SU1345285A1 - Apparatus for protecting electric units from shorting currents - Google Patents

Abstract

The invention relates to electrical engineering, namely, relay protection, and can be used to protect electrical installations from short-circuit currents. The purpose of the invention is to increase Reliability by increasing the sensitivity to intermittent arc short-circuits (short-circuit). If intermittent to. are repeated several times during the formation by the summing body of its own time delay and the sum of the durations of the flow of intermittent short-circuit currents. becomes equal to the time setting value of the protection device, while the time setting body carries the signal to the operating part. 1 il. (L

Description

The invention relates to electrical engineering, namely, to relay protection, and can be used to protect electrical installations from short-circuit currents.

The purpose of the invention is to increase reliability by increasing the sensitivity of a protection device to intermittent arcs, k, 3 .f.

The drawing shows the scheme of the proposed protection device.

The protection device contains the sensing part 15 of the pulse shaper 2, reacting 3 and the time of setting 1RSCh And organs, memory trigger 5 and summing body 6, the output of which is connected to the zero input of the trigger 5 whose information input is connected to the output of the reacting body 3, and zero output the trigger 5 is connected to the input Reset time of the setting body A and the zero input of the summing body 6, and the single one is connected to the control input of the summing body 6, the counting input of which is connected to the output of the driver 2.

The device works as follows

By K.K. in the monitored network, the reacting body 3 is triggered, the time of the setting body 4 is activated and triggering the trigger 5 triggers, which in turn allows the summing body 6 to operate. Time — the setting and summing organs start counting the pulses arriving at their counting inputs pulses. The time setting body 4, counting the required number of pulses corresponding to a given set point in time, is

signal to the executive part. I

When reducing the value of the monitored current at the input of the reacting body 3 is lower than the set value of the current over time, less than the set time of the protection device, the reacting body 3 returns to the initial state and stops further pulse counting by the master; summing authority 6 continues counting pulses. The resetting of the intermediate result of the account does not occur; with the possible subsequent occurrence of short-circuit the score will start with this intermediate result .. The summing authority, having counted the necessary

0

5 0 25 30

The number of pulses, corresponding to its own time delay, causes a signal to return the trigger to its initial state, which, in turn, stops the operation of the summing organ and generates a reset signal at the time of the master. In this case, the signal to the executive part of the protection device does not pass. I

If intermittent to. are repeated several times during the formation of the summing body 6 of their own time lag and the sum of the durations of the flow of intermittent currents short circuit. becomes equal to the time setting value of the protection device, then the driver specifies the signal to the executive part.

Thus, the proposed device allows memorizing and summing up the duration of the flow of intermittent short-circuit currents. during the time determined by the summing body's own time delay, it increases the sensitivity of the protection device to intermittent arc short-circuits. and increases the reliability of the relay protection device as a whole, and also reduces the damage caused to electrical equipment at short-circuit.

Claims (1)

Invention Formula A device for protecting electrical installations from short-circuit currents, containing a sensing part, a pulse shaper, reacting and The timing of the organs, while the output of the sensing part is connected respectively to the inputs of the pulse former and the reacting organ, the output of the pulse former is connected to the first input of the master body, the output of the responsive organ is connected to the second input, the time of the master body, characterized in that by increasing the sensitivity to intermittent arc short circuits, a trigger with memory and a summing organ are added to the device, the output of which is connected with the zero input of the trigger, the information input of which is connected to the output of the reacting authority, the zero output of the trigger is connected respectively to the Reset input, the time specifying 1345285 organ and zero input summing peace organ, the counting input of the organ, the single output of the trigger is connected to the control input of the sum connected to the output of the pulse former. pogo connected to the output of the pulse driver. Editor A. Lezhnin Compiled by Yu. Postnikov Tehred A. Kravchuk Proofreader I. Muska Order 4928/52 Circulation 617 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4