JPH0580108A - Ground shortcircuit sensing device - Google Patents

Abstract

PURPOSE:To identify the troubled point automatically by furnishing CT's on two-phase bus bars at the disconnector part in each troubled point identifying division within the yard of a sub-station, providing a ground short CT at a grounding lead on a platform of a disconnector, and connecting these CT's with trouble point identifying device. CONSTITUTION:CT's are furnished on two-phase bus bars A and C of three- phase bus bars which connect disconnector in each troubled point identifying point division within the yard of a sub-station to the bus bars, and a ground shortcircuit CT 10 is mounted on a grounding lead on a platform 5 of the disconnector. When the A-phase or C-phase CT 8 senses a trouble in the circuit and a current differential judging device 11 judges that it is a shortcircuit to cause actuation of a bus bar protection relay, it is checked if a ground shortcircuit over-current sensor 13 of the ground shortcircuit CT 10 has judged shortcircuiting. In case there is any shortcircuiting from the disconnector platform 5, judgement can be passed that there is ground shortcircuit with the disconnector in the troubled circuit. In the case the CT 10 senses no ground shortcircuit current, judgement can be passed that there is shortcircuiting in any portion other than the disconnector (bus bar) within the troubled circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground fault short-circuit failure detection device used for automatically locating a failure point when a failure occurs in a bus bar in a substation and equipment connected to the bus bar. Is.

[0002]

2. Description of the Related Art When a busbar or a connecting device in a substation has a failure, it is desirable to immediately find a failure point and isolate the failure point to minimize a power failure range.
In particular, recently, with the unmanned substation, there is a demand for a device that can automatically detect a failure point and disconnect the failure point by remote control. Conventionally, for this purpose, a system has been developed in which a CT is attached to each of the three-phase bus bars in the fault location area in the substation premises and the output thereof is transmitted to a remote control station. According to this system, it is possible to know the occurrence of an accident in the fault location section from the change in the current flowing through the bus.

In this system, however, it is determined whether the accident that occurred is a short circuit between bus bars, a ground fault in an insulator device or a disconnector that supports the bus, or a ground fault short circuit. However, it was difficult to accurately separate only the failure point. Further, in this system, it is necessary to attach the CT to each of the three-phase bus bars, which not only increases the equipment cost, but also causes a problem that the power outage construction time for attaching the CT to the existing bus bar is long.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the related art, and when an accident occurs in a substation, the kind and the accident point of the accident can be accurately discriminated at low cost. It has been completed to provide a ground fault short-circuit fault detection device.

[0005]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, detects a current of a bus line of two phases of three phases at a disconnection portion in a fault location section of a substation. And a ground fault CT for detecting the ground fault current that flows in the ground wire of the pedestal when an accident occurs, and distinguish these CTs from short-circuit faults and ground faults based on their measurement data. It is characterized in that it is connected to a fault locator.

[0006]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 and FIG. 2 are diagrams showing a separated portion which is a fault point locating section in a substation premises, and FIG. 3 is a circuit diagram thereof. In these drawings, 1 is a three-phase A, B, and C bus line, 2 is an Otsu bus line, 3 is a line, 4 is a disconnecting switch, 5 is a frame of the disconnecting switch 4, and 6 is a steel structure. In the circuit of FIG. 3, the line 3 is connected to the power source side via a circuit breaker 7, and is configured so that the disconnector 4 can supply power to either the instep bus 1 or the Otsu bus 2 on the load side.

In the present invention, CT8 is applied to the two-phase busbars A and C among the three-phase busbars that connect the disconnector 4 and the respective busbars of Kotsu.
Is installed. In the embodiment, these CT8s are optical CTs.
Therefore, it is possible to detect the current flowing through these two-phase busbars by being attached to the upper end of the optical fiber built-in insulator 9 (only the A-phase CT is shown in FIG. 2). Further, in the present invention, a ground fault CT10 for detecting a ground fault current flowing through the ground line of the pedestal 5 when an accident occurs is attached to the ground line of the gantry 5 of the disconnector 4. Since the CT10 for ground fault is attached to the ground wire of the gantry 5, it is possible to detect a ground fault that has occurred in any phase of the disconnector 4.

As shown in FIG. 4, the outputs of these CT8 are input to the fault point locator 12 via the current differential discriminator 11, and the output of the ground fault CT10 is the ground fault overcurrent detector 13.
Is input to the fault point locator 12 via. Since the optical CT is used as the CT 8 in the embodiment, the O / E and E / O converter 14 is provided before the current differential discriminator 11.

[0009]

Next, the operation of the fault locator 12 in the ground fault short-circuit fault detecting apparatus of the present invention will be described with reference to FIGS. First, as shown in FIG. 5, when the A-phase or C-phase CT8 detects a line internal failure, the current differential discriminator 11 determines that a short circuit occurs, and the busbar protection relay 7 operates, the ground fault CT10 See if the ground fault overcurrent detector 13 has determined a ground fault. If there is a ground fault from the gantry 5 of the disconnector 4, it can be determined that the disconnector 4 in the fault circuit has a ground fault short-circuit fault. When the ground fault CT10 does not detect the ground fault current, it can be determined that a short circuit fault has occurred in a portion (bus line) other than the disconnector 4 in the fault circuit.

Next, as shown in FIG. 6, the busbar protection relay 7 operates and the ground fault CT10 detects the ground fault current, although neither the A phase CT 8 nor the C phase CT8 detects a failure. In this case, it can be determined that the disconnector 4 has a ground fault. As described above, according to the present invention, when an accident occurs, it is a ground fault of the disconnector 4, a short-circuit fault of the disconnector 4,
It is possible to automatically determine which of the short-circuit faults of the bus bar.

When a short-circuit failure occurs in the B phase, the fault current always flows in the A phase and the C phase. For this reason, in the present invention, it is not necessary to attach CT8 to all three phases, and the number of CT8 installed can be reduced.

[0012]

As described above, according to the ground fault short-circuit fault detecting device of the present invention, when an accident occurs in the fault location area of the substation, it is the ground fault of the disconnector. Since it is possible to automatically determine whether it is the ground fault short-circuit fault of the disconnector or the short-circuit fault of the bus bar, it is possible to immediately disconnect the accident point from the sound part and minimize the power failure. Further, according to the present invention, it suffices to install the CTs on the two-phase busbars, and it is possible to reduce the cost and the power outage construction time as compared with the conventional one. Therefore, the present invention contributes greatly to industrial development as a ground fault short-circuit failure detection device that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a front view showing an embodiment of the present invention.

FIG. 3 is a circuit diagram showing an embodiment of the present invention.

FIG. 4 is a block diagram showing an embodiment of the present invention.

FIG. 5 is a block diagram showing the operation of the fault locator in the present invention.

FIG. 6 is a block diagram showing an operation of the fault locator in the present invention.

[Explanation of symbols]

 4 Disconnector 5 Stand 7 Circuit breaker 8 CT 10 Ground fault CT 12 Fault locator

Claims (1)

[Claims] 1. A CT for detecting a current of a bus bar of two phases out of three phases at a disconnection portion in a fault location area in a substation premises.
And a ground fault CT for detecting a ground fault current flowing in the ground wire of the pedestal when an accident occurs, and these C
A ground fault short-circuit fault detection device, wherein T is connected to a fault point locator for discriminating between a short-circuit fault and a ground fault based on the measured data.