JPH05276652A - Faint ground fault section locator - Google Patents

Abstract

PURPOSE:To provide a highly reliable faint ground fault locator in which a faint ground fault generating circuit is provided in each slave station and the slave station is inspected by generating faint ground fault based on an inspection command delivered from a master station. CONSTITUTION:The faint ground fault section locator for distribution line comprises slave stations 5-13 distributed on a high voltage distribution line 2, and faint ground fault generating circuits 14 provided at respective slave stations 5-13, wherein the function of the slave stations 5-13 is inspected by generating faint ground fault based on a command delivered from a master station 3. Since faint ground fault detecting function at each slave station can be constantly monitored, reliability of locator can be enhanced. Furthermore, since the function is inspected by taking advantage of actual distribution line, detection sensitivity is not subjected to system modification.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine ground fault section locating device for a distribution system, and more particularly to a fine ground fault section locating device having a function of inspecting the operation of slave stations distributedly arranged on a distribution line.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 63-25754 and Japanese Unexamined Patent Publication No. 02-18 have been known as conventional ground-fault section locating devices of this type.
As described in Japanese Patent No. 8034, each slave station has a timer so that the time axis of the whole system coincides with the absolute time of the master station, and the system information detected by the slave station is synchronized.
There is one that is configured to determine in which area the system micro-ground fault phenomenon has occurred. For example, when a small ground fault occurs at point F1 on the load side of the slave station 13 shown in FIG. 1, the zero phase voltage and the zero phase current change.

Since the zero-phase voltage is equal at each point in the system,
With the occurrence of the micro-ground fault, each slave station 5 to 13 detects a system change by the zero-phase overvoltage detection element (OVG element), and stores the time and system information. Since the zero-phase current mainly flows from the power supply side toward the accident point, the slave station 5, slave station 6, and slave station 13 detect the zero-phase current and the ground fault direction detection element (DG element) also operates. To do.

On the other hand, the master station regularly monitors the states of the slave stations 5 to 13, and after the occurrence of a minor ground fault accident at the F1 point,
When each slave station information is collected, all slave stations 5 to 13 are OVG.
It can be seen that the element is operating and the DG element is operating only the slave stations 5, 6, and 13.

Since the system configuration is registered in the master station in advance, it can be determined that a fine ground fault has occurred in the distribution line after the slave station 13.

However, the DG of the slave station 13 is caused by some cause (for example, an inappropriate detection level, a hardware defect, etc.).
When the element does not operate, the master station erroneously determines that a fine ground fault has occurred in the section on the power supply side of the slave stations 9 to 13 on the load side of the slave station 6. Since the power distribution system spreads in a plane, making a mistake in the accident section requires a great deal of effort for maintenance and inspection work.

[0007]

According to the above-described conventional fine ground fault section locator, the time alignment of the entire system composed of the slave stations and the master station, which are distributed, is performed by the clock synchronized with the system frequency. , It was possible to synchronize in a minute time.

However, in the conventional fine ground fault section locating device, whether or not the ground fault direction detecting element (DG element), the zero-phase overvoltage detecting element (OVG element), etc. of each slave station operate correctly in generating a fine ground fault. No inspection method was examined, and no consideration was given to changes in detection sensitivity of DG elements and OVG elements due to changes in the distribution system. Figure 4 shows the equivalent circuit for a one-wire ground fault. Assuming that the fault resistance is Rg and the system ground capacitance is C, the zero-phase voltage Vo and the zero-phase current I
o is represented by the following equation.

[0009]

[Equation 1]

[0010]

[Equation 2]

However,

[0012]

[Equation 3]

[0013]

As is clear from the equations (1), (2) and (3), if the fault point resistance Rg is constant, if the ground capacitance C changes, that is, if the system configuration is changed, The magnitudes of the zero-phase voltage Vo and the zero-phase current Io also change.

The present invention has been made in view of the above circumstances, and enables inspection of the fine ground fault detection circuit of each slave station.
It is another object of the present invention to provide a fine ground fault section locating device capable of changing a detection level of a fine ground fault in each slave station according to a system change and capable of stable and highly reliable fine ground fault section location.

