JP2020118544A - Ground fault direction determining device, ground fault direction determining system, ground fault direction determining method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground fault direction determination device, a ground fault direction determination system, a ground fault direction determination method and a program capable of determining a ground fault direction in an electric circuit only by measuring a current of the electric circuit. SOLUTION: A ground fault direction determination device 130 uses a waveform data acquisition unit 133a for acquiring current waveform data in each phase of a three-phase electric circuit and current waveform data before and after the occurrence of a ground fault acquired by the waveform data acquisition unit 133a. Based on the current vector generation unit 133d that generates the current vector of each phase before and after the ground fault occurrence and the current vector of the zero-phase current after the ground fault occurrence, and the current vector generated by the current vector generation unit 133d. The ground fault direction determination unit 133e for determining the direction of the ground fault location on the electric current is provided. [Selection diagram] Fig. 2

Description

The present invention relates to a ground fault direction determination device, a ground fault direction determination system, a ground fault direction determination method, and a program.

A ground fault may occur due to contact of trees, flying objects, and the like with overhead lines such as power transmission lines and distribution lines. When a ground fault occurs in a structure, the ground fault direction is finally determined by determining whether the ground fault occurs on the power source side or the load side with respect to the predetermined position of the structure. It is necessary to understand the location of the ground fault that occurred. A method using a zero-phase current and a zero-phase voltage is generally used to determine the ground fault direction. For example, in Patent Document 1, based on the phase difference between the zero-phase current and the zero-phase voltage at the time of the ground fault. A method of determining the ground fault direction is disclosed.

JP, 2011-217481, A

The method of Patent Document 1 requires a device such as a grounded potential transformer (GPT) capable of measuring a zero-phase voltage. However, since the device such as GPT is large and expensive, an overhead line object is required. It is difficult to install in many places. Further, in order to measure the zero-phase voltage, it is possible to use a non-contact type voltage sensor that is small in size and inexpensive, but when the non-contact type voltage sensor is applied to, for example, a low voltage line such as a distribution line, The low voltage makes it difficult to measure the voltage accurately. And such a problem exists when judging the ground fault direction of all the electric circuits including not only the overhead line object but the underground line installed in the pipeline etc. in the ground.

The present invention has been made based on such a background, and a ground fault direction determination device, a ground fault direction determination system, a ground which can determine the ground fault direction in the electric line by simply measuring the electric current of the electric line. An object of the present invention is to provide a method and a program for determining a fault direction.

In order to achieve the above object, the ground fault direction determination device according to the first aspect of the present invention,
Waveform data acquisition means for acquiring current waveform data in each phase of the three-phase circuit,
Current vector generation for generating a current vector of each phase before and after occurrence of ground fault and a current vector of zero-phase current after occurrence of ground fault, based on current waveform data before and after occurrence of ground fault acquired by the waveform data acquisition means Means and
Based on the current vector generated by the current vector generation means, a ground fault direction determination means for determining the direction on the electric path of the ground fault location,
Equipped with.

The current vector generation means performs Fourier expansion on the current waveform data acquired by the waveform data acquisition means to extract a fundamental wave component of the current waveform data, and a ground fault is generated based on the fundamental wave component. The current vectors of the front and rear phases and the current vector of the zero-phase current after the occurrence of the ground fault may be generated.

The ground fault direction determination means identifies the phase in which the current phase has changed the most as an accident phase, and the current vector of the zero-phase current after the occurrence of the ground fault matches the difference between the current vectors of the accident phase before and after the occurrence of the ground fault. If the fault point is on the load side of the current measurement position of the electric circuit, and the absolute value of the current vector of the zero-phase current after the occurrence of the ground fault is smaller than the second threshold, the fault point is determined. May be determined to be closer to the power supply side than the current measurement position of the electric path.

Based on the current vector generated by the current vector generation means, the phase in which the phase of the current changes most is specified as the fault phase, and the fault phase current value calculation means for calculating the current value before and after the occurrence of the ground fault in the fault phase Equipped with
The ground fault direction determination means, when the current value of the accident phase calculated by the accident phase current value calculation means is inverted or decreased before and after the occurrence of a ground fault, the accident point is more than the current measurement position of the electric circuit. If the current value of the accident phase after the occurrence of the ground fault calculated by the accident phase current value calculating means is larger than the current value of the accident phase before the occurrence of the ground fault, the accident point is It may be determined that it is on the load side of the current measurement position of the electric path.

