Explain with neat sketch basic trip circuit of protection relaying.
2 Answers
### Basic Trip Circuit of Protection Relaying
In power systems, a protection relay's trip circuit is essential for detecting faults and initiating the disconnection of the faulty section from the rest of the network to prevent damage.
#### Components:
1. **Protection Relay**: Detects abnormal conditions (e.g., overcurrent, short circuits).
2. **Circuit Breaker (CB)**: A device that can open or close the circuit.
3. **Trip Coil**: Part of the circuit breaker that, when energized, opens the circuit breaker.
4. **Auxiliary Relay**: Used to amplify the relay's signal.
5. **DC Supply**: Powers the trip circuit, typically from a battery.
6. **Trip Contacts**: Contacts in the relay that close upon detecting a fault, allowing current to flow through the trip coil.
7. **Indication Lamps/Alarms**: Show the status of the circuit (tripped or healthy).
#### Operation:
- Under normal conditions, the relay contacts remain open, and the trip coil is de-energized.
- When a fault is detected, the relay contacts close, energizing the trip coil.
- The energized trip coil mechanically triggers the circuit breaker to open, disconnecting the faulty section.
- The auxiliary relay or indication lamps may also activate, indicating the trip operation.
#### Sketch:
Here's a simplified sketch of the basic trip circuit:
```plaintext
+----(DC Supply)----+
| |
[Relay]---[Trip Contacts]--+
| | |
| [Trip Coil]---[Circuit Breaker]
| |
+---[Auxiliary Relay]---+
```
This sketch shows the essential elements connected in a straightforward manner, where the closing of the relay contacts allows current to energize the trip coil, causing the circuit breaker to open.
In power systems, a protection relay's trip circuit is essential for detecting faults and initiating the disconnection of the faulty section from the rest of the network to prevent damage.
#### Components:
1. **Protection Relay**: Detects abnormal conditions (e.g., overcurrent, short circuits).
2. **Circuit Breaker (CB)**: A device that can open or close the circuit.
3. **Trip Coil**: Part of the circuit breaker that, when energized, opens the circuit breaker.
4. **Auxiliary Relay**: Used to amplify the relay's signal.
5. **DC Supply**: Powers the trip circuit, typically from a battery.
6. **Trip Contacts**: Contacts in the relay that close upon detecting a fault, allowing current to flow through the trip coil.
7. **Indication Lamps/Alarms**: Show the status of the circuit (tripped or healthy).
#### Operation:
- Under normal conditions, the relay contacts remain open, and the trip coil is de-energized.
- When a fault is detected, the relay contacts close, energizing the trip coil.
- The energized trip coil mechanically triggers the circuit breaker to open, disconnecting the faulty section.
- The auxiliary relay or indication lamps may also activate, indicating the trip operation.
#### Sketch:
Here's a simplified sketch of the basic trip circuit:
```plaintext
+----(DC Supply)----+
| |
[Relay]---[Trip Contacts]--+
| | |
| [Trip Coil]---[Circuit Breaker]
| |
+---[Auxiliary Relay]---+
```
This sketch shows the essential elements connected in a straightforward manner, where the closing of the relay contacts allows current to energize the trip coil, causing the circuit breaker to open.