91, Guide for Protective Relay Applications to Power Transformers, Reference 2, the most common causes of failures are tap changers, bushing and winding failures, with additional failures from core, leads, cooling equipment and auxiliary equipment. The engineer must balance the expense of applying a particular protection scheme against the consequences of relaying on other protection or sacrificing the transformer. Allowing a protracted fault increases the potential for damage to the transformer and tank rupture with a consequent oil fire and. Comprehensive guide to transformer protection methods for preventing failures and equipment damage operating conditions in transformers. A turn-to-turn fault will resu contains substantial harmonics, particularly the second harmonic. In addition to basic relaying they may do fault locating, fault data recording, self testing, and metering. It continuously watches: When any of these values go.
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