Method for simulating power distribution line surge waveform propagation, power distribution line surge waveform propagation simulation device, and computer system

Abstract

To enable accurate determination of arrival times, arrival time differences, and propagation speed of surge waveforms by reproducing virtual surge waveforms using simulation.SOLUTION: A method includes: a step (S104) of generating a distribution line model per substation bank, which includes impedance of a distribution transformer, ground impedance between a three-phase power source and a ground transformer, a line constant of a three-phase three-wire distribution line, and ground capacitance of distribution equipment and high-voltage customer equipment of the distribution line; a step (S105) of generating a fault model that includes switches in one or more of three-phase three-wire lines, between the lines, and between each line and ground; and a step (S109) of actuating the switches of the fault model at fault timing of the power source in a faulted phase of the distribution line model. By measuring a waveform of surge voltage or surge current at one or more surge waveform observation points when the switches of the fault model are actuated, virtual surge waveform data is obtained, and the arrival times, arrival time differences, and propagation speed are determined.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a power distribution line surge waveform propagation simulation method, a power distribution line surge waveform propagation simulation device, and a computer system that reproduce a virtual surge waveform by simulation without using an actual surge waveform, thereby making it possible to correctly determine the arrival time, the difference in arrival times, and the propagation speed of the surge waveform. [Background technology]

[0002] Conventionally, in a system for locating a fault such as a ground fault occurring in a power distribution line, multiple sensors that detect surge voltage or surge current are arranged in the power distribution line, and the arrival time of the surge waveform of each sensor synchronized with a GPS (Global Positioning System) time signal (hereinafter referred to as the "surge arrival time") is identified, and the fault point is located based on the difference in the surge arrival time between a pair of sensors on either side of the fault point.

[0003] The feature of this fault location system is that it locates the fault point by the time difference when the surge waveform generated from the fault point reaches a pair of sensors on either side of the fault point, the distance between the pair of sensors, and the surge waveform propagation speed between the pair of sensors. Also, there are known methods for calculating the surge waveform propagation speed, which use the time difference when the surge waveform generated at the fault point reaches a sensor other than the pair of sensors on either side of the fault point, and which uses the switching surge waveform generated by opening and closing a pole-mounted switch on a distribution line to calculate the surge waveform propagation speed of the relevant section from the difference in surge arrival time between a pair of sensors.

[0004] In this way, in the conventional method of determining the surge waveform propagation velocity, the actual surge waveform is used to determine the surge arrival time, and then the surge waveform propagation velocity is calculated.

[0005] Patent Document 1 describes a surge detection time location method for locating the detection time of a surge voltage or surge current caused by a fault occurring at any point in a transmission / distribution line in a substation installed in the transmission / distribution line.

[0006] Patent documents 2 and 3 describe a method for determining the surge waveform propagation speed by utilizing the time difference when a surge waveform generated at a fault point reaches a sensor other than a pair of sensors sandwiching the fault point. Patent document 4 describes a method for determining the surge waveform propagation speed of a section from the difference in surge arrival time between a pair of sensors by utilizing a switching surge waveform generated by opening and closing a pole-mounted switch of a distribution line. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2000-258487 A [Patent Document 2] JP 2001-133504 A [Patent Document 3] JP 2016-142659 A [Patent Document 4] JP 2008-139145 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, the propagation of a surge waveform changes depending on the form of the distribution equipment of the power distribution line. Figure 24 shows a conventional method for determining the propagation speed of a surge waveform using adjacent sections. Here, the surge waveform observation points are A, B, and C, and the line terminal is E. A fault occurs between the surge waveform observation points B and C, and the distance between them is L. AB , L BP , L PC , L CEThen, the surge waveform propagation velocity in each section can be calculated using the formula in Fig. 24. However, because the configuration of the power distribution equipment differs in each section, there is a problem in that the surge waveform propagation velocity in that section cannot be calculated correctly.

[0009] Figure 25 shows a conventional method for determining the propagation speed of a surge waveform using the switching surge waveform of a pole-mounted switch. Here, the distance between the surge waveform observation points D and F is L DF If the surge arrival times at surge waveform observation points D and F are Td and Tf respectively, the surge waveform propagation speed between surge waveform observation points D and F can be calculated using the formula in Figure 25. However, unlike a surge waveform during a ground fault, the switching surge waveform of a switchgear does not always reach a waveform level at which the surge can be detected at the surge waveform observation point, and there are also cases where there are no pole-mounted switches, so there is a problem that the surge waveform propagation speed in the relevant section cannot be calculated correctly.

[0010] In this way, the conventional method of using an actual surge waveform to determine the surge arrival time and then calculating the surge waveform propagation velocity has the problem that it is not possible to correctly determine the surge waveform propagation velocity, which makes it impossible to accurately locate the fault point. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention aims to provide a distribution line surge waveform propagation simulation method, a distribution line surge waveform propagation simulation device, and a computer system that reproduce a virtual surge waveform by simulation without using an actual surge waveform, thereby making it possible to correctly obtain the surge arrival time, the difference in the surge arrival time, and the surge waveform propagation speed, and the features thereof are that in a fault point locating method for identifying a fault point in a distribution line using a surge voltage or surge current generated from the fault point, a distribution line model is constructed to simulate the propagation of the surge waveform of the surge voltage or surge current in the distribution line, and virtual surge waveform data is obtained to obtain the arrival time of the surge waveform at any point in the distribution line. Here, if there are multiple arbitrary points, the difference in the arrival times of the surge waveforms at those points can be obtained, and the surge propagation speed can be obtained from the difference in the arrival times of the surge waveforms at the multiple points and the distance between those points.