Based on the current waveform data acquired by the waveform data acquisition means, zero-phase current value calculation means for calculating the current value of the zero-phase current,
Based on the current value of the zero-phase current calculated by the zero-phase current value calculating means, the presence or absence of a ground fault in the electric path is detected, and waveform data extraction is performed to extract current waveform data before and after the occurrence of the ground fault in the electric path. And means,
The current vector generation means, based on the current waveform data before and after the occurrence of the ground fault extracted by the waveform data extraction means, the current vector of each phase before and after the occurrence of the ground fault and the current vector of the zero-phase current after the occurrence of the ground fault And may be generated.

A waveform data storage means for storing current waveform data in each phase of the electric circuit;
When the absolute value of the zero-phase current calculated by the zero-phase current value calculating means is larger than the first threshold value, the waveform data extracting means is synchronized with the waveform data storing means before and after the occurrence of the ground fault. The current waveform data may be extracted.

In order to achieve the above object, the ground fault direction determination system according to the second aspect of the present invention,
The ground fault direction determination device,
A monitoring device that is communicably connected to the ground fault direction determination device, and acquires a determination result of the ground fault direction in the electric path determined by the ground fault direction determination device,
Equipped with.

In order to achieve the above object, the ground fault direction determination method according to the third aspect of the present invention,
A waveform data acquisition step of acquiring current waveform data in each phase of the three-phase electric circuit,
Based on the current waveform data before and after the occurrence of the ground fault acquired by the waveform data acquisition step, the current vector generation for generating the current vector of each phase before and after the occurrence of the ground fault and the current vector of the zero-phase current after the occurrence of the ground fault Steps,
Based on the current vector generated by the current vector generation step, a ground fault direction determination step of determining the direction on the electric path of the ground fault location,
including.

In order to achieve the above object, a program according to a fourth aspect of the present invention is
Computer,
Waveform data acquisition means for acquiring current waveform data in each phase of the three-phase circuit,
Current vector generation for generating a current vector of each phase before and after occurrence of ground fault and a current vector of zero-phase current after occurrence of ground fault, based on current waveform data before and after occurrence of ground fault acquired by the waveform data acquisition means means,
Based on the current vector generated by the current vector generation means, ground fault direction determination means for determining the direction on the electric path of the ground fault location,
To function as.

According to the present invention, it is possible to provide a ground fault direction determination device, a ground fault direction determination system, a ground fault direction determination method, and a program capable of determining the ground fault direction in a power line only by measuring the current in the power line.

It is a figure which shows the whole structure of the ground fault direction determination system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the hardware constitutions of the measurement and determination apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows a mode that the current sensor which concerns on Embodiment 1 of this invention is being fixed to the horizontal arm. It is a figure which shows an example of the data table of the waveform data storage part in Embodiment 1 of this invention. It is a figure which shows the specific example of the extraction method of the waveform data in Embodiment 1 of this invention. (A) is an example of a current vector when the accident point is on the load side, and (b) is an example of a current vector when the accident point is on the power supply side. 5 is a flowchart showing a flow of ground fault direction determination processing according to the first embodiment of the present invention. (A) is an example of a current vector when the accident point is on the load side, and (b) is an example of a current vector when the accident point is on the power supply side. (A) is an example of the accident phase current value when the accident point is on the load side, and (b) is an example of the accident phase current value when the accident point is on the power supply side. It is a block diagram which shows the hardware constitutions of the measurement and determination apparatus which concerns on Embodiment 2 of this invention. 7 is a flowchart showing a flow of ground fault direction determination processing according to the second embodiment of the present invention.

Hereinafter, embodiments of a ground fault direction determination device, a ground fault direction determination system, a ground fault direction determination method, and a program according to the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are designated by the same reference numerals.

(Embodiment 1)
A ground fault direction determination device, a ground fault direction determination system, a ground fault direction determination method, and a program according to Embodiment 1 will be described with reference to FIGS. 1 to 7. Hereinafter, a case of determining the ground fault direction in a three-phase three-wire type distribution line (three-phase electric circuit) will be described as an example. The three-phase, three-wire type distribution line is composed of three lines corresponding to R phase, S phase, and T phase.

FIG. 1 is a diagram showing an overall configuration of a ground fault direction determination system 1 according to the first embodiment. The ground fault direction determination system 1 measures the current value of each phase at a single or a plurality of current measurement positions set on the distribution line, and the ground fault occurs at each current measurement position based on the measured current value of each phase. A ground fault direction indicating whether the power source side or the load side has occurred is determined. By grasping the ground fault directions at a plurality of current measurement positions of the distribution line, the user can determine at which position of the distribution line the ground fault has occurred.

The ground fault direction determination system 1 includes a measurement/determination device 100 installed at a single or a plurality of current measurement positions, and a monitoring device 200. The measurement/judgment device 100 and the monitoring device 200 are communicably connected to each other via a communication line such as the Internet.

