State estimation device, state estimation method, and state estimation program

Abstract

To provide a state estimation device, method and program for estimating a position of tapping of an automatic voltage regulator included in a power distribution system.SOLUTION: A state estimation device 2 for estimating a state of a section Ka in a power distribution system 1 including a power distribution line 11 and an automatic voltage regulator SVRa, which is connected to the power distribution line in series and capable of changing a power transformation ratio between a primary side and a secondary side by tapping, comprises: a determination unit by which, in a case where the section Ka consists of a switch SWa with sensor, a line 11a, the automatic voltage regulator SVRa and a switch SWb with sensor, the section Ka is determined in a first section and if such a determination is not made, the section Ka is determined as a second section; a first state estimation unit by which, in the case where the section Ka is determined as the first section, a state of a load (a user via nodes Na-Ni) in the first section and a position of the tapping are estimated according to a first method; and a second state estimation unit by which, in the case where the section Ka is determined as the second section, the state of the load in the second section and the position of the tapping are estimated according to a second method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a state estimation device, a state estimation method, and a state estimation program. [Background technology]

[0002] There are known techniques for estimating state values ​​such as voltage and current at each node of a power distribution system. For example, Patent Document 1 describes a method in which a power distribution system is divided into an observable subsystem and an unobservable subsystem, and a state value is uniquely estimated for the observable subsystem and a range of state values ​​is estimated for the unobservable subsystem. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6109326 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a power distribution system generally includes an automatic voltage regulator that is connected in series to a distribution line and that can change the transformation ratio between the primary side and the secondary side by a tap.

[0005] However, in the invention described in Patent Document 1, the tap position is not taken into consideration as a state value to be estimated.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a state estimation device capable of estimating the tap position of an automatic voltage regulator included in a power distribution system. [Means for solving the problem]

[0007] One invention for achieving the above object is a state estimation device that estimates a state of a section in a power distribution system including a distribution line and an automatic voltage regulator connected in series to the distribution line and capable of changing a transformation ratio between a primary side and a secondary side by a tap, the state estimation device including: a determination unit that determines the section to be a first section if the section comprises a first sensor for measuring power flow measurement values, a first line connected to the first sensor, one automatic voltage regulator connected to the first line, a second line connected to the automatic voltage regulator, and a second sensor for measuring power flow measurement values ​​connected to the second line, and determines the section to be a second section if the section is not determined to be the first section; a first state estimation unit that estimates a load state and a tap position in the first section by a first method if the section is determined to be the first section; and a second state estimation unit that estimates a load state and a tap position in the second section by a second method if the section is determined to be the second section. Other features of the present invention will become apparent from the description of this specification. [Effects of the Invention]

[0008] According to the present invention, it is possible to estimate the tap position of an automatic voltage regulator included in a power distribution system. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram for explaining a power distribution system and a state estimation device. [Figure 2] FIG. 2 is a diagram illustrating an example of a first section. [Figure 3] FIG. 10 is a diagram illustrating an example of a second section. [Figure 4] FIG. 10 is a diagram illustrating another example of the second section. [Figure 5] FIG. 2 is a diagram illustrating a hardware configuration of the state estimation device. [Figure 6] FIG. 2 is a diagram illustrating a configuration of a storage device. [Figure 7] FIG. 2 is a diagram illustrating functional blocks of the state estimation device. [Figure 8]FIG. 2 is a diagram illustrating a configuration of a state estimation unit. [Figure 9] 10 is a flowchart illustrating a process flow up to determining the classification of a section. [Figure 10] 10 is a flowchart illustrating the flow of processing up to estimating the state of a section classified as a first section. [Figure 11] 10 is a flowchart illustrating the flow of processing up to estimating the state of a section classified as a second section. [Figure 12] 10 is a flowchart illustrating the flow of processing up to estimating the state of a section classified as a second section. DETAILED DESCRIPTION OF THE INVENTION

[0010] == Implementation form == <Power distribution system> 1 is a diagram showing an example of a power distribution system 1 in which a state estimation device 2 performs state estimation. The power distribution system 1 is, for example, a high-voltage system of a 6.6 kV system, and in this embodiment includes a distribution substation 10, a distribution line 11, sensor-equipped switches SW (SWa and SWb), and automatic voltage regulators SVR (SVRa and SVRb). In addition, the distribution line 11 of the power distribution system 1 is provided with nodes N (Na to Ni) to which loads are connected.

[0011] [Distribution substation] The distribution substation 10 transforms the voltage supplied from a transmission line (not shown) and outputs a voltage of 6.6 kV to the distribution line 11.

[0012] [Power distribution lines] The distribution line 11 has the distribution substation 10 as its origin (sending node) and is connected to the distribution substation 10 in a radial manner.

[0013] [node] Nodes N (Na to Ni) are provided on the power distribution line 11. Nodes N are aggregation units managed on a pole transformer basis or a designated consumer basis. Power output from the distribution substation 10 to the power distribution line 11 is supplied to consumers (not shown) via nodes N.

[0014] Each consumer is a load of power. Consumers include facilities (for example, factories) that consume power supplied from the power distribution line 11. Therefore, the power distribution line 11 is connected to facilities that consume power from the power distribution line 11.

[0015] [Switch with sensor] The sensor-equipped switch SW is a measuring instrument that can measure the voltage, active power flow, and reactive power flow at the location where it is installed. Hereinafter, the voltage, active power flow, and reactive power flow phase measured by the sensor-equipped switch SW will be collectively referred to as "power flow measurement values" or "power flow measurement values."

[0016] The sensor-equipped switch SW periodically measures the voltage, active power flow, and reactive power flow at the point where it is installed. These measured values ​​are stored in a database (constructed in the storage device 203, for example).

[0017] The sensor-equipped switch SW is installed midway along the distribution line 11 and divides the distribution system 1 into a plurality of sections. As will be described in detail later, in this embodiment, the sections divided by the two sensor-equipped switches SWa and SWb are defined as section Ka and section Kb.

[0018] In addition, when a sensor-equipped switch SW is not installed at the end of the distribution system 1, as in section Kb, the section is defined as the section from the sensor-equipped switch SWa on the primary side (meaning the distribution substation 10 side of the distribution system 1) to the end. In other words, the end of the primary side of the section is always equipped with a sensor-equipped switch SW, and the end of the secondary side of the section (meaning the end side of the distribution system 1) is either equipped with a sensor-equipped switch SW or is the end of the distribution system 1.

