JPH04120478A - Determining method of direction of fault of trans mission line - Google Patents

Abstract

PURPOSE:To enable exact determeination of the direction of an electrical fault of a transmisson line that shows in which of the section on the right or an the left of a specified pylon thosen, as a boundaly, the fault occurs, by providing a current sensor for an overhead ground wire in a load-side span of the specified pylon. CONSTITUTION:A pylon 32 is made to be a boundary pylon serving as a boundary point in the direction of a fault of a transmission line to be discriminated, and an overhead ground wire 21 between it and the adjacent pylon 31 on the power source side is insulated in an anchor part to the pylon 32 by an insulating part 23. Now, no current due to induction from transmisson lines 1 flows through the overhead ground wire 21, and no overhead ground wire current on the right or the left section of the pylon 32 is shunted. Therefore, a current only by the induction from the trans-mission line 1 on the load side of the pylon 32 flows through an overhead ground wire 22. A current sensor 4 constructed of a dividable through- type current transformer is provided for this overhead ground wire 22 and thereby the current flowing through the overhead ground wire 22 is detected. An output of the sensor is sent to a determination circuit 7 and the position of occurrence of the fault is determined to be on the power source side of the pylon 32 when no current is derected, while it is determined to be on the load side of the pylon 32 when the current is detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for locating the direction of a fault in a power transmission line, and in particular, to a method for locating the direction of a fault in a power transmission line, in particular a method for locating an electrical fault in a power transmission line on either the left or right side of a specified pylon in the middle of the power line. This article relates to a method for determining whether a problem has occurred.

[Prior Art] Power transmission lines are necessary and indispensable equipment for today's power supply operations, and breakdowns or malfunctions of this equipment can have an extremely serious impact on today's highly electrified society, and in some cases can cause damage in all directions. It is possible that the social functions of children may be paralyzed.

For this reason, to protect power transmission lines from lightning strikes, etc., overhead ground wires are installed, and extremely reliable insulation support methods are adopted to prevent flash faults. We have not yet reached the point of completely eliminating it.

Therefore, in the event that such a failure occurs in a power transmission line, the next best task is to quickly determine the location of the failure.

As a method for detecting the location of a fault in a power transmission line, a so-called fault locator (FL) such as a surge reception method, a pulse radar method, etc., has conventionally been employed. These measures the arrival time of a fault surge, etc. at both ends of a power transmission line such as a substation, and calculate the distance to the fault point.

Recently, so-called digital PL has also been developed, which calculates the impedance to the fault point from the voltage and current measured at the power transmission end immediately after the fault and converts it into a distance.

: Problem to be solved by invention 1 However, these conventional fault rogators are large and expensive, and
Basically, it is used to locate the distance from the detection end of a substation, etc. to the fault point, so it is not advantageous to have exact accuracy, such as determining on which side of the boundary point in charge of maintenance work a fault occurred. is the current situation. In other words, in the unlikely event that a power transmission line failure occurs, it is essential to first know which section of the business is in charge, in order to respond and respond to the incident. However, there was a problem that the necessary section discrimination accuracy could not be obtained especially for failures occurring near boundary points.

The reason for this is that only the information that can be measured at the end of the power transmission line, such as at a substation, is used to detect the point of failure that has occurred in the middle of a long-distance power transmission line. This is due to the fact that the information is not used.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a power transmission line fault direction locating method that can accurately locate the direction of a fault, i.e., whether an electrical fault has occurred in a section on either the left or right side of a specific steel tower as a boundary. The purpose is to provide a method.

[Means for Solving Section U] The power transmission line failure direction locating method of the present invention provides a power transmission line having an overhead ground wire that is grounded at each tower section. At least one end of the overhead ground wire laid in the span between the two is insulated and ungrounded, and a current sensor is installed on the overhead ground wire in the load-side span of the specific tower to connect it to the power transmission line. When an electrical fault such as a short circuit fault or ground fault occurs, depending on whether or not the current sensor detects the current flowing through the overhead ground wire, it is determined whether the electrical fault is located closer to the power source than the specific tower or the load. This is to locate the direction of failure on either side.

In this case, the output of the current sensor may be converted into an optical signal by a signal conversion circuit installed on the specific steel tower, and transmitted via an optical fiber to a determination circuit installed on the specific steel tower for locating the failure direction. Preferable for measurement safety.

