Power system management device, power system management system, and power system management method

Abstract

To provide a power system management device, a power system management system, and a power system management method, which can reduce an error of a measured value of a transformer by including various errors other than that of the transformer such as an electric circuit constant, and can grasp the numerical value of the transformer with high accuracy.SOLUTION: A power system management device includes: acquisition means 32 that acquires a measured value from a measuring device 20 that measures a voltage value and / or a current value of transformers 13 and 14 connected to a power system 10; and calculation means 32 that calculates an error δ included in the measured value on the basis of the measured values of the transformers 13 and 14 acquired by the acquisition means 32. The calculation means 32 constructs a simultaneous equation of a plurality of circuit equations valid in the power system 10 in a format including the errors of the transformers 13 and 14, and solves the simultaneous equations of the constructed plurality of circuit equations to obtain an error or correction values of the measured values of the transformers 13 and 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power management device, a power system management system, and a power system management method for managing a power system based on voltage values ​​and current values ​​measured at various points in the power system. [Background technology]

[0002] Traditionally, the protection, security, monitoring, control, and maintenance support of power systems have been carried out using the electrical constants of electrical equipment and facilities such as transmission lines and transformers, and the voltage and current values ​​measured in power systems. However, the electrical constants of electrical equipment and facilities in power systems and the voltage and current values ​​measured in power systems are subject to errors in the design and manufacture of the electrical equipment and facilities, as well as errors in the measurement of their electrical characteristics. Regarding such errors, error classes are established by domestic and international standards for electrical equipment and facilities, and they are required to comply with these standards and regulations.

[0003] On the other hand, in recent years, the algorithms used to manage power grids have continued to evolve to such an extent that even the slightest error can have a significant impact on system operation. For this reason, while operations have traditionally been conducted with a margin of safety, assuming that there will be some error, it is expected that in the future, depending on the purpose of use, it will be necessary to calculate power grid voltage and current values ​​with higher precision (smaller error) than specified in standards and regulations.

[0004] Examples of methods for correcting errors in voltage and current values ​​in power systems include a method that uses a system configuration database to determine the deviation of each node using existing techniques such as power flow calculations using measured values ​​or the least squares method, and then generates weighting coefficients for error correction (e.g., Patent Documents 1 to 3); a method that allocates sensitivity coefficients according to the amount of change in power flow conditions due to changes in load, power generation, and impedance (e.g., Patent Document 4); an existing convergence calculation algorithm that defines a nonlinear optimization problem with the objective function of minimizing errors in equipment characteristics, and uses metaheuristic optimization methods such as genetic algorithms, Tabu search, and particle swarm optimization (e.g., Patent Document 5); and a method that collects measured value data of voltage and current at the node to which the node belongs and measured value data of voltage and current at other nodes to which the node does not belong, and solves a least squares problem to minimize the error in the measured values ​​of voltage and current at each node (e.g., Patent Document 6). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2015 / 083472 [Patent Document 2] Patent No. 4705563 [Patent Document 3] Patent No. 3814640 [Patent Document 4] Patent No. 4148208 [Patent Document 5] Patent No. 4337461 [Patent Document 6] Patent No. 5872732 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a power system management device, a power system management system, and a power system management method that can reduce errors inherent in the entire power system by absorbing errors inherent in the power system and / or the entire system into errors in voltage transformers and current transformers and determining the errors collectively as errors in the voltage transformers and current transformers. [Means for solving the problem]

[0007] The power system management device according to the present invention includes an acquisition means for acquiring measured values ​​from a measurement device that measures a voltage value and / or a current value of a transformer connected to a power system, and a calculation means for calculating an error included in the measured values ​​of the transformer acquired by the acquisition means, wherein the calculation means calculates a simultaneous equation of a plurality of circuit equations that hold in the power system. , the circuit equations are respectively The circuit equations are constructed in a format including the error of the transformer, and a correction value for the error or the measurement value of the transformer is obtained by solving the simultaneous equations of the constructed circuit equations. Therefore, the simultaneous equations of the plurality of circuit equations are simultaneous equations using one or more of the circuit equations of a two-terminal system model based on the electrical characteristics between a transmission line and the transformer connected on both sides of the transmission line, a multi-terminal system model based on the electrical characteristics between a plurality of transmission lines and a plurality of the transformers connected to the plurality of transmission lines, a single voltage terminal system model based on the electrical characteristics when the voltage value of the same transformer is measured by a plurality of measuring devices, and a single current terminal system model based on the electrical characteristics of currents flowing in and out of the same position of the power system. . The calculation means can also set a plurality of circuit equations that hold in the power system in a format that includes errors of the transformers, and solve a simultaneous equation of the set circuit equations. In the above power system management device, the plurality of circuit equations may be configured to be circuit equations that hold true in different ranges of the power system. In the power system management device, the circuit equation is The aforementioned Circuit equations for a two-terminal system model, or The aforementioned It can be configured to include circuit equations for a multi-terminal system model. In the power system management device, the plurality of circuit equations are The aforementioned Circuit equation for single voltage terminal system model, or The aforementioned It can be configured to include circuit equations for a single current terminal system model. In the above power system management device, the calculation means may be configured to use a set of circuit equations g(δ)=0 as a constraint condition when the error is δ, construct the simultaneous equations by Lagrange's method of undetermined multipliers, and obtain a solution to the simultaneous equations to calculate the error δ or a correction value for the measurement value of the transformer. In the above power system management device, the error may be configured to include errors other than those of the transformer that are inherent in the power system, in addition to errors of the measurement values ​​of the transformer.

[0008] A power system management system according to the present invention includes a power system having a transmission line and a transformer, a measurement device for measuring the voltage and / or current of the transformer, and the power system management device. Alternatively, the system is incorporated into a device, program, or function for preprocessing and / or additional correction of various systems that use the measured values, such as protection and security, monitoring and control, and maintenance support of the power system.