[0019] In the power distribution system 1 of Fig. 1, section Ka is a section separated by the sensor-equipped switch SWa and the sensor-equipped switch SW2b. Section Ka includes nodes Na to Ne and an automatic voltage regulator SVRa. The automatic voltage regulator SVRa is installed between nodes Nc and Nd. Note that section Ka does not include the section branching from node Na and extending from node Na to node Ni.

[0020] Furthermore, section Kb is a section defined by the sensor-equipped switch SWa and the terminal node (node ​​Ni). Section Kb includes nodes Na, Nf to Ni and an automatic voltage regulator SVRb. The automatic voltage regulator SVRb is installed between the sensor-equipped switch SWf and node Ng.

[0021] [Automatic Voltage Regulator (SVR)] The automatic voltage regulators SVR (SVRa, SVRb) are devices that are connected in series to the distribution line 11 and compensate for voltage drops in the distribution line 11.

[0022] The automatic voltage regulator SVR can change the transformation ratio between the primary and secondary sides by tapping in response to fluctuations in the secondary side voltage, and adjusts the voltage at a predetermined point on the secondary side to a preset reference voltage. The automatic voltage regulator SVR of this embodiment uses the LDC (Line Drop Compensation) method as a tap position control method.

[0023] The automatic voltage regulator SVR does not output the tap position at each time to the outside. Therefore, the tap position of the automatic voltage regulator SVR is one of the state values ​​estimated by the state estimation device 2 described later.

[0024] <Classification of sections> As described above, the sensor-equipped switch SW is placed at the end of one section of the power distribution system 1, dividing the power distribution system 1 into multiple sections. Each of the multiple sections is classified as a first section or a second section depending on the configuration of the equipment in the section. Each section will be described below.

[0025] [Definition of the first section] The first section is a section consisting of a sensor for measuring power flow, a line, and one automatic voltage regulator (SVR). The first section includes two sensors and two lines.

[0026] In the first section, one of the two lines (corresponding to the first line) is connected to one of the two sensors (corresponding to the first sensor). An automatic voltage regulator SVR is connected to one of the lines. The other of the two lines (corresponding to the second line) is connected to the automatic voltage regulator SVR. The other of the two sensors (corresponding to the second sensor) is connected to the other line.

[0027] Here, one line is connected downstream of one sensor. An automatic voltage regulator (SVR) is connected downstream of one line. The other line is connected downstream of the automatic voltage regulator (SVR). The other sensor is connected downstream of the other line.

[0028] The definition of the first section can be rephrased as follows: The first section is a section that includes a sensor-equipped switch SW on both the line from the automatic voltage regulator SVR to the distribution substation 10 side and the line to the terminal side. The first section is also a section that does not include another automatic voltage regulator SVR on either the line from the automatic voltage regulator SVR to the sensor-equipped switch on the distribution substation 10 side or the line to the sensor-equipped switch on the terminal side.

[0029] The section that meets the above definition is defined as the "first section."

[0030] The "sensor that measures the tidal current measurement value" is, for example, a switch SW with a sensor, and in this embodiment, the description will be made assuming that it is a switch SW with a sensor.

[0031] 2 is a diagram showing section K1, which is an example of a section classified as section 1. Section K1 is a section separated by sensor-equipped switch SW1 and sensor-equipped switch SW2.

[0032] Section K1 includes sensor-equipped switch SW1, sensor-equipped switch SW2, automatic voltage regulator SVR1, line 111 from sensor-equipped switch SW1 to automatic voltage regulator SVR1, line 112 from automatic voltage regulator SVR1 to sensor-equipped switch SW2, and nodes N1 to N4. Automatic voltage regulator SVR1 is installed between node N2 and node N3.

[0033] That is, section K1 consists of sensor-equipped switch SW1, line 111 connected downstream of sensor-equipped switch SW1, automatic voltage regulator SVR1 connected downstream of line 111, line 112 connected downstream of automatic voltage regulator SVR1, and sensor-equipped switch SW2 connected downstream of line 112. Therefore, section K1 is a section classified as the first section.

[0034] [Second section definition] 3 is a diagram showing a section K2, which is an example of a section classified as a second section. A second section is a section that is not classified as a first section.

[0035] 3 is a diagram showing section K2, which is an example of a section classified as a second section. Section K2 is a section separated by the sensor-equipped switch SW3 and a terminal node (node ​​N7). Section K2 includes nodes N5 to N7 and an automatic voltage regulator SVR2. The automatic voltage regulator SVR2 is installed between the sensor-equipped switch SW3 and node N5.

[0036] In other words, section K2 is not a section that is classified as a first section because the sensor-equipped switch SW3 is installed only at one end and the sensor-equipped switch SW is not installed at both ends. Therefore, section K2 is a section that is classified as a second section.

[0037] 4 is a diagram showing section K3, which is another example of a section classified as section 2. Section K3 is a section separated by sensor-equipped switches SW4 and SW5.

[0038] Section K3 includes nodes N8 to N11 and two automatic voltage regulators SVR4 and SVR5. Automatic voltage regulator SVR4 is installed between sensor-equipped switch SW4 and node N8. Automatic voltage regulator SVR5 is installed between node N9 and node N10.

[0039] In other words, since section K3 is equipped with two automatic voltage regulators SVR (SVR4, SVR5), it is not classified as a section that falls under the first section. Therefore, section K3 is classified as a section that falls under the second section.

[0040] <State estimation method> A state estimation device 2, which will be described later, performs state estimation on a section to be estimated among a plurality of sections in the power distribution system 1. The state estimation device 2 performs state estimation using a state estimation method that differs depending on the classification of the section.

[0041] The state estimation device 2 performs state estimation using Method 1 (corresponding to the first method) when the section to be estimated is classified as the first section, and performs state estimation using Method 2 (corresponding to the second method) when the section to be estimated is classified as the second section. Before describing the configuration of the state estimation device 2, Method 1 and Method 2 will be described below.

