JPH0733177Y2 - Instantaneous ground fault detection device on distribution line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device capable of reading out ground fault accident occurrence data in a high voltage distribution line at a master station.

[Conventional technology]

In order to improve the reliability of power supply, conventionally, when an accident occurs on the distribution line, the division switches are sequentially turned on to automatically detect the faulty section, disconnect the faulty section, and reverse the sections after the faulty section. A so-called DM method is adopted, in which power is transmitted to distribute to other healthy sections.

FIG. 4 is a block diagram of a power distribution system based on the DM method. The DM type distribution system is the breaker 1-1 to 1 of the substation SS.
-5, normally closed switch 2-1 to 2-8,3-1,4-1,5-1,5
-2, normally open section switch for reverse transportation 2-9,2-10,2-1
1, distribution line that is transmitted by the circuit breaker 1-1
It is composed of a, b, c, d, e, f, g, h, i, an accident detection device 9 and control devices 7-1 to 7-15 for detecting an accident section of each of the above-mentioned section switches.

Conventionally, for example, in the control method described in Japanese Patent Publication No. 57-43021, when an accident occurs in the distribution line d, the circuit breaker 1-1 of the substation SS is tripped by the accident detection signal to break the circuit breaker 1-1. With reclosing circuit of, from the power supply side,
Turn on the section switches 2-1 and 2-2, then the section switches 2-
When the accident section is turned on by 3, the circuit breaker 1-1 trips again to judge the accident section d.

As a result, power supply reliability such as the range of accidental blackouts, reduction of time, and shortening of power supply can be achieved.

On the other hand, in high-voltage distribution lines, instantaneous ground faults and short-term ground faults that do not result in the circuit breakers at substations breaking down occur. Such an accident occurs in a state where there is an accident recovery property, such as damage to the distribution line auxiliary equipment such as support insulators, deterioration of insulation, contact of trees or birds and animals with the distribution line, and the cause is eliminated. When it is done, it recovers in a short time.

5 and 6 show graphs of the ground fault resistance and the arc extinction rate, and the ground fault resistance and the natural arc extinction within 0.5 seconds, respectively.
As described above, in many ground faults, the arc may be extinguished spontaneously and the circuit breaker may not be interrupted.

Further, even when the substation detects a ground fault and breaks the circuit breaker, there are many cases where the fault has already been recovered when the circuit is closed again for detecting the fault section, that is, at the time of trial power transmission.

[Problems to be solved by the invention]

However, if there is a section where insulation deterioration of distribution line auxiliary equipment or contact with the distribution line of trees frequently occurs, the fault section detection method by reclosing at the substation makes it extremely difficult to search for the fault section. Become.

The present invention has been made in view of such conventional problems, and an object of the present invention is to grasp data of the frequency and the direction of occurrence of a micro-ground fault and facilitate detection of an accident section. .

[Means for solving problems]

In order to achieve this object, the instant ground fault detection device in the distribution line of the present invention is used in a distribution system including a distribution substation bus, a distribution breaker, an accident detection device, and a section switch.
At each of the division switch installation locations, a slave station having a ground fault accident and a ground fault accident occurrence direction detection function is installed, respectively, and a master station having a communication function is installed for each slave station, The station is provided with means for accumulating and storing in which direction and in what direction the ground fault occurred, and for the master station, the memory contents stored in the memory means of each slave station are read out and stored in the master station. It is characterized in that it is provided with a function of transmitting the information to the station and provided with means for detecting an accident section based on the stored contents.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the embodiments shown in the drawings.

FIG. 3 is a block diagram showing a control system of a distribution line to which the present invention is applied. In the figure, CB is a circuit breaker connected to the bus bar from the substation A. Further, the section switches DM1 to DM8 are connected to the high voltage busbar from the circuit breaker CB. Of these, DM1,2,3,5,7 are normally closed switchgear,
M4,6,8 are normally open switchgear. As shown in FIG. 3, the section protected by these section switches is
Section to sixth section. The normally open section switches DM4, 6, 8 are for performing reverse transmission interchange from the distribution systems on the substation B, C, D side, respectively.

The division switches DM1 to DM8 are provided with slave stations 1 to 8 for shutting off and opening them from the master station 20, respectively. As shown in FIG. 3, the slave station 2 of the division switch DM2
When a ground fault occurs in the third section, a closing command signal is sent to the slave stations 4, slave stations 6 and 8 of the normally-open section switches DM4, DM6 and DM8 through the communication line 30. Set to send. As a result, when an accident occurs in the third section, the normally open division switches DM4, 6, 8 are turned on by the signal of the slave station 2, and the reverse transmission interchange power transmission to the fourth section, the fifth section and the sixth section is performed. Done. After that, the division switches DM2, DM3, DM5,
By opening DM7, only the third section, which is the faulty section, will have a power outage, and the other healthy sections will continue to be distributed without a power outage.

In the present invention, each of the slave stations is provided with a ground fault direction detecting function to accumulate the directions of occurrence of micro-ground faults and the number of times, and the master station 20 uses the communication function with each slave station 1-8. Then, the accident direction and frequency data of each slave station are collected, and the accident section is detected based on the data.

