Information processing device, information processing method, and information processing program

Abstract

To provide an information processing device capable of accurately outputting information on a point of failure in the event of a power system ground fault.SOLUTION: There is provided an information processing device comprising: an acquisition unit for acquiring, from sensors installed in a power system, first waveform data of zero-phase current or zero-phase voltage after occurrence of a ground fault; an extraction unit configured to extract a resonance frequency of the power system caused by the ground fault based on the first waveform data under a condition of being equal to or less than a predetermined first frequency and / or equal to or greater than a predetermined second frequency lower than the first frequency; and an output unit configured to output information on a point of failure from the extracted resonance frequency using a predetermined relationship between points of failure and resonance frequencies at the time of a ground fault. The first frequency represents a maximum possible computation value of the resonance frequency computed based on a type of ground fault and system information representing components of the power system and electrical characteristics of the components, while the second frequency is a minimum possible computation value.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an information processing device, an information processing method, and an information processing program. [Background technology]

[0002] 2. Description of the Related Art There is known a technique for locating a fault point when a ground fault occurs in a power system.

[0003] For example, Patent Document 1 discloses a means for locating a fault point based on a resonant frequency determined from waveform data of a current in a power system in which a ground fault has occurred. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-165225 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the means described in Patent Document 1, for example, due to the presence of a discharge current of a distribution line of a ground fault phase, a reflected wave of a current generated at the end of a distribution line, or other noise, a peak may appear in the spectrum in a frequency band where no resonant frequency can be found.

[0006] In such a case, it becomes difficult to obtain the resonant frequency, and the location accuracy may deteriorate.

[0007] The present invention has been made in consideration of such problems, and aims to provide an information processing device that can accurately output information on the fault point when a ground fault occurs in a power system. [Means for solving the problem]

[0008] One invention for achieving the above-mentioned object is an information processing device that outputs information on a fault point when a ground fault occurs in an electric power system, comprising: an acquisition unit that acquires first waveform data of zero-phase current or zero-phase voltage after a ground fault occurs from a sensor installed in the electric power system; an extraction unit that extracts a resonant frequency of the electric power system due to the ground fault based on the first waveform data under at least one of conditions of being lower than a predetermined first frequency or higher than a predetermined second frequency lower than the first frequency; and an output unit that outputs information on the fault point from the extracted resonant frequency using a predetermined relationship between the fault point and the resonant frequency when the ground fault occurs, wherein the first frequency is the maximum value that the calculated value of the resonant frequency can take, calculated based on system information indicating the components of the electric power system and the electrical characteristics of the components, and the type of the ground fault, and the second frequency is the minimum value that the calculated value can take.

[0009] Also, an information processing method for outputting information on a fault point when a ground fault occurs in a power system includes the steps of: an information processing device acquiring first waveform data of zero-phase current or zero-phase voltage after a ground fault occurs from a sensor installed in the power system; extracting a resonant frequency of the power system due to the ground fault based on the first waveform data under at least one of conditions of being lower than a predetermined first frequency or higher than a predetermined second frequency lower than the first frequency; and outputting information on the fault point from the extracted resonant frequency using a predetermined relationship between the fault point and the resonant frequency when the ground fault occurs, wherein the first frequency is the maximum value that the calculated value of the resonant frequency can take, calculated based on system information indicating the components of the power system and the electrical characteristics of the components, and the type of the ground fault, and the second frequency is the minimum value that the calculated value can take.

[0010] Also, there is provided an information processing program that outputs information on a fault point when a ground fault occurs in a power system, the information processing device realizing an acquisition unit that acquires first waveform data of zero-phase current or zero-phase voltage after a ground fault occurs from a sensor installed in the power system, an extraction unit that extracts a resonant frequency of the power system due to the ground fault based on the first waveform data under at least one of conditions of being lower than a predetermined first frequency or higher than a predetermined second frequency lower than the first frequency, and an output unit that outputs information on the fault point from the extracted resonant frequency using a predetermined relationship between the fault point and the resonant frequency when the ground fault occurs, wherein the first frequency is the maximum value that the calculated value of the resonant frequency can take, calculated based on system information indicating the components of the power system and the electrical characteristics of the components, and the type of the ground fault, and the second frequency is the minimum value that the calculated value can take. Effect of the Invention