[0042] [Method 1] Method 1 is a method for estimating the state value of a section based on power flow measurements at both ends of the section classified as the first section and a state equation. In this embodiment, the "state value of the section" includes the load state of the section and the tap position of the automatic voltage regulator included in the section. The "load state of the section" includes the active power load and reactive power load of each node in the section.

[0043] Method 1 includes two steps, in this order: state estimation and power flow calculation. Hereinafter, a detailed description will be given based on section K1 shown in Fig. 2, which is an example of the first section.

[0044] 1-1. State estimation At this stage, the following generalized equation of state (Equation 1) is used:

[0045]

number

number

number

[0046] Here, y in Equation 2 is the power flow measurement value of the sensor-equipped switch SW that is the measurement target. v1s and v2s are the measured voltage values ​​of the sensor-equipped switches SW1 and SW2, respectively, p1s and p2s are the measured active power flows of the sensor-equipped switches SW1 and SW2, respectively, and q1s and q2s are the measured reactive power flows of the sensor-equipped switches SW1 and SW2, respectively.

[0047] Furthermore, x in Equation 3 is the state value of the section to be estimated. In Equation 3, P1 to P4 are the active power loads of nodes N1 to N4, respectively, Q1 to Q4 are the reactive power loads of nodes N1 to N4, respectively, and t is the tap position of automatic voltage regulator SVR1.

[0048] In Method 1, a solution for the state value x in section K1 can be uniquely obtained based on the state equation (Formula 1) and the measured value y (Formula 2). In this case, by using, for example, the least squares method, the state value x in section K1 can be uniquely calculated by searching for the state value x0 in section K1 that minimizes the evaluation function g in the following Formula 4.

[0049]

number

number

[0050] 1-2. Tidal flow calculation At this stage, the voltage distribution and power flow distribution of the section K1 are calculated based on the state value x of the section K1 obtained in 1-1. State Estimation, based on the following Equations 6 to 9.

[0051]

number

number

number

number

[0052] Here, the subscripts i and j correspond to points in the section. In this example, "points in the section" correspond to points in section K1 where sensor-equipped switches SW1 and SW2 are installed, or points where nodes N1 to N4 are installed.

[0053] When the subscript i corresponds to the point of the sensor-equipped switch SW1 or SW2, the subscript i is set to 1s or 2s, respectively. When the subscript i corresponds to the nodes N1 to N4, the subscript i is set to 1 to 4, respectively. The same applies to the subscript j.

[0054] P in Equations 6 and 7 i and Q i are the active and reactive power loads at point i, respectively. V i and θ i are the amplitude and phase of the voltage at point i, respectively. ij and q ij are the active and reactive power flows from point i to j, respectively.

[0055] G in formulas 6 to 9 ijis the admittance matrix Y ij is the real part of the conductance. B ij is the admittance matrix Y ij is the imaginary part of the equation and is the susceptance.

[0056]

number

[0057] where t ij is the tap position of the automatic voltage regulator SVR when an automatic voltage regulator SVR is installed between points i and j. In other words, each element of the admittance matrix depends on the tap position. Note that when an automatic voltage regulator SVR is not installed between points i and j, the element Y ij is the tap position t ij does not depend on

[0058] In addition, in Equations 6 to 9, the conductance G ij and susceptance B ij At the tap position t ij is omitted.

[0059] Furthermore, from the above explanation, the following correspondences hold in Equations 2, 8, and 9.

[0060]

number

number

number

number

[0061] The above has explained 1-1. State estimation and 1-2. Power flow calculation. By the above procedures, the state value, voltage distribution, and power flow distribution of the first section can be estimated.

[0062] [Method 2] When a section is classified as a second section, the above-described method 1 cannot uniquely estimate the section's state value. For example, in section K2 shown in Figure 3, a sensor-equipped switch SW is not installed at the downstream end, so the required number of conditions cannot be obtained for the number of section state values ​​to be estimated. Also, in section K3 shown in Figure 4, the tap positions of two automatic voltage regulators must be estimated, so the number of section state values ​​to be estimated is excessive compared to the number of conditions that can be obtained. In cases like these, the section's state value cannot be uniquely estimated.

[0063] Therefore, in Method 2, the state value of the section is estimated based on the power flow measurement value at least at the upstream end of the second section, the state equation, and information on the control method for the tap position of the automatic voltage regulator SVR.

[0064] Method 2 includes three steps in this order: load state estimation, power flow calculation, and tap position estimation. This will be described in detail below based on section K2 shown in Figure 3, which is an example of the second section.

[0065] 2-1. Estimation of load conditions In this stage, the tap position is not set as the state value of the section K2 to be estimated, but the state of the load in the section K2 is estimated with the tap position fixed at a predetermined value (initial value). In this stage, the following generalized state equation (Equation 15) is used.

[0066]

number

number

number

[0067] In this stage, similar to Method 1, the fixed tap position t of x (Equation 17) is calculated based on the state equation (Equation 15) and the measured value y (Equation 16). ini In this case, as in Method 1, by using, for example, the least squares method, searching for the state value x0 that minimizes the evaluation function g similar to the above-mentioned Equation 4, the fixed tap position t ini It is possible to uniquely calculate the state value excluding

[0068] 2-2. Tidal flow calculation At this stage, power flow calculation is performed based on the state values ​​of section K2 obtained in 2-1. Load State Estimation, and the power flow distribution in section K2 is calculated. The power flow calculation here can be performed using the same procedure as in 1-2. Power Flow Calculation.

[0069] 2-3.Voltage calculation At this stage, the state value x of the section K2 is calculated based on the fixed tap position t ini Based on the state values ​​excluding (a), the voltage at a predetermined target point (corresponding to the second point) on the secondary side of the automatic voltage regulator SVR2 is calculated.

[0070] Specifically, the voltage at the target point (corresponding to the second voltage) is calculated based on the voltage (corresponding to the first voltage) at a specified point (corresponding to the first point) on the secondary side of the automatic voltage regulator SVR2 from the calculation results and the amount of voltage drop from the specified point to the target point downstream, which is obtained from a specified formula in the information related to the control method.

[0071] Here, the predetermined point on the secondary side of the automatic voltage regulator SVR2 may be, for example, a point at node N3 adjacent to the secondary side of the automatic voltage regulator SVR, and the target point may be a point downstream a preset distance from the automatic voltage regulator SVR.