The measurement/determination device 100 is installed, for example, on each power pole on which a distribution line is installed. The measurement/determination device 100 includes three current sensors corresponding to each phase of the distribution line, and measures the current value (instantaneous value) of each phase of the distribution line at a predetermined sampling interval (for example, about 0.5 msec). Then, the ground fault direction at each current measurement position of the distribution line is determined based on the current value of each phase.

The monitoring device 200 is, for example, a general-purpose computer, and when acquiring the determination result of the ground fault direction of the distribution line from the measurement/determination device 100, notifies the user that an abnormality has occurred. The monitoring device 200 regularly monitors whether or not the waveform data of the current stored with the time stamp when the ground fault occurs is acquired from the measurement/judgment device 100, and transferred from the measurement/judgment device 100 with the time stamp. Based on the waveform data of the current before and after the occurrence of the ground fault, an accident aspect, current waveform, etc. are displayed on the display.

FIG. 2 is a block diagram showing a hardware configuration of the measurement/determination device 100 according to the first embodiment. The measurement/determination device 100 includes three current sensors 110 corresponding to each phase of the distribution line, an A/D (analog/digital) converter 120, and a ground fault direction determination device 130. In the current sensor 110, the A/D converter 120, and the ground fault direction determination device 130, the current signal acquired by the current sensor 110 is converted into a digital signal by the A/D converter 120 and processed by the ground fault direction determination device 130. As described above, the communication is connected via a wired or wireless communication line.

FIG. 3 is a diagram showing a state in which the non-contact type current sensor 110 according to the first embodiment is fixed to the horizontal arm. Each phase of the distribution line is erected on a horizontal arm via an insulator. The current sensor 110 is not limited to the non-contact type current sensor, and may be a contact type current sensor.

The current sensor 110 includes a coil 111 and a current transformer (CT) 112. The current sensor 110 is arranged in association with each phase of the distribution line and is fixed to a horizontal arm that extends horizontally from the utility pole body.

The coil 111 is fixed to the horizontal arm so as to intersect with the magnetic field generated by the current flowing through the distribution line. When a current flows through the distribution line, an electromotive force is generated in the coil 111 based on Lenz's law. Although the number of turns of the coil 111 is arbitrary, it is, for example, one. Since the current flowing through the coil 111 is inversely proportional to the resistance of the electric wire forming the coil 111, the electric wire of the coil 111 preferably has a small resistance and a large diameter. For example, when the electric wire is made of a copper material, its diameter is about 3.2 mm.

The current transformer 112 is fixed to the coil 111 and measures the current value flowing through the coil 111 based on Ampere's law. The current transformer 112 detects the current of the coil 111 generated by the magnetic field generated around the distribution line, and outputs a value proportional to the current value of the distribution line to the A/D converter 120.

Returning to FIG. 2, the A/D converter 120 converts the current signal output by the current sensor 110 into a digital signal, and outputs the digital signal to the ground fault direction determination device 130. The A/D converter 120 converts a current signal, which is an analog signal, into a digital signal at a predetermined sampling frequency (for example, about 0.5 msec).

The ground fault direction determination device 130 is, for example, a small general-purpose computer (single board computer). The ground fault direction determination device 130 includes a communication unit 131, a storage unit 132, and a control calculation unit 133. The respective units of the ground fault direction determination device 130 are mutually connected by an internal bus or the like.

The communication unit 131 is an interface that can be connected to a communication network such as the Internet or another peripheral device such as another A/D converter. The communication unit 131 transfers the waveform data of the current from the A/D converter 120, which shows the time change of the current value, to the storage unit 132.

The storage unit 132 includes a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, and the like. The storage unit 132 stores programs executed by the control calculation unit 133 and various data. In addition, the storage unit 132 functions as a work memory for the control calculation unit 133 to execute processing. Further, the storage unit 132 includes a waveform data storage unit 132a that stores the current value of each phase so as to include the current waveform data before and after the occurrence of the ground fault.

FIG. 4 is an example of a data table of the waveform data storage unit 132a according to the first embodiment. The waveform data storage unit 132a stores the current value measured by the current sensor 110 corresponding to each phase (CH) of the distribution line in the order of measurement. In the example of FIG. 4, 2000 areas from 0 to 1999 are secured, and when the address No reaches 1999, the area returns to 0. For example, for 0.5 ms sampling, one second of data is stored. Current waveform data is sequentially stored in a buffer area (for example, a ring buffer or the like) formed in the waveform data storage unit 132a, and the last updated address No, the last updated time (update time), and the last The processed address number is also stored.

The control calculation unit 133 includes a CPU (Central Processing Unit) and the like, and controls each unit of the ground fault direction determination device 130. The control calculation unit 133 includes a timer that measures time. The control calculation unit 133 executes the program stored in the storage unit 132 to execute the ground fault direction determination process of FIG. 7.

