Trip Coil Supervision Circuit

Such trip circuit supervision tcs relays are intended for a continuous supervision of circuit breaker trip circuit and to give an alarm for loss of auxiliary supply faults on the trip coil or its wires independent of the breaker position faults on the breaker auxiliary contacts and faults in the supervision relay itself.

Trip coil supervision circuit.

There are different contacts connected in series along a trip circuit of an electrical circuit breaker there must be some situation when the circuit breaker should not trip even a faulty current passes through its power contacts. Permanant positive is given to one end of coil of 95a and now the other end of coil of 95a gets the negative voltage coming through the tripping coil nc auxillary contact of the breaker. The supervision relay type tcs is intended for a continuous supervision of circuit breaker trip circuit and gives an alarm for loss of auxiliary supply faults on the trip coil or its wires independent of the breaker position. With references for single pole and 3 pole and a wide range of voltages vdf.

This relay has three coils namely rla rlb and main coil tcs of the relay as shown in the figure above. We will be using areva make vax31 type trip circuit supervision relay. Arteche trip circuit supervision relays monitor trip coil circuit in open close states and during circuit breaker operation. So in order to check the condition of the trip circuit is essential in power system protection.

The relay is a member of siemens reyrolle protection devices product family. Both versions detect the following conditions. It is used to monitor and supervise the integrity of a circuit breaker s trip coil and other wiring circuits of low voltage and medium voltage networks. Such situations are low gas pressure in sf 6 circuit breaker low air pressure in pneumatic operated circuit breaker etc in this situation the trip coil of the cb.

The supervision function in three steady states of circuit breaker trip circuit is below image in normal condition the indicator led glows green and output relays are in picked up condition. Tcs relays are used for dc supervision via lor trip coil generating an alarm and avoiding open close commands under faulty conditions or when breaker tripping mechanism is not ready to operate. Pre close trip supervision post close trip supervision. Failure of trip supply open circuit of trip coil of trip circuit wiring.

Trip circuit supervision relay is provided to monitor the healthiness of trip coil. When the circuit breaker is closed post closing supervision only while type vax 31 and mvaxm 31 relays monitor the trip circuit continuously both pre closing and post closing supervi sion. Trip coils are nothing but an electromagnetic coil which is used to trip the circuit breaker during the fault condition. In the event of a fault the measuring current goes below the operating value of the relay 0 3 0 7 ma or completely stops flowing.

As there are two trip coils therefore there will be two trip circuit supervision relays and hence two different circuits.