Does the three-stage protection simulate the operation of each relay? why?
According to meet the need to set the delay is different, need to adjust.
The scope of protection must not include the full length of the protected line. Because only when the short-circuit current is greater than the protection of the action current, the protection can be action.
According to meet the needs of the set. Because the protection of the action current is to escape the end of the line short circuit current to set the maximum, to ensure that in other modes of operation and short circuit type, the protection range is not beyond the line range.