[0009] The power system management method according to the present invention is a power system management method that acquires measured values ​​from a measuring device that measures voltage values ​​and / or current values ​​of a plurality of transformers connected to the power system, and calculates errors included in the measured values ​​based on the acquired measured values, and further constructs a system of simultaneous equations of a plurality of circuit equations that hold in the power system in a format that includes errors of the transformers, and calculates the system of simultaneous equations of the plurality of circuit equations that have been constructed. , the circuit equations are respectively By solving this, the correction value for the error or the measurement value of the transformer is obtained. Therefore, the simultaneous equations of the plurality of circuit equations are simultaneous equations using one or more of the circuit equations of a two-terminal system model based on the electrical characteristics between a transmission line and the transformer connected on both sides of the transmission line, a multi-terminal system model based on the electrical characteristics between a plurality of transmission lines and a plurality of the transformers connected to the plurality of transmission lines, a single voltage terminal system model based on the electrical characteristics when the voltage value of the same transformer is measured by a plurality of measuring devices, and a single current terminal system model based on the electrical characteristics of currents flowing in and out of the same position of the power system. . [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a power system management device, a power system management system, and a power system management method that can reduce errors in transformer measurements and grasp transformer values ​​with high accuracy. In addition, it is possible to incorporate various errors, such as those of transmission lines, transformers, and generator constants, into the transformer and correct them as errors of the transformer connected to the targeted system. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a power system management system according to an embodiment of the present invention; [Figure 2] 4 is a flowchart showing a power system management process according to the present embodiment. [Figure 3] 10A and 10B are diagrams for explaining the effect when the measurement value correction process according to the present embodiment is executed in a two-terminal system model. [Figure 4] 10A and 10B are diagrams for explaining the effect when the measurement value correction process according to the present embodiment is executed in a multi-terminal system model. [Figure 5] 1 is a diagram illustrating an example of a power system according to a first embodiment. [Figure 6] 4 is a graph showing the measurement results of voltage values ​​and the results of correcting the measurement values ​​in Example 1. [Figure 7] 4 is a graph showing the measurement results of current values ​​and the results of correcting the measurement values ​​in Example 1. [Figure 8] 10 is a graph showing the measurement results of voltage values ​​and the results of correcting the measurement values ​​in Example 2. [Figure 9] 10 is a graph showing the measurement results of current values ​​and the results of correcting the measurement values ​​in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] The power system management system according to the present invention includes a power system management device that measures voltage and / or current values ​​at each location (each transformer) in the power system and outputs the measured voltage and current values ​​to an external management system, and various management systems that perform protection, security, monitoring, control, maintenance support, etc. of the power system based on the voltage and current values ​​output from the power system management device. Electrical devices and equipment such as transmission lines and transformers that make up the power system are subject to errors due to design and manufacturing, as well as measurement errors in their electrical characteristics. However, since there is no means for determining the true values ​​for each electrical device and equipment, it is not possible to determine the appropriate voltage and current values ​​at each location in the power system. As a result, it has sometimes been difficult to perform protection, security, monitoring, control, maintenance support, etc. of the power system with high accuracy.

[0013] In this invention, a power system is subdivided into multiple system models, and a circuit equation g that holds for each system model is set in a format that includes an error δ in the measurement value of the transformer. Using the set of multiple circuit equations g and the set of errors δ in the measurement values ​​of multiple transformers, the Lagrange method (Lagrange is often translated as Lagrange, and Lagrange and Lagrange are synonymous; the same applies below) is used to calculate the minimum error δ and a correction value obtained by subtracting the error δ from the measurement value. Furthermore, in this invention, by classifying the entire power system into multiple system models, it is possible to determine not only the errors of the transformers themselves, but also errors inherent in the entire power system by absorbing them into the transformer errors. An embodiment of the present invention is described below. Note that a power system generally refers to a configuration that integrates power generation, transformation, transmission, and distribution to supply electricity to consumers. In this embodiment, the minimum configuration of the power system can be a configuration consisting of two measurement points and power equipment connecting the two points, for example, two electric power stations (or two transformers) connected by a transmission line.

[0014] FIG. 1 is a configuration diagram of a power system management system 1 according to this embodiment. The power system management system 1 according to this embodiment includes a power system 10 having a transmission line 12 and transformers 13 and 14, a measuring device 20 that measures the current and voltage values ​​of the transformers 13 and 14 (voltage transformer 13 and current transformer 14), and a power system management device 30 that calculates an error δ in the measured values ​​of the transformers 13 and 14 or a correction value obtained by subtracting the error δ from the measured value based on the measured values ​​(voltage and current values) of the measuring device 20. Although not shown, the power system management system 1 also includes various external management systems that perform protection, security, monitoring, control, maintenance support, and the like of the power system based on the voltage and current values ​​output from the power system management device 30. The power system management system 1 according to this embodiment will now be described with reference to FIG. 1.

[0015] In the example shown in Figure 1, power system 10 has five substations 11A-11E, which are connected to power transmission lines 12A-12E, respectively. Of power transmission lines 12A-12E, power transmission line 12A is a bus. Note that Figure 1 illustrates a configuration in which five substations 11A-11E are connected to power transmission lines 12A-12E, but the number of substations 11A-11E connected to power system 10 is not limited and may be four or less, or six or more.

[0016] In the power system 10 shown in Fig. 1, the power station 11A is directly connected to the bus 12A. The power station 11B is connected to the bus 12A via the transmission line 12B. The power station 11C is connected to the bus 12A via the transmission lines 12C and 12CD, and the power station 11D is connected to the bus 12A via the transmission lines 12D and 12CD. In addition, the power station 11E is connected to the bus 12A via the transmission line 12E.

[0017] Each of the electric power stations 11A to 11E has a voltage transformer 13A to 13E and a current transformer 14A to 14E. Measuring devices 20A to 20E are connected to the voltage transformers 13A to 13E and the current transformers 14A to 14E, respectively. A ~V Eand the current value I of current transformers 14A to 14E A ~I E In the following description, the voltage transformers 13A to 13E are also referred to simply as voltage transformers 13, the current transformers 14A to 14E are also referred to simply as current transformers 14, and the measuring devices 20A to 20E are also referred to simply as measuring devices 20. Similarly, the voltage values ​​V of the voltage transformers 13A to 13E are also referred to simply as voltage transformers 13, the current transformers 14A to 14E are also referred to simply as current transformers 14, and the measuring devices 20A to 20E are also referred to simply as measuring devices 20. A ~V E is simply the voltage value V and the current value I of the current transformers 14A to 14E. A ~I E is also simply referred to as the current value I.

[0018] In this embodiment, the measuring device 20 measures the voltage value V F and the current value I F The measuring device 20F measures the voltage value V on the bus bar 12A side of the transmission line 12CD. G and the current value I G A measuring device 20G measures the voltage value V on the bus 12A side of the power transmission line 12E. E and the current value I E The measuring device 20H measures the above.

[0019] The measuring devices 20A to 20H each have an associated circuit such as an input filter and an analog / digital conversion circuit built in, and output the measured voltage value V A ~V H and the current value I A ~I H is converted from an analog signal to a digital signal and transmitted to the power system management device 30.

[0020] Power system management device 30 has a storage device 31, a calculation device 32, a communication device 33, and a database 34. Power system management device 30 acquires the voltage value V and the current value I measured by measurement device 20 from measurement device 20 via communication device 33. Then, based on the acquired voltage value V and current value I, power system management device 30 calculates the voltage value V and the current value I with a smaller error.

[0021] Furthermore, database 34 stores electrical constants such as impedance Z of transmission line 12. By executing a dedicated program stored in storage device 31 with arithmetic device 32, power system management device 30 has an acquisition function for acquiring the electrical constants stored in database 34 and voltage values ​​V and current values ​​I from measurement device 20, an error calculation function for calculating error δ in the measurement values ​​of voltage transformer 13 and current transformer 14 based on the acquired voltage values ​​V and current values ​​I, and a correction function for correcting voltage value V of voltage transformer 13 and current value I of current transformer 14 based on the calculated error δ in the measurement values. Each function of power system management device 30 will be described below.

