SVERKER900 - Testing negative sequence overcurrent protection

Unbalance phase currents in a power system that exceed the allowable normal operation limit can indicate abnormal condition or even existence of fault(s) in the system. The operating principal unbalance over current protection is normally based on measurement of negative sequence component of unbalance phase currents. Similar to phase over current protection, normally a pick up (start) threshold and a definite time delay for operation can be set.