[0011] According to the present invention, it is possible to provide an information processing device capable of outputting information on a fault point with high accuracy when a ground fault occurs in a power system. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing an example of a power system 1 in which an information processing device 2 locates a fault point. [Diagram 2] 2 is a diagram illustrating a hardware configuration of an information processing device 2. FIG. [Diagram 3] FIG. 2 is a diagram illustrating functional blocks of the information processing device 2. [Figure 4] FIG. 1 is a diagram illustrating a distribution line 11 in which a ground fault has occurred. [Diagram 5] FIG. 2 is a diagram showing an example of waveform data D1. [Figure 6] FIG. 2 is a diagram showing an equivalent circuit of the power system 1 when a single line-to-ground fault occurs at one node. [Figure 7] FIG. 2 is a diagram showing an RLC circuit obtained by condensing an equivalent circuit of the power system 1. [Figure 8]FIG. 13 is a diagram showing a spectrum obtained by performing a fast Fourier transform on waveform data D1. [Figure 9] This is a spectrum obtained by performing a fast Fourier transform on the waveform data D2. [Figure 10] FIG. 11 is a diagram showing a predetermined relationship between a fault point and a resonant frequency when a ground fault occurs. [Figure 11] 13 is a flowchart illustrating a process executed by the information processing device 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] == Implementation form == <<Power system 1>> 1 is a diagram showing an example of a power system 1 in which an information processing device 2 described later locates a fault point. The power system 1 includes a distribution substation 10, a distribution line 11, and a plurality of nodes N installed at predetermined positions on the distribution line 11. k (k is a natural number) and sensor-equipped switches SW1 and SW2 installed at predetermined positions on the distribution line 11.

[0014] [Distribution Substation 10] The distribution substation 10 transforms the voltage supplied from a transmission line (not shown) and outputs a voltage of 6.6 kV to the distribution line 11.

[0015] [Power distribution line 11] A plurality of distribution lines 11 are radially connected to the distribution substation 10, with the distribution substation 10 serving as the origin (sending node). Only one distribution line 11 is shown in Fig. 1. The distribution line 11 is a three-phase AC distribution line.

[0016] [node] Multiple nodes N k (1≦k≦M) are provided on a power distribution line 11. In FIG. 1, nodes N1 to N4 are shown. In this embodiment, the node is an aggregation unit managed on a pole transformer (not shown) basis. Node N kA load and a consumer such as a solar power generation facility are connected to the distribution substation 10 via a pole transformer. The power output from the distribution substation 10 to the distribution line 11 is k The power is supplied to consumers via

[0017] [Switches with sensors SW1, SW2] The sensor-equipped switches SW1 and SW2 are switches having sensors capable of measuring measurement values ​​at their installed positions at regular intervals. The measurement values ​​of the sensor-equipped switches SW1 and SW2 include at least the voltage of the distribution line 11 and the current flowing through the distribution line 11 at the installation points of the sensor-equipped switches SW1 and SW2. The measurement values ​​of the sensor-equipped switches SW1 and SW2 are output to and stored in a measurement value DB3 (described later).

[0018] In this embodiment, two sensor-equipped switches SW1 and SW2 are installed on one distribution line, but there is no particular limit to the number of sensor-equipped switches.

[0019] Next, before describing the information processing device 2, the measurement value DB 3 and system information DB 4 will be described.

[0020] <<Measurement value DB3>> The measurement value DB3 stores the measurement values ​​of the sensor-equipped switches SW1 and SW2. The measurement values ​​of the sensor-equipped switches SW1 and SW2 are used when the information processing device 2 locates the position of a fault point. The measurement value DB3 stores the measurement values ​​measured within a predetermined period of time in the past (for example, one week).

[0021] <<System information DB4>> The system information DB 4 stores system information I1 of the power system 1 and information I2 regarding the power system 1 at the time of a fault.

[0022] <System information I1> The system information I1 is information indicating components of the power system 1 and electrical characteristics of the components. The system information I1 includes information indicating the position of a node, information indicating a connected node, information on impedance, and information on ancillary devices.

[0023] That is, in this embodiment, the nodes on the power distribution line 11 are assigned node numbers that are greater on the downstream side of the power distribution line 11.

[0024] Note that the method of assigning node numbers here is merely an example and is not limited to this. Any method of assigning node numbers that allows each of a plurality of nodes to be identified may be used.

[0025] In the following description, "node N k " (k is a natural number), this refers to the node assigned node number k.

[0026] Returning to the explanation of the system information I1, the information indicating the node position, the information relating to impedance, and the information relating to the connected node will be explained.

[0027] [Information indicating the node's location] The information indicating the node positions is information for identifying the positions of each of a plurality of nodes. The information indicating the node positions is a position on a map. The position on the map can be expressed by latitude and longitude.

[0028] [Information about the connected node] The information about the connected nodes is stored in multiple nodes N k The nodes N1 are adjacent upstream for each of the nodes (2≦k≦M). Note that the most upstream node, node N1, does not have information about the nodes to which it is connected.

[0029] [Information about impedance] The information about impedance is, for example, impedance Z for the power system 1. When the current injected into each of the multiple nodes is I and the voltage of each of the multiple nodes is V, the impedance Z is expressed by the following equation.

number

[0030] In the following description, the power system 1 includes M nodes (nodes N1 to N M In this case, the voltage V, current I, and impedance Z are expressed by the following equations.

number

number

number

[0031] That is, the voltage V and the current I are a matrix with M rows and 1 column, and the impedance Z is a matrix with M rows and M columns. Hereinafter, the impedance Z in Equation 4 will be particularly referred to as the "impedance matrix Z."

