JPS59149717A - Protecting relay - 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 having a five-check circuit for performing analog check after a filter section.

[Technical background of the invention]

Conventional protective relays, such as overcurrent relay 1, convert the input current taken in from the protected system into a size that is easy to handle in the relay device, input it to a current-voltage converter, convert it into a voltage signal, and then filter it. This filter cuts the DC component and harmonic component contained in the input current, extracts the basic component, and then outputs "1'" when the output is above a predetermined value using the level detector. It is configured as follows. When inspecting an overcurrent relay with such a configuration, apply one inspection voltage between the input terminals of the filter in accordance with the inspection command, and check whether or not this inspection input causes an output from the level detector. , checking to see if the relay is in working order.

In this case, the inspection voltage value applied at the time of inspection (the magnitude of this secondary voltage is taken into account) needs to be determined as follows in order to enable inspection even under the worst conditions.

In other words, the maximum power flow of the protected system is input, the maximum power flow and the inspection input are applied in opposite phases, and a large inspection input is applied so that the combined input exceeds the operating value of the relay to enable inspection. There is a need. In other words, the voltage eV1r generated on the secondary side of the input transformer 10 at the time of maximum power input
,, If the 1 voltage k generated when inputting the operating value of the relay is 71M, then the inspection voltage ■ is the following formula: Vl > VIL + VIM + α (where α: inspection margin) ・(1) must be satisfied, and it is relatively There was a drawback that resulted in a large value.

[Purpose of the invention]

An object of the present invention is to provide a protective relay that is almost unaffected by the maximum power flow during inspection and can be inspected with a small inspection voltage.

[Summary of the invention]

An input transformer inputs the amount of electricity obtained from the protected system and converts this input into a predetermined value, and a relay determines whether the output of this transformer exceeds a predetermined value. A protective relay is characterized in that it lowers the secondary impedance of the input transformer and adds inspection input to a location where there is little shunt to the secondary side of the input transformer.

[Embodiment of the Invention] In the figure, l is an input transformer, which transforms the overflow Ii taken in from the protected system to an appropriate size and insulates it in a four-dimensional manner. The output current of this input transformer 1 is applied to a resistor R2 so as to produce a proportional voltage of 1. Both terminals of this resistor RZ are connected to the active filter 30 input terminal 'I+tl. The input terminal t1 is connected to the (-) input terminal of the operational amplifier OP through a first input resistor R1, a second input resistor R2 and a capacitor "tk, while the input terminal t2 is connected to the (-) input terminal of the operational amplifier OP.
is connected to the (''-) input terminal of Moreover, the connection point between the second input resistor R2 and the capacitor C1 is connected to the (+) input terminal of the operational amplifier (OP) via the resistor R3, and the connection point between the second input resistor R2 and the capacitor C1 is connected to the (+) input terminal of the operational amplifier (OP) via the capacitor C2. Connect to the output terminal of Furthermore, a feedback resistor R4 is connected between the (-) input terminal and the output terminal of the operational amplifier (OP). The output signal of the operational amplifier (OP) is input to a level detection circuit 4, and it is determined whether or not the level is higher than a predetermined operating level. The output of this level detector 4 is input to the next stage time-limited return circuit 5 and made continuous. The above configuration is the circuit as the main body of the overcurrent relay. For such an AT device, the amount of electricity to be checked is the input terminal t! of the filter 3! and 1st. It is designed to be supplied between the connection point J of the second human power resistance.

That is, 2 is an inspection transformer for converting the inspection human power V into an appropriate magnitude, and a resistor RT is connected between its output terminals. The terminal bottom pressure of this resistor RT is assumed to be .

This voltage is applied between the connection point J1 and the input terminal 1 through the output contact 7f of the auxiliary relay 6 which is driven by the inspection command.

To explain the operation shown in the figure, when the auxiliary relay 6 is driven by an inspection command during inspection, its output contact 7 is closed. Then, the secondary voltage ■2 of the inspection transformer 2 is 1. Since the voltage is applied between 5 points, V,=V;. Enter here
Inspect the secondary solder pressure of input transformer 1 corresponding to 1st stream I.
Consider the influence on 1 pressure vJ.

First, during inspection, connect 1 between points 11 and 5 using resistor BT.
It will be done. Here, if the relationship between resistor R1 and RT is 6a1>BT, then the secondary voltage V1 of input transformation a1 is equal to that of resistor R1 and resistor F.
Due to the voltage division ratio of LT, almost no voltage is generated across the resistor 1'LT'. Next, under normal conditions, contact 7 is open, and resistor RT is not inserted between points 12 and 5.

In other words, during inspection, the signal vl corresponding to the input current I is
Since it is greatly attenuated by the resistor FLT, it is hardly affected by the maximum power flow during inspection.

From this, there is no need to consider the maximum power flow input for the inspection voltage V, and it is better to check it with the inspection input at a value that has some margin in the relay's operating value.

That is, if the 1 voltage generated on the secondary side of the input transformer 10 when an operating value is input is vlM, then the inspection voltage {circle around (2)} is given by the following equation.

V,>V,,+α (However, α: inspection margin)...
(2) This equation (2) means that the inspection voltage itself can be reduced by t.

Similarly, in the explanation of the present invention, the case of an overcurrent relay was explained, but even in the case of an overgust relay, the secondary side and beyond can be configured using the same principle by simply changing the input transformer &, so the same inspection circuit as the present invention can be used. can be applied.

Further, it is also applicable to a relay in which the inspection input is configured by an oscillator or the like inside the relay.

〔Effect of the invention〕

As described above, the present invention enables inspection by applying one inspection pressure to a part of the filter circuit when performing analog inspection after the filter section. The inspection voltage can be reduced to enable inspection even at the opposite phase of the maximum power flow.

[This is K] It is possible to reduce the burden on the power supply for inspection and to downsize the transformer for inspection.

[Brief explanation of the drawing]

The drawing is a block diagram of a protective relay device according to the present invention. 1.Input transformer 2.Inspection transformer 3.Filter 4.Level detection circuit 5.Time-limited return circuit 6.Auxiliary relay 7.A of auxiliary relay 6
contact

Claims (1)

[Claims] In a relay consisting of an input transformer that inputs the amount of electricity obtained from the protected system and converts this input into a predetermined value, and a level detector that generates an operating output when the output of this transformer exceeds a predetermined value, A protective relay characterized in that the secondary impedance of the transformer is lowered by a check signal, and the check input amount is applied to a portion where there is little shunt to the secondary side of the input transformer.