The result of locating the fault direction can be transmitted to a remote point by wire or wirelessly.6 Also, the signal converting circuit and the determining circuit can detect the induced voltage induced in the overhead ground wire, which has at least one end insulated and ungrounded. can create a power supply.

Overhead ground wire (G
W) has at least one end insulated and ungrounded. Therefore, if an electrical failure occurs in the power transmission line on the power source side from the specified steel tower where the current sensor is installed, current will flow through the overhead ground wire on the power source side from the specified steel tower due to the induction of the main line current, but the overhead ground wire on the load side will flow. On the other hand, if an electrical failure occurs on the load side of a specific tower, a large current will flow in the overhead ground wire on the load side due to the induction of the main line current.

Therefore, there is a noticeable difference in the overhead ground wire current monitored by the current sensor installed on the overhead ground wire in the load side span depending on whether the electrical fault is on the power supply side or the load side.
It is possible to extremely accurately and easily determine whether a failure has occurred in the left or right direction with respect to a specific steel tower as a boundary.

When implementing the method of the present invention, a signal conversion circuit that converts the detection signal of the current sensor into an optical signal and a determination circuit that locates the fault direction are installed on a specific steel tower that is to be a boundary point on the power transmission line. However, the location results can be transmitted and displayed at a remote location, such as a maintenance office, by transmission means such as fiber optics or telephone lines, or by radio.

In addition, the induced voltage induced in the insulated overhead ground wire in the power supply side span of the power transmission line can be used as a power source for the device installed in the steel tower.

[Example] Hereinafter, an example of the method for locating the direction of a fault in a power transmission line according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of a locating device according to the power transmission line fault direction locating method of the present invention, and FIG. 2 is a block diagram showing the configuration of the device.

A power transmission line 1 is supported by a large number of steel towers 3, and an overhead ground wire 2 is laid above the power transmission line 1.

A specific steel tower 32 among these towers 3 is positioned as a boundary tower, which is the boundary point in the direction of the power transmission line fault to be determined, and is located at the boundary point of the transmission line failure direction, and is located at the border point of the adjacent tower 31 on the power source side of the power transmission line.
The overhead ground wire 21 is insulated by an insulating part 23 at the part where it is tied to the boundary steel tower 32. Therefore,
The overhead ground wire 21 on the power supply side does not form a closed circuit via the tower and the ground, so current induced from the power transmission line 1 does not flow, and the overhead ground wire current between the left and right sections of the boundary tower 32 does not flow. In the overhead ground wire 22 on the load side, only the current of the induction valve from the power transmission line 1 on the load side than the boundary steel tower 32 flows.

A current sensor 4 made of a splittable through-type current transformer (CT) is installed on the overhead ground wire 22, and detects the current flowing through the overhead ground wire 22. Current sensor 4
The output is converted into an optical signal by the optical signal conversion circuit 5 and sent to the determination circuit 7 through the optical fiber 61.

When an electrical fault such as a short circuit fault or a ground fault occurs in the power transmission line, the determination circuit 7 determines whether the current sensor 4 detects a current flowing through the overhead ground wire or not, and determines whether the location of the electrical fault is the boundary. The failure direction is determined as to whether it is on the power supply side or the load side relative to the steel tower 32.

That is, when no overhead ground wire current is detected by the current sensor, it is determined that the fault occurrence location is on the power supply side from the boundary steel tower 32, and when overhead ground wire current is detected, the fault occurrence location is determined to be on the load side. It is determined that

The determination result by the determination circuit 7 is sent via another optical fiber 62 to a remote location, for example, a remote monitoring device installed in the office of the department in charge of maintenance, and the result is displayed.

The power supply for each circuit 5.7 installed in the steel tower section is the power supply circuit 8.
It is obtained from the voltage induced in the insulated overhead ground wire 21. That is, as shown in FIG. 2, after converting the induced voltage to a low voltage by a step-down transformer 81 and further converting it to direct current, a charging control circuit 82 charges a rechargeable battery 83 in preparation for a power transmission stop and stabilizes the voltage. conversion circuit 8
FIG. 3 is an explanatory diagram of current distribution along a power transmission line showing the operation of the power transmission line fault direction locating device of the present invention.