[0032] In Equation 2, the component V of the voltage V k (1≦k≦M) is node N k In addition, in Equation 3, the component I of the current I k (1≦k≦M) is node N k is the injection current into the

[0033] In Equation 4, the component Z of the impedance matrix Z kl (1≦k≠l≦M) is the node N k and node N l is the impedance between

[0034] In addition, in Equation 4, the diagonal components Z of the impedance matrix Z kk is the node N k This corresponds to the impedance of the entire power system 1 when the reference voltage is 1.

[0035] [Additional Equipment Information] The auxiliary device information is stored in multiple nodes N kThis is information indicating the auxiliary devices provided in each of the (1≦k≦M) power grids. The auxiliary devices are the sensor-equipped switches SW1 and SW2, the pole transformer, and other devices.

[0036] <Information I2 about power system 1 at the time of the failure> The information I2 on the power system 1 during the fault is k This is information showing an equivalent circuit of the power system 1 according to the type CF of a ground fault when a fault occurs at (1≦k≦M).

[0037] Here, the "ground fault type CF" refers to any one of a single-line ground fault, a double-line ground fault, and a triple-line ground fault. An equivalent circuit of the power system 1 according to the ground fault type CF will be described in detail later with reference to the drawings.

[0038] <<Information processing device 2>> The information processing device 2 is a device that outputs information about a fault point when a ground fault occurs in the power system 1. The hardware configuration and functional blocks of the information processing device 2 will be described below in that order.

[0039] <Hardware configuration of information processing device 2> 2 is a diagram illustrating a hardware configuration of an information processing device 2 according to an embodiment of the present invention. The information processing device 2 is a computer having a CPU (Central Processing Unit) 200, a memory 201, a communication device 202, a storage device 203, an input device 204, an output device 205, and a recording medium reading device 206.

[0040] [CPU200] The CPU 200 executes information processing programs stored in the memory 201 or the storage device 203 to realize various functions of the information processing device 2.

[0041] [Memory 201] The memory 201 is, for example, a RAM (Random-Access Memory) and is used as a temporary storage area for various programs, data, and the like.

[0042] [Communication device 202] The communication device 202 exchanges various programs and data with other computers via the network.

[0043] [Storage device 203] The storage device 203 is a non-transitory (eg, non-volatile) storage device that stores various data to be executed or processed by the CPU 200.

[0044] [Input device 204] The input device 204 is a device that accepts commands and data input by a user, and includes an input interface such as a keyboard and a touch sensor that detects a touch position on a touch panel display.

[0045] [Output Device 205] The output device 205 is, for example, a display or a printer.

[0046] [Recording medium reader 206] The recording medium reader 206 reads various data such as information processing programs recorded on the recording medium 3 such as an SD card, a DVD, or a CD-ROM, and stores the data in the storage device 203 .

[0047] <Function blocks of information processing device 2> 3 is a diagram illustrating functional blocks of the information processing device 2. The information processing device 2 includes an acquisition unit 210, a filter unit 211, an extraction unit 212, and an output unit 213.

[0048] [Acquisition unit 210] The acquisition unit 210 acquires, from a sensor-equipped switch installed in the power system 1, waveform data D1 (corresponding to "first waveform data") of a zero-phase current or a zero-phase voltage after a ground fault occurs.

[0049] In this embodiment, the waveform data D1 is acquired only from the sensor-equipped switch SW1 on the upstream side out of the sensor-equipped switches SW1 and SW2.

[0050] When a ground fault occurs, in the power system 1, the distribution line 11 in which the ground fault has occurred is identified by the protective relay system, and the banks of the power system 1 are notified of the occurrence of the ground fault.

[0051] 4 is a diagram illustrating a distribution line 11 in which a ground fault has occurred. As shown in this figure, when a bank 12 is configured in a power system 1, the distribution line 11 in which a ground fault has occurred is identified. At this time, waveform data D1 is acquired from a sensor-equipped switch SW1 installed in the distribution line 11 in which a ground fault has occurred.

[0052] In this embodiment, the acquiring unit 210 acquires waveform data D1 of a zero-phase current. The acquiring unit 210 acquires, as the waveform data D1, waveform data D1 of a fundamental wave component for a period of one to several cycles after the occurrence of a ground fault.

[0053] 5 is a diagram showing an example of waveform data D1, in which the waveform of the zero-phase current from 50 [msec] to 150 [msec] is shown.

[0054] The time when the ground fault occurred is 100 [msec]. Before 100 [msec], the zero-sequence current is almost zero. After 100 [msec], the zero-sequence current shows a sine wave waveform.

[0055] It is assumed that the time when the ground fault occurred is known, and that no system change such as the opening of a switch by a protective relay or the like occurs during one to several cycles of the waveform data D1.

