Patent ID: 11764568

Abstract:
Provided is a determination method of differential protection suitable for an electricity transmission line with multi-terminal T-connection. The determination method includes: sampling and calculating all phase currents, and calculating a maximum fault component current Δİmax in phase current amplitudes of each phase current, a differential current Icd in the each phase current, a resistive current Ires in the each phase current and a vector sum ΔİΣ of fault component currents except Δİmax in the phase current amplitudes of the each phase current; and comparing the maximum fault component current Δİmax in phase current amplitudes of each phase current and a threshold setting value Imax0, determining a value of a resistive coefficient K corresponding to the phase current amplitudes of the each phase current according to a comparison result, and performing differential determination on the differential current Icd and the resistive current Ires in phase current amplitudes of the each phase current according to a differential determination formula: if the differential current Icd of the target phase satisfies the above differential determination formula, it is determined that a fault occurs in an area of the target phase.