[0022] The power system management device 30 is connected to the measuring devices 20A to 20E via a wired and / or wireless communication network, and the acquisition function of the power system management device 30 acquires, via the communication device 33, the voltage value V of the voltage transformer 13 and the current value I of the current transformer 14 measured by the measuring device 20 from the measuring device 20 of the power system 10. For example, in the example shown in FIG. 1 , the acquisition function acquires the voltage values ​​V of the voltage transformers 13A to 13F and the current value I of the current transformer 14 measured by the measuring device 20 from the measuring devices 20A to 20E of the power system 10. A ~V F and the current value I of current transformers 14A to 14H A ~I H Get.

[0023] The error calculation function of the power system management device 30 calculates an error δ inherent in the measured value of the voltage value of the voltage transformer 13 based on the voltage value V of the voltage transformer 13 and the current value I of the current transformer 14 acquired by the acquisition function. V and an error δ inherent in the measurement value of the current value of the current transformer 14. I In the following, a configuration in which the error rate is calculated as the error δ is exemplified, but the present invention is not limited to this configuration, and for example, a configuration in which the difference between the measured value and the true value is calculated as the error δ is also possible.

[0024] Specifically, the error calculation function first obtains the impedance Z of the power transmission line 12 from the database 34. The error calculation function also calculates a circuit equation that holds for each predetermined region in the power system 10, with an error δV and error δ I In this embodiment, four types of circuit equations are used depending on the size of the area of ​​the power system 10: a two-terminal system model, a multi-terminal system model, a single voltage terminal system model, and a single current terminal system model. Each type of circuit equation will be explained below, but the present invention is not limited to these four circuit equations.

[0025] The circuit equation of the two-terminal system model is a circuit equation that holds between one transmission line 12 and two voltage transformers 13 and current transformers 14 connected on both sides of the transmission line 12. For example, in the example shown in FIG. 1, an example of the circuit equation of the two-terminal system model is a circuit equation that holds in an area P1 consisting of the transmission line 12B and the voltage transformers 13B and 13F and current transformers 14B and 14F located on both ends of the transmission line 12B. For example, in the area P1 in the power system 10, the voltage value V of the voltage transformer 13F is F The true value of V FT , the current value I of the current transformer 14F F The true value of I FT , the voltage value V of the voltage transformer 13B B The true value of V BT , the impedance of transmission line 12B is Z B In this case, in the region P1, the circuit equation shown in the following formula (1) is logically established.

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[0026] However, as described above, there is an error δ between the true value and the measured value of the voltage transformer 13 and the current transformer 14. Therefore, when the measured value of the voltage value of the voltage transformer 13F is expressed as V F , the measured current value of the current transformer 14F is I F , the measured voltage value of the voltage transformer 13B is V B The voltage value V of the voltage transformer 13F is F The error inherent in VF , the current value I of the current transformer 14F F The error of δ IF , the voltage value V of the voltage transformer 13BB The error of δ VB In this case, the relationship between the true value, the measured value, and the error is expressed as the following formula (2).

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[0027] Then, by substituting the above formula (2) into the above formula (1), the voltage value V of the voltage transformer 13F is obtained as shown in the following formulas (3) and (4). F Error δ VF , the current value I of the current transformer 14F F Error δ IF , the voltage value V of the voltage transformer 13B B Error δ VB The circuit equation for the following is obtained. Note that the following equation (4) is an expansion of the following equation (3).

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[0028] In this way, for the region P1 of the power system 10, the circuit equation g P1-1 Similarly, for the region formed by the transmission lines 12CD, 12C, 12D, and 12E and the voltage transformers 13C to 13F and current transformers 14C to 14H located on the sides of these transmission lines, the circuit equation g P1-2 ,g P1-3 ,···,g P1-L As shown in the above formula (4), it is set in a form including the error δ of the measurement values ​​of 13C to 13F and current transformers 14C to 14H. As a result, as shown in the above formula (4), the circuit equations g P1-1 ,g P1-2 ,···,g P1-L will be set.

[0029] Furthermore, a circuit equation g of the multi-terminal system model is set as a circuit equation of the system model. The circuit equation g of the multi-terminal system model is a circuit equation that holds between a plurality of transmission lines 12 and a plurality of voltage transformers 13 and current transformers 14 connected to the plurality of transmission lines 12. For example, in the example shown in FIG. 1, an example of the circuit equation of the multi-terminal system model is a circuit equation that holds in an area P2 consisting of transmission lines 12B, 12CD, 12C, and 12D and voltage transformers 13B to 13D and 13F and current transformers 14B and 14F connected thereto. In this area P2, the true value of the voltage value of voltage transformer 13G is expressed as V GT , the true value of the current of the current transformer 14G is I GT , the true value of the voltage value of the voltage transformer 13C is V CT , the true value of the current value of the current transformer 14C is I CT , the true value of the voltage value of the voltage transformer 13D is V DT , the true value of the current value of the current transformer 14D is I DT , the impedance of the transmission line 12CD is Z CD , the impedance of the transmission line 12C is Z C , the impedance of transmission line 12D is Z D In this case, the two circuit equations shown in the following expressions (5) and (6) are logically established.

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[0030] The voltage measurement value of voltage transformer 13G is V G , the current measurement value of current transformer 14G is I G , the voltage measurement value of voltage transformer 13C is V C , the current measurement value of the current transformer 14C is I C , the voltage measurement value of the voltage transformer 13D is V D , the current measurement value of the current transformer 14D is I D The error in the voltage value of the voltage transformer 13G is δ VG , the error in the current value of the current transformer 14F is δ IF , the error in the voltage value of the voltage transformer 13C is δVC , the error in the current value of the current transformer 14C is δ IC , the error in the voltage value of the voltage transformer 13D is δ VD , the error in the current value of the current transformer 14D is δ ID In this case, the above equations (5) and (6) can be expressed as the voltage value error δ VG ,δ VC ,δ VD and current error δ IG ,δ IC ,δ ID The circuit equations are obtained in the form

[0031]

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[0032] In this way, the above equations (7) and (8) for the region P2 are expressed as the circuit equation g P2-1 ,g P2-2 Similarly, as shown in the above equations (7) and (8), multiple circuit equations g P2-3 ,g P2-4 ,···,g P2-M is set in a format including the errors of the voltage transformer 13 and the current transformer 14.

[0033] Furthermore, a circuit equation that holds for a single voltage transformer 13 is set as the circuit equation for the single voltage terminal system model. Specifically, when the voltage value of one voltage transformer 13 in the power system 10 is measured by a plurality of measuring devices 20, the circuit equation is set by taking advantage of the fact that the voltage values ​​of these measuring devices 20 are equal. For example, in the example shown in FIG. 1, the voltage value of voltage transformer 13F is measured by measuring devices 20F and 20G. In this case, as shown in FIG. 1, the true value of the voltage value of voltage transformer 13F measured by measuring device 20F is set as V FT , the true value of the voltage value of the voltage transformer 13F measured by the measuring device 20G is V GTIn this case, the following equation (9) is theoretically established as a single voltage terminal system model of the voltage transformer 13F.

