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.
Trip coil supervision circuit.
Trip circuit supervision relay is provided to monitor the healthiness of trip coil.
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.
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.
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.
Failure of trip supply open circuit of trip coil of trip circuit wiring.
The 7pj13 trip circuit supervision relay is an electronic circuit based relay.
So in order to check the condition of the trip circuit is essential in power system protection.
Arteche trip circuit supervision relays monitor trip coil circuit in open close states and during circuit breaker operation.
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 coils are nothing but an electromagnetic coil which is used to trip the circuit breaker during the fault condition.
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.
Hence 95a relay gets operated and so its contact is closed and so positive is.
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.
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.
With references for single pole and 3 pole and a wide range of voltages vdf.
As there are two trip coils therefore there will be two trip circuit supervision relays and hence two different circuits.
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.
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.
We will be using areva make vax31 type trip circuit supervision relay.
This relay has three coils namely rla rlb and main coil tcs of the relay as shown in the figure above.
Pre closing supervision and post closing supervision circuits are used to sense the trip coil healthiness.