[0012] Another feature of the present invention is that it includes the steps of generating a distribution line model including any one or more, or all, of the impedances of the three-phase power source and distribution transformer, the impedance to ground of the grounding transformer, the line constants of the three-phase three-wire distribution line, and the capacitance to ground of the distribution equipment and high-voltage consumer equipment installed on the distribution line; generating a fault model including switches in any one or more, or all, of each line of the three-phase three-wire line, between each line, and between each line and ground; and operating a switch of the fault model based on the fault time timing or the phase timing of the power supply voltage (hereinafter referred to as fault timing) of the distribution line model, and measuring the waveform of the surge voltage or surge current at a waveform observation point of any location when the switch of the fault model is operated to obtain virtual surge waveform data.

[0013] Another feature of the present invention is that the power distribution equipment of the power distribution line model includes one or more of a power distribution line (overhead wire / power cable), an insulator, a lightning arrester, an arcing horn, a pole-mounted transformer, a pole-mounted switchgear, a voltage regulator, and an overhead ground wire.

[0014] Another feature of the present invention is that the distribution line model is based on one pole-span unit with the same line length and distribution equipment arrangement as the distribution line, and the distribution line model is configured in one pole-span units, or is configured by integrating multiple pole-span units into one equipment based on one pole unit.

[0015] Another feature of the present invention is that the fault model uses the fault phase, fault timing and fault resistance of the fault that has occurred.

[0016] Another feature of the present invention is a distribution line surge waveform propagation simulation device that simulates the propagation of a surge waveform of a surge voltage or surge current generated from a fault point on a distribution line, comprising: a distribution line model including any one or more, or all of the impedances of a three-phase power source and a distribution transformer, the impedance to ground of a grounding transformer, the line constants of a three-phase three-wire distribution line, and the earth capacitances of distribution equipment and high-voltage consumer equipment installed on the distribution line; a fault model including switches in any one or more, or all of the lines, between each line, and between each line and the ground of the three-phase three-wire line; and means for operating a switch of the fault model in response to a fault in the distribution line model, and measuring the waveform of the surge voltage or surge current at a waveform observation point at any location when the switch of the fault model is operated to obtain virtual surge waveform data.

[0017] Further, the computer system for simulating the propagation of a surge voltage or surge current generated from a fault point of a distribution line includes a storage means for storing information, a processing means for processing information, an output means for outputting data processed by the processing means as a file, and an input means for receiving commands from an external program, and the storage means stores distribution line connection information of an actual distribution system for each substation bank, a line constant of the distribution line per unit length, and constant information of the capacitance to ground for each distribution facility, and the input means stores a specific distribution line, a fault phase, a fault pole, fault timing, a waveform observation pole (waveform observation point), time series resolution (simulation calculation interval), time series recording, and the like, which are used for simulating the propagation of a surge voltage or surge current generated from a fault point of a distribution line from the outside as simulation condition information. When a record length (simulation calculation time) is specified, the distribution line connection information and the constant information for that substation bank are automatically read from the storage means, and the processing means associates the line constants and the ground capacitance for each of the distribution equipment with the distribution line length and the distribution equipment position, generates in the memory an electrical equivalent circuit of a distribution line model based on one pole-to-pole units, and generates in the memory a fault model based on the faulted phase, faulted utility pole, and waveform observation utility pole (waveform observation point) read by the input means, and also, the processing means starts a simulation based on the waveform record length and time resolution read by the input means, generates a virtual fault at the fault timing read by the input means, and stores time series data of the virtual surge waveform of the waveform observation utility pole (waveform observation point) in the storage means as a file. Effect of the Invention

[0018] According to the distribution line surge waveform propagation simulation method and distribution line surge waveform propagation simulation device of the present invention, the distribution line targeted for the analysis of the arrival time of the surge waveform propagation in fault location of the distribution line can be expanded into a virtual distribution line model, and the state of the surge waveform (arrival time of the surge waveform) at the time of a fault, whose propagation speed changes depending on the installation status of the distribution equipment and the electrostatic capacitance constant to ground for each connection between utility poles, can be simulated. Here, by providing time series data (discrete data and time data) of two or more virtual surge waveforms, it is also possible to obtain the difference in the arrival time of the surge waveform and the propagation speed.

[0019] In addition, by modeling the connection information of actual power distribution lines and power distribution equipment information on a pole-to-pole basis, it is possible to simulate how the surge waveforms of surge voltage and surge current during a fault accident propagate through overhead lines and power cables.By reproducing two or more virtual surge waveforms (virtual surge waveforms) without using the actual surge waveform (measured surge waveform), it is possible to determine the difference in arrival time and propagation speed of the surge waveforms.

[0020] In addition, since actual faults can be reproduced through simulation, it is possible to simulate (analyze) the propagation of surge waveforms on multiple arbitrary utility poles and the propagation of surge waveforms during a fault, thereby predicting the arrival time of the surge waveform.

