主变采用双分支接线形式的改造方案

当设计为三台主变的110kV变电站中第三台主变尚未投运时，其中一台主变的低压侧往往采用双分支接线的方式进行供电，随着负荷的增加，双分支部分的902断路器上的负荷电流会达到一个很高的数值，严重威胁断路器的安全稳定运行。在选择了最优的一次高压部分改造方案的基础上，提供了二次继电保护的二次回路改造、定值整定等方面的方案。通过实际运行经验可见，该方案能够在3#主变投运前作为一种有效的解决方案。

Reconstruction Scheme of Main Transformer with Double Branch Connection

When the third main transformer of 110 kV substation designed for three main transformers has not yet been put into operation, the low-voltage side of one main transformer often uses double branch connection to offer power. With the increase of load, the load current on 902 circuit-breaker on the double branch will reach a very high value, which will seriously threaten the safe and stable operation of 902 circuit-breaker. On the basis of choosing the best reconstruction scheme for the primary high voltage part, he reconstruction and setting schemes for the secondary relay protection is provided. The practical operation experience shows that the proposed scheme can be used as an effective solution before No. 3 main transformer being put into operation.