采用异步联网限制短路电流的实际应用和分析

Practical application and analysis of short-circuit current limiting by asynchronous grid interconnection

500 k V主网短路电流超标问题已成为广东电网近年来运行最突出的问题之一。现有的运行措施可将超标站点短路电流暂时降低至安全水平,但电网整体的短路电流水平仍较高,且牺牲了部分系统安全可靠性,从长远来看通过直流背靠背异步互联限制短路电流是可行的解决办法。以2018年广东500 k V电网为研究对象,建立直流背靠背异步联网模型,从短路电流限制效果、系统可靠性等方面进行仿真计算,并与传统运行措施进行对比,可以得出,采用直流背靠背异步互联措施具有更好的限流效果和更高的安全可靠性,验证了该方案在短路电流限制方面的有效性和优越性。

The main problem of 500 k V short-circuit current overweight has become one of the most prominent issues of Guangdong power grid in recent years. The existing operation measures can reduce excessive short-circuit current to safe levels temporarily,but the short circuit current level of the whole power grid is still high,with sacrificing the part safety and reliability of the system. In the long run,limiting short-circuit current through the back-to-back HVDC asynchronous interconnection is a feasible solution. Taking Guangdong 500 k V power grid in 2018 as the research object,the model of back-to-back HVDC asynchronous interconnection model is established. And with the simulation of the short circuit current limiting effect and the system reliability,compared with traditional operation measures,we can obtain that back-to-back HVDC asynchronous interconnection has better short circuit current limiting effect and higher safety and reliability. The effectiveness and superiority of the scheme in short-circuit current limiting are verified.