Functionally, the control calculation unit 133 includes a waveform data acquisition unit 133a, a zero-phase current value calculation unit 133b, a waveform data extraction unit 133c, a current vector generation unit 133d, and a ground fault direction determination unit 133e. Prepare

The waveform data acquisition unit 133a acquires the latest current waveform data stored after the previous calculation from the ring buffer of the waveform data storage unit 132a.

The zero-phase current value calculator 133b calculates the current value of the zero-phase current by summing the current values of the respective phases acquired by the waveform data acquisition unit 133a. When there is no ground fault in the distribution line (in steady state), the zero-phase current value is almost zero.

The waveform data extraction unit 133c uses the current stored in the waveform data storage unit 132a as a trigger when it is determined that the absolute value of the zero-phase current calculated by the zero-phase current value calculation unit 133b is larger than the first threshold value. The waveform data of the current before and after the trigger (before and after the occurrence of the ground fault) is extracted from the waveform data. When the waveform data is extracted and the waveform data after the trigger is insufficient, the waveform data extraction unit 133c waits for the processing until the acquisition of the waveform data is completed. Further, the waveform data extraction unit 133c extracts the waveform data of each phase synchronized for one cycle before and after the trigger, excluding the current waveform data immediately before the trigger.

FIG. 5 shows a specific example of a method for extracting synchronized waveform data for one cycle before and after the trigger. In the specific example of FIG. 5, the waveform for one cycle is acquired from the time point two cycles before the trigger, and the waveform for one cycle is extracted from the time point one cycle after the trigger. The waveform data extraction method is not limited to the case of FIG. 5, and any waveform can be extracted as long as it is a waveform that is synchronized for one cycle before and after the trigger, and that avoids the vicinity of the trigger. Good.

Returning to FIG. 3, the current vector generation unit 133d performs the Fourier expansion on the waveform data of each phase extracted by the waveform data extraction unit 133c, and the sin wave component of the fundamental wave of each phase before and after the occurrence of the ground fault and By calculating the peak values of the cos wave components, the current vector of each phase before and after the occurrence of the ground fault and the current vector of the zero-phase current I ₀ after the occurrence of the ground fault (zero-phase current vector) are generated. The current vector can be treated as a complex number a+bj (a and b are real numbers and j is an imaginary number), for example.

The ground fault direction determination unit 133e determines the ground fault direction in the distribution line based on the current vector of each phase before and after the occurrence of the ground fault and the zero-phase current vector after the occurrence of the ground fault, which is generated by the current vector generation unit 133d. To do.

FIG. 6A is an example of a current vector when the accident point is on the load side, and FIG. 6B is an example of a current vector when the accident point is on the power supply side. In FIG. 6, the thick arrow indicates the current vector before the accident, and the thin arrow indicates the current vector after the accident.

If the peak value of the cos wave component of the fundamental wave is the X component and the peak value of the sin wave component of the fundamental wave is the Y component, a current vector can be drawn on the XY coordinates as shown in FIG. If the sum of the crest value of the cos wave component of the fundamental wave of each phase after the occurrence of the ground fault is the X component and the sum of the crest value of the sin wave component is the Y component, as shown in FIG. A zero-phase current vector can be drawn.

When the fault point is on the load side of the current measurement position as shown in FIG. 6A, the zero-phase current vector after the occurrence of the ground fault is substantially equal to the difference between the current vectors of the fault phase (S phase). On the other hand, as shown in FIG. 6B, when the fault point is on the power supply side of the current measurement position, the components of the zero-phase current I ₀ are evenly distributed to each phase, and the zero-phase current I ₀ that flows through the distribution line. Since the absolute value of depends on the electrostatic capacity after the attachment point, it is significantly smaller than the load-side accident that depends on the electrostatic capacity of the entire bank including other feeders.

Therefore, the ground fault direction determination unit 133e determines that the fault point is on the power supply side of the current measurement position when the zero-phase current vector after the occurrence of the ground fault is substantially equal to the difference between the current vectors of the fault phase. In addition, when the ground fault phase cannot be specified and the absolute value of the zero-phase current I ₀ after the occurrence of the ground fault is smaller than the second threshold, the ground fault direction determination unit 133e determines that the fault point is on the power supply side of the current measurement position. Is determined.

Since the measurement/determination device 100 uses a non-contact type sensor as the current sensor 110, the _zero- phase current I ₀ based on the measurement error is detected even when the ground fault does not actually occur. There are cases. When there is a measurement error in the zero-phase current I ₀ , the ground fault direction determination device 130 may previously calculate a correction coefficient that minimizes the zero-phase current I ₀ at the time when no ground fault occurs. ..