[0016]

A fine ground fault section locating device of the present invention has slave stations distributedly arranged on a high-voltage distribution line, and the slave stations detect the system information of each part of the system and the fine ground fault detection provided in the slave stations. In a fine ground fault section locating device that detects an operation result of an element, collects the detected information in a master station, and locates a fine ground fault section of the distribution system, each of the slave stations includes a high voltage distribution line and a ground. It has a fine ground fault generation circuit that inserts impedance via a switch element to generate a fine ground fault, and a slave station specified by a command from the master station generates a fine ground fault,
The master station is characterized in that the slave station is inspected by collecting the system information detection result of each slave station at this time and confirming the operation status of each slave station.

Further, the fine ground fault section locating device of the present invention disperses the slave stations on the high voltage distribution line, and the slave station displays the system information of each part of the system and the operation result of the fine ground fault detection element provided in the slave station. In the fine ground fault section locating device that detects and collects the detected information in the master station and locates the fine ground fault section of the power distribution system, the master station generates a fine ground fault that is distributed and arranged on the high voltage distribution line. For slave stations that have circuits, by sequentially changing the slave stations that generate a fine ground fault at each inspection, the high-frequency components generated depending on the location of the fine ground fault on the distribution line and the magnitude of the fine ground fault can be From the detection status at each slave station, the high frequency attenuation characteristics of the system are measured and stored in advance, and when a fine ground fault occurs in the system,
The feature is that the orientation of the fine ground fault section and the magnitude of the fine ground fault are estimated from the high frequency detection status of each slave station and the high frequency attenuation characteristic of the above-mentioned system.

Further, the fine ground fault section locating device of the present invention disperses the slave stations on the high-voltage distribution line, and the slave station displays the system information of each part of the system and the operation result of the fine ground fault detection element provided in the slave station. In the fine ground fault section locating device that detects and collects the detected information in the master station and locates the fine ground fault section of the distribution system, the master station collects from each slave station at the time of inspection of each slave station. It is characterized in that the detection level of the fine ground fault in each slave station is reset from the master station based on the system information.

[0019]

[Function] By sequentially generating a fine ground fault for each slave station distributed on the distribution line, the operation check of each slave station can be performed, and the detection level of the fine ground fault due to the system change can be actually detected. Since it can be confirmed by generating a fine ground fault in the above, the detection level can be set to an optimum value.

Further, from the operation inspection, the main station can know the high frequency attenuation characteristic of the system from the detection state of the high frequency generated by the fine ground fault in each slave station according to the place where the fine ground fault occurs. When a ground fault occurs, the orientation of the fine ground fault section and the magnitude of the fine ground fault can be estimated from the high frequency detection status of each slave station.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of a fine ground fault section locating device according to the present invention. In the figure, a distribution transformer 1
A master station 3 for collecting information on the entire system is installed on the secondary side. The master station 3 determines from which section of the system the fine ground fault has occurred based on the collected system information, and performs section orientation.

Further, the master station 3 is provided with a communication section 4 for communicating between the master station 3 and groups of slave stations 5 to 13 distributed along the planar high voltage distribution line 2.

The slave stations 5 to 13 take in various state quantities of the system and detect an abnormality (state change) of the system, and the master station 3
It further has a communication function with respect to, and further has a fine ground fault generating section 14 for generating a fine ground fault by inserting the impedance element 142 between the high voltage distribution line and the ground through the switch element 141.

Next, FIG. 2 shows a concrete configuration of the slave station in FIG.
Shown in. In the figure, the fine ground fault section locating device according to the present invention includes a fine ground fault generating unit 14, a zero phase current input unit 16, a zero phase voltage input unit 17, a DG element 18, and an OVG element 19.
A clock generation unit 20, a counter 21, a logical operation unit 22, a non-volatile memory 23, a communication processing unit 24,
It has a voltage transformer 30, a power failure detection unit 31, and a backup timer 32. The fine ground fault generator 14 includes a switch element 141 and an impedance element 142.