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[0034] In addition, the voltage measurement value of voltage transformer 13F measured by measuring device 20F is V F , the voltage measurement value of voltage transformer 13G measured by measuring device 20G is V G The error in the voltage value of the voltage transformer 13F measured by the measuring device 20F is δ VF The error in the voltage value of voltage transformer 13G measured by measuring device 20G is δ VG In this case, the above formula (9) can be expressed as the following formula (10).

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[0035] Therefore, the circuit equation shown in the above equation (10) is the circuit equation g of the single voltage terminal system model for the single voltage transformer 13F. P3-1 Similarly, as shown in the above formula (10), the voltage value errors δ V The circuit equation for the single voltage terminal system model is g P3-2 ,g P3-3 ,···g P3-N will be set.

[0036] Furthermore, a circuit equation that is established for a single current transformer 14 is set as the circuit equation of the single current terminal system model. Specifically, the circuit equation is set by utilizing the fact that the sum of the current flowing into and out of a certain point in the power system 10 is zero. Specifically, the true value I of the current value of the current transformer 14 is TK In this case, the current values ​​flowing into and out of a certain point in the power system can be theoretically expressed as in the following equation (11).

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[0037] Also, the current measurement value of the current transformer 14 is I K , the error in the current value of the current transformer 14 is δ IK In this case, the above formula (11) can be expressed as the following formula (12).

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[0038] Therefore, the circuit equation shown in the above equation (12) is the circuit equation g of the single voltage terminal system model for the single current transformer 14. P4-1 Similarly, as shown in the above equation (12), the current value error δ I The circuit equation for the single current terminal system model is g P4-2 ,g P4-3 ,···g P4-P will be set.

[0039] The error calculation function uses Lagrange's undetermined multiplier method to find the minimum voltage error δ V and current value error δ I Specifically, the error calculation function calculates the Lagrange multipliers for the circuit equations g{g = g P1-1 ,g P1-2 ,···g P1-L ,g P2-1 ,g P2-2 ,···g P2-M ,g P3-1 ,g P3-2 ,···g P3-N ,g P4-1 ,g P4-2 ,···g P4-P In this case, g(δ), δ, and λ are defined as shown in the following equation (13).

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[0040] The error calculation function is the Lagrange multiplier λ{λ=λP1-1 ,λ P1-2 , λ P1-L ,λ P2-1 ,λ P2-2 , λ P2-M ,λ P3-1 ,λ P3-2 , λ P3-N ,λ P4-1 ,λ P4-2 , λ P4-P} is introduced into the Lagrange function to calculate the error δ. Specifically, the error calculation function uses Lagrange's undetermined multiplier method to calculate the error δ (voltage value error δ V and current value error δ I The voltage error δ is calculated by using the relationship between the voltage error δ and the Lagrange multiplier λ as shown in equations (14) and (15). V and current value error δ I An example of the simultaneous equations constructed in the example shown in FIG. 1 is shown as the following equations (16) and (17).

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[0041] In this way, the error calculation function calculates the voltage value error δ of the voltage measurement values ​​V of all voltage transformers 13 measured in the power system 10 by Lagrange's undetermined multiplier method. V and the current value error δ of the current measurement value I of the current transformer 14 I Using the circuit equation g, we create simultaneous equations and solve for the minimum voltage error δ V and current value error δ I By calculating the voltage value error δ of the voltage measurement values ​​V of all the voltage transformers 13, V and the current value error δ of the current measurement value I of the current transformer 14I For example, in the example shown in FIG. 1, the error calculation function calculates the voltage value error δ VA ~δ VH and current value error δ IA ~δ IH The circuit equation includes g P1-1 ,g P1-2 ,···g P1-L ,g P2-1 ,g P2-2 ,···g P2-M ,g P3-1 ,g P3-2 ,···g P3-N ,g P4-1 ,g P4-2 ,···g P4-P By using this, the error δ that satisfies equations (14) and (15) is obtained, and the voltage value error δ VA ~δ VH and current value error δ IA ~δ IH The circuit equation g is not limited to the above configuration, and an equation formulated by known electric circuit theory, such as Ohm's law or Kirchhoff's law, can be used based on the power system configuration, etc.

[0042] Next, a description will be given of the correction function of the power system management device 30. The correction function corrects the voltage value error δ calculated by the error calculation function. V and current value error δ I Based on this, the voltage correction factor R V and current correction factor R I In this embodiment, the voltage value error δ V is the error rate of the voltage value V, and the current value error δ I is the error rate of the current value I. Therefore, the correction function is to subtract the voltage value error δ from 1. V The value obtained by subtracting (1-δ V ) as the voltage correction factor R V The correction function calculates the current value error δ I The value obtained by subtracting (1-δ I ) as the current correction factor R I The correction function calculates the voltage correction factor R V and current correction factor RI is stored in the database 34.

[0043] In addition, the correction function uses multiple voltage correction factors R calculated in the past from the database 34. V and current correction factor R I and the voltage correction factor R V and current correction factor R I and multiple previously calculated voltage correction factors R V and current correction factor R I and based on the corrected voltage correction factor R V ' and the modified current correction factor R I Specifically, the correction function calculates the voltage correction factor R V and multiple voltage correction factors R calculated from the present to a predetermined period ago. V and the average corrected voltage correction factor R V Similarly, the correction function calculates the current correction rate R I and multiple current correction factors R calculated from the present to a predetermined period ago. I and the average of the corrected current correction factor R I In this way, the voltage correction factors R V and current correction factor R I The average value of the corrected voltage correction factor R V ' and the modified current correction factor R I By calculating as ', hunting can be prevented and the correction factor can be stabilized.

[0044] Furthermore, the correction function is a modified voltage correction factor R V ' and the modified current correction factor R I Based on this, the voltage adjustment correction factor R appropriate for each management system (application) is V '' and adjustment current correction factor R I The correction function calculates the adjustment voltage correction factor R V '' and adjustment current correction factor R I1, the voltage measurement value V of the voltage transformer 13 and the current measurement value I of the current transformer 14 measured by each measuring device 20 are corrected using the voltage measurement value V of the voltage transformer 13 and the current measurement value I of the current transformer 14. For example, in the example shown in FIG. A ~V F and the current measurement value I of current transformers 14A to 14H A ~I H , and the adjusted voltage correction factor R calculated according to each management system. V '' and adjustment current correction factor R I By multiplying by '', the voltage measurement value V of the voltage transformers 13A to 13F corresponding to each management system is obtained. A ~V F The voltage correction value V A '~V F ' and the current measurement value I of current transformers 14A to 14H A ~I H The correction value of I A ' ~I H ' can be calculated.