[0021] Furthermore, for distribution lines that do not include waveform observation points, the processing burden on computers can be reduced by integrating the distribution equipment between multiple utility poles into a single piece of equipment. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating a schematic diagram of a tree-structured power distribution line. [Diagram 2] 13 is a flowchart of a dedicated program for simulating a surge waveform propagation in a power distribution line. [Diagram 3] FIG. 2 is a diagram showing one record of DATA1 (electric pole span information) used in the present invention. [Figure 4] FIG. 1 is a diagram showing one record of DATA2 (pole transformer information) used in the present invention. [Diagram 5] FIG. 2 is a diagram showing one record of DATA3 (high-voltage customer facility information) used in the present invention. [Figure 6] FIG. 11 is a diagram showing DATA4 (constant information) used in the present invention. [Figure 7] FIG. 13 is a diagram showing DATA5 (intermediate data) used in the present invention. [Figure 8] FIG. 13 is a diagram showing the relationship between intermediate data and other information. [Figure 9] FIG. 1 shows a model of the main power and earthing transformers of a substation. [Figure 10] FIG. 13 is a diagram showing a record group of intermediate data. [Figure 11] FIG. 13 is a diagram showing a relationship between intermediate data and a power distribution line system. [Figure 12] FIG. 2 is a diagram showing the relationship between a power distribution line system and node numbers. [Figure 13] FIG. 13 is a diagram showing the relationship between a three-phase T-type circuit and node numbers. [Figure 14] FIG. 13 is a diagram showing an image of codification of a power distribution line model. [Figure 15] FIG. 13 is a diagram showing a model of a virtual ground fault point. [Figure 16] FIG. 13 is a diagram showing an image of fault model coding. [Figure 17] FIG. 1 is a basic schematic diagram of a power distribution line. [Figure 18] FIG. 2 is a diagram illustrating a virtual power distribution line model. [Figure 19] 10 is a flowchart showing details of an intermediate data generation process. [Figure 20] FIG. 1 is a diagram showing a power distribution line (system diagram) on which surge waveform propagation is recorded (Example 1). [Figure 21] FIG. 4 is a diagram showing a comparison between an actual surge waveform and a virtual surge waveform (Example 1). [Figure 22] FIG. 13 is a diagram showing a power distribution line (system diagram) on which surge waveform propagation was recorded (Example 2). [Figure 23]FIG. 11 is a diagram showing a comparison between an actual surge waveform and a virtual surge waveform (Example 2). [Figure 24] FIG. 1 is a diagram showing a conventional method for determining a surge propagation speed using adjacent sections. [Diagram 25] FIG. 1 is a diagram showing a conventional method for determining surge propagation speed using a switching surge waveform of a pole-mounted switchgear. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention will now be described.

[0024] In the present invention, broadly speaking, a tree-structured distribution line is configured by combining nodes (utility poles and distribution equipment) and branches (distribution lines) so that it is a continuous connection, including branch lines, from the starting substation to the end, and a distribution line model is constructed using a general-purpose computer, a storage device, a program, and a necessary information data group, in which the electrical constants (RLC electrical circuit) of the branch lines and the distribution equipment of the nodes are associated and the nodes are connected by branches, in which the distribution line is modeled as an electrical circuit equivalent, and a fault model is constructed in which switches are included in one or more or all of the three-phase three-wire lines and between each line, and between each line and the ground, and the distribution line model and fault model are used to obtain virtual surge waveform data by simulation.

[0025] FIG. 1 is a diagram showing a schematic diagram of a power distribution line having a tree structure.

[0026] In order to construct a distribution line model of the tree-structured distribution line in Fig. 1, information consisting of the impedance of the distribution transformer 1, the impedance to ground of the three-phase power source 2 and the earthing transformer 3, the line constants of the three-phase three-wire distribution line 4, and the capacitance to ground of the utility poles and distribution equipment 5 installed on utility poles, etc. (hereinafter referred to as constant information (see Fig. 6)) is made into a database. A specific distribution line 6 that propagates a surge waveform within a substation (bank) is a combination of 5 nodes (utility poles and distribution equipment) and 4 branches (distribution lines) that connect them. In addition, the nodes in Fig. 1 are based on utility pole units, and the branches that connect them are composed of the three-phase three-wire electrical equivalent circuits of the lines between the nodes and the distribution equipment, and are simply described here as a single line. In addition, as will be described later, a fault model and a waveform observation point are set at a specific node.

[0027] The distribution line connection information starting from a substation of a specific distribution line 6 includes, as connection information at a branch connecting utility poles that are nodes based on one utility pole unit, the length and type of overhead wire or power cable used for the distribution line of the branch, the utility pole number (unique number) of the own utility pole that is the node and the counterpart utility pole on the load side, the pole-mounted switch and voltage regulator installed at the branch as utility pole span information of DATA1 in Fig. 3, the pole-mounted transformer capacity installed on the utility pole and the contract capacity of the high-voltage customer's power receiving equipment as pole-mounted transformer information of DATA2 in Fig. 4 and high-voltage customer equipment information of DATA3 in Fig. 5, and these are stored in a database by substation bank unit for each substation. By setting the counterpart utility pole of the distribution line connection information of the tree-structured distribution system to the load side from the own utility pole, it shows the connection information of all lines starting from the substation to the terminal including the branch to the load side. For this database, a database managed by a power company may be used, or the distribution line connection information (DATA1 in FIG. 3, DATA2 in FIG. 4, and DATA3 in FIG. 5) may be extracted and edited by extracting only specific distribution line connection information from a distributed data group. The line constants of the distribution line and the capacitance constant to ground according to the distribution equipment in the constant information in FIG. 6 may be obtained from catalog values ​​or actual measurements.