Specifically, when Ir, Is, and It are current values of the R phase, S phase, and T phase at the time when the ground fault does not occur, and kr, ks, and kt are correction coefficients, respectively, The correction coefficients kr, ks, and kt may be determined so that the equation (1) holds.
kr·Ir+ks·Is+kt·It=0 (1)

Then, the correction coefficients kr, ks, and kt are multiplied by the R-phase, S-phase, and T-phase current values, respectively, and the sum of the multiplied values is calculated to calculate the corrected zero-phase current I ₀ , The presence or absence of a ground fault in the distribution line may be determined based on the corrected zero-phase current I ₀ .

(Ground fault direction determination process)
Next, with reference to FIG. 7, a flow of a series of processes relating to the determination of the ground fault direction, which is executed by the control calculation unit 133 of the ground fault direction determination device 130 according to the first embodiment of the present invention, will be described. FIG. 7 is a flowchart showing the flow of the ground fault direction determination processing according to the first embodiment. The ground fault direction determination process is a process of determining the ground fault direction in the distribution line based on the current waveform data acquired from the A/D converter 120. The ground fault direction determination process is started when the ground fault direction determination device 130 is activated.

First, the waveform data acquisition unit 133a acquires the latest post-current waveform data stored after the previous calculation from the current waveform data stored in the ring buffer of the storage unit 132 (step S1).

Next, the zero-phase current value calculation unit 133b calculates the current value of the zero-phase current I ₀ by summing the current values of the respective phases based on the current waveform data acquired in step S1 (step S2). ..

Next, the waveform data extraction unit 133c determines whether or not the absolute value of the zero-phase current I ₀ is larger than the first threshold value (step S3). The first threshold value is set in advance in consideration of the type of overhead line object, the material forming the overhead line object, the diameter of the overhead line object, the grounding state of the overhead line object, the equipment connected to the overhead line object, and the like.

When the current value of the zero-phase current I ₀ is larger than the first threshold value (step S3; Yes), the waveform data extraction unit 133c determines that the value of the zero-phase current I ₀ is greater than the first threshold value. Using as a trigger, the waveform data before and after the trigger (before and after the occurrence of the ground fault) is extracted from the waveform data stored in the ring buffer of the storage unit 132 (step S4). In step S4, a waveform that is synchronized for one cycle before and after the trigger is extracted while avoiding the waveform immediately near the trigger. On the other hand, when none of the current values of the zero-phase current I ₀ is larger than the first threshold value (step S3; No), the control calculation unit 133 returns the process to step S1.

Next, the current vector generation unit 133d executes the Fourier expansion on the waveform data of each phase extracted in step S4 to obtain the peak values of the sin wave component and the cos wave component of the fundamental wave before and after the occurrence of the ground fault, respectively. By the calculation, the current vector of each phase before and after the occurrence of the ground fault and the zero-phase current vector after the occurrence of the ground fault are generated (step S5).

Next, the ground fault direction determination unit 133e determines the ground fault direction at each current measurement position of the distribution line based on the current vector generated in step S5 (step S6).

More specifically, first, the ground fault direction determination unit 133e identifies the phase having the largest difference between the current vectors before and after the occurrence of the ground fault generated in step S5 as the accident phase. Next, the ground fault direction determination unit 133e calculates the difference between the current vector before the occurrence of the ground fault and the current vector after the occurrence of the ground fault in the identified accident phase. Next, when the calculated difference between the zero-phase current vector after the occurrence of the ground fault and the current vector of the fault phase is substantially the same, the ground fault phase is determined, and the ground fault direction determination unit 133e causes the ground fault location ( It is determined that the accident point) is on the load side of the current measurement position. On the other hand, when the difference between the calculated zero-phase current vector after the occurrence of the ground fault and the current vector of the fault phase does not match, or when the ground fault phase cannot be identified, the ground fault direction determination unit 133e causes the ground fault direction determination unit 133e It is determined whether the current value of the zero-phase current I ₀ is smaller than the second threshold value.

When the current value of the zero-phase current I ₀ after the occurrence of the ground fault is smaller than the second threshold value, the ground fault direction determination unit 133e determines that the ground fault location is on the power supply side of the current measurement position. On the other hand, when the current value of the zero-phase current I ₀ after the occurrence of the ground fault is larger than or equal to the second threshold value, the ground fault direction determination unit 133e determines that the ground fault location is the load side of the current measurement location. The second threshold value is based on the ground-fault current value when the device is attached to the load side electrostatic capacity and the power source side is completely grounded.

Next, the control calculation unit 133 outputs the determination result in the direction of the ground fault determined in step S6 to the file in association with the waveform data of the current before and after the occurrence of the ground fault and the time data at the time of measuring the waveform data (step S7). ), and the process returns to step S1. The above is the flow of the ground fault direction determination processing. When the monitoring device 200 acquires the data (file) stored in the measurement/judgment device 100, it creates a display screen showing the data and displays it on the display. Depending on the configuration of the communication line, waveform data may be transferred from the measurement/judgment device 100 to the monitoring device 200 in step S7, or a mail including information indicating that a ground fault has been detected may be transmitted.

