Connect the ground fault relay / controls to the resistor assembly either by wiring to the CT terminals or the shorting terminal block. Abstract—Validating proper current transformer (CT) and voltage transformer (VT) wiring, terminations, and grounding is fundamental to successful performance of the protection system. Occasionally, errors in CT and VT connections can occur, such as missing or broken neutral wires, multiple or. Protective relays and devices have been developed over 100 years ago to provide "lastline"of defense for the electrical systems. Where continuity of service is a high priority, high-resistance grounding can add the safety of a grounded system while minimizing the risk of service interruptions due to grounds. Ground fault protection emphasizes keeping the fault current below the fibrillation threshold and for a period of less than a heartbeat, in the range of 60–300 ms. It has been established that the electric shock energy which a human body can endure, without damage has a relationship with Figure. While ground-fault protective schemes may be elaborately developed, depending on the ingenuity of the relaying engineer, nearly all schemes in common practice are based on one or more of the methods of ground-fault detection discussed in this article.
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