[0045] The correction function then outputs the voltage correction value V' and the current correction value I' to various existing or future power system management systems. For example, the correction function outputs the voltage correction value V' and the current correction value I' calculated according to a fault location system to a fault location system that locates a fault point on the transmission line 12. This allows the fault location system to locate the fault point on the transmission line 12 with higher accuracy than before, using the calculated voltage correction value V' and current correction value I' and the impedance Z of the transmission line 12. Similarly, the correction function outputs the voltage correction value V' and the current correction value I' calculated for each management system to various existing or future power system management systems that perform power system protection, security, monitoring, control, maintenance support, etc., allowing these management systems to appropriately perform power system protection, security, monitoring, control, maintenance support, etc. In this way, the power system management device 30 according to this embodiment will operate as a pre-processor for various management systems that are already installed or will be installed in the future to manage the power system, or will be incorporated into these management systems, coexisting with or integrated with them.

[0046] Next, the power system management process according to this embodiment will be described. Fig. 2 is a flowchart showing the power system management process according to this embodiment. The power system management process according to this embodiment is performed by the arithmetic unit 32 of the power system management device 30.

[0047] 2, first, in step S101, the acquisition function of the power system management device 30 acquires electrical constants such as the impedance Z of each power transmission line 12 stored in the database 34. For example, in the example shown in FIG. 1, the acquisition function acquires the impedance Z of each power transmission line 12B to 12E from the database 34. B ~Z E can be obtained.

[0048] In step S102, simultaneous equations are constructed using the circuit equations by the error calculation function of the power system management device 30. For example, in the example shown in FIG. 1, the error calculation function constructs simultaneous equations using the circuit equations g P1 and the circuit equation g of the multi-terminal system model that holds in the region P2 P2 , the circuit equation g of the single voltage terminal system model when the voltage value of a single voltage transformer 13 is measured by multiple measuring devices 20 P3 , the circuit equation g of the single current terminal system model that holds for the current inflow and outflow at a point in the power system 10 P4 The simultaneous equations using the above are expressed as the voltage value error δ of the voltage measurement value V of the voltage transformer 13. V , and the current value error δ of the current measurement value I of the current transformer 14 I It is constructed in a format that includes.

[0049] In step S103, the acquisition function of the power system management device 30 acquires the voltage measurement value V and the current measurement value I measured by the measurement device 20. For example, in the example shown in FIG. 1, the acquisition function acquires the voltage measurement value V of the voltage transformers 13A to 13F. A ~V Fand the current measurement value I of current transformers 14A to 14H A ~I H Get.

[0050] In step S104, the error calculation function calculates the voltage value error δ V and current value error δ I By solving the simultaneous equations using V and current value error δ I For example, in the example shown in FIG. 1, the error calculation function calculates the circuit equation g constructed in step S102 as shown in the above equations (16) and (17). P1 ~g P4 By solving the simultaneous equations, the voltage error δ V and current value error δ I can be calculated.

[0051] In step S105, the voltage value error δ calculated in step S104 is corrected by the correction function. V (Error rate δ of voltage value V V ) and current value error δ I (Error rate δ of current value I I ) based on the voltage correction factor R V and current correction factor R I As described above, in this embodiment, the voltage value error δ V and current value error δ I indicates the error rate of the voltage value V and the current value I. Therefore, in step S105, the correction function calculates the voltage value error δ from 1. V The value obtained by subtracting (1-δ V ) as the voltage correction factor R V Calculate the current value error δ from 1. I The value obtained by subtracting (1-δ I ) as the current correction factor R I The correction function can be calculated as follows: V and current correction factor R I are stored in the database 34.

[0052] Then, in step S106, the correction function of the power system management device 30 corrects the voltage correction factor R calculated in step S104. V and current correction factor R I , and the voltage correction factor R calculated within the most recent fixed period V and current correction factor R I Based on the corrected voltage correction factor R V ' and the modified current correction factor R I In this embodiment, the voltage correction factor R V and current correction factor R I is stored in the database 34 every time it is calculated, and thus the database 34 stores a plurality of previously calculated voltage correction factors R V and current correction factor R I The correction function refers to the database 34 and stores a plurality of voltage correction factors R calculated within a certain period from the present time, for example. V and current correction factor R I These average values ​​are then used as the corrected voltage correction factor R V ' and the modified current correction factor R I It can be calculated as:

[0053] In step S107, the correction function is used to correct the corrected voltage correction factor R calculated in step S106. V ' and the modified current correction factor R I 'Based on the adjustment voltage correction factor R per management system V '' and adjustment current correction factor R I For example, the correction function calculates the voltage correction factor R V is multiplied by a predetermined adjustment coefficient n1 to obtain the adjustment voltage correction factor R for the fault location system. V '' is calculated, and for other control systems, the voltage correction factor R V By multiplying this by a predetermined adjustment coefficient n2, the adjustment voltage correction factor R for the management system is obtained. V Similarly, the correction function can calculate the current correction factor R I is multiplied by a predetermined adjustment coefficient m1 to obtain the adjustment current correction factor R for the fault location system. I'' is calculated, and for other control systems, the current correction factor R I By multiplying this by a predetermined adjustment coefficient m2, the adjustment current correction factor R for the management system is obtained. I '' can be calculated. V '' and adjustment current correction factor R I '' can be expressed as a vector value defined by complex numbers.

[0054] In step S108, the adjustment voltage correction factor R for each management system calculated in step S107 is calculated by the correction function. V '' and adjustment current correction factor R I ', the voltage correction value and current correction value for each management system are calculated. For example, the correction function calculates the voltage correction factor R for the fault location system. V '' and adjustment current correction factor R I '' is calculated, this adjustment voltage correction factor R V '' and adjustment current correction factor R I By multiplying the voltage measurement value V of the voltage transformer 13 and the current measurement value I of the current transformer 14 by "", the voltage correction value V' and the current correction value I' for the fault location system can be calculated.

[0055] In step S109, the power system management device 30 transmits the voltage correction value V' and the current correction value I' for each management system calculated in step S108 to each external management system. As a result, each external management system performs management control such as protection and security, monitoring and control, and maintenance support for the power system based on the voltage correction value V' and the current correction value I' acquired from the power system management device 30.

[0056] In step S110, the power system management device 30 determines whether a certain period of time has elapsed. Until the certain period of time has elapsed, the process returns to step S103, where a voltage correction value V' and a current correction value I' are calculated for the latest voltage measurement value V and current measurement value I, and the calculated voltage correction value V' and current correction value I' are transmitted to each management system, thereby managing the wiring system as a whole. If the certain period of time has elapsed, the process returns to step S101, where the latest electrical constants are acquired again (step S101) and a simultaneous equation is constructed using the circuit equations of the latest system model (step S102), and then the above-mentioned processing (steps S103 to S110) is performed.