The ground fault direction determination device 130 according to the first embodiment, based on the current waveform data before and after the occurrence of the ground fault in the distribution line, the current vector of each phase before and after the occurrence of the ground fault and the zero-phase current I ₀ after the occurrence of the ground fault. Current vector generation unit 133d that generates a current vector and a ground fault direction determination unit that determines the direction on the distribution line of the ground fault location (ground fault direction) based on the current vector generated by the current vector generation unit 133d. 133e. Therefore, it is not necessary to measure the voltage in the distribution line, and the ground fault direction in the distribution line can be determined even when the distribution line is not provided with a grounding transformer or the like.

(Embodiment 2)
A ground fault direction determination device 130, a ground fault direction determination system, a ground fault direction determination method, and a program according to the second embodiment will be described with reference to FIGS. 8 to 11. Hereinafter, in the second embodiment, a method of determining the ground fault direction when a ground fault occurs in the power transmission line will be described.

FIG. 8A shows a specific example of the current vector when the accident point is on the load side, and FIG. 8B shows a specific example of the current vector when the accident point is on the power supply side. In FIG. 8, as in the case of FIG. 6, the thick arrow indicates the vector before the accident, and the thin arrow indicates the vector after the accident. Since a neutral grounding resistor (NGR) is connected to the power transmission line, the current value in the accident phase becomes large even when the accident point is on the power supply side, which is the same as in the first embodiment. The same method cannot determine the ground fault direction.

9A shows an example of the current value of the accident phase when the accident point is on the load side, and FIG. 9B shows an example of the current value of the accident phase when the accident point is on the power supply side. is there. The current values in FIG. 9 are represented by positive and negative current values based on the vector phase of each phase before the accident. When there is an accident point on the load side as shown in FIG. 9A, the current value in the accident phase does not reverse before and after the occurrence of a ground fault, but when there is an accident point on the power supply side as shown in FIG. 9B. , The current value in the accident phase is reversed or decreased before and after the occurrence of the ground fault. Therefore, in the second embodiment, the ground fault direction in the power transmission line is determined based on the change in the current value in the accident phase before and after the occurrence of the ground fault.

FIG. 10 is a block diagram showing the hardware configuration of the measurement/determination device 100 according to the second embodiment. The control calculator 133 functionally further includes a fault phase current value calculator 133f. The fault phase current value calculation unit 133f specifies the fault phase based on the current vectors of the respective phases before and after the occurrence of the ground fault generated by the current vector generation unit 133d, and calculates the current values of the fault phase before and after the occurrence of the ground fault. .. The phase of the accident phase can be calculated by taking the arc tangent (tan ⁻¹ ) of the X component and the Y component of the current vector corresponding to the accident phase. Further, the current value of the accident phase before the occurrence of the ground fault can be calculated by multiplying the current vector before the occurrence of the ground fault by the sin wave corresponding to the phase before the occurrence of the accident and integrating the current vector.

The ground fault direction determination unit 133e determines the ground fault direction in the power transmission line based on the current values of the fault phase before and after the occurrence of the ground fault calculated by the fault phase current value calculation unit 133f. More specifically, the ground fault direction determination unit 133e determines that there is an accident point closer to the power supply side than the current measurement position when the positive/negative of the current value is inverted or decreased before and after the occurrence of the ground fault. Further, the ground fault direction determination unit 133e measures the current when the positive/negative of the current value is not reversed before and after the occurrence of the ground fault and the current value after the occurrence of the ground fault is larger than the current value before the occurrence of the ground fault. It is determined that there is an accident point on the load side of the position.

(Ground fault direction determination process)
Next, with reference to FIG. 11, a flow of the ground fault direction determination processing executed by the control calculation unit 133 of the ground fault direction determination device 130 will be described. FIG. 11 is a flowchart showing the flow of the ground fault direction determination processing according to the second embodiment.

First, the control calculation unit 133 executes the same processing as steps S1 to S5.

Next, the fault phase current value calculation unit 133f identifies the fault phase based on the current vector of each phase before and after the occurrence of the ground fault generated by the current vector generation unit 133d, and the current value of the fault phase before and after the occurrence of the ground fault. Is calculated (step S6A).

Next, the ground fault direction determination unit 133e determines the ground fault direction in the transmission line based on the current values of the fault phase before and after the occurrence of the ground fault calculated by the fault phase current value calculation unit 133f (step S6B).

