Explain with neat sketch, the Pilot wire protection scheme applied to transmission line.

Explain with neat sketch, the Pilot wire protection scheme applied to transmission line.
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1 Answer

Answer :

Pilot Wire Protection scheme of Transmission Line :

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Figure shows the single line diagram of Merz price voltage balance system for pilot wire protection of three phase transmission line. The pair of CTs in each line is connected in series with a relay, in such a way that under normal conditions, their secondary voltages are equal and opposite. Because current entering is equal to current leaving, they cancel out and no current flows through relay coil. Suppose a fault occurs at point F, the current entering and leaving are different, hence causing current to flow through the relay, which gives trip signal to the circuit breaker for protection of transmission line.

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