The communication processing section 24 is composed of a decoding section 25, a communication information editing section 26, a communication control section 27, and a communication line connecting section 28.

In the above structure, the zero-phase current detected by the zero-phase current transformer 15 provided in the high voltage distribution line 2 is
Input processing including A / D conversion is performed in the zero-phase current input unit 16. In addition, the zero-phase voltage input unit 17 is used for the high voltage distribution line 2
The zero-phase voltage is detected by taking in the ground voltage of each of the three phases. The zero-phase voltage signal thus detected is input to the DG element 18 which detects the ground fault direction together with the zero-phase current signal output from the zero-phase current input section 16. In addition, the zero-phase voltage signal is an OVG that detects a zero-phase overvoltage.
Input to element 19. The system information indicating the system state change detected by the DG element 18 and the OVG element 19 is input to the logical operation unit 22. The logical operation unit 22 detects an abnormality of the system based on the system information such as the input state change and outputs a control command such as a disconnection command to a switch (not shown). DG element 1
8 and OVG element 19 are both set to sensitively respond to a fine ground fault and the like, so that the detection value is lower than that of the protection relay provided at the outlet of the distribution line 2 because the detection is performed with high sensitivity. There is.

On the other hand, the clock generator 20 is the high voltage distribution line 2
The one-phase voltage to ground is input, the system frequency is detected from the voltage waveform, a clock pulse synchronized with that frequency is generated and output to the counter 21.
The counter 21 counts clock pulses that are input and measures time. The setting and resetting of the counter 21 is controlled by the logical operation unit 22. Every time the system state change information is input from the DG element 18 and the OVG element 19, the logical operation unit 22 reads the count value of the counter at that time,
The nonvolatile memory 23 is configured to store the state change information and the content of the count value in association with each other.

The slave stations 5 to 13 and the master station 3 are capable of multidirectional communication via the communication line 29, and a known communication system such as a dedicated line system or a power line carrier system can be applied. The communication processing unit 24 on the slave station side is the communication line connection unit 2.
8, communication control unit 27, decoding unit 25, communication information editing unit 26
It is configured to include. The master station information fetched from the communication line 29 to the communication line connection unit 28 is extracted by the communication control unit 27 to the own station. The extracted information from the master station is decoded by the decoding unit 25 and transmitted to the logical operation unit 22.

On the other hand, in the transmission from the slave station to the master station, the information output from the logical operation unit 22 is converted into a predetermined transmission format by the transmission information editing unit 26, and the communication control unit 27 and the communication line connection unit 28 are connected. It is supposed to be done through.

The fine ground fault generating section 14 in which the impedance 142 is inserted between the one phase of the high voltage power distribution line 2 and the ground through the switch element 141 is controlled by the logical operation section 22.

The operation of the fine ground fault section locating device having the above configuration will be described below. FIG. 3A shows a voltage waveform of the system taken in by the clock generation unit 20 of the slave station. The entire device operates with a clock synchronized with this system voltage.

When the master station 3 gives an inspection command to the slave station 5 at time t ₁ , the slave station 5 causes the logical operation unit 22 to synchronize the system voltage with the fine ground fault generator 14 at time t ₂ . The switch element 141 is ON-controlled and turned OFF at time t ₃ .
As a result, the zero-phase voltage Vo and the zero-phase current Io are generated in the system as shown in FIGS. Occurrence time (t ₃
-T ₂ ) is the minimum time (about several cycles) at which the operation of each element of the slave station can be confirmed, and the time that does not affect other protection relays.

Next, the master station 3 monitors the state of each slave station after time t ₄ , confirms that the OVG element is operating at time t _2, and the OVG element circuit of each slave station is normal. And confirm the simultaneity of time. Regarding the DG element, it is confirmed from the system configuration that the slave station to be operated operates and the slave station to be inactive does not operate. The master station 3 gives an inspection command to the slave station 5 at the time t ₁ , but next time the slave station 6 is selected, and the slave stations to which the inspection command is given are changed every time the inspection is performed. The operation of the DG element can be confirmed.

