why we use REF and Differential Protection in one
transformers?my doubt is both protections are operated in
internal fault only.why we want to use 2 protections?please
clarify.
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Answer Posted / raveendra nath
Differential protection provides excellent protection for
phase- to-phase and most phase - to - earth faults, this
element is less sensitive for single- phase-to-earth faults
close to the earth point in solidly earthed transformers.
For these faults (i.e fault at transformer winding turns
nearer to neutral point ), phase current changes very
little, but large current flows in the neutral.
| Is This Answer Correct ? | 3 Yes | 5 No |
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