[0056] [Filter section 211] The filter unit 211 filters the waveform data D1 at a predetermined frequency f u (corresponding to the "first frequency") or a frequency component greater than a given frequency f l (corresponding to the "second frequency") removes frequency components lower than

[0057] In this embodiment, the filter unit 211 filters the waveform data D1 at a frequency f u Higher frequency components and frequency f l Remove smaller frequency components.

[0058] As a result, the filter unit 211 generates waveform data D2 (corresponding to "second waveform data"). l is the frequency f u is a lower frequency than

[0059] The filter unit 211 generates waveform data D2 by applying a bandpass filter to the waveform data D1, the bandpass filter being a combination of a transfer function H2(s) as a lowpass filter and a transfer function H1(s) as a highpass filter, as shown in the following equation, where s is a Laplace operator.

number

number

[0060] The filter unit 211 is an optional configuration and does not necessarily have to be provided. However, for convenience of explanation, the frequency f u and frequency f l I will explain this in detail.

[0061] frequency f u is the maximum value that the resonant frequency F can take, calculated based on the system information I1 and the type of earth fault CF. On the other hand, the frequency f l is the minimum value that the calculated resonant frequency F can take.

[0062] Specifically, the frequency f u is a sending node (node ​​N0) of the power system 1 or a node N downstream of the sending node N0. k1 This is the resonant frequency obtained based on an equivalent circuit (described later) of power system 1 when a ground fault occurs at node (corresponding to the "first node").

[0063] Also, the frequency f l is the node N k1 Node N downstream k2 This is the resonant frequency obtained based on an equivalent circuit (described later) of power system 1 when a ground fault occurs at node (corresponding to the "second node").

[0064] In this embodiment, the node N k1 The node N0 is the sending node, and the node N k2 The downstream end node N of the distribution line 11 M Let us assume that.

[0065] The above-mentioned "equivalent circuit of the power system 1" will be explained. k FIG. 2 is a diagram showing an equivalent circuit of the power system 1 when a line-to-ground fault occurs at (1≦k≦M).

[0066] The information processing device 2 locates the fault point using the voltage, current, and impedance expressed in a symmetric coordinate system expressed by zero phase, positive phase, and negative phase. Therefore, in Fig. 6, the voltage V, the current I, and the impedance matrix Z are given a superscript (0, 1, or 2) indicating that they are expressed in a symmetric coordinate system.

[0067] In the representation using the symmetrical coordinate system, the superscript "0" means zero-sequence, the superscript "1" means positive sequence, and the superscript "2" means negative sequence.

[0068] In Figure 6, Z kk 1 , Z kk 2 and Z kk 0 are the nodes N k These are the positive-phase, negative-phase, and zero-phase impedances on the power grid 1 side as seen from the outside.

[0069] Also, V k 1 , V k 2 and V k 0 are the nodes N kThese are the positive, negative and zero sequence voltages before a fault occurs (when the system is healthy). k 1 , I k 2 and I k 0 are the positive-sequence, negative-sequence and zero-sequence earth fault currents, respectively, after a fault occurs at node k. Also, R k is the resistance of the fault point.

[0070] The possible range of the resonant frequency F can be approximately determined by the following analysis using the equivalent circuit shown in FIG.

[0071] In this analysis, the following six preconditions are imposed. First, the positive and negative sequence components of the line impedance of the distribution line 11 are equal (i.e., the line impedance is balanced). Second, the ends of the distribution line 11 are considered to be open.

[0072] Third, the high resistance grounding point due to the earthing type potential transformer (EVT) on the secondary side of the distribution line 11 is considered to be open. Fourth, the resistance components of the distribution line 11, load, and distribution substation transformer of the phase where no fault occurs (healthy phase) are considered to be in parallel. However, since the resistance component of the distribution substation transformer is sufficiently small compared to the distribution line 11 and the load, the positive sequence component of the distribution line 11 and the load is considered to be zero.

[0073] Fifth, the capacitance to earth of the positive and negative phase components is considered to be short-circuited because the load and pole transformer are inserted in parallel, and the value is set to zero. Sixth, the zero-phase component of the capacitance is set to the capacitance to earth.

[0074] In this case, the equivalent circuit of Fig. 6 can be contracted to the RLC circuit shown in Fig. 7. The resistance R [Ω], inductance L [H], and capacitance C [F] in the RLC circuit of Fig. 7 are expressed by the following equations.

number

number

number

[0075] Here, R f is the resistance of the fault point, d is the distance from the sending node N0 to the fault point, R1 is the line resistance (positive sequence component) per unit length of the distribution line 11 [Ω / km], R0 is the line resistance (zero sequence component) per unit length of the distribution line 11 [Ω / km], R T1 is the resistance value [Ω] of the distribution transformer. Note that "distance" refers to the distance from the sending node N0 unless otherwise specified.

[0076] L1 is the line inductance (positive sequence component) per unit length of the distribution line 11 [H / km], L0 is the line inductance (zero sequence component) per unit length of the distribution line 11 [H / km], L T1 is the reactance of the distribution transformer [H].

