大规模交直流混联电网送端交流故障对受端电网的影响

Influence of AC fault at sending end on receiving-end networks of large-scale AC/DC hybrid power grid

为满足新能源消纳跨区大规模输电的需要,我国建设投产多个常规直流、特高压直流及柔性直流输电工程,实现了大区电网之间的异步互联,形成了复杂的大型交直流混联系统。基于近期发生的实际故障案例,分析交直流混联电网送端交流系统故障对直流系统输送功率和受端交流电压产生的影响,以及受端直流滤波器跳开、相邻直流受端换相失败的原因,指出电网存在直流送端落点过于密集、交流滤波器分组容量偏大、换相失败预测能力不足等问题,并提出相应解决措施,为后续交直流混联电网的发展建设提供参考。

In order to meet the need for large-scale transmission of new energy consumption across regions,China has built and put into operation several conventional DC,UHVDC and flexible DC transmission projects and has realized asynchronous interconnection between large power grids and formed a complex large-scale AC-DC hybrid system.Based on the recent fault cases,the paper analyzes the impact of AC/DC hybrid system fault on DC system transmission power and AC voltage at the receiving end,as well as the causes of DC filter tripping at the receiving end and commutation failure at the adjacent DC receiving ends.Moreover,the paper indicates that there exist such problems as dense DC points at receiving end,larger gound capacity of AC filters and poor commutation failure prediction.Finally,it proposes solutions,providing references for future AC-DC hybrid power grid development and construction.