云广±800kV直流工程孤岛运行过电压水平研究

Study on the Overvoltage Level of Yunnan-Guangdong ±800kV DC Transmission Project in Islanded Operation Mode

孤岛运行作为云广特高压直流输电工程的设计运行方式之一,能够有效地提高南方电网的稳定水平,但必须以解决过电压问题为前提。基于一次设备实测参数和实际的控制保护系统,对云广特高压直流孤岛方式下的过电压水平进行了计算,结果表明:各种故障工况下操作过电压水平均满足规程要求,最大仅为1.71 p.u.;交流滤波器/电容器组断路器断口暂态恢复电压最大值不超过1 300 kV。各种工况下的暂时过电压水平较高,最高达1.66 p.u.,但持续时间短;除了双极ESOF时避雷器最大吸收能量较大外,其他故障工况下避雷器最大吸收能量为3 895 kJ,占标称设计值的43.8%,裕度较大。因此,孤岛运行方式下设备的过电压水平、避雷器能耗以及大组滤波器开关断口暂态恢复电压均满足要求。

One of the normal operation modes designed for Yunnan ？？Guangdong UHVDC project is islanded operaton,which can effectively improve the stability level of China Southern Power Grid（CSG）,but with a premise of overvoltage being controled.Based on the on-site test parameters of primary equipments and the actual control and protection system of the project,this paper does calculation on the overvoltage level in islanded operation models,and the results are as follows： The maximum switching overvoltage of 1.71 p.u.in various fault conditions meets the demands of regulations.The maximum transient recovery voltage across AC filter/capacitor bank circuit breakers is less than 1 300 kV.The maximum transient overvoltage is relatively higher with a maximum value of 1.66 p.u.,but its duration time is short.The maximum arrester absorption energy in various fault conditions except the bipole ESOF case is less than 3 895 kJ,only 43.8% of the nominal value and thus has a large margin.Hence,the overvoltage level,arrester absorption energy and transient recovery voltage across AC filter bank circuit breakers are all in control.