[0077] C0 is the ground capacitance per unit length of the distribution line 11 [F / km], and D is the length [km] of the distribution line 11 in the entire distribution system.

[0078] In the RLC circuit of FIG. 7, when resistance R, inductance L, and capacitance C are used, the resonant frequency F [Hz] is expressed by the following formula.

number

[0079] Also, 1 / LC>>(R / 2L) 2 Since the above formula is satisfied, the resonance frequency F of the formula 10 is approximately expressed by the following formula using the formulas 7 to 9.

number

[0080] In the distribution line 11 where a ground fault occurs, the distance d from the sending node N0 to the fault point is between 0 (zero) and d e (the distance to the end of the power distribution line 11). Therefore, the frequency band in which the calculated value of the resonant frequency F can be taken is expressed by the following formula.

number

[0081] From the above, the frequency f u and frequency f l is expressed by the following formula:

number

number

[0082] In other words, f in Equation 13 u is the upper limit of the resonant frequency after a ground fault occurs. l is the lower limit of the resonant frequency after a ground fault occurs.

[0083] [Extraction part 212] Returning to FIG. 4, the extraction unit 212 extracts the resonant frequency of the power system 1 due to a ground fault from the waveform data D1 as a frequency f u or frequency f l Extraction is carried out under at least one of the above conditions.

[0084] 8 is a diagram showing a spectrum obtained by performing a frequency analysis (in this embodiment, a fast Fourier transform) on the waveform data D1. In this diagram, the horizontal axis represents frequency [Hz], and the vertical axis represents intensity [dB].

[0085] Two peaks P1 and P2 can be seen in the spectrum shown in Fig. 8. Peak P1 is a peak that corresponds to the resonance frequency. Peak P2 is a peak caused by an unnecessary waveform such as noise.

[0086] Furthermore, in a frequency band lower than the peak P1, a frequency band having a higher intensity than the two peaks P1 and P2 can be confirmed.

[0087] In FIG. 8, frequency f u and frequency f l The horizontal axis value corresponding to the frequency f is indicated by a dashed line. u Less than or equal to frequency f l Extraction is carried out under the above conditions.

[0088] This results in a frequency f u Less than or equal to frequency f l From the above frequency band, the resonance frequency F corresponding to the peak P1 can be extracted.

[0089] In this case, if the above condition (frequency f u Less than or equal to frequency f l If the above conditions are not imposed, there is a possibility that the resonance frequency corresponding to peak P1 will not be extracted as the resonance frequency. For example, there is a possibility that either the frequency corresponding to peak P2 or a frequency in a lower frequency band than peak P1 will be erroneously extracted. According to the extraction unit 212 of this embodiment, it is possible to prevent such errors.

[0090] As described above, the filter unit 211 may have any configuration. The method of extracting the resonant frequency from the spectrum shown in FIG. 8 is based only on the waveform data D1, and is not based on the waveform data D2 generated by the filter unit 211.

[0091] The extraction section 212 may extract the resonance frequency further based on the waveform data D2. Fig. 9 shows a spectrum obtained by performing a fast Fourier transform on the waveform data D2.

[0092] 8 and 9, it can be seen that the peak value of peak P2 is lower in Fig. 9. Furthermore, it can be seen that the intensity of the frequency band lower than peak P1 is greatly attenuated in Fig. 9.

[0093] Furthermore, in the spectrum of FIG. 9, the peak value of the peak P1 corresponding to the resonant frequency appears as a local maximum value and a maximum value.

[0094] In this way, by using the filter section 211, the resonance frequency corresponding to the peak P1 becomes clearer and easier to extract from the spectrum.

[0095] [Output section 213] 3, the output unit 213 outputs information on the fault point from the resonant frequency extracted by the extraction unit 212. The output unit 213 outputs the fault point located from the extracted resonant frequency.

[0096] At this time, the output unit 213 uses a predetermined relationship between the fault point and the resonant frequency when a ground fault occurs. Fig. 10 is a diagram showing a predetermined relationship between the distance d to the ground fault point and the resonant frequency F when a ground fault occurs, where the horizontal axis is the distance d [km] to the ground fault point and the vertical axis is the resonant frequency F [Hz].

[0097] The relationship shown in FIG. 10 can be created by a lumped parameter system model (Equations 7 to 9) or an instantaneous value analysis in a lumped parameter system.

[0098] As can be seen from Fig. 10, the resonant frequency F is a decreasing function of the distance d to the ground fault point. Therefore, if the resonant frequency F after the fault occurs can be identified, the distance d to the ground fault point can be uniquely determined using the relationship shown in Fig. 10.

[0099] In this embodiment, the fault point information is the located fault point (i.e., the distance d to the ground fault point), but is not limited to this. As another example, the fault point information may be the range of the distance d where the possibility of it being a fault point is equal to or greater than a predetermined value.