[0057] In the above-described embodiment, the power system management device 30 calculates the corrected voltage correction factor R V ' and the modified current correction factor R I In the above example, the power system management device 30 calculates the voltage correction factor R', and then calculates the voltage correction value V' and the current correction value I' for each management system based on the calculated voltage correction factor V' and the current correction value I', and transmits the calculated voltage correction factor V' and the current correction value I' to each management system. However, the present invention is not limited to the above configuration, and may be configured as follows. That is, the power system management device 30 calculates the voltage correction factor R' based on the voltage value and current value measured this time. V and current correction factor R I is calculated and stored in the database 34. Then, the voltage correction factor R V and current correction factor R I Based on this, the corrected voltage correction factor R V ' and the modified current correction factor R I In this way, every time a measurement value is obtained from the measuring device 20, the corrected voltage correction factor R V ' and the modified current correction factor R I Instead of calculating ', the corrected voltage correction factor R V ' and the modified current correction factor R I ' is calculated, and the most recently calculated corrected voltage correction factor R V ' and the modified current correction factor R IIn addition, instead of calculating the voltage correction value V' and the current correction value I' for each management system and transmitting them to the management system, the voltage correction factor R' for each management system can be calculated at regular intervals. V '' and adjustment current correction factor R I '', and in each management system, the adjustment voltage correction factor R V '' and adjustment current correction factor R I The voltage correction value V' and the current correction value I' can be calculated using the above formula. The certain period can be set as appropriate, such as one month or one year, taking into consideration the operational history and performance of various systems.

[0058] As described above, the power system management device 30 according to this embodiment acquires measurement values ​​(measured voltage value V and measured current value I) from the measurement device 20 that measures the voltage values ​​and / or current values ​​of the multiple transformers 13, 14 connected to the power system 10, constructs a simultaneous equation of multiple circuit equations g that hold in each region of the power system 10 in a form that includes the errors δ of the multiple transformers 13, 14, and calculates the error δ by solving this simultaneous equation of circuit equations g. More specifically, the power system management device 30 calculates the voltage value error δ that satisfies the above equation (15) for the Lagrange function shown in the above equation (14) by the Lagrange method using the multiple circuit equations g. V and current value error δ I The calculation program for calculating the voltage value error δ with the smallest error is executed by the arithmetic unit 32. V and current value error δ Iδ can be calculated. As a result, in this embodiment, even if the true voltage value of voltage transformer 13 or the true current value of current transformer 14 are unknown, the error of the measured values ​​relative to the true values ​​can be reduced, and correction values ​​for the voltage and current values ​​can be calculated. These correction values ​​can be used to manage the power system 10 with high accuracy. For example, reducing this margin by improving the error δ is expected to improve the operational efficiency of equipment and business operations depending on the purpose and function of various systems. For example, a fault location system uses transmission line impedance as a reference and aims to identify the location of a fault based on the voltage and current at the time of the fault. Improving the measurement accuracy of voltage and current values ​​is expected to reduce the time and personnel required for patrols, thereby contributing to maintenance efficiency. Furthermore, collecting measurement values ​​from transformers 13 and 14 over a wide range of the power system and calculating correction values ​​is particularly effective when the range of the power system handled by various management systems, i.e., the input measurement range, is set to be wide. This makes it possible to build a management system that operates while correcting errors using measurement values ​​over a wide range.

[0059] 3 is a diagram for explaining the effect of correcting the voltage measurement value V of the voltage transformer 13 and the current measurement value I of the current transformer 14 by the power system management device 30 according to this embodiment in a two-terminal system model. In the example shown in FIG. 3, in the two-terminal system model of the power system 10 shown in FIG. 1, the voltage value V of the voltage transformer 13G G error (error rate) δ VG 0.9%, the voltage value V of voltage transformer 13B B error (error rate) δ VB is assumed to be -0.5%. In this case, the minimum voltage value error δ VG and voltage value error δ VB By calculating the voltage error δ VG is set to 0.185%, and the voltage error δ VB can be calculated as 0.194%. VG ,δ VB Using this, the voltage measurement value V GVoltage error δ VG Voltage correction value V G ', and the voltage measurement value V B Voltage error δ VB Voltage correction value V B ' can be sought.

[0060] 4 is a diagram for explaining the effect of correcting the voltage measurement value V of the voltage transformer 13 and the current measurement value I of the current transformer 14 by the power system management device 30 according to this embodiment in a multi-terminal system model. In the example shown in FIG. 4, in the multi-terminal system model of the power system 10 shown in FIG. 1, the voltage value V of the voltage transformer 13G G error (error rate) δ VG 0.9%, the voltage value V of voltage transformer 13B B error (error rate) δ VB 0.3%, the voltage value V of the voltage transformer 13C C error (error rate) δ VC -0.5%, the voltage value V of voltage transformer 13D D error (error rate) δ VD For example, the power system management device 30 uses the circuit equation g shown in the above equations (7) and (8) to find the minimum error δ VG ,δ VB ,δ VC ,δ VD By calculating the voltage value V G Voltage value error δ VG 0.139%, voltage value V B Voltage value error δ VB 0.158%, voltage value V C Voltage value error δ VC 0.154%, voltage value V D Voltage value error rate δ VD can be calculated as 0.126%. VG ,δ VB ,δ VC ,δ VD , the voltage measurement value V G Voltage error δ VG Voltage correction value V excluding G', voltage measurement value V B Voltage error δ VB Voltage correction value V excluding B ', voltage measurement value V C Voltage error δ VC Voltage correction value V excluding C ', voltage measurement value V D Voltage error δ VD Voltage correction value V excluding D ' can be calculated.

[0061] In addition, in the two-terminal system model shown in Figure 3, the voltage value V of voltage transformer 13G G Voltage value error rate δ VG In the multi-terminal system model shown in Fig. 4, the voltage value V of voltage transformer 13G has decreased from 0.9% to 0.185%. G Voltage value error rate δ VG It can be seen that the voltage value V of the voltage transformer 13B in the two-terminal system model shown in FIG. B Voltage value error rate δ VB and the voltage value V of the voltage transformer 13C in the multi-terminal system model shown in Figure 4. C Error rate δ VC This means that while the error during measurement is -0.5% in both cases, the error rate after correction is 0.154% for the multi-terminal system model shown in Fig. 4, which is smaller than the 0.194% for the two-terminal system model shown in Fig. 3. In this way, by using a circuit equation that includes many transmission lines 12, voltage transformers 13, and current transformers 14, it is possible to reduce the error.

