Electromagnetic transient suppression for thyristor switch-based auto-passing neutral section system

The auto-passing neutral section (ANS), applied in the traction substation or section post (SP), is one of the effective methods to improve the continuity of power supply, and the electromagnetic transient is the key issue impacting its application value. An equivalent switching circuit is established to reveal the causes of the electromagnetic transient. The suppression methods for reducing transient overvoltage and inrush current are proposed, adopting an improved RLC filter to suppress the transient overvoltage with low active power loss, and a switching strategy to minimize magnetic flux variation. The correctness of the proposed methods has been confirmed by simulation and experimental results, which can improve the transient performance and increase the practicality of the ANS.