[0100] In this case, the output unit 213 may further use the width of the peak corresponding to the resonant frequency in addition to the resonant frequency F extracted by the extraction unit 212. This makes it possible to output a distance range corresponding to the width of the resonant frequency F centered on the ground fault point.

[0101] According to the information processing device 2 described above, when a ground fault occurs in the power system 1, it is possible to output information on the fault point with high accuracy.

[0102] <Processing Executed by Information Processing Device 2> The process executed by the information processing device 2 will be described with reference to a flowchart. Fig. 11 is a flowchart illustrating the process executed by the information processing device 2. This process includes steps S101 to S105.

[0103] When a ground fault occurs, first, in step S101, the acquisition unit 210 acquires waveform data D1 of the zero-phase current or the zero-phase voltage after the occurrence of the ground fault from the sensor-equipped switch SW1. In this embodiment, the acquisition unit 210 acquires waveform data D1 (FIG. 5) of the zero-phase current.

[0104] Next, in step S102, the filter unit 211 applies a predetermined frequency f u Larger frequency components and a given frequency f l Remove smaller frequency components.

[0105] frequency f u and frequency f l are values ​​calculated in advance using Formula 13 and Formula 14, respectively. The filter unit 211 generates waveform data D2 by applying a transfer function H1(s) (Formula 5) as a high-pass filter and a transfer function H2(s) (Formula 6) as a low-pass filter to the waveform data D1.

[0106] Next, in step S103, the extraction unit 212 extracts the resonant frequency of the power system 1 due to the ground fault based on the waveform data D2 generated in step S102, as a frequency f u Less than or equal to frequency f l Extraction is carried out under the above conditions.

[0107] At this time, the extraction section 212 performs frequency analysis on the waveform data D2 to obtain the spectrum shown in Fig. 9. Then, the extraction section 212 extracts the resonance frequency corresponding to the peak P1 from the spectrum in Fig. 9.

[0108] Next, in step S104, the output unit 213 locates the fault point from the resonant frequency F extracted in step S103. At this time, the output unit 213 uses a predetermined relationship (FIG. 10) between the fault point and the resonant frequency when a ground fault occurs.

[0109] Finally, in step S105, the output unit 213 outputs the fault point located in step S104 via the output device 205.

[0110] Through the above procedure, when a ground fault occurs in the power system 1, the information processing device 2 locates the fault point and outputs the result.

[0111] == Variation 1 == In the above embodiment, the resonant frequency F can take the following values: M It is assumed that a ground fault occurs at any point in the section.

[0112] However, if the section of the power system 1 in which a ground fault is believed to have occurred can be further limited, the range in which the resonant frequency F can take on can also be further limited.

[0113] For example, in a power distribution automation system, if a permanent fault accompanied by a power outage occurs, it is possible to identify the switch section in which the ground fault occurred by time-limited sequential switching, such as by reclosing the switch.

[0114] In addition, the fault section indicator will show the direction in which a ground fault has occurred even if it does not result in a permanent fault, so it may be possible for the system to grasp this.

[0115] Therefore, it may be possible to identify the section where a ground fault has occurred by using information from a power distribution automation system or a fault section indicator.

[0116] At this time, the identified section is node N k1 to node N k2 Here, the section is up to node N k1 is a node at the upstream end or upstream of the upstream end of the section of the power system 1 where a ground fault has occurred, which is estimated by a predetermined method. k2 is the downstream end of the section or a node downstream of the downstream end.

[0117] And node N k1 to node N k2 The section from the sending point to the sending point is converted to a distance of d1 to d2. In this case, the resonant frequency F that can be taken after a ground fault occurs is further limited to the range of Equation 12, and is expressed by the following equation.

number

[0118] In other words, the upper limit of the resonant frequency F in this case is the frequency f u and the lower limit frequency f l is expressed by the following formula:

number

number

[0119] Thus, frequency f u and frequency f lWhen is determined, it becomes easier to extract the resonance frequency F, and the accuracy of the resonance frequency F is improved.

[0120] ==Variation 2== In the above embodiment and modification 1, the node N k (1≦k≦M) are the nodes that actually exist. However, this is not limited to this, and in addition to the nodes that actually exist, the adjacent nodes N k and node N k+1 One or more virtual nodes may be set on the power distribution line 11 between (1≦k≦M−1).

[0121] In this case, there is no distinction between actually existing nodes and virtual nodes, and both are referred to as "nodes." In this case, the impedance matrix of Equation 4 is rewritten taking into account the location of the added virtual node, etc. This makes it possible to output information about the ground fault point more precisely.

[0122] == Variation 3 == In the above embodiment and variant 1, the upper and lower limits of the resonant frequency are determined by analysis using a lumped parameter model. However, it is also possible to determine the upper and lower limits by using an instantaneous value analysis simulation using a distributed parameter model.

[0123] In this case, a ground fault is simulated when the distance to the fault point is 0 (sending point) and D (terminal), and the upper and lower limits can be found by extracting the resonant frequency through waveform analysis at that time.