[0028] Surge waveform propagation is affected not only by the path along which the surge waveform propagates from the faulty utility pole to the waveform observation utility pole (waveform observation point), but also by the impedance of the distribution transformer at the substation and the branch lines of the specific distribution line 6 and other circuits 7 other than the specific distribution line 6 in the same bank. For this reason, the distribution line model requires information on a substation bank basis, and is configured with an electrical equivalent circuit based on the distribution line connection information on a substation bank basis, with the utility pole as the base, and mainly on the distribution equipment's capacitance to ground, as shown in the constant information in Figure 6.

[0029] In addition, in consideration of the processing power of a general-purpose computer and the calculation time required for constructing a model, it is possible to combine multiple pieces of distribution line connection information (Figs. 3 to 5) between utility poles into one piece using constant information (Fig. 6). In particular, for branch lines and other distribution lines other than the surge waveform propagation path from the faulted utility pole to the waveform observation utility pole (waveform observation point), it is effective in reducing the processing load on a general-purpose computer to integrate and combine the capacitances to ground, including all the distribution equipment included in the line, into a single electrical equivalent circuit.

[0030] The construction of the power distribution line model and the fault model and the power distribution line surge waveform propagation simulation function are executed by making a general-purpose computer function with a dedicated program and a general-purpose circuit analysis program. The dedicated program has a function of generating model code of an electrical equivalent circuit that can be simulated in the general-purpose circuit analysis program and a function of controlling the general-purpose circuit analysis program by an external command.

[0031] Next, the dedicated program will be described.

[0032] Figure 2 shows a flowchart of the dedicated program. Note that the numbers with "S" indicate steps.

[0033] In S101 (information data reading process), data files of simulation condition information, distribution line connection information (FIGS. 3 to 5), and constant information (FIG. 6) are read from the storage device in which they are stored, and are saved in the memory of a general-purpose computer.

[0034] The simulation condition information includes information on the specific distribution line through which the surge waveform is propagated, the faulty phase, the faulty utility pole, the fault timing, the waveform observation utility pole (waveform observation point), the time series resolution (simulation calculation interval), and the time series record length (simulation calculation time).

[0035] The distribution line connection information is tree-structured distribution line connection information starting from the substation of the substation bank to which a specific distribution line belongs to the load side, and is made up of DATA1 (electric pole span information) in Fig. 3, DATA2 (pole transformer information) in Fig. 4, DATA3 (high voltage customer equipment information) in Fig. 5, and other information on substation equipment, and is made up of connections between nodes and branches of electrical equivalent circuits. The constant information is DATA4 (constant information) in Fig. 6, and the constant information is used to set the numerical values ​​of the constants of the multiple electrical equivalent circuits.

[0036] DATA1 (utility pole span information) consists of a group of records of basic information for the branches between nodes starting from the substation to the end of the branch line in substation bank units, and includes the own utility pole number and the other utility pole number that are the nodes, as well as information on the type of wire and length of the line. Since the substation is the starting point, the other utility pole node is created so that it is on the load side of the own utility pole node.

[0037] DATA2 (pole transformer information) consists of a group of records of pole transformers installed in the same substation bank, and includes information such as the pole number of the installation location and the capacity of the pole transformer.

[0038] DATA3 (high-voltage customer equipment information) consists of a group of records of high-voltage customers installed in the same substation bank, and includes information such as the pole number of the installation location and the contract capacity of the power receiving equipment.

[0039] DATA4 (constant information) includes power supply information of the substation equipment, line constants of each distribution line type per unit, and capacitance to ground for each distribution equipment, etc. The information in DATA1 to DATA4 is shown as an example and is not limited thereto.

[0040] Returning to Fig. 2, in S102 (intermediate data generation process), an electrical equivalent circuit for one branch that is the basis between utility poles that are nodes of the distribution line model based on the utility pole unit is constructed, and intermediate data required for generating a distribution line model code that can be simulated by a general-purpose circuit analysis program is generated. The process in S102 (intermediate data generation process) will be described in detail later.

[0041] Figure 7 shows an example of DATA5 (intermediate data), which can be generated based on information from the record groups DATA1 (utility pole span information), DATA2 (pole transformer information), and DATA3 (high-voltage customer equipment information) and DATA4 (constant information).

[0042] DATA1 (utility pole span information) has records of data between one utility pole for each substation bank, and the total number of records in DATA1 (utility pole span information) and the number of records in DATA5 (intermediate data) will match. Figure 8 shows the relationship between the intermediate data and other information. DATA5 (intermediate data) is composed of information such as the utility pole span information in DATA1, the pole-mounted transformer information in DATA2, and the high-voltage customer equipment information in DATA3, and is composed of the constant information in DATA4. In a tree-structured distribution system, nodes are based on utility poles, and DATA5 (intermediate data) is branch information that constitutes branches that connect nodes, with the partner utility pole being on the load side of the own pole, and shows connection information starting from the substation to the end, and the branches are composed of electrical equivalent circuits, and the distribution system is expressed by the connection of multiple electrical equivalent circuits. The pole-to-pole line constants and distribution equipment-to-ground capacitance constants in DATA5 (intermediate data) are calculated as circuit constants of the electrical value circuit, and here the pole transformer (DATA2) installed on the other pole, which is the node connected to the load side of the own pole node, and the distribution equipment of the high-voltage consumer (DATA3) are configured as part of the distribution equipment ground capacitance. This is because the other pole node on the load side for the branch connecting the own pole node and the other pole node is uniquely determined, so the equipment ground capacitance can be set accurately without duplication. The own pole, which is the node on the power source side for the branch, has multiple branches for one node at the branch point, so the node for the branch cannot be uniquely determined. DATA5 (intermediate data) shows the branch and is composed of an electrical equivalent circuit, and the electrical equivalent circuit here is characterized as a T-type circuit.

