Studies on series compensation of UHV transmission line

Series compensation technology is an effective method of improving stability limit and transfer capability. However, the high fault current and over voltage caused by its specific transient process will make system equipment working in bad condition and threat the running of system. The article takes Jindongnan - Nanyang - Jingmen UHV AC transmission demonstration project as example, uses electromagnetic transient simulation program PSCAD/EMTDC, analyses the switching over voltage of the system with series compensation equipment. The result shows that over-voltage multiplier is too large and the system can not run stably. Then several voltage-restriction measures are listed,and theoretical analysis and simulation prove that the measures can restrict the switching over voltage effectively and make the system running safely and stably.