Next, the control calculation unit 133 executes the process of step S7 and returns the process to step S1 again. The above is the flow of the ground fault direction determination processing according to the second embodiment.

The ground fault direction determination device 130 according to the second embodiment is configured to determine the ground fault direction in the power transmission line based on the current values in the accident phase before and after the occurrence of the ground fault. Therefore, the ground fault direction can be determined without measuring the voltage of the transmission line.

The present invention is not limited to the above-mentioned embodiment, and the modifications described below are possible.

(Modification)
In the above embodiment, the ground fault direction in the distribution line or the transmission line is determined, but the present invention is not limited to this. The ground fault direction determination system 1 according to the first embodiment may be applied to any type of ungrounded line, and the ground fault direction determination system 1 according to the second embodiment may be applied to any type of grounded line. You may.

Although the current sensor 110 including the coil 111 and the CT 112 is used in the above-described embodiment, the present invention is not limited to this. For example, the current sensor 110 including an amplifier circuit that amplifies a current signal may be used. Further, the split type hole CT may be used in consideration of attachment to a horizontal arm or the like. When the split type hole CT is used, the sensor part may be attached so that the magnetic fields generated by the currents flowing through the wires intersect.

In the above embodiment, the current value is measured by the non-contact current sensor 110 for insulation, but the present invention is not limited to this. For example, in a device such as a switch to which a CT is attached, its secondary output may be directly input to the A/D converter 120, or a current sensor (auxiliary CT) may be attached to the secondary output line.

In the above embodiment, the current value of the current flowing through the overhead wire was measured, but the present invention is not limited to this. For example, the current sensor 110 may be provided on each of the power supply side cable side and the load side cable side of the substation, and the current flow of the overhead wire may be measured by acquiring waveform data with each current sensor 110.

In the above-mentioned embodiment, the judgment result of the ground fault direction is notified to the user via the output means such as a display, but the present invention is not limited to this. For example, by providing a contact output such as a photo MOS (Metal Oxide Semiconductor) relay to the ground fault direction determination device 130 and operating a circuit breaker connected to the overhead line object based on the determination result of the ground fault direction, It may be configured to cut off the current.

In the above embodiment, when a ground fault is detected in a distribution line or the like, the determination result of the ground fault direction and the waveform data of the current before and after the occurrence of the ground fault are output in a file in association with the time data, and a predetermined value is output. The file was transferred to the monitoring device 200 at the timing, but the present invention is not limited to this. For example, when a ground fault is detected by a distribution line or the like, when the measurement/judgment device 100 directly notifies the communication terminal of the user that the ground fault is detected by means such as an email, the monitoring device 200 May be omitted.

In the second embodiment, the control calculation unit 133 has the current vector calculation unit 133d, but the present invention is not limited to this. If the control calculation unit 133 is configured to calculate the current value of each phase before and after the occurrence of the ground fault and specify the phase having the largest difference in current value as the accident phase, the phase of each phase is specified to specify the accident phase. It is not necessary to calculate the current vector.

In the above embodiment, the ground fault direction determination device 130 displays the ground fault direction determination result on the display of the monitoring device 200, but the present invention is not limited to this. For example, a display (display unit) may be provided in the ground fault direction determination device 130 and the determination result may be output to the display unit.

In the above-described embodiment, the data such as the waveform data is stored in the storage unit 132 of the ground fault direction determination device 130, but the present invention is not limited to this. For example, all or part of various data may be stored in an external server or computer via a communication network.

In the above embodiment, the Internet is used as the communication network, but the present invention is not limited to this. For example, the communication network may be realized by using a LAN (Local Area Network), a dedicated line, or the like.

In the above-described embodiment, the ground fault direction determination device 130 operates based on the program stored in the storage unit 132, but the present invention is not limited to this. For example, the functional configuration realized by the program may be realized by hardware.

In the above embodiment, the ground fault direction determination device 130 is, for example, a general-purpose computer, but the present invention is not limited to this. For example, the ground fault direction determination device 130 may be realized by a dedicated system or may be a computer provided on the cloud. Further, the process executed by the ground fault direction determination device 130 is realized by, for example, a device having the above-described physical configuration executing a program stored in the storage unit 132. It may be realized as a program, or may be realized as a storage medium in which the program is recorded.

In addition, the program for executing the above-described processing operation can be read by a computer such as a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk), and an MO (Magneto-Optical Disk). An apparatus that executes the above-described processing operations may be configured by storing the program in a recording medium, distributing the program, and installing the program in a computer.

The above embodiments are mere examples, and the present invention is not limited to these, and various embodiments are possible without departing from the spirit of the invention described in the claims. The constituent elements described in each of the embodiments and modifications can be freely combined. The invention equivalent to the invention described in the claims is also included in the present invention.