[0043] Intermediate data required for S104 (distribution line model code generation process) is generated by S102 (intermediate data generation process), and code that can be simulated by a general-purpose circuit analysis program is generated by the following processes from S103.

[0044] In S103 (code generation process for three-phase power supply, etc.), the impedance of the distribution transformer taking into account the upper system and the impedance to ground of the three-phase power supply and the earthing transformer are calculated based on the substation equipment information of the distribution line connection information and DATA4 (constant information), and a code is generated in the memory of a general-purpose computer.

[0045] Figure 9 shows a model based on a three-phase three-wire system, with the main power supply composed of each phase power supply and the distribution transformer's phase reactance considering the upper system, the earthing transformer composed of a three-winding wire and a limiting resistor, and the model code is generated in S103 (three-phase power supply code generation process). In Figure 9, N+0, N+1, and N+2 indicate the nodes for each phase and refer to the first utility pole on the substation side.

[0046] In S104 (distribution line model code generation process), node numbers are assigned so that the substation is continuously connected to the terminal including the branch line based on the own utility pole number and the other utility pole number of DATA5 (intermediate data), and at the same time, a code that can be simulated by a general-purpose circuit analysis program is generated in the memory of a general-purpose computer based on the branch information (inter-utility pole line constant values ​​of R, L, and C) of DATA5 (intermediate data). For example, if the record group of DATA5 (intermediate data) is REC01 to REC05 shown in Fig. 10, the continuous distribution line system based on the own utility pole number and the other utility pole number will be as shown in Fig. 11.

[0047] Next, consecutive nodes are assigned to each utility pole based on Fig. 11. Fig. 12 shows this. Among REC01 to REC05, records with multiple own utility pole numbers (for example, REC02 and REC04) indicate that the utility pole has a branch line. Since the electrical equivalent circuit indicated by the record of DATA5 (intermediate data), which is the minimum configuration of the distribution line model, is configured as a three-phase T-type circuit, as shown in Fig. 13, new nodes are provided for the distribution equipment-to-ground capacitance and the ground capacitance due to the line constant C between utility poles, with the electrical equivalent circuit of the node and the branch between the nodes being a T-type circuit based on the utility pole unit, and the node numbers are assigned based on N+0, and at the same time, branch information is assigned based on DATA5 (intermediate data).

[0048] Figure 14 shows an image of the node number and branch information of one record (between one utility pole) of DATA5 (intermediate data) model coded. In this way, all records of DATA5 (intermediate data) are model coded. Note that the phases N+0, N+1, and N+2 of the first utility pole on the substation side in Figure 13 match the node numbers N+0, N+1, and N+2 of each phase of the substation equipment in Figure 9 in S103 (code generation process for three-phase power supply, etc.).

[0049] In S105 (fault model code generation process), a fault model code is generated in the memory of a general-purpose computer from the simulation condition information, namely, the fault phase (one or more of each line of the three-phase three-wire system, between each line, and between each line and ground), the faulty utility pole (the node is identified from the utility pole number), the fault resistance value (Rg), and the fault timing (the time timing of the on-time t1 and the off-time t2, which may be the phase timing of the power supply voltage).

[0050] Fig. 15 shows a hypothetical fault model consisting of an open / close switch S that connects specified nodes N+n and XX+n, and a fault resistor Rg that connects node XX+n and the ground, and Fig. 16 shows an image of fault model coding. Here, the lines are a simplified representation of a three-phase three-wire system represented by one line, and the open / close switch S between the lines and the ground is a one-line ground fault in one of the three lines. Open / close switches can also be set between each line and between the lines and the ground, making it possible to represent various faults. In this way, a fault model can be set at any node.

[0051] As described above, the power distribution line model code and the fault model code are generated by S101 to S105, and the power distribution line model and the fault model are constructed.

[0052] FIG. 17 shows a schematic diagram of a power distribution line, and FIG. 18 shows a virtual power distribution line model in which the schematic power distribution line of FIG. 17 is modeled as a T-shaped RLC electrical equivalent circuit of a three-phase three-wire system.

[0053] In S106 (surge current / voltage calculation code generation process), calculation conditions are set based on the waveform observation utility pole (waveform observation point) in the simulation condition information, in this case to measure the surge zero-phase current and voltage by combining the voltage of each phase of the three-phase distribution line and the current of each phase, and the calculation code is generated in the memory of a general-purpose computer. Since what is observed as a surge is calculated as the current and voltage of each phase, it is also possible to observe the surge current and voltage of each phase individually. In this way, the waveform observation point can be arbitrarily set to a node that is a utility pole.

[0054] In S107 (calculation condition code generation process), a calculation condition code for the simulation calculation time and calculation interval is generated in the memory of a general-purpose computer from the time series resolution (simulation calculation interval) and time series record length (simulation calculation time) indicated in the simulation condition information. If not indicated, the default values ​​are, for example, 50 milliseconds for the calculation time and 0.1 microseconds for the calculation interval.

[0055] In S108 (file saving process), the model code data generated in the memory up to this point is stored as a data file in a specified folder in the storage device.

[0056] In S109 (simulation start process), the external command that enables the simulation and the information of the model code data file stored in the specified folder are passed as arguments to the general-purpose circuit analysis program, and the simulation is started. As a result, virtual surge waveform data (discrete data and time data) of the specified surge waveform observation utility pole (waveform observation point) is generated in the memory of the general-purpose computer.

