JPH10229633A - Protective relay - Google Patents

Abstract

(57) [Summary] In a ground fault distance relay device, there is provided a highly reliable device capable of preventing a malfunction in a two-line ground fault at the back and capable of performing a normal operation in a three-line ground fault in the front. The purpose is to provide. A 44G is advanced in the event of a two-line ground fault at the rear, and the phase-side relay element malfunctions.
4G-DO lag phase element correctly detects external accident,
A distance protection relay device characterized in that the above malfunction is prevented. [Effect] It is possible to construct a highly reliable system capable of preventing a malfunction due to a ground fault of two lines behind and performing a correct operation in the event of a ground fault of three lines ahead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective relay for a transmission line, and more particularly to a protective relay using a ground fault distance relay.

[0002]

2. Description of the Related Art As a protective relay for a transmission line system,
A distance protection relay using a ground fault distance relay is applied to a direct grounding system.

[0003] As a method of applying this distance protection relay device, for example, “Distance relay” in the standard concept (digital edition) of the system protection relay system issued by the Manager of the Protection Control Section in the Engineering Department of the Federation of Electric Power Companies of Japan. This is a method disclosed in “Electrical method”. If a ground fault distance relay is used, the leading phase of the ground fault distance relay on the power supply end side malfunctions in the event of a two-wire ground fault behind the power supply terminal in the non-power system at the other end of the positive-phase power supply system. A measure is taken to lock the advance relay by the element. This concept is shown in the block diagram of FIG. Ground fault distance relays 44G-1 to 3-4,
High-speed undervoltage relays 27Gφ-1 to 27G-3 which operate according to the magnitude of the phase voltage are provided as relay elements.

In recent years, digital relays have been used for these relay elements, and their characteristics are shown in FIGS.
Shown in In the drawing, a range indicated by hatching indicates an operation region. Among them, the characteristics of the ground fault distance relay element are shown in detail as shown in FIG.
The configuration is such that the output of the ground fault distance relay 44G is established only when all the operating conditions of the four elements L2 and D1 are satisfied.

[0005]

However, the conventional high-speed undervoltage relay has a malfunction prevention method for a two-line ground fault at the rear, which provides the following response in the event of a forward accident.

This response is shown in Table 1.

[0007]

[Table 1]

In the event of a forward three-line ground fault, the high-speed undervoltage relay 27Gφ operates in all three phases, and the open signals T1 to T3 to the circuit breaker are output to prevent the output of all phases of the ground fault distance relay 44G. This causes inconveniences that are not output.

For this reason, conventionally, the operation of the short-circuit distance relay has been conventionally performed in the case of the three-line ground fault in front of the vehicle, and the operation has been divided.

However, in recent years, there is a strong need to further improve the operational reliability of the protective relay device, and there is an increasing need for a protective relay device that performs normal non-operation in a rear accident and normal operation in a front accident. I have.

[0011]

In order to solve the above problems, the present invention provides an accident detecting means for detecting a transmission line accident in a transmission line, and a ground for specifying the location of a transmission line accident point in the transmission line. In a protective relay device that is equipped with a short-circuit distance relay and that outputs an open signal to the circuit breaker to protect the transmission line, when a two-line ground fault occurs behind the protective relay device, the directional element for determining the external accident of the short-to-ground distance relay is disabled. An open signal to the circuit breaker is output on condition of operation.

Further, the present invention relates to a protective relay device,
As the directional element for external accident determination, the directional element for the internal accident determination of the ground fault distance relay uses an element of the opposite polarity, and the open signal to the circuit breaker is output under the condition that these directional elements for external accident determination do not operate. It was done.

Further, in the protective relay device according to the present invention, the output of the leading phase side of the ground fault distance relay is blocked by the lagging phase element of the external accident judging element.

In the present invention, such a configuration is provided,
The above problem is solved by paying attention to the elements constituting the ground fault distance relay and using the elements that operate with the opposite polarity of the operation area of the inward direction element DI among the elements described in FIG.

The use of this element 44G-DO prevents a malfunction due to the above-mentioned two-line ground fault behind and prevents the system from unnecessarily blocking the output of the ground distance relay in a three-line ground fault in front. FIG. 1 is a block diagram, and FIG. 2 shows the characteristics of the malfunction preventing external accident determination element 44G-DO.

By operating on the lag phase element of the 44G-DO in this manner, the advance phase of the 44G is blocked.