[0124] ==Summary== As described above, the information processing device 2 according to the embodiment is an information processing device 2 that outputs information on a fault point when a ground fault occurs in the power system 1, and includes an acquisition unit 210 that acquires waveform data D1 of a zero-phase current or a zero-phase voltage after a ground fault occurs from a sensor installed in the power system 1, and a resonant frequency F of the power system 1 due to a ground fault is calculated based on the waveform data D1 at a predetermined frequency f u or frequency f u lower than a given frequency f lThe present invention is provided with an extraction unit 212 that extracts the fault point under at least one of the above conditions, and an output unit 213 that outputs information on the fault point from the extracted resonant frequency using a predetermined relationship between the fault point and the resonant frequency when a ground fault occurs, and u is the maximum value that the resonant frequency calculated based on the system information indicating the components of the power system 1 and the electrical characteristics of the components and the type of ground fault can take, and frequency f l is the minimum value that the calculated value can take.

[0125] According to such a configuration, the range in which the resonance frequency F should be extracted from the spectrum of the waveform data D1 is limited, improving the accuracy of the extracted resonance frequency F. Therefore, the accuracy of the outputted information on the fault point is improved.

[0126] In the information processing device 2, the extraction unit 212 extracts a frequency f u Less than or equal to frequency f l Extraction is performed under the above conditions. With this configuration, the range in which the resonance frequency F should be extracted from the spectrum of the waveform data D1 is further limited, improving the accuracy of the extracted resonance frequency F. This further improves the accuracy of the outputted information on the fault point.

[0127] In the information processing device 2, a frequency f u is the sending node of the power system 1 or a node N downstream of the sending node. k1 This is a resonant frequency obtained based on the equivalent circuit of the power system 1 when a ground fault occurs at the power system 1. With this configuration, the range in which the resonant frequency F should be extracted from the spectrum of the waveform data D1 is further limited, improving the accuracy of the extracted resonant frequency F. Therefore, the accuracy of the outputted fault point information is further improved.

[0128] In the information processing device 2, a frequency f l is the node N k1 Node N downstream k2This is a resonant frequency obtained based on the equivalent circuit of the power system 1 when a ground fault occurs at the output of the power system 1. Since the range in which the resonant frequency F should be extracted from the spectrum of the waveform data D1 is further limited, the accuracy of the extracted resonant frequency F is improved. Therefore, the accuracy of the output information on the fault point is further improved.

[0129] In the information processing device 2, the node N k1 is a node at the upstream end or a node upstream of the upstream end of the section of the power system 1 in which a ground fault estimated by a predetermined method has occurred, and node N k2 is the downstream end of the section or a node downstream of the downstream end. With this configuration, the range in which the resonance frequency F is to be extracted from the spectrum of the waveform data D1 is further limited, improving the accuracy of the extracted resonance frequency F. Therefore, the accuracy of the outputted information on the fault point is further improved.

[0130] In the information processing device 2, the output unit 213 outputs the fault point located from the extracted resonant frequency F. With this configuration, it is possible to output the specific position of the located fault point.

[0131] In the information processing device 2, the waveform data D1 is subjected to a frequency f u The greater frequency component or frequency f l The system further includes a filter unit 211 that removes smaller frequency components to generate waveform data D2, and an extraction unit 212 extracts the resonant frequency based on the waveform data D2. With this configuration, unnecessary information such as noise is removed from the waveform data D2, improving the accuracy of the extracted resonant frequency F. This further improves the accuracy of the output fault point information.

[0132] The information processing method of the embodiment is an information processing method for outputting information on a fault point when a ground fault occurs in a power system 1, and includes a step of an information processing device 2 acquiring waveform data D1 of a zero-phase current or a zero-phase voltage after a ground fault occurs from a sensor-equipped switch SW1 installed in the power system 1, and calculating a resonant frequency F of the power system 1 due to the ground fault at a predetermined frequency f based on the waveform data D1.u or frequency f u lower than a given frequency f l The method includes a step of extracting the fault point under at least one of the above conditions, and a step of outputting information on the fault point from the extracted resonant frequency F using a predetermined relationship between the fault point and the resonant frequency F when a ground fault occurs, and the frequency f u is the maximum value that the resonant frequency calculated based on the system information indicating the components of the power system 1 and the electrical characteristics of the components and the type of ground fault can take, and frequency f l is the minimum value that the calculated value can take.

[0133] According to such a method, the range in which the resonance frequency F should be extracted from the spectrum of the waveform data D1 is limited, improving the accuracy of the extracted resonance frequency F. Therefore, the accuracy of the outputted information on the fault point is improved.

