沙角B电厂6.3kV厂用电快速切换装置的改造

针对沙角B电厂6.3kV厂用电系统每段母线均设有1个工作电源和2个备用电源的特殊性,机组正常起停机时,通过分散控制系统(distribution control system,DCS)操作员站或按钮输出指令至同期装置、厂用电快速切换装置(以下简称快切装置),选择待并的工作电源和备用电源,进行正常的厂用电切换;当机组发生事故停机或处于不正常运行状态时,装置能自动将厂用电切换到备用电源,实现厂用电系统内部的自动快速切换。为此,根据6.3kV厂用电系统接线方式的特点,在DCS上设计相应的操作画面,修改厂用电快切装置内部逻辑,增加备用电源1与备用电源2之间的切换逻辑,实现了厂用电正常切换和事故切换,改造成功。

Transformation of Fast Switching Device of 6.3 kV Auxiliary Power Supply in Shajiao B Power Plant

Owing to the particularity of 6.3 kV auxiliary power system in Shajiao B Power Plant that each bus section is equipped with one operating power source and two standby sources, during normal startup and shutdown of unit, instructions are sent to synchronizer and fast switching device of auxiliary power supply via operator station or button of distributed control system （DCS）, thereby selecting the operating power supply and standby supply to be integrated for normal auxiliary power switching. In case of emergency shutdown or abnormal operation of unit, auxiliary power can be switched automatically to standby power by the device to realize automatic fast switching in auxiliary power system. According to the connection characteristics of 6.3 kV auxiliary power system, normal and emergency switching of auxiliary power is realized by designing corresponding operating interface on DCS, amending the inner logic of fast switching device of auxiliary power supply, and adding logic of switching between Standby Sources l and 2. The results of the transformation are satisfactory.