二滩水电站电气主接线设计中的一些考虑

Some key considerations of the design of the main electric connection of Ertan Hydro Station

二滩水电站在四川电力系统中占有极重要的地位 ,在电气主接线的选择上采用了可靠而灵活的接线方案 ,最终实施的电气主接线方案是 5 0 0kV侧 6回进线、4回出线 ,为 2串 4/ 3加 2串 3/ 2接线 ,并预留 1回出线位置 ,具有可扩展性。其主要特点为 :发电机和主变压器采用单元接线 ,发电机出口装设断路器 ;5 0 0kVGIS设备布置在地面与出线场相结合 ,采用干式电缆与主变压器连接 ;出线断路器不装合闸电阻 ,高压侧不装并联电抗器 ,变压器中性点采用直接接地方式。通过各机组投运前的调试和正式投运后的实践证明 ,二滩电站采用的电气主接线具有运行灵活、操作方便的优点。

The Ertan Hydro Station occupies a very important place in the Sichuan Power System. Its main electric connection adopts a reliable and flexible connection alternative. The main electric connection alternative selected in the preliminary design stage is optimized and its final main electrical connection alternative is 500 kV, 6 loops of incoming line and 4 loops of outgoing line. At the same time, one loop of outgoing line is reserved in advance in order to make it expandable. The characteristics of such main electric connection are as follows. The generator transformer unit connection is adopted and a circuit breaker is installed in the exit of generator. 500 kV GIS is arranged on ground in combination with its outgoing line field and is connected with main transformer by dry type cable. Its high voltage side is not equipped with parallel reactor and the neutral point of transformer is achieved by the direct grounding way. The practices of the debugging of all generating units before operation and the final actual operation showed that the main electric connection adopted in the Ertan Hydro Station has the advantages of flexible operation and easy handing.