With the above configuration, in the transmission line system of FIG. 3, a two-line ground fault, for example, a BC-phase ground fault occurs at a point F behind the power supply end of the ground fault distance relay 44G installed at the electric substation A. Then, the internal determination element 44G-
DI, B-phase, C of each element of external accident judgment element 44G-DO
The impedance seen by the phase is as shown in FIGS. That is, 44G-DI operates (malfunction) for the B-phase element and 44G-DO operates (normal operation) for the C-phase element.
4G-2 is output, but 44G-DO3 operates and IN
Since the AND condition of AND2 is not satisfied by the output of V3, the open signal T3 to the circuit breaker is not output, so that malfunction can be prevented.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment according to the present invention.

A ground fault distance relay 44G and an external accident judging element 44G-DO are provided.
The circuit breaker opening signals T1 to T3 are established when the DO is not operated.

The external accident judging element 44G-DO is characterized in that it operates with a polarity opposite to that of the internal judging element 44G-DI of the ground fault distance relay 44G, and its characteristic diagram is shown in FIG. .

The open signals T1 to T3 to the circuit breaker are 44G
And the delay phase non-operation of 44G-DO is output as a condition, and the specific logical conditions are as follows.

T1 = 44G-1 · 44G-DO2 T2 = 44G−2 · 44G-DO3 T3 = 44G−3 · 44G-DO1 Table 2 shows the response at the time of the transmission line accident according to the present invention. At the time of the BC phase ground fault, even if 44G-2 is operated, the external determination element 44G-DO3 is operated and the circuit breaker open signal is blocked.

[0024]

[Table 2]

On the other hand, at the time of the front three-line ground fault, 44G-1
Since the circuit breaker opening signals T1 to T3 are all satisfied because of the operation of .about.3 and the failure of 44G-DO1.about.3, the system of the normal operation in the case of a rear accident to be solved and the system of the normal operation in the front accident can be realized.

In addition to the above-described embodiment of the present invention, in the ground fault distance relay system, first to third stage elements are generally used as ground fault distance relay elements.
This is because it is in accordance with the standard concept of the system protection relay system issued by the Protection Control Section Manager's Conference of the Electric Power Industry Federation, and the first to third stages are based on the external judgment element of the present invention. Obviously, a blocking condition can be applied.

[0027]

According to the present invention, it is possible to provide a system capable of properly operating not only in the case of an external accident but also in the event of a three-line ground fault in the forward direction, which has not been able to operate accurately in the past. Therefore, the present invention can be expected to improve the operation-side reliability.

The external accident judging element, which is a feature of the present invention, can be embodied by making the polarity of the internal judging element, which is one of the components of the conventional ground fault distance relay, reverse. Can be used as is,
Since there is no need to provide a dedicated relay unlike the conventional malfunction prevention method, there is an effect that a simple relay device can be realized.

[Brief description of the drawings]

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

FIG. 2 is a characteristic diagram of an external accident determination element which is a component of the present invention.

FIG. 3 is a diagram showing an application of the device according to the present invention to a transmission line system and a transmission line accident situation for response explanation.

FIG. 4 is a drawing for describing a block diagram for preventing a malfunction when a two-line ground fault occurs behind a ground fault distance relay of the conventional distance protection relay device.

FIG. 5 is a characteristic diagram of a ground fault distance relay.

FIG. 6 is a characteristic diagram of a high-speed undervoltage relay.

FIG. 7 is a diagram illustrating characteristics of a ground fault distance relay in detail from constituent elements.

FIG. 8 is a characteristic diagram illustrating the response of a ground fault distance relay element.

FIG. 9 is a characteristic diagram illustrating the response of a ground fault distance relay element.

[Explanation of symbols]

27Gφ: High-speed undervoltage relay, 44G: Ground fault distance relay, T1 to T3: Circuit breaker open signal, 44G-DO: External accident determination element.

Claims (3)

[Claims] An accident detecting means for detecting a transmission line fault in a transmission line, a ground fault distance relay for specifying a location of a transmission line fault point in the transmission line, and outputting an open signal to a circuit breaker to transmit the transmission line. In a protective relay device for protecting an electric wire, an open signal to the circuit breaker is output on condition that a direction element for judging an external accident of the ground fault distance relay does not operate at a two-line ground fault behind the protective relay device. A protective relay device characterized in that: 2. The protection relay device according to claim 1, wherein the external fault judging direction element is a component having a polarity opposite to that of the internal fault judging direction element of the ground fault distance relay. A protective relay device for outputting an open signal to a circuit breaker on condition that an element does not operate. 3. The protection relay device according to claim 1, wherein an output of a ground-fault distance relay is advanced by a delay-side element of the external accident determination element.