SU1534513A1 - Device for checking isolators for fouling level - Google Patents

Abstract

This invention relates to electrical engineering, in particular to monitoring the level of contamination of insulators. The goal is to increase the reliability of work. For this, the device containing a leakage current comparator with the executive body is supplemented with blocks for adjusting the sensitivity and delay, which makes it possible to automatically change the sensitivity of the circuit during operation with a ground fault. The presence of a delay unit prevents false alarms during short-term overvoltages. The device is based on the logical elements NOT and OR. 1 hp f-ly, 1 ill.

Description

one

(21) 4200868 / 24-07

(22) 02.25.87

(46) 07.01.90. Bul one

(71) Moscow Institute of Agricultural Production Engineers V.P. Gorchkina

(72) T.R.Surikov, A.E. Orlovich, A.I. Selivakhnn, R.Sh.Sagutdinov, Yu.A.Apoltsev, I.L.Slonov

and V.G.Holovatsky

(53) 621.315 (088.8)

(56) USSR author's certificate

9 737887, cl. G 01 R 31/02, 1977.

USSR author's certificate 4. Ш7044, кл. H 01 H 17/60, 1986.

(54) DEVICE TO CONTROL THE LEVEL OF POLLUTION OF INSULATORS (57) The invention relates to electrical engineering, namely to the control of the level of contamination of insulators. The goal is to increase the reliability of work. For this purpose, the device containing a leakage current comparator with the executive body is supplemented with sensitivity and delay control units, which allows the circuit sensitivity to be automatically changed during operation with a ground fault. The presence of a delay unit prevents false alarms during short-term overvoltages. The device is based on the logical elements NOT and OR. 1 e.p, f-ly, 1 ill.

r to

The invention relates to electrical engineering and can be used in complete switchgears (KRU) and in complete transformer substations (KTP).

The aim of the invention is to improve the reliability of the device.

The drawing shows a block diagram of the device.

The device comprises a resistor 1 through which the support insulator is connected to the ground loop. In parallel with the resistor, an overvoltage protection device 2 is turned on. The comparator 3 has two inputs, one of which is connected to the resistor 1, the second to the sensitivity adjustment unit 4, which is controlled by means of a centralized signaling starting element 5 with a ground fault.

The comparator 3 is connected to the input of the delay unit 6, the output of which is connected to the input of the memory, body 7, and the output of the latter is connected to the input of the executive circuit by 8..

The sensitivity adjustment unit 4 comprises the first element NO 9 connected between the input of the unit and the first source 10 of the reference voltage SP

00

ate

00

wives The second element HF 11 and the third element NOT 12 are connected in series between the input of the unit 4 and the second source 13 of the reference voltage.

A comparator, a memory unit, a sensitivity adjustment unit can be made on the basis of microcircuits.

The device works as follows.

When the surface of the contaminated insulator is moistened, leakage current begins to flow along it. If a current flows through resistor 1, then a voltage signal appears at the first input of comparator 3. If this signal is greater than the voltage generated by block 4 at the second input of comparator 3, the latter will trigger and a signal of log 1 will appear at the input of block 6 of delay. The time delay of block 6 of delay is selected so that signals not received by memory unit 7 arcing and switching overvoltages. When a signal appears at the input of the storage unit 7, the main element of which is the trigger, the latter overturns, causing the actuator 8 to operate. When the comparator 3 returns to its initial state, the storage unit 7 and the executive body remain in a dead state insulator contamination. The device acts on the signal. The sensitivity control unit allows you to set the required level of operation of the device depending on the mode of operation of the network. If the starting organ of the centralized signaling of the earth fault is open, then at the output of the element HE 9 the signal is equal to the log. 1, which triggers the source 10 of the reference voltage and establishes a triggering threshold corresponding to the normal operation of the network. If the network works with a phase to earth fault, the voltage of the intact phases increases in the emergency state.

five

0

five

0

five

0

five

0

A centralized earth fault protection is jammed and pin 5 is closed. At the output of elements 9 and 10 signals log.O. At the output of element 12 - a signal log., The second source 13 of the reference voltage is triggered, forming the threshold of operation corresponding to the closure

to the ground.

The introduction of a sensitivity control unit allows controlling the degree of contamination of the insulators in both normal and emergency mode of the network.

Claims (2)

1. A device for monitoring the level of contamination of the isolators of a complete switchgear with a central earth fault alarm, containing a shunt connected to a comparator, a memory, the output of which is connected to the input of the executive body, characterized in that equipped with sensitivity and delay adjustment blocks, the input of the sensitivity adjustment block connected to the triggering unit of the centralized signaling about the earth fault, and the output - with the second input of the comparator, the output of which is connected to a delay unit connected in series with the memory unit. 2. The device according to claim 1, of which is that the sensitivity control unit contains the first, second and third elements of the NOT, the first and second sources of reference voltage, and the first element is NOT connected between the input of the sensitivity control unit and the first source the reference voltage, and the successively connected second and third elements NOT between the input of the sensitivity control unit and the second source of the reference voltage, the outputs of the reference voltage sources are the outputs of the control unit vstvitelnosti. From isolator