engleski

Sensitive turn-to-turn fault protection for power transformers

Three most typical weaknesses of the analogue power transformer differential relays have been: 1. Long operating time in case of heavy internal faults followed by main CT saturation 2. Unwanted operations for external faults and transformer inrush 3. Bad sensitivity for low-level internal faults, such as winding turn-to-turn faults With the introduction of the numerical technology the first two problems could be handled in much better way [4]. However sensitivity for internal winding turn-to-turn faults did not improve much. This paper introduces the new protection principle, which will improve differential relay sensitivity for minor internal turn-to-turn faults. However, the first two classical disadvantages are as well efficiently removed by applying the solution described in the paper.

power transformer; sensitive differential protection; turn-to-turn fault

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