1 Ground fault direction determination system 100 Measurement/determination device 110 Current sensor 111 Coil 112 Current transformer 120 A/D converter 130 Ground fault direction determination device 131 Communication unit 132 Storage unit 132a Waveform data storage unit 133 Control calculation unit 133a Waveform data Acquisition unit 133b Zero-phase current value calculation unit 133c Waveform data extraction unit 133d Current vector generation unit 133e Ground fault direction determination unit 133f Accident phase current value calculation unit 200 Monitoring device

Claims (9)

Waveform data acquisition means for acquiring current waveform data in each phase of the three-phase circuit,
Current vector generation for generating a current vector of each phase before and after occurrence of ground fault and a current vector of zero-phase current after occurrence of ground fault, based on current waveform data before and after occurrence of ground fault acquired by the waveform data acquisition means Means and
Based on the current vector generated by the current vector generation means, a ground fault direction determination means for determining the direction on the electric path of the ground fault location,
A ground fault direction determination device including. The current vector generation means performs Fourier expansion on the current waveform data acquired by the waveform data acquisition means to extract a fundamental wave component of the current waveform data, and a ground fault is generated based on the fundamental wave component. Generate the current vector of each phase before and after and the current vector of the zero-phase current after the occurrence of the ground fault,
The ground fault direction determination device according to claim 1. The ground fault direction determination means identifies the phase in which the current phase has changed the most as an accident phase, and the current vector of the zero-phase current after the occurrence of the ground fault matches the difference between the current vectors of the accident phase before and after the occurrence of the ground fault. If the fault point is on the load side of the current measurement position of the electric circuit, and the absolute value of the current vector of the zero-phase current after the occurrence of the ground fault is smaller than the second threshold, the fault point is determined. Is determined to be on the power supply side of the current measurement position of the electric circuit,
The ground fault direction determination device according to claim 1. Based on the current vector generated by the current vector generation means, the phase in which the phase of the current changes most is specified as the fault phase, and the fault phase current value calculation means for calculating the current value before and after the occurrence of the ground fault in the fault phase Equipped with
The ground fault direction determination means, when the current value of the accident phase calculated by the accident phase current value calculation means is inverted or decreased before and after the occurrence of a ground fault, the accident point is more than the current measurement position of the electric circuit. If the current value of the accident phase after the occurrence of the ground fault calculated by the accident phase current value calculating means is larger than the current value of the accident phase before the occurrence of the ground fault, the accident point is Determined to be on the load side of the current measurement position of the electric circuit,
The ground fault direction determination device according to claim 1. Based on the current waveform data acquired by the waveform data acquisition means, zero-phase current value calculation means for calculating the current value of the zero-phase current,
Based on the current value of the zero-phase current calculated by the zero-phase current value calculating means, the presence or absence of a ground fault in the electric path is detected, and waveform data extraction is performed to extract current waveform data before and after the occurrence of the ground fault in the electric path. And means,
The current vector generation means, based on the current waveform data before and after the occurrence of the ground fault extracted by the waveform data extraction means, the current vector of each phase before and after the occurrence of the ground fault and the current vector of the zero-phase current after the occurrence of the ground fault Generate and
The ground fault direction determination device according to any one of claims 1 to 4. A waveform data storage means for storing current waveform data in each phase of the electric circuit;
When the absolute value of the zero-phase current calculated by the zero-phase current value calculating means is larger than the first threshold value, the waveform data extracting means is synchronized with the waveform data storing means before and after the occurrence of the ground fault. Extract current waveform data,
The ground fault direction determination device according to claim 5. A ground fault direction determination device according to any one of claims 1 to 6,
A monitoring device that is communicably connected to the ground fault direction determination device, and acquires a determination result of the ground fault direction in the electric path determined by the ground fault direction determination device,
A ground fault direction determination system including. A waveform data acquisition step of acquiring current waveform data in each phase of the three-phase electric circuit,
Based on the current waveform data before and after the occurrence of the ground fault acquired by the waveform data acquisition step, the current vector generation for generating the current vector of each phase before and after the occurrence of the ground fault and the current vector of the zero-phase current after the occurrence of the ground fault Steps,
Based on the current vector generated by the current vector generation step, a ground fault direction determination step of determining the direction on the electric path of the ground fault location,
A ground fault direction determination method including. Computer,
Waveform data acquisition means for acquiring current waveform data in each phase of the three-phase circuit,
Current vector generation for generating a current vector of each phase before and after occurrence of ground fault and a current vector of zero-phase current after occurrence of ground fault, based on current waveform data before and after occurrence of ground fault acquired by the waveform data acquisition means means,
Based on the current vector generated by the current vector generation means, ground fault direction determination means for determining the direction on the electric path of the ground fault location,
Program to function as.