Risk assessment on Auto - reclosing for mixed overhead - cable lines

The integration of cable lines in HV power grids, traditionally based on overhead lines, raises several issues related to the behavior and operation of the grids. The question about the time for restoration of the power supply in case of failures is relevant. The publication examines the risks associated with auto-reclosing for mixed overhead - cable lines. In the research, different scenarios were considered, both in terms of the share and location of the cable section, and in terms of the sequence of operation of the circuit breakers. The study is conducted in ATP-EMTP, the main issue is the presence of residual charges in the cable line. The magnitude of the arising overvoltages is checked and the load of the surge arresters at the transition point and at the cross-bonding points of the screen is assessed. Methods for limiting overvoltages in auto-reclosing are analyzed.