JPH0446517A - Protective relay - Google Patents

Abstract

PURPOSE:To improve reliability against a system accident by connecting a simplified back-up protective relay and making use of its function only when a device is controlled into a locked state. CONSTITUTION:When short circuit or a earth fault occurs in a protected section, a main detection relay (MTX) and an accident detection relay (FDX 1) are operated and excited, the a-contact of the MTX and the a-contact of the FDX 1 are closed, and trip output is transmitted in a moment. When wrong automatic inspection or wrong continuous monitoring is detected and auxiliary relays (28 TX) are energized through an OR gate (OR), a trip circuit including the MTX and the FDX 1 is locked, but a simplified back-up protective relay is operated to energize auxiliary relays (FDX 2) after the time limit of an on-delay timer. When the a-contacts are closed and an auxiliary relay (28 TXH) is energized, trip output is transmitted with the AND of the a-contact of the 28 TXH and the a-contacts of the FDX 2.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a protective relay device that has a monitoring function such as automatic inspection or constant monitoring, and locks the device when an automatic monitoring failure is detected. .

(Conventional technology) The configuration of a conventional device will be explained with reference to FIG.

The main detection relay is the main part of the device and has the function of operating reliably in the event of a short-circuit or ground fault in the protected area, and drives the auxiliary relay MTX via the relay driver RDI.

The accident detection relay has the function of operating in the event of a short circuit or ground fault regardless of the protection zone, and relay driver RD2
, drives the auxiliary relay FDX. The accident detection relay is provided as a fail-safe for the main detection relay.

The main detection relay and accident detection relay have an automatic monitoring function through automatic inspection and constant monitoring, and when an automatic monitoring failure is detected, the auxiliary relay 28TX is driven via the OR gate OR2 and the relay driver RD3.

The circuit breaker disconnection circuit will be explained with reference to FIG.

When a short-circuit or ground fault occurs in the protection system section, the main detection relay and fault detection relay explained in Figure 3 operate, and the auxiliary relays MTX and FDX are energized, and as shown in Figure 4, the a contact of MTX and the contact of FDX are activated. The a contact closes and a trip output is generated to trip the circuit breaker within the protection zone.

(Problem to be solved by the invention) If an automatic inspection failure or constant monitoring failure occurs in Figure 1, 28TX is excited and the b contact of 28TX in Figure 4 opens, and the main detection relay side detects the accident. Regardless of the fault on the relay side, the trip circuit will be locked, and all protection functions will be lost for future accidents within the protection zone. Therefore, for devices that protect particularly important systems, duplication of devices or backup protection has traditionally been implemented. However, when an automatic monitoring failure occurs in a device that does not have redundant protection devices, the transmission line becomes unprotected and the only option is to suspend the transmission line.

However, in recent years, it has become difficult to treat power transmission lines as suspended due to demand constraints, and because they are not particularly important systems, it is not necessary to install duplication or backup protection. For this reason, there has been a demand for a means that can provide protection in a simple manner.

An object of the present invention is to solve the above-mentioned problems and to provide a protective relay device that is more reliable and does not become completely unprotected from system accidents even if the device is locked due to an automatic monitoring failure.

[Structure of the invention]

(Means and effects for solving the problem) In the present invention, in addition to the main detection relay and the accident detection relay, a simple backup protection function is provided, which is composed of an undervoltage relay and a ground fault elapsed voltage relay.
The system is configured so that the simple back-up protection function is utilized only when the main detection relay or accident detection relay is in a device lock state due to an automatic inspection failure or constant monitoring failure. For,
It is designed to ensure that the breaker in the protected area can be tripped.

(Example) Examples will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the relay configuration and trip circuit of a protective relay device according to the present invention. In FIG. 2, the same parts as in FIGS. 3 and 4 are designated by the same reference numerals, and their explanation will be omitted.

The simple backup protection relay shown in FIG. 1 is composed of elements for detecting short-circuits and ground faults in the system. - For example, the OR of the outputs of a short-circuit undervoltage relay and a ground-fault overvoltage relay is used as a simple backup protection relay.

The output of the simple backup protection relay is sent via the on-day timer TI and relay driver RD4 to the auxiliary relay FDX 2.
to drive. The auxiliary relay 28 T The structure is such that trip output is output using the ant of the a contact.

Now, if a short circuit or ground fault occurs within the protection zone, the main detection relay and detection relay shown in Figure 1 will operate, and when MTX and FDXI are energized, the second
The A contact of MTX and the A contact of FDX l in the figure close, and a trip output is instantaneously generated.

Next, when an automatic inspection failure or constant monitoring failure is detected in Figure 1, when 28TX is energized via the OR gate, a trip is triggered by the main detection relay (MTX) and fault detection relay (FDX 1) in Figure 2. The circuit is locked. If a short-circuit or ground fault occurs in the system, the simple back-up protection relay shown in FIG. 1 operates, and after the on-delay timer TI expires, FDX 2 is energized, and as shown in FIG.
FDX 2 (7) When the a contact is closed and 28TX11 is energized, a trip is output by the AND of the a contact of 28TXH and the a contact of FDX 2.

Since the simple back-up protection relay is used only when the device has an automatic monitoring failure, there is no need to add automatic inspection and constant monitoring functions, and constant monitoring alone is sufficient.

〔Effect of the invention〕

As explained below, in a protective relay device that has an automatic monitoring function such as automatic inspection or constant monitoring, and locks the device when an automatic monitoring failure is detected, a simple backup protection relay is installed to prevent automatic inspection or constant monitoring. By configuring the function of the simple backup protection relay to be utilized only when a monitoring failure occurs and the equipment is locked, the system will not become unprotected even if the equipment is locked due to an automatic monitoring failure, preventing system accidents. It is possible to provide a more reliable protective relay device 7 that can reliably trip the circuit breaker in the protection zone.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of a protective relay device according to the present invention, Fig. 2 is a trip circuit diagram of an embodiment of a protective relay device according to the present invention, and Fig. 3 is a general protective relay device. FIG. 4 is a block diagram of the electrical device, and is a trip circuit diagram of a general protective relay device. OR...Or gate TI...On-day timer RDI, RD2, RD3, RD4...
・Relay driver MTX, FDX 1, 28TX,
FDX 2, 28TH --- Auxiliary relay agent Patent attorney Noriyuki Chika

Claims (1)

[Claims] In the first protective relay device that has an automatic monitoring function such as automatic inspection or constant monitoring, a simple second accident detection function is added, and when the automatic monitoring fails, the first protection function is locked and the second protection relay is added. A protective relay device characterized by having a simple backup protection function that issues a trip command to a circuit breaker using only the output of an accident detection function.