The study of ground distance protection of 500kV quadruple-circuit transmission lines on the same tower

This paper presents a kind of algorithm, which can decouple the electrical quantities of quadruple-circuit transmission lines and get completely independent 12 sequence components of quadruple-circuit transmission lines on the same tower system. Based on the analysis of transformation matrix and the impedance matrix of 12 sequence components, the principle of ground impedance relay and the corresponding protection setting scheme are discussed. Through PSCAD / EMTDC simulation software, the power transmission system model with quadruple-circuit transmission lines on the same tower under the voltage of 500 kV are established. The correct operation of protection scheme has been verified with extensive simulation studies.