[0072] As described above, the automatic voltage regulator SVR2 of this embodiment employs the LDC method as the tap position control method. In this case, the "predetermined formula for information related to the control method" is the following formula 18.

[0073]

number

[0074] Equation 18 is the voltage v at the target point on the secondary side of the automatic voltage regulator SVR2. S2 This is the formula to calculate v SVR2 is the voltage at a given point on the secondary side of the automatic voltage regulator SVR2. R2 and X2 are the resistance and reactance from the given point to the target point, respectively. P SVR2 and Q SVR2 are the active power flow and reactive power flow on the secondary side of the automatic voltage regulator SVR2, respectively.

[0075] In Equation 18, the sum of the second and third terms on the right side is the amount of voltage drop from a predetermined point on the distribution line 11 to the target point.

[0076] 2-4. Tap position estimation At this stage, the voltage v calculated in 2-3. Voltage Calculation S2 Based on the difference between the reference voltage included in the control method information and the voltage v S2 The tap position of the automatic voltage regulator SVR2 is estimated by simulating the LCD method so that is the reference voltage.

[0077] The tap position estimated by the above procedure is called the updated tap position t new (corresponding to the second position). The updated tap position t new is the tap position that the automatic voltage regulator SVR2 would have actually changed if the actual load state of the section K2 was the state obtained in the above 2-1. Estimation of the load state. In other words, the updated tap position t new is the initial value t ini It can be expected that the value is closer to the actual tap position than

[0078] We have explained 2-1. Load state estimation, 2-2. Power flow calculation, 2-3. Voltage calculation, and 2-4. Tap position estimation above. These steps constitute one cycle, and by repeating this cycle, it is possible to obtain a tap position that is closer to the actual tap position. This process is called "convergence calculation" and will be explained in detail below.

[0079] 2-5. Convergence calculation 2-4. Tap position t of automatic voltage regulator SVR2 obtained by estimating the tap position new Once again, ini Then, execute steps 2-1. Load state estimation to 2-4. Tap position estimation again, and the updated tap position t new Then, we repeat this process.

[0080] This repetition may continue until a predetermined number of times is reached, or the repetition may be repeated until the updated tap position t new is the initial value t ini This may be continued until the tap position in the section K2 classified as the second section is estimated with higher accuracy.

[0081] As described above, by classifying the sections of the power distribution system 1 into the first section or the second section and estimating the state using a method corresponding to each classification, the tap position of the automatic voltage regulator SVR can be estimated.

[0082] <State Estimation Device> The state estimation device 2 is a device that estimates the state of a section in the power distribution system 1. The hardware configuration and functional blocks of the state estimation device will be described below.

[0083] Hardware configuration of the state estimation device 5 is a diagram showing the hardware configuration of a state estimation device 2 according to one embodiment of the present invention. The state estimation device 2 is a computer having a CPU (Central Processing Unit) 200, a memory 201, a communication device 202, a storage device 203, an input device 204, an output device 205, and a recording medium reader 206.

[0084] The CPU 200 executes the state estimation program 3 stored in the memory 201 or the storage device 203 to realize various functions of the state estimation device 2 .

[0085] The memory 201 is, for example, a RAM (Random-Access Memory) and is used as a temporary storage area for various programs, data, and the like.

[0086] The storage device 203 is a non-transitory (eg, non-volatile) storage device that stores various data to be executed or processed by the CPU 200.

[0087] FIG. 6 shows how the state estimation program 3 and the system information table 4 are stored in the storage device 203.

[0088] Various functions of the state estimation device 2 are realized by reading out various data such as the state estimation program 3 and the system information table 4 stored in the storage device 203 into the memory 201 and executing or processing them by the CPU 200.

[0089] The state estimation program 3 is a general term for programs for realizing the functions of the state estimation device 2 according to this embodiment, and includes, for example, application programs, an OS (Operating System), various libraries, etc. that run on the state estimation device 2.

[0090] The system information table 4 is a table in which the configuration of the power distribution system 1, the electrical characteristics of the devices that make up the power distribution system 1, and the like are recorded.

[0091] The system information table 4 stores data required for simulating the power distribution system 1 using equations such as state equations and power flow equations.

[0092] The input device 204 is a device that accepts commands and data input by the user, and includes an input interface such as a keyboard and a touch sensor that detects a touch position on a touch panel display.

[0093] The output device 205 is, for example, a display or a printer.

[0094] The communication device 202 exchanges various programs and data with other computers via the network 5 .

[0095] The recording medium reader 206 reads various data such as the state estimation program 3 and the system information table 4 recorded on the recording medium 6 such as an SD card, DVD, or CD-ROM, and stores the data in the storage device 203 .

[0096] State estimator function block 6 is a diagram showing functional blocks of the state estimation device 2. The state estimation device 2 includes an acquisition unit 210, a determination unit 211, a state estimation unit 212 (corresponding to a first state estimation unit), a state estimation unit 213 (corresponding to a second state estimation unit), and an output unit 214.

[0097] These functions are realized by the hardware of the state estimation device 2 executing a state estimation program 3 according to this embodiment.

[0098] [Acquisition unit 210] The acquisition unit 210 refers to the system information table 4 and acquires the configuration of the section to be estimated and the electrical characteristics of the section. The "configuration of the section" refers to, for example, the number and arrangement of sensor-equipped switches, nodes, and automatic voltage regulators (SVRs) in the section. The "electrical characteristics of the section" refers to the admittance matrix (Equation 10), resistance, reactance (Equation 18), etc. in the section.

[0099] [Determination unit 211] The determining unit 211 determines, based on the configuration of the section acquired by the acquiring unit 210, whether the section to be estimated is a first section or a second section.

[0100] Specifically, when the section to be estimated meets the definition of the first section described above, the determination unit 211 determines the section to be the first section. On the other hand, when the determination unit 211 does not determine the section to be the first section, the determination unit 211 determines the section to be the second section.

[0101] In the following description, the "sensor for measuring the power flow measurement value" is the sensor-equipped switch SW.

[0102] [State Estimation Unit 212] The state estimation unit 212 estimates the state values ​​(load state and tap position) of the first section when the determination unit 211 determines that the section to be estimated is the first section. At this time, the state estimation unit 212 estimates the state values ​​of the section by the above-mentioned method 1.