[0057] In S110 (waveform data file saving process), the virtual surge waveform data obtained by the simulation of the general-purpose circuit analysis program is stored as a data file in a specified folder in the storage device. Here, an external command that enables file saving and information on the specified folder are passed as arguments, and the virtual surge waveform data file is saved.

[0058] Next, the process in S102 (intermediate data generation process) will be described in detail with reference to Fig. 19, which is a specific flowchart of S102 (intermediate data generation process).

[0059] In S201 (set line constants), the line constants R, L, and C calculated based on DATA4 (constant information) from the line type, size, and length in DATA1 (pole span information) are stored in a memory area (variable) for the inter-pole line constant R, a memory area (variable) for the inter-pole line constant L after calculation, and a memory area (variable) for the ground-to-ground capacitance constant C.

[0060] In S202 (distribution equipment constant (insulator) setting), it is assumed that there are two insulators per electric wire on the utility pole, and the insulator constant C calculated based on DATA4 (constant information) is added and stored in the memory area (variable) for the capacitance constant C to ground.

[0061] In S203 (distribution equipment constant (pole-mounted switch) set), if the pole-mounted switch section number in DATA1 (pole span information) is other than 0, the pole-mounted switch constant C calculated based on DATA4 (constant information) is additionally stored in the memory area (variable) for the ground-to-ground capacitance constant C.

[0062] In S204 (setting of distribution equipment constants (overhead ground wire)), the constant C calculated based on the length of DATA1 (utility pole span information) and DATA4 (constant information) is added and stored in the memory area (variable) for the ground-to-ground capacitance constant C.

[0063] In S205 (distribution equipment constant (voltage regulator) set), the voltage regulator constant C calculated based on DATA4 (constant information) from the voltage regulator capacity of DATA1 (utility pole span information) except for 0 kVA is added and stored in the ground capacitance constant C memory area (variable).

[0064] In S206 (pole transformer search), all records in DATA2 (pole transformer information) are searched for that have a matching pole number in DATA1 (pole span information) and a pole number in DATA2 (pole transformer information).

[0065] If one or more pole transformer records are found, proceed from S207 (whether or not there is a pole transformer) to S208 (set distribution equipment constants (pole transformer)), and the pole transformer constant C calculated based on DATA4 (constant information) from the capacity of DATA2 (pole transformer information) is added and stored in the memory area (variable) for the capacitance constant C to ground, and then proceed to S209. However, if no pole transformer records are found, proceed directly to S209.

[0066] In S209 (high voltage customer equipment search), all records in DATA3 (high voltage customer equipment information) are searched for that have a matching pole number in DATA1 (utility pole span information) and a pole number in DATA3 (high voltage customer equipment information).

[0067] If a record of the high-voltage customer equipment is found, proceed from S210 (presence or absence of high-voltage customer equipment) to S211 (set distribution equipment constants (high-voltage customer equipment)), and add the constant C of the high-voltage customer equipment calculated based on DATA4 (constant information) from the contract capacity of DATA3 (high-voltage customer equipment information) to the memory area (variable) for the ground-to-ground capacitance constant C, and then proceed to S212. However, if no record is found, proceed directly to S212.

[0068] In S212 (belonging of distribution line), it is determined whether it is a specific distribution line that propagates a surge waveform within the bank or another line, and if it is determined to be a specific distribution line, in S213 (generate record of specific distribution line), the constants stored in the memory area (variables) up to that point are stored as one record. Also, if it is determined to be another line, in S215 (generate record of other lines), the ground-to-ground capacitances C of all other lines are generated together as one record. Note that the line constants R and L of the other lines are dummy values. Here, a distinction is made between a specific distribution line and another line, but all may be expressed in terms of utility poles, and there is no restriction on the distribution line model as to whether they should be grouped together as an electrical equivalent circuit.

[0069] In S214 (EOF), it is determined whether all records of DATA1 (utility pole span information) have been completed, and the process of generating intermediate data (DATA5) is repeated until all records have been completed. The number of records in DATA5 (intermediate data) and DATA1 (utility pole span information) is the same, and is the same as the number of branches connecting nodes that are utility poles, and is also the same as the number of nodes (partner utility poles) on the load side of the branches. In other words, this process means that it is possible to cover all the line connections (branches) within the bank.

[0070] When the above S102 (intermediate data generation process) is completed, intermediate data necessary for generating a distribution line model code that can be simulated by a general-purpose circuit analysis program is generated. Here, the line load is not expressed, but it may be expressed.

[0071] Example 1 In Example 1, for a distribution line where an actual surge waveform at the time of a single-line ground fault in a fault was observed, a virtual distribution line model was constructed based on the schematic distribution system shown in FIG. 20, and a simulation was performed.

[0072] The measured surge waveform has the time synchronized by GPS recorded, and time series data (discrete data and time data) of the surge waveform passing through surge observation poles A, B, and C is recorded.

[0073] 21 shows a comparison between the virtual surge waveform obtained by the simulation in Example 1 and the actually measured surge waveform. The arrival portion of the virtual surge waveform can be determined by focusing on the rising change portion of the surge waveform, and it was confirmed that the actual surge waveform and the virtual surge waveform are similar to each other.

