27-06-21 Isolator

Isolator:-  Isolator is a off load device, the isolator always works in off load condition. Isolator is a widely used device in transmission & distribution. It is connected with circuit breaker & busbar.

Isolator Symbol

Types of Isolator:- 

1) Center break isolator- 32kv to 220kv

2) Pentograph isolator- 66kv 

3) Knee isolator- 800kv (HVDC, HVAC)

Isolator

Difference Between Isolator & Circuit Breaker:-

Isolator: 

1) Off load device (No load)

2) Never sense fault

3) Manually operated

4) Cost is less

5) It is not use while current flows through the line.

Circuit Breaker:

1) On load device

2) Always sense fault & trip the circuit

3) Automatically operated device

4) Cost is more

5) It is use while current flows through the line.

23-06-21 Relay

Relay:- Relay is nothing but an electrical switching circuit.

Relay is a monitoring & sensing device.

The function of a realy is to monitor the parameters & sense any abnormalities in the circuit.

Realy control electrical circuit by opening & closing contacts in another circuit.

Relay does not trip any circuit, Relay sends a command or signal to the Circuit Breaker for tripping purpose.

Relay symbol

Types of Relay:- 

1) Electro thermal realy

2) Electro mechanical relay

3) Solid state relay

4) Hybrid relay

5) Polarized relay

6) Non polarized relay

7) Buchholz relay

Relay

22-06-21 Circuit Breaker

Circuit Breaker:- A device which can make or break the circuit manually or automatically under normal & faulty condition.

                             OR

Circuit breaker is a automatically operated electrical switch device.

It protects electrical circuit & machine through any electrical fault.                                                               

Types of Circuit Breaker:- According to Voltage Level There are Three Types,

1) Low Voltage CB:- MCB, MCCB, ELCB, ACB, RCCB. (Under 1 Kilo Voltage)

2) Medium Voltage CB:- VCB, ACB (1KV to 72KV)

3) High Voltage CB:- ABCB, OCB, SF6, VCB    (Above 72.5KV)

                                 

Circuit Breaker