Now, as shown in FIG. 3(a), there is a short-circuit failure in the power transmission line on the power source side of the boundary steel tower 32 where the current sensor 4 is installed.
When an electrical fault such as a ground fault occurs, fault current flows through the main line from the power supply side to the fault point. Due to the induction caused by this fault current, the overhead ground wire 2 is grounded at multiple points by each steel tower 3.
Because the current flows through the overhead ground wires (GW) distributed in No current flows through the overhead ground wire 22 that has been closed.

This result is more noticeable in FIG. 3(b), which shows a case where a failure occurs on the power supply side and closer to the tower 32 than the boundary tower 32. That is, if the overhead ground wire 21 is not insulated and is electrically connected to the steel tower 32 like a normal steel tower section, the overhead ground wire 21 is An induced current also flows through the ground wire 22, making the lick determination unclear.

On the other hand, if the electrical failure occurs on the load side of the boundary tower 32, as shown in FIGS. 3(C) and (d),
A large overhead ground wire current induced from the main line current flows through the overhead ground wire 22 where the current sensor 4 is installed.

Therefore, even if an electrical failure occurs on either the power supply side or the load side, by monitoring the current in the overhead ground wire 22 with the current sensor 4, the failure can occur in either the left or right direction with the boundary steel tower 32 as the border. It is possible to determine very accurately and easily whether or not a problem has occurred.

In the embodiment described above, the determination port F! Although the transmission from +7 to the remote monitoring device W9 is performed by optical fiber 62, it is also possible to transmit by other transmission means, such as a telephone line or wirelessly.

In addition, in the above embodiment, an application example was shown for a power transmission line in which the power source side and the load side are fixed, but in a power transmission line where the direction of power flow is changed, a device similar to that of the steel tower 32 is installed on the adjacent steel tower 31. However, it is also possible to use different methods depending on the direction of the current.

: Effects of the Invention As explained above, according to the method for locating the direction of a fault in a power transmission line of the present invention, it is possible to very accurately locate the direction in which a faulty section of a power transmission line exists, using a specific tower as a boundary point. Moreover, it has a very remarkable effect that it can be implemented with a simple and inexpensive structure.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a locating device showing an embodiment of the power transmission line fault direction locating method of the present invention, Fig. 2 is a block diagram showing the configuration of the locating device of Fig. 1, and Fig. 3 shows its operation. FIG. 3 is an explanatory diagram of current distribution along a power transmission line. In the diagram, 1 is the power transmission line, 2, 2L 22 is the overhead ground wire (GW)
, 23 is the insulation part, 3 is the steel tower, 31 is the adjacent steel tower, 32 is the boundary steel tower (specific steel tower), 4 is the split type through-type current transformer (
CT); 5 is an optical signal conversion circuit; 61
．． 62 is an optical fiber, 7 is a determination circuit, 8 is a power supply circuit, 8
1 is a step-down transformer, 82 is a charging control circuit, 83 is a rechargeable battery, 84 is a voltage stabilizing circuit, and 9 is a remote monitoring device.

Claims (1)

[Scope of Claims] 1. In a power transmission line having an overhead ground wire grounded at each tower section, an overhead ground wire installed in the span between a specific tower in the middle and a tower adjacent to the power supply side. At least one end of the transmission line is insulated and ungrounded, and a current sensor is installed on the overhead ground wire in the load side span of the specified tower to prevent electrical failures such as short circuits and ground faults from occurring on the power transmission line. In this case, depending on whether or not the current sensor detects a current flowing through the overhead ground wire, the direction of the electrical fault is determined as to whether the location of the electrical fault is on the power supply side or the load side of the specific steel tower. Transmission line fault direction locating method. 2. In the method according to claim 1, a determination is made that the output of the current sensor is converted into an optical signal by a signal conversion circuit installed on the specific steel tower, and the direction of the fault installed on the specific steel tower is determined by an optical fiber. A power transmission line fault direction locating method characterized by transmitting information to a circuit. 3. A power transmission line failure direction locating method according to claim 1 or 2, characterized in that the fault direction locating result is transmitted to a remote location by wire or wirelessly. 4. The method according to claim 2, wherein the power supply for the signal conversion circuit and the determination circuit is created from the induced voltage induced in the overhead ground wire, which has at least one end insulated and ungrounded. Fault direction locating method.