荆门热电厂4号机励磁回路技术改造

现场试验和运行经验显示荆门热电厂4号机励磁回路存在灭磁开关运行不可靠的问题。线性电阻灭磁易在转子上产生高电压,灭磁时间长,而转子过电压保护效果又较差,针对以上问题,进行了相关设备的技术改造,采用氧化锌(ZnO)非线性电阻灭磁。介绍了基于高能ZnO电阻的过电压保护器工作原理,结合ZnO电阻性能、灭磁装置和转子过电压保护的相关技术要求总结了灭磁系统技术参数的选择、计算方法。现场发电机空载和短路试验情况下灭磁试验表明,该项改造达到了预期效果。

Exciting circuit retrofitting of Jingmen thermal power plant unit 4

Field test and operation experience show that,the field circuit breaker of Jingmen thermal power plant unit 4 is not reliable,the linear resistance for field suppression offen generates high voltage on rotor,the suppression time is long,and the performance of rotor over-voltage protection is poor.For that,the exciting circuit retrofitting is carried out:the nonlinear ZnO resistor is applied for field suppression.The operating principle of over-voltage protection based on high performance ZnO resistor is introduced,and the technical parameter selection and calculation methods of field suppression system are presented with technical requirements of ZnO resistor,field suppression equipment and rotor over-voltage protection.Field test under no-load and short circuit conditions show the expected effect of this retrofitting is obtained.