特高压1000kV降压220kV变压器的应用前景分析

Application prospect analysis for 1 000 kV/220 kV UHV transformer

特高压电网是未来电网发展的重要方向,使用1 000 kV降压220 kV变压器,可以缩短电源和负荷之间的电气距离,节约土地资源和工程投资,但同时也会增加短路电流,必须对其应用前景进行综合分析。针对上述问题,设定了同样的输送容量,比较了使用1 000 kV降压220 kV变压器的直接降压方案和传统1 000 kV降压500 kV再降压220 kV的两级降压方案的经济性。针对不同的电网发展水平,用PSASP软件计算了传统两级降压方案和直接降压方案的短路电流水平,分析了直接降压方案对短路水平的影响。最后综合经济性和短路电流两方面的因素,得到1 000 kV降压220 kV变压器的应用场合需满足的条件,为工程实践提供参考。

UHV is a promising technology for the development of grid. 1 000 kV/220 kV transformer will shorten electric distance between power supplies and load, which will lead to lower cost and smaller occupation for transmission project. But it can also raise short circuit current level. Thus it is essential to analyze the prospect of 1 000 kV step-down 220 kV transformer comprehensively. This paper compares the cost of direct step-down scheme by using 1 000 kV/220 kV transformer and the conventional step down scheme by using 1 000 kV/500 kV in series with 500 kV/220 kV transformer for the same transmission capacity. The short circuit current level of the two aforementioned schemes are also analyzed by PSASP for different gird develop stages. The requirements for using 1 000 kV/220 kV transformer are finally summarized as a practice reference.