JPS5818859B2 - Protective relay inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protective relay inspection device having an electromagnetic auxiliary relay in its output stage.

One of the additional features of protective relays is that they are desired to be easy to maintain and inspect, and static protective relays that use transistors, etc. to form the intended protective relay circuit are also equipped with inspection devices. There is.

FIGS. 1 and 2 show a conventional inspection device included in a protective relay.

In Figure 1, the protective relay receives a state detection signal from the object to be protected, such as the power system, and detects an abnormal state from a change in the input signal. It consists of an auxiliary relay X that issues a protection command.

For such protective relays, the inspection device is
A prohibition circuit G1 is provided between Y and the auxiliary relay X, and a pseudo signal (inspection signal) of an abnormality to be protected is inputted to the relay main body RY from a memory circuit FF such as a flip-flop set at the time of inspection.

This inspection signal is processed appropriately depending on whether the main body RY is a stationary type or an electromagnetic mechanical type.

Simultaneously with the start of inspection, the time-limited return circuit MM is activated to lock the detection output of the relay main body RY with the inhibition circuit G1.

If there is a detection output in the relay main body RY during this lock period, the memory circuit FF is reset by the output, it is determined that the protective operation up to the stage before the inhibition circuit G1 is normal, and the inspection is completed.

However, in the inspection device shown in Fig. 1, the relay body R
In order to prevent the auxiliary relay X from responding to the inspection output of Y and outputting a protective output, the output is output during that time.

Therefore, the operation of the auxiliary relay X and the inhibition circuit G1 cannot be inspected.

In other words, even if there is a failure in the prohibition circuit G□ itself or a break in the coil of the auxiliary relay There are drawbacks to be judged.

The conventional inspection device shown in FIG. 2 is capable of inspecting up to the auxiliary relay.

That is, two relay bodies RY0. of the same configuration. RY2
and auxiliary relay X1. X2 is installed in parallel, and the auxiliary relay
1. The output contacts of X2 are connected in series, and the relay body RY1.
Give check signals alternately to RY2.

As a result, the relay that gave the check signal (for example, RY
If 1) is normal, it can be checked by contact operation of the attached auxiliary relay X1, and since the contact of X2 is open at that time, no erroneous protection output will be issued.

Similarly, RY2 can be inspected by contact operation of X2.

However, the inspection device as shown in FIG. 2 requires two protective relays to obtain one protection output, which has the drawback of making the inspection device expensive.

An object of the present invention is to provide an inspection device that can inspect the protective operation including the auxiliary relay without duplicating the protective relay.

FIG. 3 shows an embodiment of the present invention, and the same parts or parts having the same functions as those in FIG. 1 are designated by the same reference numerals.

From the memory circuit FF set by the inspection command to the relay body R
A check signal is given to Y, and if the relay main body RY operates normally, a drive signal for the auxiliary relay X is output through the inhibition circuit G1.

The auxiliary relay X is driven by turning on the transistor TR1.

The drive current of the auxiliary relay X is detected by an inverter circuit consisting of resistors R1 and R2 and a transistor TR2, and the memory circuit FF is reset and the gate of the AND circuit G2 is opened.

The AND gate G2 obtains a pulse having a width corresponding to the time delay from when the memory circuit FF is reset until it is reset, and activates the instantaneous operation time limit recovery circuit OM.

The above OM is the relay main body R by resetting the memory circuit FF.
It has a return time that is longer than the time until the return of Y, and locks the drive signal to the auxiliary relay X.

Note that in order to obtain a pulse with an appropriate width at the output of the AND circuit G2, a delay circuit (indicated by a broken line block in the figure) may be provided to delay the reset input of the memory circuit FF.

In such a configuration, the time from when the drive signal is output to the auxiliary relay
, the AND circuit G2, and the memory circuit FF are configured with semiconductor circuits, the time can be extremely shortened, and the first drive signal can be locked before the auxiliary relay X operates.

Therefore, the output contact of the auxiliary relay X is not turned on and no protection command is issued to the outside.

Since the inverter circuit detects that the drive current has flowed through the auxiliary relay X, the protective operation including the auxiliary relay X can be inspected.

For example, the coil of auxiliary relay X may be disconnected or the prohibited circuit G1. If there is a failure in the transistor TR1, no current will flow through the auxiliary relay coil, so the output of the inverter circuit will be at logic ++091, and an abnormality in the protective operation can be detected.

Note that even if the coil of auxiliary relay become.

Although the inspection results in the above-mentioned inspection device can be checked on an appropriate signal line, it is preferable to check the output or input of the instantaneous operation time limit return circuit OM.

This is because the instantaneous operation time limit return circuit OM was activated when there was a check signal and a drive signal to the auxiliary relay X was issued.
This is because it is performed for the first time under the D condition.

As clarified above, the inspection device according to the present invention does not require duplication of protective relays, and thus can reduce the cost of the device.

Furthermore, it has the advantageous effect of allowing inspection of the protective operation including the auxiliary relay at the final output stage.

[Brief explanation of the drawing]

1 and 2 are block diagrams for explaining a conventional protective relay inspection device, and FIG. 3 is a block diagram showing an embodiment of the present invention. RY...Protective relay body, X...Auxiliary relay, FF...Memory circuit, MM......
Time-limited return circuit, G1...Prohibition circuit, OM...
...instantaneous action time-limited return circuit.

Claims (1)

[Claims] 1. In a protective relay in which a detection signal or an inspection signal input via a memory circuit is input to the protective relay body, and an electromagnetic auxiliary relay is provided in the protection output stage of the protective relay body, the output of the protective relay body is prohibited circuit. is used as a control input for the first drive switch circuit of the auxiliary relay, and the auxiliary relay is provided with a detection circuit that detects when the drive current starts flowing, and the detection signal of this detection circuit and the check point are ANDed. An AND circuit that operates under the conditions is provided, and this AND
A means is provided for inhibiting the output of the prohibition circuit using the output of the circuit, and the detection circuit and the AND circuit are provided before the driving current starts flowing to the auxiliary relay and the contacts of the auxiliary relay are switched when the inspection signal is input. An inspection device for a protective relay, characterized in that the application of a drive signal to the auxiliary relay is prohibited in a signal path of a prohibition circuit.