农网改造常用分档并联电容器组的选型分析

Analysis on Selection of Stepping Shunt Capacitor Bank for Rural Grids Reconstruction

随着国家电网对农网改造力度的加大,越来越多的农网开始加装并联电容器,用于提高功率因数,降低线损。由于农网负荷较特殊,无功补偿容量不大,招标中经常要求采用10 kV框架式电容器,电容器组分档补偿,串联电抗器不分档的补偿模式。采用该补偿模式后,可以简化一次接线复杂程度,降低设备造价,但是带来了电抗率不匹配和谐波放大的问题。本文介绍了电容器组分档补偿和不分档串联电抗器配合使用时,电抗率变化和谐波放大的情况,并就这种常用的补偿模式提出了参数配置建议。

With the increase of reconstruction of rural power grid in China,shunt capacitors are installed on more and more rural grids to improve power factor and reduce line loss.Since particularity of load at rural grids and small amount of reactive power compensation,it is normally required in the tender to adopt 10 kV frame capacitor,stepping compensation of capacitor bank or non-stepping compensation of series reactor bank.Adoption of the compensation mode can simplify complexity of primary wiring,reduce cost of equipment,but bring such problems as non-match of reactance and harmonic amplification.In this paper,the case of reactance variation and harmonic amplification is described in case of coordination use of stepping compensation of capacitor and non-step compensation of series reactor,and the suggestion on ratings disposition of such normally used compensation mode is proposed.