受端系统负荷对高压直流输电的影响

在仲夏电网极大负荷运行期间，HVDC受端逆变器常有换流不稳定现象出现。该文探讨了地区负荷对逆变器换流容量的影响情况，在负荷幅值和功率因数变化的情况下，短路(换相)电流受到的影响，考虑了线间不对称短路的换相电流状态，提出电容补偿和静止无功补偿器(SVC)可以改善系统短路容量的见解。文中通过实例，从原理上进行了相关计算和仿真，结果表明，地区负载过大，会极大影响系统的短路电流，从而导致直流输电不稳定现象；而采用串联电容补偿或静止无功补偿器不失为一种可选的增大换相电流的方法，但仅增大系统局部的短路容量。

Influence of Receiving End Load on HVDC Transmission

At receiving end of HVDC line,commutation failure often emerges during heavy power system load in heavy load season. The influence of local load on commutation capacity in inverters side is investigated,and the commutation current under load variation with different power factors is analyzed. It is mentioned that capacitor and static var compensator (SVC) can increase short circuit current at converting branch. Calculation and simulation results show that heavy load can influence the short circuit current greatly which can result in HVDC commutation failure. Series capacitor compensation and SVC can improve local short circuit current effectively.