[0074] In this simulation, the sampling period (the simulation calculation interval) was set to 0.1 μsec, but is not limited to this. The time series record length (simulation calculation time) of the general-purpose circuit analysis program was set to 2 msec, and the fault timing was set to close the circuit using a switch at an arbitrary earth-to-earth voltage phase and arbitrary earth-fault resistance at the earth fault point 1 msec after the start of calculation. Note that various methods can be applied to analyze the difference in arrival time of the target surge waveform, such as human observation and judgment, the threshold method, and the two-voltage method.

[0075] Example 2 In Example 2, a virtual distribution line model was constructed based on the schematic distribution system of FIG. 22, which is a distribution line different from that in Example 1, and a comparison was made between the actually measured surge waveform in the event of a one-line ground fault and the virtual surge waveform obtained by simulation.

[0076] Fig. 23 shows a comparison between the virtual surge waveform obtained by the simulation in Example 2 and the actually measured surge waveform. As can be seen from Fig. 23, the actual surge waveform and the virtual surge waveform are similar, and it is understood that the arrival time of the surge waveform in the event of a ground fault can be predicted by determining the propagation state (analysis) and arrival time of the surge waveform in the event of a ground fault by simulation.

[0077] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified in various ways. In the present invention, for example, a simulation can be performed using a known general-purpose circuit analysis program, but an original simulation program may be created and used to perform the simulation. In addition, for example, the standard for each utility pole may be a group of a plurality of poles, or a group of a plurality of pole-mounted transformers or switches installed in a single utility pole unit, as long as the distribution line does not include a waveform observation point.

[0078] It is also possible to determine the difference in arrival time of the surge waveform at any number of points, and further, the surge propagation speed can be determined from the difference in arrival time of the surge waveform at multiple points and the distance between those points.

[0079] Furthermore, the present invention can be realized not only as a power distribution line surge waveform propagation model simulation method, but also as a power distribution line surge waveform propagation model simulation device and a power distribution line surge waveform propagation simulation computer system.

[0080] Specifically, a distribution line surge waveform propagation simulation device that simulates the propagation of a surge waveform of a surge voltage or surge current generated by a fault in a distribution line includes a distribution line model in units of a substation bank that includes one or more, or all, of the impedances of the three-phase power source and distribution transformer, the impedance to ground of the grounding transformer, the line constants of a three-phase, three-wire distribution line, and the earth capacitances of the distribution equipment and high-voltage consumer equipment installed on the distribution line, a fault model that includes switches in one or more, or all, of each line of the three-phase, three-wire lines, between each line, and between each line and the ground, and a means for operating a switch of the fault model based on the fault time timing of the distribution line model or the phase timing of the power source (fault timing), and obtains virtual surge waveform data by measuring the waveform of the surge voltage or surge current at a waveform observation point of any location when the switch of the fault model is operated.

[0081] A computer system for simulating the propagation of a surge waveform of a surge voltage or a surge current generated by a fault in a distribution line includes a storage means for storing information, a processing means for processing information, an output means for outputting data processed by the processing means as a file, and an input means for receiving a command from an external program, the storage means storing distribution line connection information of an actual distribution system for each substation bank, a line constant of a distribution line per unit length, and constant information of a capacitance to ground for each distribution facility, and the input means storing specific simulation condition information from outside, such as a constant distribution line, a faulted phase, a faulted utility pole, fault timing, a waveform observation utility pole (waveform observation point), a time series resolution (simulation calculation interval), a time series record length (simulation calculation interval), a time series record length (time series record length ... When a virtual ground fault is generated at the timing of the virtual ground fault read by the input means, the processing means automatically reads in the distribution line connection information and the constant information for each substation bank from the storage means, and the processing means associates the line constants and the earth capacitance for each distribution equipment with the distribution line length and the distribution equipment position, generates in the memory an electrical equivalent circuit of a distribution line model based on a utility pole unit, and generates in the memory a fault model based on the faulted phase, the faulted utility pole, and the waveform observation utility pole (waveform observation point) read by the input means, and the processing means starts a simulation based on the time series resolution (simulation calculation increment) and time series record length (simulation calculation time) read by the input means, generates a virtual ground fault at the timing of the virtual ground fault read by the input means, and stores the time series data of the virtual surge waveform of the waveform observation utility pole (waveform observation point) in the storage means as a file. It should be noted that the "time" in the present invention does not necessarily mean an absolute time, but may also mean a relative time (hour) based on, for example, the time when the switch of the fault model is turned on. [Explanation of symbols]

[0082] 1. Distribution transformer 2...Three-phase power supply 3. Grounding transformer 4. Power distribution lines 5. Utility poles and distribution equipment 6...Specified distribution line N + n (n:0, 1, 2,...)...node (name) REC01~REC05: Intermediate data records AA01~AA04, BB02, BB03...Pole number S101: Step for reading simulation condition information, distribution line connection information, and constant correspondence table S102: Intermediate data generation process step S103: Step for generating code for three-phase power supply, etc. S104: Power distribution line model code generation process step S105: Fault model code generation process step S106: Surge current / voltage calculation code generation process step S107: Calculation condition code generation process step S108 File save process step S109: Simulation start processing step S110: Waveform data file saving process step S101: Step to read simulation condition information, distribution line connection information, and constant correspondence table S102: Intermediate data generation process step S103: Step for generating code for three-phase power supply, etc. S104: Power distribution line model code generation process step S105: Fault model code generation process step S106: Surge current / voltage calculation code generation process step S107: Calculation condition code generation process step S108 File save process step S109: Simulation start processing step S110: Waveform data file saving process step S201: Step for setting line constants S202: Steps for setting distribution equipment constants (insulators) S203: Steps for setting distribution equipment constants (pole-mounted switches) S204: Steps for setting distribution equipment constants (overhead ground wire) S205: Steps for setting distribution equipment constants (voltage regulators) S206: Pole transformer inspection steps S207: Step to determine whether or not there is a pole-mounted transformer S208: Steps for setting distribution equipment constants (pole transformers) S209: Steps for investigating high-voltage consumer equipment S210: Step to determine whether high-voltage consumer equipment is present S211: Step for setting distribution equipment constants (high voltage customer equipment) S212: Step for determining the distribution line's affiliation S213: Step for creating a specific distribution line record S214: Step for determining whether all records of utility pole span information have been completed S215: Steps for creating other line records