FIG. 1 is a block diagram showing a configuration of a slave station having such a function. In the figure, a zero-phase current transformer ZCT and a zero-phase voltage detector ZPD are installed on the distribution line.The zero-phase current Io and the zero-phase voltage Vo, which are the detection signals, are respectively detected by the zero-phase current detection circuit. 41 and the zero-phase voltage detection circuit 42.
The output signals of these circuits 41 and 42 are output as digital signals and input to the CPU 43 for digital processing by the microcomputer.

When a ground fault occurs, the zero-phase current transformer ZCT detects the zero-phase current and the zero-phase voltage detector ZPD detects the zero-phase voltage, which are input to the relay 40. In relay 40,
It is input to the CPU 43 via each detection circuit. In CPU43,
The levels of the zero-phase current Io and the zero-phase voltage Vo are detected, and when they are equal to or more than a set value and a ground fault continues for a set operation time or longer, they are stored in the nonvolatile memory 44 in the ground fault direction.

The ground fault direction is detected by the phase of the zero phase current Io and the phase of the zero phase voltage Vo.
This is performed by determining whether the power source side (hereinafter, this direction is the A direction) or the load side (hereinafter, this direction is the B direction) with respect to the ZCT installation position. Figure 2 shows non-volatile memory 44
And the exchange of signals with the CPU 43. In the figure, in the non-volatile memory 44, there are an address 0001, which is an area for accumulating the number of ground faults in the A direction, and an address 0002, which is an area for accumulating the number of ground faults in the B direction. Each time it is detected, the number of times is accumulated in any address.

As shown in FIG. 1, the stored contents are transmitted to the master station 20 via the communication line 30 in response to a slave station number designation and a read request signal from the master station 20. That is, from the master station 20 to the communication line at regular time intervals, for example, once a day or every time the ground fault overvoltage relay installed in the substation operates.
This is done by reading the cumulative total in each direction through 30. When there is a request from the master station for information, the slave station specifies the address of the non-volatile memory 44, reads the total number of A direction ground fault detections and the total number of B direction ground fault detections in the memory, and communicates with the communication circuit. 45
The data is transmitted to the master station 20 via. The master station 20 judges the cumulative total and detects the instantaneous ground fault accident section. For example, if three instantaneous ground fault accidents occur in the third section shown in Fig. 3, the cumulative total obtained by the master station through communication is: Slave station 1: B direction 3 times Slave station 2: B direction 3 times Station 3: A direction is three times, and since the directions of slave station 2 and slave station 3 are reversed, it can be determined that an accident has occurred between slave station 2 and slave station 3, that is, in the third section.

In order to detect an instantaneous ground fault that the substation does not detect, the sensitivity of the relay 40 of the sectional switch DM is set to be high with respect to the sensitivity of the detector of the substation.

The above has described the detection of a minor ground fault accident and the collection of data.However, in order to turn on the normally open section switch and disconnect the faulty section for a normal ground fault, the It goes without saying that different normal ground fault detection levels are set in different areas of the non-volatile memory 44.

[Effect of device]

As described above, in the present invention, the master station having a communication function is installed for the slave stations provided at the respective division switch installation locations, and the accumulated direction and the number of occurrences of the fine ground faults in the slave stations are set. I read it from time to time. As a result, it becomes possible for the master station to collectively detect a section in which a fine ground fault occurs. Therefore, it is possible to search for a section in which a slight ground fault has occurred, and it is possible to take measures to prevent the occurrence of a ground fault.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a relay device of the present invention,
2 is a block diagram showing a configuration example of a non-volatile memory, FIG. 3 is a block diagram showing a configuration example of a distribution line fault section detection system to which the relay device of the present invention is applied, and FIG.
Block diagram of DM system distribution system, Fig. 5 is a graph showing the relationship between ground fault resistance and arc extinction rate, and Fig. 6 is a graph showing the relationship between ground fault resistance and spontaneous arc extinction within 0.5 seconds. is there. CB: Circuit breaker DM, DM1 to DM8: Division switch 1 to 8: Slave station, 20: Master station 30: Communication line, 40: Relay 41: Zero-phase current detection circuit 42: Zero-phase voltage detection circuit 43: CPU, 44: Non-volatile memory 45: Communication circuit, 46: ROM

Continued front page (72) Hideto Kawazoe 1-1, Oitakitamachi, Saga City, Saga Prefecture Togami Electric Co., Ltd. (72) Tatsumi Ikeda 1-1, Oitakitamachi, Saga City, Saga Prefecture Togami Denki Seisakusho

Claims (1)

[Scope of utility model registration request] 1. A distribution system comprising a distribution substation busbar, a distribution circuit breaker, an accident detection device, and a classification switch, and a function of detecting a ground fault and a direction of occurrence of a ground fault at the location where each classification switch is installed. We will set up each slave station with
Set up a master station with a communication function for these slave stations,
Each of the slave stations is provided with means for accumulating and storing in what direction and in what direction the ground fault accident occurred, and for the master station, the storage content stored in the storage means of each slave station is read out, A device for detecting an instantaneous ground fault in a distribution line, which has a function of transmitting this to a master station and is provided with means for detecting an accident section based on the stored contents.