In High Impedance protection, for external fault conditions, the secondary current from the CT's of the unfaulted phases circulate through the secondary of the saturated CT (of the faulted phase), as the unfaulted CT's see the saturated CT secondary as a low impedance than the relay combined with the stabilising resistor.However for internal faults, how does the secondary current from the CT's circulate through the relay, why don't it pass through the CT which has the low impedance among them?
Red Flag Submitted
Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action.
Reply To This Thread
Posting in the Eng-Tips forums is a member-only feature.