中文摘要：

负荷少而线路对地电容大的送端电网，在严重故障情况下由并网转为孤网运行，此时孤网呈容性，其安全运行涉及特殊的控制问题。指出在网络呈容性时，存在低励限制器不能有效限制发电机进相运行的可能性，且可能对电网运行产生不利影响。针对由并网转为孤网运行且网络呈容性的系统，表明对发电机进行降低机端电压的控制，有利于机组进相能力的充分利用，以达到紧急控制孤网系统电压的目的。结合实际电网的情况，讨论了紧急电压控制可能遇到的具体问题，并提出了分轮分步的控制策略。

英文摘要：

When turning into isolated operation after a large disturbance, power becomes capacitive. Special control problems are involved in an export power network with little load and large charging the isolated operation＇s safety. This paper presents that under-excitation limiter may fail to limit generator＇s leading phase operation and even produces adverse effect on system operation, when the network is capacitive. For an isolated capacitive network, the paper suggests that properly reducing generator＇s terminal voltage may make use of generation＇s leading phase operation so as to achieve emergency voltage control of the system. Meanwhile, practical issues of the control process are discussed, and a multi-rounds and multi-steps＇ emergency voltage control strategy is proposed accordingly.