基于因果关系的新能源接入受端电网连锁故障演化路径和机理分析OA

With the continuous development of ultra-high-voltage direct current(UHVDC)transmission and new energy,the coupling relationship among AC,DC,and new energy in receiving power grids has become increasingly complex.Improper handling of a single AC fault can easily lead to systematic cascading failures,posing a serious threat to the safe operation of receiving power grids.To reveal the evolution mechanisms of cascading failures in receiving power grids,this paper first derives the causal relationships among key events,including DC commutation failure,high/low voltage ride-through and disconnection of new energy sources,and DC blocking.Subsequently,the impact of DC commutation failure on the low-voltage ride-through performance of new energy under different tie-line impedances and commutation failure prevention(CFPREV)control are analyzed.Finally,based on causal relationships,the evolution mechanisms and paths of cascading failure in receiving power grids are revealed.A complex receiving-end power grid model is built in PSCAD/EMTDC,and typical cascading fault simulation cases are conducted to verify the correctness of the proposed analysis of cascading failure evolution paths and mechanisms.