Circuit breaker:
A circuit breaker is a device that can make or break circuits either remote control or manually under normal operating conditions. A circuit breaker breaks a contact under fault conditions. A circuit breaker controlling and switching device that is disconnect or isolate the equipment under heavy fault conditions.
The circuit breaker having of fixed and moving contacts made from tungsten material. The moving contacts are connected to the operating mechanism. When a fault occurs in the system moving contacts separated from fixed contacts and fault current will be interrupted
Relay:
The relay is a device that detects the fault in the system and gives the control signal to the breaker which is disconnect or isolate the system from the rest of the system and the fault current will be interrupted. The relay is the only controlling device that gives the fault signal to the circuit breaker. The relay detects abnormal conditions in the power system by measuring the electrical quantities which differ under normal and abnormal conditions. The electrical quantities like voltage, current and phase angle are changed under fault conditions,
The relay consists of measuring instruments like the Current transformer and the Potential transformer which are measures current and voltage in the power system. The relay coil is operated by the current transformer current during abnormal conditions. The relay coil is connected to the tripping coil. The tripping coil gives the commands to the circuit breaker to trip and interrupt heavy fault in the power system.
Difference Between Relay and Circuit Breaker :
| Relay | Circuit Breaker |
|---|---|
| The relay is a switching and sensing device that gives the signal to the circuit breaker when a heavy fault occurs in the power system. | The circuit breaker breaks the circuit automatically when the circuit breaker receives the signal from the relay. |
| The relay is a switching device that is closed or opens the contacts electronically or electromechanically. | The circuit breaker provides interruption of high fault current and fault detection is provided by a relay inside the circuit breaker. |
| The relay is a switching and fault sensing device. The relay only detects the fault current and gives the signal to the circuit for tripping purposes. | The circuit breaker is isolate or disconnect the equipment during a fault condition. so The circuit breaker is isolating or disconnecting the device. |
| The relay is used to control one circuit among the various circuits. | The circuit breaker is used to control one per circuit like isolating switch. |
| The relay only senses fault signal and send it to the circuit for isolating purpose. | The circuit breaker makes or breaks the circuit when needed. |
| The relay operated on low power and voltage signals and isolate the circuit through the circuit breaker when needed. | The circuit breaker operated on low as well as high power and voltage levels and the circuit breaker acts as on-load switches. |
| The relay is used as an amplifier. The relay converts one signal into many signals. | The circuit breaker can not be used as an amplifier. The circuit breaker receives the signal from the relay and works based on it. |
| The relay can be directional or non-directional. | The circuit breaker is only non-directional. |
| The relay has low power contacts | The circuit breaker is only non-directional. |
Difference Between Relay and Circuit Breaker
1. The Relay is a sensing and controlling device. The circuit breaker is a protective and controlling device.
2. The relay only senses the fault signal and give it to the circuit breaker for isolating the circuit. The circuit breaker can make or break the contacts. The relay only senses the fault and the relay can not break the contacts.
3. The relay is used to control the one circuit among the various circuits. The circuit breaker is used to control one per circuit like an isolation switch.
4. The circuit breaker is a device that is used to detect and prevent the formation of arc in the circuit. The relay is a device that is not able to prevent the arc in the circuit.
5. The relay can be directional or non-directional and the circuit breaker is only directional.
6. The relay is used as an amplifier. The relay converts one signal into many signals. the circuit breaker can not be used as an amplifier. the circuit breaker receives the signal from the relay and works based on it.
7. The relay operated on low power and voltage signals and isolate the circuit through the circuit breaker when needed. the circuit breaker operated on low as well as high power and voltage levels and the circuit breaker acts as on-load switches.
8. The relay is used to control one circuit among the various circuits. the circuit breaker is used to control one per circuit like isolating switch.
9. The relay is included in the circuit breaker and the circuit breaker can not be included in the relay.
10. The relay is a switching and sensing device that gives the signal to the circuit breaker when a heavy fault occurs in the power system. The circuit breaker breaks the circuit automatically when the circuit breaker receives the signal from the relay.