Safety Feature: To prevent unnecessary tripping due to power surges during synchronization, the relay incorporates a time delay of 5 seconds.
Reverse Power Trip Relay
The Reverse Power Trip Relay is a crucial protective device used in electrical systems, particularly for generators. It operates based on the principles of Faraday’s law of induction and Lenz’s law.
Working Principle
- Eddy Currents: Loops of electrical current induced within a conductor due to Faraday’s law of induction.
- Lenz’s Law: An eddy current creates a magnetic field that opposes the magnetic field that created it.
Components and Structure
- Aluminum Disc: A lightweight, non-magnetic disc mounted on a spindle with low-friction bearings.
- Magnetic Field Coils: Both voltage and current coils produce magnetic fields that pass through the disc.
- Trip Contacts: Located on the spindle.
- Stopper: The disc rests against this under normal power flow conditions.
Operation
Normal Power Flow:- The disc bears against the stopper.
- Trip contacts on the spindle remain open.
- Eddy Current Generation: Magnetic fields from the coils pass through the disc, causing eddy currents.
- Torque Production: The interaction between the eddy currents and magnetic fields produces a torque effect on the disc.
- Disc Rotation: When power reverses, the disc rotates away from the stopper.
- Contact Closure: As the disc rotates, the contacts close, triggering the circuit breaker to trip.