[0103] The state estimation unit 212 includes an acquisition unit 212a and an estimation unit 212b, each of which will be described below.

[0104] ·Acquisition unit 212a The acquisition unit 212a acquires the power flow measurement values ​​from the sensor-equipped switches SW installed at both ends of the first section (Equation 2).

[0105] ·Estimation section 212b The estimation unit 212b estimates the state of the section by the above-mentioned method 1 (1-1. Estimation of state). That is, the estimation unit 212b estimates the state of the first section (the state of the load and the tap position of the automatic voltage regulator SVR) by solving the above-mentioned formulas 1 to 3.

[0106] The estimation unit 212b may further calculate the voltage distribution and power flow distribution in the first section based on the obtained load state in the first section, the tap position of the automatic voltage regulator SVR, and Equations 6 to 9 (1-2. Power flow calculation).

[0107] [State estimation unit 213] The state estimation unit 213 estimates the state values ​​(load state and tap position) of the second section when the determination unit 211 determines that the section to be estimated is the second section. At this time, the state estimation unit 213 estimates the state values ​​of the section by the above-mentioned method 2.

[0108] 8 is a diagram showing the configuration of the state estimation unit. State estimation unit 213 includes an acquisition unit 213a, an estimation unit 213b (corresponding to a first estimation unit), a power flow calculation unit 213c, an estimation unit 213d (corresponding to a second estimation unit), a determination unit 213e (corresponding to a first determination unit), a determination unit 213f (corresponding to a second determination unit), a voltage calculation unit 213g, and a position estimation unit 213h. Each of these will be described below.

[0109] ·Acquisition unit 213a The acquisition unit 213a acquires the power flow measurement value from the sensor-equipped switch SW in the second section (Equation 16). The acquisition unit 213a acquires the power flow measurement value at the end of section K of the power distribution system 1. As described above, in this embodiment, the acquisition unit 213a acquires the power flow measurement value from the sensor-equipped switch SW at regular intervals.

[0110] ·Estimation section 213b The estimation unit 213b estimates the current measurement value acquired by the acquisition unit 213a and the predetermined initial position t ini (corresponding to the first position) and the load state of the second section is estimated using (2-1. Estimation of load state).

[0111] Specifically, the estimation unit 213b estimates the tap position from the initial position t ini With the load state of the second section fixed at , the load state of the second section is estimated by solving the above-mentioned equations 15 to 17.

[0112] When the convergence calculation described above is performed (2-5. Convergence Calculation), the estimation unit 213b calculates the updated position t new (the tap position estimated by the estimation unit 213d described later) is reset to the initial position t iniThe load state of the second section is estimated as follows.

[0113] At this time, the estimation unit 213b calculates the initial position t ini and the updated position t new If they are not the same, the updated position of the tap t new Let us recalculate the initial position t ini The load state of the second section is estimated as follows.

[0114] ·Tide flow calculation section 213c The power flow calculation unit 213c performs power flow calculation for the second section based on the estimation result of the estimation unit 213b (2-2. Power flow calculation). That is, the power flow calculation unit calculates the power flow distribution for the second section using the estimation result of the estimation unit 213b and equations obtained by applying the above-mentioned equations 4 to 7 to the second section.

[0115] ·Estimation part 213d The estimation unit 213d estimates the tap position based on the calculation result of the power flow calculation unit 213c and information on the control method for the tap position of the automatic voltage regulator SVR (2-4. Estimation of tap position). The estimated tap position is the updated position t new is.

[0116] ·Judgment unit 213e When the convergence calculation is performed (2-5. Convergence Calculation), the determination unit 213e determines the initial position t ini and the updated position of the tap, t new If it is determined that they are the same, the determining unit 213e ends the iteration of the convergence calculation and updates the tap position t new is set as the tap position. If the determining unit 213e determines that they are not the same, it continues the iteration of the convergence calculation.

[0117] ·Judgment unit 213f When the convergence calculation is performed (2-5. Convergence Calculation), the determination unit 213f determines the initial position t ini and the updated position of the tap, t newWhen it is determined that the number of times that the tap position t is not the same as the predetermined number of times has passed, the determining unit 213f ends the iteration of the convergence calculation and updates the tap position t new is set as the tap position. Furthermore, when the determining unit 213f determines that the predetermined number of times has not been reached, it continues the iteration of the convergence calculation.

[0118] Voltage calculation unit 213g The voltage calculation unit 213g calculates the state value x of the section at the fixed tap position t ini Based on the state values ​​excluding (a), the voltage at a predetermined target point on the secondary side of the automatic voltage regulator SVR is calculated (2-3. Voltage calculation).

[0119] Specifically, the voltage calculation unit 213g calculates the voltage v at a predetermined point (corresponding to the first point) on the secondary side of the automatic voltage regulator SVR from the calculation results. SVR2 (corresponding to the first voltage) and the voltage drop amount from the predetermined point to the downstream target point (corresponding to the second point) obtained from a predetermined formula (Formula 18) of the information on the control method, S2 (corresponding to the second voltage) is calculated.

[0120] ·Position estimation part 213h The position estimation unit 213h estimates the voltage v S2 Based on the difference between the reference voltage included in the information about the control method and the voltage v2 at the target point, the tap position is estimated so that the voltage v2 at the target point becomes the reference voltage (2-4. Estimation of Tap Position). The estimated tap position is called the updated position t new Let's say.

[0121] [Output section 214] The output unit 214 outputs the state value of the section estimated by the state estimation unit 212 or the state estimation unit 213.

[0122] With the above configuration, the sections of the power distribution system 1 are classified into first sections or second sections, and the state is estimated using a method according to each classification, thereby making it possible to estimate the tap position.

[0123] <Processing up to determining the section classification> 9 is a flowchart illustrating the flow of processing up to when the state estimation device 2 determines the classification of a section. This processing includes steps S101 to S103. Here, this processing will be explained using the power distribution system 1 shown in FIG. 1 as an example.

[0124] First, in step S101, the acquisition unit 210 refers to the system information table 4 and acquires the configuration of the section to be estimated.

