Research on the solution of the abnormality of DC protection LAN network communication between converter station based on TDC platform

The DC protection inter-station LAN network communication of the TDC platform adopts a dual LAN network structure, that is, the bipolar DC protection of the station is connected to the inter-station LAN1 and LAN2 switches to form a communication cross-redundant structure, and is sent to the opposite station through the protection interstation communication router. The station bipolar DC protection then retains the required information as needed and discards the redundant information. This paper analyzes a maloperation event of DC metal loop longitudinal differential protection caused by inter-station communication structure defects in Puer-Qiaoxiang HVDC, and proposes three optimization measures: library file upgrade, single LAN operation and adding redundant communication channels, and abnormal data detection logic block. The feasibility is verified on site, which solves the problem of abnormal communication between DC protection stations under TDC platform, and improves the stability and safety of DC protection operation.