核电厂电机空载电流三相不平衡问题研究  

Research on Three-phase Unbalance of No-load Current of Nuclear Power Plant Motor

作　　者：张贵志 ZHANG Guizhi(Fujian Fuqing Nuclear Power Co.,Ltd.,Fuzhou 350300,China)

机构地区：[1]福建福清核电有限公司,福建福州350300

出　　处：《电工技术》2022年第3期130-134,152,共6页Electric Engineering

摘　　要：针对某核电5、6号机组在安装调试阶段500 kV电源供电情况下多台电机空载电流不平衡的问题,通过采用T形等效电路的方法推导出电压不平衡对电机空载电流不平衡的影响公式,将公式计算所得电机空载电流不平衡度与现场实测电机空载电流不平衡度进行对比,数据结果一致,证明了虽然目前500 kV电网电压的不平衡度是合格的,但会导致电机空载试验三相电流不平衡度大于10%。进一步结合杆塔线路布置、各回路出线电压及线路压降公式对500 kV电网电压不平衡原因进行分析,确认为500 kV架空线路参数不平衡导致,可采用换位或变换各输电线路相序排列的措施来减少电力系统正常运行时的不平衡电压。Aiming at the unbalanced no-load current of multiple motors under the condition of 500 kV power supply during the installation phase of the unit No.5 and No.6,by adopting the T-shaped equivalent circuit method,the formula for the influence of voltage unbalance on the unbalanced motor no-load current is derived,and the unbalanced degree of the no-load current of the motor calculated by the formula is compared with the measured unbalanced degree of the motor no-load current on site.The data results are consistent,which proves that although the current unbalance of the 500 kV grid voltage is qualified,it will cause the three-phase current unbalance of the motor to be greater than 10%in the no-load test.Further,combined with the tower line layout,outgoing line voltage of each circuit and line voltage drop formula,the causes of voltage imbalance of 500 kV power grid are analyzed.It is confirmed that it is caused by parameter imbalance of 500 kV overhead line.The measures of transposition or transformation of phase sequence arrangement of each transmission line can be adopted to reduce the unbalanced voltage during normal operation of power system.

关 键 词：电机 空载电流不平衡 电压不平衡 

分 类 号：TM623[电气工程—电力系统及自动化]