无专用高压备用变压器时厂用电源切换方式探讨

Discussion on Change-Over Mode of Auxiliary Power without Special High-Voltage Standby Transformer

GB 50660—2011《大中型火力发电厂设计规范》对高压厂用备用变压器的配置作了简化。这一修改对2012年3月以后建设的电厂提出了几个新的讨论专题:是否设置专用的高压备用变压器;如不设专用高压备用变压器,厂用电源切换将如何实现。以宜昌某电厂为依托,对无专用高压备用变压器时的厂用电源切换方式进行分析,比较了用分散控制系统(distributed control systems,DCS)实现负荷切除与用厂用电快切装置实现负荷切除2种方式的利弊,并选择了最优方案。宜昌某电厂采用的方案具有保证快切成功率,减少快切对另一台机组的冲击,减少各专业间的配合环节等优点,可供相同接线类型电厂借鉴。

The configuration of high-voltage auxiliary standby transformer has been simplified in ‘ Large and Medium-Sized Thermal Power Plant Design Code （GB 50660-2011 ） ＇, which has presented several new discussion topics for the power plants built after March 2012, such as whether set a special high-voltage standby transformer; if not, how to realize the high speed change-over. Based on a power plant in Yichang, this paper analyzed the change-over mode of auxiliary power without special high-voltage standby transformer, compared the advantages and disadvantages of shedding load schemes which were using DCS or high speed change-over device respectively. Finally, the optimal scheme was selected and adopted in this power plant, which could ensure the success rate of high speed change-over, reduce its impact on another unit and the coordination of each profession, and provide references for the power plants with same connection type as well.