According to the present embodiment, since it is possible to check the operation of the detecting elements of the system information of each slave station and to confirm the simultaneity of time,
It has a great effect on improving the reliability of the device.

Next, another embodiment of the fine ground fault section locating device of the present invention will be described below. The waveforms of the zero-phase voltage and the zero-phase current at the time of the micro-ground fault are not limited to those starting from the zero point of the sine wave and ending at the zero point as shown in FIGS. 3B and 3C. In particular, at the beginning of occurrence of a fine ground fault, discharge often starts at the peak point of voltage. Another embodiment focuses on this point. As shown in FIG. 5, when an inspection command is received at time t ₁ , the switch of the fine ground fault generating section is turned on at time t ₂ which is the peak point of the voltage. The ON control is performed so that the operation of each slave station is inspected. In this case, since the switch is turned on at the voltage peak point, there is a transient response as shown in FIGS. 5B and 5C, and the waveform has a high-frequency component.

At the slave station, DG element 1 responding to the fundamental wave
8. In addition to the operating status of the OVG19 element, the magnitude of this high frequency component is measured and given to the master station as system information. Since the high frequency component attenuates with distance, the point of occurrence of the fine ground fault is the largest and becomes smaller as the distance increases.

At the time of inspection, the master station 3 checks the DG element 1 of each slave station.
8. In addition to checking the operation of the OVG19 element, the magnitude of the high frequency component is measured and the high frequency attenuation characteristic of the system is obtained. Thereby, when a fine ground fault occurs in the system, it becomes possible to locate the distance from the fine ground fault section and the slave station installation point.

That is, as shown in FIG. 6, the magnitude of the high-frequency voltage due to the fine ground fault when the slave station 5 is inspected is v _{5 at} the slave station ₅ and v ₅ 'at the slave station 6, The magnitudes of the high-frequency voltage due to a slight ground fault when inspected by the slave station 6 are v ₆ and v ₆ ′. As a result, the attenuation characteristic of the high frequency from the slave station 5 to the slave station 6 has a slope shown by a straight line of v ₅ -v ₅ ′, and the attenuation characteristic of the high frequency from the slave station 6 to the slave station 5 is v ₆ −v ₆ ′. The slope is indicated by the straight line. Therefore, when a high frequency voltage of va is obtained at the slave station 5 and vb is obtained at the slave station 6 due to a fine ground fault of the system,
For the accident point, a dotted line is drawn from va and vb in parallel with the inclination of the high frequency characteristic, and the intersection is the accident occurrence point, and the magnitude vF of the high frequency voltage can be known. According to this embodiment, there is a great effect that the distance from the fine ground fault occurrence section and the slave station installation point can be located.

Next, still another embodiment of the fine ground fault section locating device of the present invention will be described.

The slave station controls the switch element 141 of the fine ground fault generating section 14 to be turned on only by the slave station designated by the instruction from the master station 3 by the logical operation section 22, but the other slave stations are also inspected at the same time. By receiving the command, the magnitude of the zero-phase voltage and the zero-phase current during the fine ground fault occurrence period by the inspection is measured, and the measurement result is displayed together with the detection level separately from the operation of the DG element 18 and the OVG element 19. I will send it to 3.

The master station 3 confirms the operation result of each slave station and checks whether the values of the zero-phase voltage and current input to each slave station are correct and whether the detection level is the same as that of the other slave stations. If there is a difference, the master station 3 resets the detection level of the slave station through communication. As a result, it is possible to eliminate the variation in the characteristics of the fine ground fault detection among the slave stations.

Further, in this embodiment, by changing the system, the magnitude of the zero-phase voltage and the zero-phase current changes even if the ground fault point resistance is constant. Is determined to be appropriate for the current system, and the detection level of the fine ground fault of each slave station can be reset by the command from the master station 3, so even if the system is changed, the fine ground fault is detected. The detection sensitivity of can be kept constant.

