JPS6082018A - Protective relaying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a protective relay device, and more particularly to a protective relay device that takes measures to prevent interruption and tripping in the event of a relay failure.

[Technical background of the invention]

FIG. 1 shows a conventional automatic monitoring circuit (consisting of constant monitoring and inspection functions described later) of a protective relay device with an interruption position tripping circuit. In the figure, P is the (+) 1 line of the control power supply, normally open contacts 2ml and 3al are the contacts of the first protective relay for detecting faults in the power system, and normally open contacts 4ml are installed for the same purpose. A second volume different from the above 2al + 3ml
Normally, if an accident occurs in the power system, either one of the 2ml, 3ml, or both of the above-mentioned 2ml, 3ml, or both will operate, and the contact 6 in the figure will be transmitted through the normally closed contact 1b due to the operation of 4al. The on-off trip coil is energized and an on-off trip occurs.

Here, the normally closed contact 1b is closed when the relay is normal, but if a failure occurs, the relay failure detection circuit shown in Figure 2 is activated, and the contact is opened and the interruption is tripped. This is a contact provided to prevent this.

FIG. 2 shows a detection section of a conventional automatic monitoring circuit for detecting relay failure. The protective relay device is always on standby, but in the event of a sudden power system accident, it can reliably detect this and trip the appropriate circuit breaker in the circuit shown in Figure 1. It is their responsibility to do so. Therefore, it is very important to detect these defects in advance, since it is impossible to perform the above-mentioned duties if the relay is in a defective state.

FIG. 2 shows an example of an automatic monitoring circuit provided for this purpose. In the figure, the normally open contacts 2a2, 3a2゜4a2 are the protective relay contacts 2al + for planning the disconnection of the breaker row in Figure 1.
:3.A contact point that performs the same response as 81+4ml,
If any one of them is activated, the time-limited relay 5 is energized, and the relay 1 is activated after a predetermined time period, and its normally closed contact 1b blocks the breaker row disconnection circuit shown in FIG. Here, the time limit relay 5 is provided to obtain a short time limit for the purpose of preventing the blocking relay 1 from operating in the event of an actual system fault. This feature is usually called constant monitoring.

On the other hand, the normally open contacts 21, 31, 41 in FIG.
This corresponds to an inspection failure of a protective relay with 3 a 1 r 4 a 1. Generally, this inspection circuit applies alternating current or direct current electricity to the relay to be inspected to force the relay to operate, and after confirming this operation, removes the applied electricity and confirms that the relay is It is configured to determine that the inspection is in good condition when it returns to normal. Conversely, if this series of operations is not performed, it is determined that the inspection is defective. If any of the above-mentioned protective relays becomes defective during such an inspection, any of the normally open contacts 21, 31, 41 will close, energize the blocking relay 1, and the above-mentioned constant monitoring will be performed. In the same way as when the relay is defective, the breaker row is prevented from being removed.

[Problems with background technology]

The conventional method shown in FIGS. 1 and 2 has the following problems. That is, the conventional method has the disadvantage that all tripping functions are blocked by a failure in either one of the relays having contacts 2al or 3al. This phenomenon will be specifically explained in detail below.

Now, assuming a protective relay device for selectively cutting off only the protected section of a power transmission line, contact 280 (subscripts l and 2
, the same applies hereafter), an undervoltage relay as the contact 3a port, a ground fault overcurrent relay as the contact 1 port, and a phase comparison relay having an intra-section selection interrupting ability as the contact 1 port 4a. Here, the ground fault overcurrent relay is used because the undervoltage relay indicated by port 2a cannot operate in the event of a ground fault (usually called a slight ground fault) that involves a high fault point resistance, such as contact with a tree, because the voltage drop in the system is small. This is a high-sensitivity relay that was installed with this in mind. In a device configured as described above, if a fault occurs in the ground fault overcurrent relay due to constant monitoring or inspection, the sequence shown in FIG. 2 will eventually cause the device to lose its shutoff function. This is due to a defect in the relay used to deal with the aforementioned micro-ground fault, which occurs very rarely as a system fault, and also nullifies the ability to shut off against normal faults, which have a much higher probability of occurring. . That is,
A defect in a circuit that has a low overall contribution can cause even a circuit that has a normal protective function and a high contribution to stop functioning.

Note that the phase comparison relay shown at contact 4a is an important element in determining the selective breaking performance of the protection zone, so it is optimal to block all tripping circuits in the event of a failure in this relay. Sh. The configuration is shown in FIG.