[0125] In this example, if the section to be estimated is section Ka, the acquisition unit 210 acquires data indicating the relative positions of the sensor-equipped switch SW (SWa, SWb), automatic voltage regulator SVRa, and nodes Na to Ne. On the other hand, if the section to be estimated is section Kb, the acquisition unit 210 acquires data indicating the relative positions of the sensor-equipped switch SW (SWa), automatic voltage regulator SVRb, and nodes Na, Nf to Ne.

[0126] Next, in step S102, the determination unit 211 determines whether or not the section is the first section based on the configuration of the section acquired by the acquisition unit 210 in step S101 and the definition of the first section described above.

[0127] In this example, if the section to be estimated is section Ka, section Ka consists of a sensor-equipped switch SWa, a line 11a connected to the sensor-equipped switch SWa, one automatic voltage regulator SVRa connected to line 11a, a line 11b connected to the automatic voltage regulator SVRa, and a sensor-equipped switch SWb connected to line 11b, and therefore the determination unit 211 determines that section Ka is the first section.

[0128] In step S102, if the determination unit 211 determines that the section is not the first section (S102: N), the process proceeds to step S103. In step S103, the determination unit 211 determines that the section to be estimated is the second section, and ends the process.

[0129] In step S102, if the determining unit 211 determines that the section is the first section (S102: Y), the section to be estimated is determined to be the first section, and the process ends.

[0130] <Processing up to estimating the state of the section classified as the first section> 10 is a flowchart illustrating the flow of processing up to estimating the state of a section classified as the first section. This processing includes steps S201 to S203. Here, this processing will be explained using section Kb of the power distribution system 1 shown in FIG. 1 as an example. As described above, section Ka is a section classified as the first section.

[0131] First, in step S201, the acquisition unit 212a acquires power flow measurement values ​​from the sensor-equipped switches SW installed at both ends of the section classified as the first section.

[0132] In this example, the acquisition unit 212a acquires power flow measurement values ​​from each of the sensor-equipped switches SW (SWa, SWb) installed at both ends of the section Ka.

[0133] Next, in step S202, the estimation unit 212b estimates the load state of the section and the tap position of the automatic voltage regulator SVR.

[0134] In this example, the estimation unit 212b estimates the active power load and reactive power load at each of the nodes Na to Ne in the section Ka, as well as the tap position of the automatic voltage regulator SVRa, by the above-described method 1 (1-1. State estimation).

[0135] Next, in step S203, the output unit 214 outputs the state of the section estimated by the estimation unit 212b in step S202, and the process ends.

[0136] In this example, the output unit 214 outputs the state of the section Ka (the active power loads and reactive power loads at each of the nodes Na to Ne and the tap positions of the automatic voltage regulator SVRa), and then ends the process.

[0137] <Processing up to estimating the state of the section classified as the second section> 11 is a flowchart illustrating the flow of processing up to estimating the state of a section classified as a second section. This processing includes steps S301 to S307. Here, this processing will be explained using section Kb of the power distribution system 1 shown in FIG. 1 as an example. As described above, section Kb is a section classified as a second section.

[0138] First, in step S301, the acquisition unit 213a acquires the power flow measurement value of the sensor-equipped switch SW on the upstream side of the section classified as the second section.

[0139] In this example, the acquisition unit 213a acquires a power flow measurement value from the sensor-equipped switch SWa installed at the upstream end of the section Kb.

[0140] Next, in step S302, the estimation unit 213b estimates the predetermined initial position t ini Set.

[0141] In this example, the tap position of the automatic voltage regulator SVRb is set. The tap position to be set at this time may be any position. For example, the tap position that results in an intermediate transformation ratio within the range between the minimum and maximum transformation ratios is set as the initial position t ini Let's say.

[0142] Next, in step S303, the estimation unit 213b calculates the tap position from the initial position t ini The load state of the section is estimated with the load fixed at .

[0143] In this example, the estimation unit 213b estimates the tap position as the initial position t ini With the load currents fixed at , the active power loads and reactive power loads at the nodes Na and Nf to Ni are estimated (2-1. Load estimation above).

[0144] Next, in step S304, the power flow calculation unit 213c performs power flow calculation for the section being estimated based on the estimation result by the estimation unit 213b in step S303.

[0145] In this example, the power flow calculation unit 213c performs power flow calculation for the section Kb based on the active power loads and reactive power loads at each of the nodes Na, Nf to Ni estimated in step S303 (2-2. Power flow calculation above).

[0146] Next, in step S305, the voltage calculation unit 213g calculates the voltage at a predetermined target point on the secondary side of the automatic voltage regulator SVR based on the calculation result of the power flow calculation unit 213c in step S304.

[0147] In this example, the voltage calculation unit 213g calculates the voltage at a predetermined target point on the secondary side of the automatic voltage regulator SVRb based on the calculation result of the power flow calculation unit 213c in step S304.

[0148] Next, in step S306, the position estimation unit 213h calculates the voltage v of the target point based on the difference between the voltage v2 of the target point and the reference voltage included in the information related to the control method. S2 The tap position is estimated so that the reference voltage is t. The estimated tap position is then called the updated position t new Let's say.

[0149] In this example, the position estimation unit 213h estimates the tap position of the automatic voltage regulator SVRb.

[0150] Next, in step S307, the output unit 214 outputs the state of the section (load state and tap position) estimated by the estimation unit 213d and the position estimation unit 213h, and the process ends.

[0151] In this example, the output unit 214 outputs the state of section Kb (active power loads and reactive power loads at each of nodes Na and Nf to Ni, and the tap position of automatic voltage regulator SVRb), and then ends the process.

[0152] <Processing until the state of the section classified as the second section is estimated (convergence calculation)> 12 is a flowchart illustrating the process flow up to estimating the state of a section classified as the second section, and is a flowchart for performing convergence calculations. This process includes steps S401 to S409. Here again, this process will be described using section Kb of the power distribution system 1 shown in FIG. 1 as an example.

[0153] Here, steps S401 to S406 are the same processes as steps S301 to S306 described above, respectively, and therefore a description thereof will be omitted.

[0154] In step S407, the determination unit 213e determines the initial position t ini and the updated position of the tap, t new It is determined whether or not the values ​​are the same.

[0155] In this example, the determination unit 213e determines the initial tap position t ini and the updated position of the tap, t new It is determined whether or not the values ​​are the same.

