Why balanced earth fault protection system is not used for phase-phase fault protection. Clearly show with necessary diagram
Why balanced earth fault protection system is not used for phase-phase fault protection.
Clearly show with necessary diagram
Balanced Earth fault is also known as restricted earth fault.
This protection scheme is applicable for small generators where the differential & self-balanced protection is not applied.
Also, it is mainly used in the power transformer to detect the transformer's internal earth fault.
In this protection scheme, the current transformer is mounted on each phase, known as phase CT.
Also, a current transformer is mounted on the neutral conductor known as neutral CT.
The secondaries of Phase CT are connected in parallel with the secondary of Neutral CT across the relay.
The connections are made such that the secondary unbalance current of phase CT & secondary current of neutral CT will oppose each other.
If both the secondary current of Phase & Neutral CT is equal in magnitude, no resultant current will circulate through the relay coil.
Hence, the relay will not respond to the unbalancing of the phase current.
Step by step
Solved in 2 steps with 1 images
