ABSTRACT:-
Normally power systems and net works are operated under variable complex stresses.In power systems the faults are not avodable even after taking utmost care at every stage-from planning to maintainance. The grounding of a circuit reduces potential stresses under fault condition. Power feeding from delta delta or if there is no accessibility for star connected transformers occasionally shorted to ground is very common-un-intentional grounding occurs any where from the feeding system to utilization equipment The main objective of grounding neutral is to make a short circuit current sufficient in magnitude for the relay action. This article restricted to zig-zag type with oil filled transformers. The neutral point is usually available at every voltage level from generator to transformers. In the absence of a power transformer of suitable capacity, connection and design a separate grounding transformer can be used .
They are inductive devices intended primarily to provide a neutral point for grounding purpose. The main purpose of this paper is to discuss about the difference between Earthing transformer and Power transformer and to discuss about the designing of earth transformers.