[0062] Furthermore, the error δ can be reduced by using a larger number of circuit equations. It is desirable to use as many circuit equations as can be logically enumerated in the power system 10, but the number of circuit equations to be used is not limited. The domain and number of circuit equations should be within a range that does not significantly deviate from the required performance of the target system, and the balance of the overall design is well known. [Example]

[0063] Example 1 Next, a first example of the power system management system 1 according to this embodiment will be described. FIG. 5 is a schematic diagram showing the configuration of the power system of this first example. In this first example, as shown in FIG. 5, the A and B busbars of three actual electric power stations X, Y, and Z are connected by transmission lines M1, M2, N1, and N2, respectively. Explaining the configuration shown in FIG. 5 in relation to the configuration shown in FIG. 1, the A busbar of electric power station Y corresponds to 12A in FIG. 1, the A busbar of electric power station X corresponds to 11B, the A busbar of electric power station Z corresponds to 11E, and the B busbar of electric power station Y corresponds to 11A. Furthermore, the A busbar 12A and the B busbar 11A of electric power station Y are connected by a busbar tie circuit breaker. Furthermore, although not shown in Figure 1, it is assumed that on the side of the second busbar 11A of electrical station Y, similar to the side of the first busbar 12A of electrical station Y, there are second busbars 11B' and 11E' connected to the second busbar 11A, and the second busbar of electrical station X shown in Figure 5 corresponds to 11B', and the second busbar of electrical station Z corresponds to 11E'.

[0064] In this Example 1, the actual voltage and current values ​​for each of the A and B busbars of electric power stations X, Y, and Z were measured, and the measured voltage value V and current value I were corrected using a measurement value correction process to calculate the corrected voltage value V' and corrected current value I'. The voltage measurement results in this Example 1 are shown in FIG. 6(A). In the example shown in FIG. 6(A), the measurement results are expressed as a percentage of the ratio of the measured voltage value V to the reference voltage value (measured voltage value V / reference voltage value - 1). In the power system shown in FIG. 5, the A and B busbars of electric power station Y are connected by a busbar tie, and theoretically, the voltage values ​​are the same. However, as shown in FIG. 6(A), in this Example 1, the measured voltage value V of the A busbar (YA in FIG. 6(A)) at electric power station Y was measured to be relatively lower than the measured voltage value V of the B busbar (YB in FIG. 6(A)).

[0065] In contrast, the corrected voltage correction value V' of the A busbar and B busbar of substations X, Y, and Z is shown in Figure 6(B). As described above, in the power system shown in Figure 5, the A busbar and B busbar of substation Y are connected by a busbar tie, and theoretically, the voltage values ​​are the same. Furthermore, substations X and Z are connected via transmission lines M1 and M2 and the transmission line impedance of transmission lines N1 and N2. By setting a circuit equation based on this relationship and constructing simultaneous equations as in Equations 16 and 17 above, it is possible to calculate the voltage value error ΔV for each A and B busbar of substations X, Y, and Z, and to calculate the voltage correction value V'. As shown in Figure 6(B), by performing the measurement value correction process according to this embodiment, for example, the voltage measurement value V is corrected at the A busbar and B busbar of substation Y, resulting in approximately the same voltage correction value V' (YA' and YB' shown in Figure 6(B)). In the example shown in FIG. 6B, the measurement results are also shown as a percentage of the ratio of the voltage correction value V' to the reference voltage value (voltage correction value V' / reference voltage value - 1).

[0066] Note that this Example 1 is based on the results of measurements in an actual electrical system, and the true voltage values ​​are unknown, but as shown in Figure 6(A), the measured voltage value V of the A bus bar of electric power station Y (YA in Figure 6(A)) was measured to be relatively lower than the measured voltage value V of the B bus bar (YB in Figure 6(A)), which is presumably due to the influence of transformer errors, input converter errors, etc. Later, by repairing and replacing the equipment, the difference between the measured voltage value V of the A bus bar of electric power station Y and the measured voltage value V of the B bus bar was improved. In this way, by using the measurement value correction method according to this embodiment, the voltage measurement value V is corrected by taking into account the interdependencies based on electrical circuit theory of power stations X, Y, Z, and the transmission lines M1, M2, N1, and N2 connecting the power stations, the power flows (active power and reactive power) flowing therethrough, and the voltage values ​​of power station X, Y, and Z, which are determined depending on the phase. This makes it possible to determine a voltage correction value V' with sufficient accuracy for practical use, even from the perspective of an operator engaged in power distribution operations, and it has been confirmed that the power system management system 1 according to this embodiment is a practical system.

[0067] In addition, in the configuration shown in Fig. 5, the measurement results of the current values ​​in the transmission lines M1, M2, N1, and N2 of each of the electric power stations X, Y, and Z are shown in Fig. 7(A), and the corrected results of the current values ​​are shown in Fig. 7(B). In the examples shown in Figs. 7(A) and (B), the measurement results are shown as a percentage of the ratio of the measured current value I or corrected current value I' to the reference current value (measured current value I or corrected current value I' / reference current value). For example, when focusing on transmission line M1, the measured current value XM1 on the electric power station X side and the measured current value YM1 on the electric power station Y side are in an input / output relationship, so in theory, their magnitudes are approximately the same. Similarly, the current measurement value XM2 on the electric power station X side and the current measurement value YM2 on the electric power station Y side, the current measurement value YN1 on the electric power station Y side and the current measurement value ZN1 on the electric power station Z side, and the current measurement value YN2 on the electric power station Y side and the current measurement value ZN2 on the electric power station Z side are also in an input / output relationship, so in theory their magnitudes will be almost the same. For the actually measured current measurement value I, as shown in Figure 7(A), the current measurement value XM1 on the electric power station X side and the current measurement value YM1 on the electric power station Y side, the current measurement value XM2 on the electric power station X side and the current measurement value YM2 on the electric power station Y side, the current measurement value YN1 on the electric power station Y side and the current measurement value ZN1 on the electric power station Z side, and the current measurement value YN2 on the electric power station Y side and the current measurement value ZN2 on the electric power station Z side were almost the same, and although the true value was unknown, it was assumed that the current measurement value I contained almost no error and was close to the true value. This can also be seen from the fact that, as shown in Figure 7(B), the current correction value I' is also approximately the same between the current correction value XM1' on the substation X side and the current correction value YM1' on the substation Y side, the current correction value XM2' on the substation X side and the current correction value YM2' on the substation Y side, the current correction value YN1' on the substation Y side and the current correction value ZN1' on the substation Z side, and the current correction value YN2' on the substation Y side and the current correction value ZN2' on the substation Z side, and the measured current values ​​I at each substation X, Y, and Z are also approximately the same. Note that in transmission lines with large charging currents, the current values ​​that are in an input / output relationship may not be the same due to the influence of admittance, but by performing calculations based on dependencies that take admittance into account, it is possible to achieve a configuration that eliminates the influence of admittance as much as possible, and in the above, the expression "approximately the same value" is used to include current values ​​that have been adjusted in this way.In the measurement value correction process according to this embodiment, as shown in FIG. 7(A), even if the measurement value is estimated to contain almost no error and be close to the true value, the correction value is calculated as a numerical value close to the true value (or the measurement value). From this point of view, it has been confirmed that the power system management system 1 according to this embodiment is a system that is fully practical.