[0156] In step S407, if the determining unit 213e determines that they are not the same (S407: N), the process proceeds to step S408. In step S407, if the determining unit 213e determines that they are the same (S407: Y), the process proceeds to step S409.

[0157] In step S408, the determination unit 213f determines the initial position t ini and the updated position of the tap, t new It is determined whether the number of times that the number of times is not the same reaches a predetermined number.

[0158] In step S408, if the determining unit 213f determines that the number of times that the taps are not the same is less than the predetermined number of times (S408: Y), the process returns to step S403. ini The updated position of the tap t new Let's say.

[0159] In step S408, if the determining unit 213f determines that the number of times that the values ​​are not the same has reached the predetermined number (S408: N), the process proceeds to step S409.

[0160] In step S409, the output unit 214 outputs the state of the section (load state and tap position) estimated by the estimation unit 213d and the position estimation unit 213h, and the process ends.

[0161] In this example, the output unit 214 outputs the state of section Kb (active power loads and reactive power loads at each of nodes Na and Nf to Ni, and the tap position of automatic voltage regulator SVRb), and then ends the process.

[0162] By the above processing, it becomes possible to estimate the tap position of the automatic voltage regulator SVRb included in the power distribution system 1.

[0163] In the above embodiment, the section Kb shown in Fig. 1 has been taken as an example for explanation. Note that even in the section K3 classified as the second section shown in Fig. 4, the state estimation device 2 that executes the process based on the above method 2 can uniquely estimate the state of section K3 (i.e., the load state and the tap positions of each of the automatic voltage regulators SVR3 and SVR4).

[0164] Specifically, when the processing shown in FIG. 11 is applied to section K3, in step S301, the acquisition unit 213a acquires the power flow measurement values ​​from the sensor-equipped switches SW (SW4, SW5) installed at the upstream end of section K3.

[0165] Next, in step S302, the initial tap positions of the automatic voltage regulators SVR (SVR4, SVR5) are set. The initial tap positions t ini4 , t ini5 can be any value, as in the case of the section Kb.

[0166] Next, in step S303, the estimation unit 213b calculates the initial positions of the taps of the automatic voltage regulators SVR (SVR4, SVR5) as t ini4 , t ini5 With the load current fixed at , the active power load and reactive power load at each of the nodes N8 to N11 are estimated (2-1. Load estimation above).

[0167] Next, in step S304, power flow calculation unit 213c performs power flow calculation for section K3 based on the active power loads and reactive power loads at each of nodes N8 to N11 estimated in step S303 (2-2. Power flow calculation above).

[0168] Next, in step S305, the voltage calculation unit 213g calculates the voltages of predetermined target points on the secondary sides of the automatic voltage regulators SVR4 and SVR5 based on the calculation results of the power flow calculation unit 213c in step S304 (2-3. Voltage calculation above).

[0169] Next, in step S306, the position estimation unit 213h estimates the tap positions for each of the automatic voltage regulators SVR4 and SVR5 based on the difference between the voltage at the target point and the reference voltage included in the information on the control method, so that the voltage at the target point becomes the reference voltage. The tap positions at this time are referred to as the updated tap positions t new4 , t new5 Let's say.

[0170] Furthermore, when the convergence calculation process shown in FIG. 12 is applied to section K3, in step 407, it is determined whether the initial tap position and the updated tap position are the same for each of the automatic voltage regulators SVR4 and SVR5.

[0171] At this time, if the initial tap positions and updated tap positions for both automatic voltage regulators SVR4 and SVR5 are the same (S408: Y), the process proceeds to step S409; otherwise, the process proceeds to step S408.

[0172] ==Summary== As described above, the state estimation device 2 of the embodiment is a state estimation device 2 that estimates the state of a section in a power distribution system 1 that includes a distribution line 11 and an automatic voltage regulator SVR that is connected in series to the distribution line 11 and is capable of changing the transformation ratio between the primary side and the secondary side by a tap, and includes: a determination unit 211 that determines the section to be the first section if the section meets the definition of a first section, and determines the section to be the second section if the section is not determined to be the first section; a state estimation unit 212 that estimates the load state and tap position in the first section by a first method if the section is determined to be the first section; and a state estimation unit 213 that estimates the load state and tap position in the second section by a second method if the section is determined to be the second section.

[0173] According to this configuration, the sections of the power distribution system 1 are classified into first sections or second sections, and the state is estimated using a method according to each classification, thereby making it possible to estimate the tap position.

[0174] In the state estimation device 2, the state estimation unit 213 includes an acquisition unit 213a that acquires power flow measurement values ​​from a sensor on the upstream side of the second section, an estimation unit 213b that estimates the load state in the second section using the power flow measurement values ​​acquired by the acquisition unit 213a and a first position indicating the tap position, a power flow calculation unit that performs power flow calculation for the second section based on the estimation result of the estimation unit 213b, and an estimation unit 213d that estimates the second tap position based on the calculation result of the power flow calculation unit and information about the control method for the tap position of the automatic voltage regulator SVR. With this configuration, the tap position can be uniquely estimated not only in the first section but also in the second section.

[0175] In the state estimation device 2, the state estimation unit 213 further includes a determination unit 213e that determines whether the first position and the second position are the same, and if the first position and the second position are not the same, the estimation unit 213b estimates the load state in the second section by assuming the tap position estimated by the estimation unit 213d as the first position. With this configuration, the tap position can be estimated with high accuracy in estimating the state value in the second section.

[0176] In the state estimation device 2, the state estimation unit 213 further includes a determination unit 213f that determines whether the number of times the first position and the second position are not the same has reached a predetermined number, and if the number is less than the predetermined number, the estimation unit 213b estimates the load state in the second section by assuming the tap position estimated by the estimation unit 213d as the first position. With this configuration, the tap position can be estimated with greater accuracy in estimating the second section.

[0177] In the state estimation device 2, the estimation unit 213d includes: a voltage calculation unit 213g that calculates a second voltage at a predetermined point based on a first voltage at a first point on the secondary side of the automatic voltage regulator SVR among the calculation results and an amount of voltage drop from the first point to a second point downstream obtained from a predetermined equation in the information related to the control method; and a position estimation unit 213h that estimates a second position based on the difference between the second voltage and a reference voltage included in the information related to the control method so that the second voltage becomes the reference voltage. With this configuration, it is possible to easily estimate the tap position in estimation of the second section.

