What happens when the polarity changes in CT? Explain
briefly?
Answer Posted / m s venkateswara rao
polarity of the CT secondary is depend up on the polarity of CT primary. For example current flow in primary of a CT is considered from P1 to P2 current flow in secondary will be from S1 to S2. If the CT is used for multi function meter to measure the Active power, apparent power will show negative readings if polarity is changed. If is used for protection and the type of protection is considered is non directional over current/ earth fault there is no difference in CT polarity change. If it is directional over current/earth fault relay will not operate because it will never seance positive value as the protection type is directional.So by changing the polarity of CT, protection for which we opted will defeated.
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