[0068] Example 2 Furthermore, in Example 2, in a configuration similar to that shown in Fig. 5 described above, substations S, T, and U were connected by transmission lines M1, M2, N1, and N2, and the voltage and current values ​​of the A busbar and B busbar of substations S, T, and U were measured. The measured voltage measurement value V and current measurement value I were corrected by the measurement value correction method according to this embodiment to obtain a voltage correction value V' and a current correction value I'. Note that substations S, T, and U in Example 2 are real substations different from substations X, Y, and Z in Example 1 described above.

[0069] FIG. 8(A) shows the voltage measurement values ​​V of the electric power stations S, T, and U, and FIG. 8(B) shows the corrected voltage values ​​V' of the electric power stations S, T, and U. Note that in the examples shown in FIGS. 8(A) and 8(B), the measurement results are also shown as a percentage of the ratio of the voltage measurement value V or the voltage correction value V' to the reference voltage value (voltage measurement value V or voltage correction value V' / reference voltage value - 1). In the example shown in FIG. 8(A), at electric power station S, the voltage measurement value V of the A bus (S-A in FIG. 8(A)) was measured as a relatively higher value than the voltage measurement value V of the B bus (S-B in FIG. 8(A)). In contrast, by performing the measurement value correction process according to this embodiment, it was found that the voltage measurement values ​​V of the A bus and the B bus of electric power station S were corrected to approximately the same corrected voltage values ​​(S-A' and S-B' shown in FIG. 8(B)).

[0070] 9A shows the measurement results of the current values ​​at the transmission lines M1, M2, N1, and N2 of each of the substations S, T, and U, and FIG. 9B shows the corrected results of the current values. In the examples shown in FIGS. 9A and 9B, the measurement results are also shown as a percentage of the ratio of the measured current value I or corrected current value I' to the reference current value (measured current value I or corrected current value I' / reference current value). As shown in FIGS. 9A and 9B, as in the example shown in FIG. 7, the current measurement value SM1 on the substation S side and the current measurement value TM1 on the substation T side, the current measurement value SM2 on the substation S side and the current measurement value TM2 on the substation T side, the current measurement value TN1 on the substation T side and the current measurement value UN1 on the substation U side, and the current measurement value TN2 on the substation T side and the current measurement value UN2 on the substation U side, which are in an input / output relationship, are almost identical. Therefore, although the true value is unknown, it is assumed that the measured current value I contains almost no error and is close to the true value. Therefore, the correction values, too, are almost identical: the current correction value SM1' on the electric power station S side and the current correction value TM1' on the electric power station T side; the current correction value SM2' on the electric power station S side and the current correction value TM2' on the electric power station T side; the current correction value TN1' on the electric power station T side and the current correction value UN1' on the electric power station U side; and the current correction value TN2' on the electric power station T side and the current correction value UN2' on the electric power station U side; and the values ​​are also almost the same as the current measurement value I.

[0071] As described above, from Examples 1 and 2, it was found that even when the measurement value contains errors due to transformer errors, input converter errors, etc., a correction value is calculated to reduce the errors, and it was found that the power system management system 1 according to this embodiment is fully sufficient for practical use.

[0072] Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments. Various modifications and improvements can be made to the above-described embodiments, and such modifications and improvements are also included in the technical scope of the present invention. [Explanation of symbols]

[0073] 1. Power grid management system 10…Power system 11, 11A~11E...Electricity station 12, 12A to 12E... Power lines 13, 13A to 13G...Voltage transformer 14, 14A~14H...Current transformer 20, 20A~20H...Measuring equipment 30…Power system management device 31...Storage device 32...Arithmetic device 33...Communication equipment 34...Database

Claims

1. an acquisition means for acquiring measured values ​​from a measurement device that measures a voltage value and / or a current value of a transformer connected to the power system; a calculation means for calculating an error included in the measurement value based on the measurement value of the transformer acquired by the acquisition means, the calculation means constructs a system of multiple circuit equations that hold in the power system in a format in which each of the circuit equations includes an error of the transformer, and solves the system of multiple circuit equations that has been constructed to determine a correction value for the error or the measurement value of the transformer; the simultaneous equations of the plurality of circuit equations are simultaneous equations using one or more of circuit equations of a two-terminal system model based on electrical characteristics between a transmission line and the transformer connected on both sides of the transmission line, a multi-terminal system model based on electrical characteristics between a plurality of transmission lines and a plurality of the transformers connected to the plurality of transmission lines, a single-voltage terminal system model based on electrical characteristics when voltage values ​​of the same transformer are measured by a plurality of measuring devices, and a single-current terminal system model based on electrical characteristics of currents flowing in and out of the same position in the power system.

2. The power system management device according to claim 1 , wherein the plurality of circuit equations are circuit equations that hold true in different ranges of the power system.

3. The power system management device according to claim 1 , wherein the plurality of circuit equations include a circuit equation of the two-terminal system model and a circuit equation of the multi-terminal system model.

4. 4. The power system management device according to claim 1, wherein the plurality of circuit equations include a circuit equation of the two-terminal system model or a circuit equation of the multi-terminal system model.

5. 4. The power system management device according to claim 1, wherein the plurality of circuit equations include a circuit equation of the single voltage terminal system model or a circuit equation of the single current terminal system model.

6. 6. The power system management device according to claim 1, wherein the calculation means uses a set of circuit equations g(δ)=0 as a constraint condition when the error is δ, constructs the simultaneous equations by Lagrange's method of undetermined multipliers, and obtains a solution of the simultaneous equations to calculate the error δ or a correction value for the measurement value of the transformer.

7. 7. The power system management device according to claim 1, wherein the error includes errors of the transformer measurement value as well as errors of other factors present in the power system than the transformer.

8. an electric power system having transmission lines and transformers; a measuring device for measuring a voltage value and / or a current value of the transformer; A power system management system comprising: the power system management device according to any one of claims 1 to 7.

9. A power system management method comprising: acquiring measured values ​​from a measuring device that measures voltage values ​​and / or current values ​​of a plurality of transformers connected to a power system; and calculating errors included in the measured values ​​based on the acquired measured values, constructing simultaneous equations of a plurality of circuit equations that hold in the power system in a format in which the circuit equations each include an error of the transformer, and solving the constructed simultaneous equations of the plurality of circuit equations to determine a correction value for the error or the measurement value of the transformer; the simultaneous equations of the plurality of circuit equations are simultaneous equations using one or more of the circuit equations of a two-terminal system model based on the electrical characteristics between a transmission line and the transformer connected on both sides of the transmission line, a multi-terminal system model based on the electrical characteristics between a plurality of transmission lines and a plurality of the transformers connected to the plurality of transmission lines, a single-voltage terminal system model based on the electrical characteristics when the voltage value of the same transformer is measured by a plurality of measuring devices, and a single-current terminal system model based on the electrical characteristics of currents flowing in and out of the same position in the power system.

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