Performance Improvement for Pilot Protection of Double Circuit Lines on the Same Tower Based on Power Converse Accurate Identification

The power converse phenomenon, which frequently occurs on double circuit lines on the same tower, can cause the pilot protection of non-fault lines misoperation. Firstly the reasons for the occurrence of power converse and its influence on pilot protection are clarified. Then this paper presents a performance improvement scheme for pilot protection of double circuit lines on the same tower based on the fully using the substation-area information. The scheme consists of two parts, which are accurate identification method for power converse and determining method of blocking delay during power converse period. It identifies the power converse according to the different trips of circuit breakers on the faulted line and adjusts the blocking time of non-fault line in real time. A typical model of double circuit lines was established in PSCAD to verify the correctness of the proposed scheme and carried out a detailed comparison with existing methods. The simulation results show that the proposed scheme can accurately identify the occurrence of power reversal and strictly match the blocking time of the pilot protection with the time period of power converse. Therefore, the protection performance has been effectively improved.