[Purpose of the invention]

The present invention has been made with the aim of solving the above problems, and the purpose is that even if a fault occurs in a relay that is designed to remove a breaker row, the circuit breaker row removal circuit due to the defective relay The purpose of this invention is to provide a protective relay device designed to improve the operating rate of the device by blocking only the tripping circuits having normal protection functions and not blocking the tripping circuits having other normal protection functions.

[Summary of the invention]

In order to achieve the above object, the present invention provides a system for detecting faults in a power system by using at least two or more relays.
A first relay group that produces an output if any one of them operates, a second relay that is installed separately from the first relay and serves the same purpose, and a device that detects a failure in the 1S second relay group. The circuit consists of a first relay group and a second relay group.
In a system in which the circuit breaker is disconnected when both relays operate, if any relay in the first relay group is defective, only the circuit breaker disconnect circuit configured with the defective relay is blocked. , all tripping circuits are blocked when the second relay is defective.

[Embodiments of the invention]

Examples will be described below with reference to the drawings. FIG. 3 shows a circuit breaker disconnection circuit according to the present invention, and FIG. 4 shows a relay failure detection circuit according to the present invention.

Note that the same parts as in FIGS. 1 and 2 will be described with the same reference numerals.

In Fig. 4, normally open contacts 2a 1, 2a2, 2a3
When the constant monitoring of a protective relay having a
Only the circuit breaker disconnection circuit by 4al is blocked.

In exactly the same way, in the event of a failure in the constant monitoring of the protective relay having the normally open contacts 3a1, 3a2, 3a3, only the breaker disconnection circuit formed by the normally closed contacts 12b and 3al and 4al is blocked. These responses are exactly the same when the protective relay is inspected incorrectly. In addition, in the case of failure of the protective relay having the normally open contacts 4al, 4a2, 4a3, and 4a4 in FIG. This is in accordance with the above explanation.

Next, the operation of the present invention will be explained. As mentioned above, the gist of the present invention is to prevent only the tripping route caused by the defective relay even if a failure occurs in a protective relay device having a plurality of circuit breaker disconnection circuits. It is. The effect will be explained by comparing this with the above-mentioned specific example.

Now, if a fault occurs in the ground fault overcurrent relay having normally open contacts 3ml, 3a2.3a3, only the breaker disconnection circuit using this relay and the phase comparison relay is blocked. Therefore, even in this case, the tripping circuit using the undervoltage relay and the phase comparison relay can keep the device in operation while maintaining its normal protective function. In exactly the same way, according to the present invention, even in the event of a failure of the undervoltage relay, it is possible to maintain the tripping function of the earth fault overcurrent, relay and phase comparison relay.

The above explanation has been given for the case where there are two routes for disconnecting the circuit breaker, but it is also applicable to the case where there are two or more tripping routes. It's pretty obvious.

〔Effect of the invention〕

As explained above, in a protective relay device having a plurality of disconnection routes for a breaker, even in the event that a faulty relay occurs, only the tripping route due to the defective relay is blocked, and the tripping route due to a healthy relay is prevented. By configuring the route so that it continues to function, it is possible to provide a protective relay device that can improve the operating rate.

[Brief explanation of the drawing]

Fig. 1 shows a circuit breaker disconnection circuit for a protective relay port device having a conventional automatic monitoring circuit. Fig. 2 shows a conventional relay circuit failure detection circuit V1. Fig. 3 shows a circuit breaker tripping circuit 7 according to the present invention. , FIG. 4 shows a relay defect detection circuit 7 according to the present invention. P, N...Positive and negative bus bars of the control power supply 1.11.12...Auxiliary relay 280.380r for detecting defects in the protective relay 4 A port...Positive relay for planning circuit breaker removal Normally open contacts (1, 2, 3 and 4 correspond to the opening) 5... Time-limited relay 6... Breaker coil section 21.22.23... Closed when inspection failure of protective relay for trip planning Fig. 3 Fig. 4

Claims (1)

[Claims] A first relay group that has a plurality of relays that detect accidents in the power system and that generates an output when any one of the relays operates, and a second relay that is installed separately from each of the relays. and an automatic monitoring circuit for detecting a defect in each of the first and second relays, and when any one of the first relay group and the second relay operates, an interrupter is provided. In a protective relay device that performs tripping, when one of the relays in the first relay group is defective, only the breaker trip circuit constituted by the corresponding defective relay is blocked, and when the second relay is defective, the breaker tripping circuit is blocked. Protective relay device 0 characterized by blocking all trip circuits