[0134] The information processing program according to the embodiment is an information processing program for outputting information on a fault point when a ground fault occurs in a power system 1, and includes an information processing device 2, which includes an acquisition unit 210 that acquires waveform data D1 of a zero-phase current or a zero-phase voltage after a ground fault occurs from a sensor-equipped switch SW1 installed in the power system 1, and a resonant frequency F of the power system 1 due to a ground fault is calculated based on the waveform data D1 at a predetermined frequency f u or frequency f u lower than a given frequency f l An extraction unit 212 that extracts the fault point under at least one of the above conditions, and an output unit 213 that outputs information on the fault point from the extracted resonant frequency F using a predetermined relationship between the fault point and the resonant frequency F when a ground fault occurs are realized, and the frequency f u is the maximum value that the resonant frequency F can take, calculated based on the system information indicating the components of the power system 1 and the electrical characteristics of the components, and the type of ground fault, and the frequency f l is the minimum value that the calculated value can take.

[0135] According to such a program, the range in which the resonance frequency F should be extracted from the spectrum of the waveform data D1 is limited, improving the accuracy of the extracted resonance frequency F. Therefore, the accuracy of the outputted information on the fault point is improved. [Explanation of symbols]

[0136] power system 1 Distribution Substation 10 Power Lines 11 Bank 12 Data processing device 2 CPU 200 Memory 201 Communication device 202 Storage device 203 Input Device 204 Output Device 205 Recording medium reader 206 Acquisition Department 210 Filter section 211 Extraction part 212 Output section 213

Claims

1. An information processing device that outputs information on a fault point when a ground fault occurs in a power system, an acquisition unit that acquires first waveform data of a zero-phase current or a zero-phase voltage after a ground fault occurs from a sensor installed in the power system; an extractor that extracts a resonant frequency of the power system due to the ground fault based on the first waveform data under at least one of a condition of being equal to or lower than a predetermined first frequency or equal to or higher than a predetermined second frequency that is lower than the first frequency; an output unit that outputs information on the fault point from the extracted resonant frequency using a predetermined relationship between the fault point and the resonant frequency when the ground fault occurs; Equipped with The first frequency is a maximum value that the calculated value of the resonant frequency can take, the calculated value being calculated based on system information indicating components of the power system and electrical characteristics of the components, and the type of the ground fault, The second frequency is the minimum value that the calculated value can take. Information processing device.

2. 2. The information processing device according to claim 1, The extraction unit extracts the frequency band under a condition that the frequency is equal to or lower than the first frequency and equal to or higher than the second frequency. Information processing device.

3. 2. The information processing device according to claim 1, the first frequency is a resonant frequency obtained based on an equivalent circuit of the power system when the ground fault occurs at a sending node of the power system or a first node downstream of the sending node; Information processing device.

4. 4. The information processing device according to claim 3, the second frequency is a resonant frequency obtained based on an equivalent circuit of the power system when the ground fault occurs at a second node downstream of the first node; Information processing device.

5. 5. The information processing device according to claim 4, the first node is an upstream end of a section of the power system in which the ground fault estimated by a predetermined method has occurred, or a node upstream of the upstream end; The second node is a downstream end of the section or a node downstream of the downstream end. Information processing device.

6. 2. The information processing device according to claim 1, The output unit outputs the fault point located from the extracted resonant frequency. Information processing device.

7. The information processing device according to any one of claims 1 to 6, a filter unit configured to remove a frequency component higher than the first frequency or a frequency component lower than the second frequency from the first waveform data to generate second waveform data, The extraction unit extracts the resonance frequency further based on the second waveform data. Information processing device.

8. An information processing method for outputting information on a fault point when a ground fault occurs in a power system, comprising: An information processing device, acquiring first waveform data of a zero-phase current or a zero-phase voltage after a ground fault occurs from a sensor installed in the power system; extracting a resonant frequency of the power system due to the ground fault under at least one of a condition of being equal to or lower than a predetermined first frequency or equal to or higher than a predetermined second frequency lower than the first frequency, based on the first waveform data; outputting information on the fault point from the extracted resonant frequency using a predetermined relationship between the fault point and the resonant frequency when the ground fault occurs; Including, The first frequency is a maximum value that the calculated value of the resonant frequency can take, the calculated value being calculated based on system information indicating components of the power system and electrical characteristics of the components, and the type of the ground fault, The second frequency is the minimum value that the calculated value can take. Information processing methods.

9. An information processing program for outputting information on a fault point when a ground fault occurs in a power system, In the information processing device, an acquisition unit that acquires first waveform data of a zero-phase current or a zero-phase voltage after a ground fault occurs from a sensor installed in the power system; an extractor that extracts a resonant frequency of the power system due to the ground fault based on the first waveform data under at least one of a condition of being equal to or lower than a predetermined first frequency or equal to or higher than a predetermined second frequency that is lower than the first frequency; an output unit that outputs information on the fault point from the extracted resonant frequency using a predetermined relationship between the fault point and the resonant frequency when the ground fault occurs; Realize this, The first frequency is a maximum value that the calculated value of the resonant frequency can take, the calculated value being calculated based on system information indicating components of the power system and electrical characteristics of the components, and the type of the ground fault, The second frequency is the minimum value that the calculated value can take. Information processing program.

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