中性线的转换对UPS性能的影响和对策

由于低压配电系统接地故障保护（GFP）的需要，市电与备用发电机组电源转换电路必须采用4极自动转换开关（ATS），而有些4极ATS在转换过程中存在中性线中断现象，严重影响了UPS的正常运行，由此引发的UPS故障和负载停电事件越来越受到关注。文中分析电信和数据中心常用市电和备用发电机组电源转换电路的性能及其对GFP和UPS运行的影响，提出工程实用解决方案。

Impact of Neutral Line Switching on UPS performance and the Countermeasures

In order to meet the ground fault protection （GFP） needs of low voltage distribution systems, the 4-pole automatic transfer switch （ATS） must be used for the transfer switch circuit between utility and standby generator set. But some 4-pole ATS adopt “break before make” neutral pole that can cause the neutral line interruption. Such interruption has a serious impact on the UPS performance and even causes critical load power cuts, which has attracted more and more attention at present. This paper describes some transfer switch circuits used in telecommunications and data centers, analyses their performance and effects on GFP and UPS operations. Practical engineering solutions are also proposed.