[0043]

As described above, according to the fine ground fault section locating device of the present invention, each slave station inserts an impedance between the high voltage power distribution line and the ground through a switch element to generate a fine ground fault. The slave station specified by the command from the master station has a minute ground fault generation circuit, and the master station generates a minute ground fault, and the master station collects the system information detection results of each slave station at this time and Since the slave stations are inspected by confirming the operating status of the stations, it is possible to constantly monitor the fine ground fault detection operation of each slave station, which has the effect of improving the reliability of the device. ..

Further, according to the fine ground fault section locating device of the present invention, since the operation inspection using the actual distribution line is performed,
There is an effect that the detection sensitivity of the fine ground fault is not affected by the system change.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an overall configuration of an embodiment of a fine ground fault section locating device according to the invention.

FIG. 2 is a block diagram showing a specific configuration of a slave station in the fine ground fault section locating device shown in FIG.

FIG. 3 is an explanatory diagram showing an example of an operation of the fine ground fault section locating device according to the present invention.

FIG. 4 is a circuit diagram showing an equivalent circuit at the time of a one-line ground fault of a distribution line.

FIG. 5 is an explanatory diagram showing an example of an operation of the fine ground fault section locating device according to the present invention.

FIG. 6 is an explanatory diagram showing an example of the operation of the fine ground fault section locating device according to the present invention.

[Explanation of symbols]

 1 Distribution transformer 2 High-voltage distribution line 3 Parent station 4 Communication section 5 Slave station 6 Slave station 7 Slave station 8 Slave station 9 Slave station 10 Slave station 11 Slave station 12 Slave station 13 Slave station 14 Micro-ground fault generating section 15 Zero-phase current transformer 16 Zero-phase current input section 17 Zero-phase voltage input section 18 DG element 19 OVG element 20 Clock generation section 21 Counter 22 Logical operation section 23 Non-volatile memory 24 Communication processing section 25 Decoding section 26 Communication information editing section 27 Communication Control unit 28 Communication line connection unit 29 Communication line 30 Voltage transformer 31 Power failure detection unit 32 Backup timer 141 Switch element 142 Impedance element

Claims (3)

[Claims] 1. A slave station is distributedly arranged on a high-voltage distribution line, the slave station detects system information of each part of the system and an operation result of a fine ground fault detection element provided in the slave station, and the detected information is transmitted to a parent. In a fine ground fault section locating device that collects at a station and locates a fine ground fault section of the distribution system, each of the slave stations inserts an impedance via a switching element between the high-voltage power distribution line and the ground to perform a fine ground fault. The slave station specified by the command from the master station generates a fine ground fault, and the master station collects the system information detection results of each slave station at this time. A fine ground fault section locating device characterized in that the slave stations are inspected by checking the operating status of each slave station. 2. A slave station is dispersedly arranged on a high-voltage distribution line, the slave station detects the system information of each part of the system and the operation result of a fine ground fault detection element provided in the slave station, and the detected information is used as a parent. In the fine ground fault section locating device that collects at the station and locates the fine ground fault section of the power distribution system, the master station checks the slave stations that have the fine ground fault generating circuits distributed on the high voltage distribution line every inspection. By sequentially changing the slave stations that generate a fine ground fault, the detection status in each slave station of the high-frequency component generated according to the location of the fine ground fault on the distribution line and the magnitude of the fine ground fault Measures and stores the high-frequency attenuation characteristics of the, and when a fine ground fault occurs in the system, the orientation of the fine ground fault section and the magnitude of the fine ground fault are determined from the high-frequency detection status of each slave station and the high-frequency attenuation characteristics of the system. A fine ground fault section locating device characterized in that the height is estimated. 3. A slave station is distributedly arranged on a high-voltage distribution line, the slave station detects system information of each system section and an operation result of a fine ground fault detection element provided in the slave station, and the detected information is transmitted to a parent. In the micro-ground fault section locating device that collects at the station and locates the micro-ground fault section of the distribution system, the master station is based on the grid information collected from each slave station at the time of inspection of each slave station, A fine ground fault section locating device, characterized in that the detection level of the fine ground fault is reset from the master station.