Claims

1. A distribution line surge waveform propagation simulation method, in a fault location method for identifying a fault point in a distribution line using a surge voltage or surge current generated from the fault point, characterized in that the propagation of a surge waveform of a surge voltage or surge current in the distribution line is simulated by constructing a distribution line model and obtaining virtual surge waveform data, thereby determining the arrival time of the surge waveform in any location in the distribution line.

2. 2. The method for simulating surge waveform propagation on a power distribution line according to claim 1, further comprising the step of: determining a difference in arrival time of the surge waveform at a plurality of said arbitrary locations;

3. 3. The method for simulating surge waveform propagation on a power distribution line according to claim 2, further comprising the step of: determining a surge propagation speed from a difference in arrival time of the surge waveform at the plurality of locations and a distance between the locations.

4. A step of generating a distribution line model including one or more, or all of the following: a three-phase power source, an impedance of a distribution transformer, an impedance to ground of a grounding transformer, a line constant of a three-phase three-wire distribution line, and an earth capacitance of a distribution facility and a high-voltage customer facility installed on the distribution line; A step of generating a fault model including a switch in each line of a three-phase three-wire system, between each line, and between each line and ground, or in any one or more of these, and A step of operating a switch of the fault model according to a fault time timing of the power distribution line model or a phase timing of a power supply voltage, 4. The method for simulating a surge waveform propagation in a power distribution line according to claim 1, further comprising the steps of: measuring a waveform of a surge voltage or a surge current at a waveform observation point of an arbitrary location when a switch of the fault model is operated, and obtaining virtual surge waveform data.

5. The method for simulating a surge waveform propagation in a power distribution line according to claim 4, characterized in that the power distribution equipment of the power distribution line model includes one or more of a power distribution line (overhead wire / power cable), an insulator, a lightning arrester, an arcing horn, a pole-mounted transformer, a pole-mounted switchgear, a voltage regulator, and an overhead ground wire.

6. 6. The method for simulating surge waveform propagation on a power distribution line according to claim 4 or 5, characterized in that the power distribution line model is based on a one-span unit with the same line length and distribution equipment arrangement as the power distribution line, and the power distribution line model is configured in one-span units, or is configured by integrating a plurality of pole-span units into one equipment based on the one-span unit.

7. 7. The method for simulating a surge waveform propagation in a power distribution line according to claim 4, wherein the fault model uses a fault phase, a fault timing, and a fault resistance of an occurred fault.

8. A power distribution line surge waveform propagation simulation device that simulates the propagation of a surge waveform of a surge voltage or surge current generated from a fault point in a power distribution line, a distribution line model including one or more, or all of the following: a three-phase power source, an impedance of a distribution transformer, an impedance to ground of a grounding transformer, a line constant of a three-phase three-wire distribution line, and an earth capacitance of a distribution facility or a high-voltage consumer facility installed on the distribution line; A fault model including a switch in any one or more of, or all of, each line of a three-phase three-wire system, between each line, and between each line and ground; A means for operating a switch of the fault model according to a fault time timing of the power distribution line model or a phase timing of a power supply voltage, A power distribution line surge waveform propagation simulation device, characterized in that a waveform of a surge voltage or surge current is measured at an arbitrary waveform observation point when a switch of the fault model is operated, and virtual surge waveform data is obtained.

9. A computer system for simulating a surge waveform propagation in a power distribution line, comprising: a storage means for storing information; a processing means for processing information; an output means for outputting data processed by the processing means as a file; and an input means for receiving a command from an external program, the computer system simulating the propagation of a surge waveform of a surge voltage or a surge current generated from a fault point in the power distribution line, the storage means stores distribution line connection information of an actual distribution system for each substation bank, a line constant of a distribution line per unit length, and constant information of a capacitance to ground for each distribution facility; the input means, when a specific distribution line, a faulted phase, a faulted utility pole, a fault timing, a waveform observation utility pole (waveform observation point), a time series resolution (simulation calculation interval), and a time series record length (simulation calculation time) through which a surge waveform is propagated within the substation bank unit are specified from the outside as simulation condition information, automatically reads the distribution line connection information and the constant information for the substation bank unit from the storage means; The processing means associates the line constants and the capacitance to ground for each of the distribution equipment with the distribution line length and the distribution equipment location, generates an electrical equivalent circuit of a distribution line model based on one utility pole unit in a memory, and generates a fault model in a memory based on the faulty phase, the faulty utility pole, and the waveform observation utility pole (waveform observation point) read by the input means, The processing means starts a simulation based on the time series record length (simulation calculation time) and time resolution (simulation calculation interval) read by the input means, generates a virtual fault at the fault timing read by the input means, and stores time series data of a virtual surge waveform of a waveform observation utility pole (waveform observation point) in the storage means as a file.

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