摘要
核电厂辅助变压器作为备用电源,长期处于空载热备用工况,一般采用三相三绕组分裂变压器Yn0yn-yn-12+d或Yn0-d-d-11接线方式,空载运行时辅助变压器在高压侧或电源线路发生缺相故障,其各侧电压相量和电压序分量没有明显变化,且空载变压器励磁电流的大小为1%~5%额定电流,并具有显着的谐波含量,很难利用现有的电气保护方案进行检测。如果不能及时检测缺相故障,将会对核电厂的安全运行产生严重的威胁。针对上述问题,提出了外加电源注入式核电厂辅助变压器缺相保护方案,检测注入电压、电流,当电流、电压、阻抗满足判据时,判定为发生缺相故障,经延时给出报警信号并通知运行人员及时处理,解决空载工况下辅助变压器高压侧缺相故障难以检测的问题,提升了核电厂辅助变压器系统的运行可靠性。
As the standby power supply, the auxiliary transformer of the nuclear power plant is in the no-load hot standby condition for a long time. Generally, the wiring mode of the three-phase and three-winding split transformer Yn0 yn-yn-12+d or Yn0-d-d-11 is adopted. During no-load operation, the auxiliary transformer has open phase fault on the high-voltage side or power line, and the electric voltage phasor and voltage sequence component on each side have no obvious change, The excitation current of no-load transformer is 1%~5% of rated current and has significant harmonic content, so it is difficult to detect by using the existing electrical protection scheme. If the open phase fault can’t be detected in time, it will pose a serious threat to the safe operation of nuclear power plant. In this paper, the open phase fault protection scheme base on injecting external power for the auxiliary transformer of nuclear power plant is proposed to detect the injection voltage and current. When the current, voltage and impedance meet the criteria, it is determined that the open phase fault occurs. After time delay, an alarm signal is given and the operator is notified to deal with it in time, so as to solve the problem that it is difficult to detect the open phase fault at high voltage side of the auxiliary transformer under no-load condition, The operation reliability of the auxiliary transformer system in nuclear power plant is improved.
作者
黄昌军
陈海龙
张轩
王静涛
李栋
徐立明
肖志刚
HUANG Chang-jun;CHEN Hai-long;ZHANG Xuan;WANG Jing-tao;LI Dong;XU Li-ming;XIAO Zhi-gang(Jiangsu Nuclear Power Co.,Ltd.,Lianyungang,Jiangsu Prov.222000,China;XJ Electric Co.,Ltd.,Xuchang,Henan Prov.461000,China)
出处
《中国核电》
2022年第3期347-352,共6页
China Nuclear Power
关键词
辅助变压器
空载
缺相
外加电源
注入式
auxiliary transformer
no-load
openphase
external powersupply
injection type
