value obtained by subtracting the measured value of the second connection end voltage from the measured value of the voltage and a value indicating the first voltage drop; estimating a connection end connected to the first distribution line, out of the first connection end and the second connection end, based on at least the first time correlation and the second time correlation; The power grid state estimation method includes:

7. Computer, a measurement value acquiring unit that acquires measurement values ​​of a voltage and a power flow at a first switch installed on a first distribution line, a measurement value of a first connection end voltage at a first connection end of a second switch having one end connected to the first distribution line, and a measurement value of a second connection end voltage at a second connection end of the second switch; a voltage drop calculation unit that calculates a value indicating a first voltage drop from the first switch to the second switch using the measured value of the power flow; a correlation calculation unit that calculates a first time correlation between a value obtained by subtracting a measurement value of the first connection end voltage from the measurement value of the voltage and a value indicating the first voltage drop, and calculates a second time correlation between a value obtained by subtracting a measurement value of the second connection end voltage from the measurement value of the voltage and the value indicating the first voltage drop; a determination unit that estimates a connection end connected to the first distribution line, out of the first connection end and the second connection end, based on at least the first time correlation and the second time correlation; A program to function as a

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