Optimization scheme of grounding distance protection based on substation-area information for double-circuit transmission lines on same tower

Due to the influence of mutual inductance between double-circuit transmission lines on same tower, the grounding distance protection based on single interval electrical quantity has some problems, such as inaccurate distance measurement of fault lines, reverse direction misoperation of non-fault lines and terminal fault override. Based on the characteristics of information sharing between different bays in the smart substation, a unit configuration scheme of double-circuit transmission lines on same tower is constructed. The realization scheme of information acquisition and interaction at the process layer is designed. The zero-sequence compensation coefficient is adaptively selected by using the circuit breaker position and the grounding switch position of the double-circuit transmission lines. The fault line and fault phase are selected based on six-phase current information of double-circuit transmission lines and six-sequence component method, and the zero-sequence current self-adaptive compensation of the adjacent line for grounding distance protection is realized according to the line selection results, while the zero-sequence current compensation of the adjacent line is no longer used for the non-fault line. Theoretical analysis and digital simulation show that the proposed scheme of unit configuration and grounding distance protection can realize the zero-sequence current self-adaptive compensation of the adjacent line in double-circuit transmission lines, and solve the problem of reverse direction misoperation of non-fault lines caused by the blind zero-sequence current compensation of adjacent line. © 2021, Electric Power Automation Equipment Press. All right reserved.