Capacitive current compensation method for differential protection of EHV/UHV lines

The capacitive current compensation method widely used now for current differential protection is the phase compensation method based on ∏ model. Analysis shows that, ∏ model simulates the line with external fault quite precisely and there is bigger error when it is used to simulate the line with internal fault, which should be considered in the parameter setting of fault current differential protection. The error is relatively smaller for the full current differential protection. A 1000 kV 600 km line is built with EMTP to verify the conclusions.