[0178] The state estimation method of the embodiment is a state estimation method for estimating the state of a section in a power distribution system 1 that includes a distribution line 11 and an automatic voltage regulator SVR that is connected in series to the distribution line 11 and whose transformation ratio between the primary side and the secondary side can be changed by a tap, and includes the steps of: determining the section as a first section if the section meets the definition of a first section; and determining the section as a second section if the section is not determined to be the first section; estimating the load state and tap position in the first section using the first method if the section is determined to be the second section; and estimating the load state and tap position in the second section using the second method if the section is determined to be the second section.

[0179] According to this method, the sections of the power distribution system 1 are classified into first sections or second sections, and the state is estimated using a method according to each classification, thereby making it possible to estimate the tap position.

[0180] The state estimation program of the embodiment is a state estimation program that estimates the state of a section in a power distribution system 1 that includes a distribution line 11 and an automatic voltage regulator SVR that is connected in series to the distribution line 11 and whose transformation ratio between the primary side and the secondary side can be changed by a tap, and causes a computer to realize: a determination unit 211 that determines the section to be the first section if the section meets the definition of a first section, and that determines the section to be the second section if the section is not determined to be the first section; a state estimation unit 212 that estimates the load state and tap position in the first section by a first method if the section is determined to be the first section; and a state estimation unit 213 that estimates the load state and tap position in the second section by a second method if the section is determined to be the second section.

[0181] According to such a program, the sections of the power distribution system 1 are classified into first sections or second sections, and the state is estimated using a method according to each classification, thereby making it possible to estimate the tap position. [Explanation of symbols]

[0182] 1:Power distribution system 10: Distribution substation 11: Power lines 2: State estimator 200:CPU 201: Memory 202: Communication equipment 203: Storage device 204: Input device 205: Output device 206: Recording medium reader 210: Acquisition Department 211: Judgment Department 212: State estimation unit 212a: Acquisition part 212b: Estimation part 213: State estimation unit 213a: Acquisition part 213b: Estimation part 213c: Tidal flow calculation section 213d: Estimation section 213e: Judgment section 213f: Judgment section 213g: Voltage calculation section 213h:Position estimation part 214: Output section 3: State estimation program 4: Lineage information table 5: Network 6: Recording media

Claims

1. A state estimation device that estimates a state of a section in a power distribution system including a distribution line and an automatic voltage regulator that is connected in series to the distribution line and is capable of changing a transformation ratio between a primary side and a secondary side by a tap, comprising: a determination unit that determines the section as a first section when the section comprises a first sensor for measuring power flow measurement values, a first line connected to the first sensor, one automatic voltage regulator connected to the first line, a second line connected to the automatic voltage regulator, and a second sensor for measuring power flow measurement values ​​connected to the second line, and that determines the section as a second section when the section is not determined to be the first section; a first state estimation unit that, when the section is determined to be the first section, estimates a load state and a tap position in the first section by a first method; a second state estimation unit that, when the section is determined to be the second section, estimates a load state and a tap position in the second section by a second method; A state estimation device comprising:

2. 2. The state estimation device according to claim 1, The second state estimation unit an acquisition unit that acquires tidal current measurement values ​​from a sensor on the upstream side of the second section; a first estimation unit that estimates a load state in the second section using the power flow measurement value acquired by the acquisition unit and a first position that indicates a position of the tap; a power flow calculation unit that performs a power flow calculation for the second section based on the estimation result of the first estimation unit; and a second estimation unit that estimates a second position of the tap based on a calculation result of the power flow calculation unit and information related to a control method for the tap position of the automatic voltage regulator; A state estimation device comprising:

3. 3. The state estimation device according to claim 2, The second state estimation unit a first determination unit that determines whether the first position and the second position are the same; The first estimation unit If the first position and the second position are not the same, the position of the tap estimated by the second estimation unit is set as the first position, and the load state of the second section is estimated. State estimator.

4. 4. The state estimation device according to claim 3, The second state estimation unit a second determination unit that determines whether the number of times the first position and the second position are not the same has reached a predetermined number, The first estimation unit If the number of times is less than the predetermined number of times, the position of the tap estimated by the second estimation unit is set as the first position, and the load state of the second section is estimated. State estimator.

5. The state estimation device according to any one of claims 2 to 4, The second estimation unit a voltage calculation unit that calculates a second voltage at the second point based on a first voltage at a first point on the secondary side of the automatic voltage regulator among the calculation results and a voltage drop amount from the first point to a second point downstream, the voltage drop amount being obtained from a predetermined equation of information related to the control method; a position estimation unit that estimates the second position based on a difference between the second voltage and a reference voltage included in the information related to the control method so that the second voltage becomes the reference voltage; A state estimation device comprising:

6. A state estimation method for estimating a state of a section in a power distribution system including a distribution line and an automatic voltage regulator connected in series to the distribution line and capable of changing a transformation ratio between a primary side and a secondary side by a tap, comprising: The computer a step of determining the section as a first section when the section comprises a first sensor for measuring a power flow measurement value, a first line connected to the first sensor, one automatic voltage regulator connected to the first line, a second line connected to the automatic voltage regulator, and a second sensor for measuring a power flow measurement value connected to the second line, and determining the section as a second section when the section is not determined to be the first section; When the section is determined to be the first section, estimating the load state and the position of the tap in the first section by a first method; If the section is determined to be the second section, estimating the load state and the position of the tap in the second section by a second method; A state estimation method including:

7. A state estimation program for estimating a state of a section in a power distribution system including a distribution line and an automatic voltage regulator connected in series to the distribution line and capable of changing a transformation ratio between a primary side and a secondary side by a tap, the program comprising: On the computer, a determination unit that determines the section as a first section when the section comprises a first sensor for measuring power flow measurement values, a first line connected to the first sensor, one automatic voltage regulator connected to the first line, a second line connected to the automatic voltage regulator, and a second sensor for measuring power flow measurement values ​​connected to the second line, and that determines the section as a second section when the section is not determined to be the first section; a first state estimation unit that, when the section is determined to be the first section, estimates a load state and a tap position in the first section by a first method; a second state estimation unit that, when the section is determined to be the second section, estimates a load state and a tap position in the second section by a second method; A state estimation program that realizes this.

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