Study on the Maximum Outgoing Line Count of 750 kV Substations and Exploration of a Bus Short-circuit Current Suppression Method

Abstract

With the development and construction of new power systems, the power grid structure is becoming increasingly interconnected, and the issue of short-circuiting currents in UHV systems will gradually manifest over the next five years. Existing measures for short-circuit current control typically involve using standby units, lines, and main transformers. However, conventional measures are gradually unable to meet the control requirements, necessitating strict control of the network topology during the planning phase and the exploration of new technologies and methods to keep pace with the evolving era. This paper studies the maximum outgoing line count of 750 kV substations, providing theoretical references applicable to practical operations for planning departments. A conceptual method based on fast-switching technology to suppress the current during a short circuit at the 750 kV voltage level is proposed, establishing the groundwork for the practical implementation of high-speed switching technology in the 750 kV voltage-level power grid.