Analysis of Limiting Measures of Three-phase Short-circuit Current of 500kV Intensive Receiving-end Power Grid in the Early Stage of UHV Construction

This paper took the intensive receiving-end power grid as the research object and analysed the problems of three-phase short-circuit current over-limited of 500kV intensive power grid in the early stage of UHV construction. Firstly, this paper analysed the influence factors of the short-circuit current based on self-impedance analysis model of two-port network theory and the equivalent model of UHV power grid. Then, the applicable current-limiting measures were put forward. Finally, this paper proposed one scheme to solve the problems of three-phase short-circuit current over-limited of 500kV buses in one practical receiving-end power grid and verified the feasibility of this scheme from three different aspects. Aiming at the over-limited influential factors, the applicable current-limiting measures can be taken as follows: separating the 500kV bus at UHV substation, lapping the lines outside the substation and decentralizing the power supplies. The proposed measures can effectively solve the problems of short-circuit current over-limited in the early stage of UHV construction and provide reference for other power grid.