电压互感器二次回路压降对电能计量影响

Effect of the PT Secondary Loop Voltage Drop on Power Energy Measurement

电压互感器二次压降直接反映电能表进线侧电压对电压互感器就地端子箱侧电压的偏移程度,它的大小直接影响电能计量的准确性。对计量回路中电压互感器二次压降产生的原因进行分析,并结合火力发电厂关口计量回路改造实例,提出解决方案和改造措施。事实证明,采取装设计量专用的电压互感器二次回路,缩短导线长度,增大二次导线截面积,减小接点接触电阻,减少电压互感器二次负荷等技术措施,能有效降低电压互感器二次压降值。

The secondary voltage drop of the potential transformer is the direct reflection of how the primary voltages on the electric energy meters deviate from those on the on-site terminal boxes.Its value directly influences the accuracy of the energy meters.Causes of voltage drop are analyzed and solutions are suggested combined with modification of the gateway meter circuits in power plants.Measures to reduce the voltage drop have been proved effective,such as fitting the special measurement loops to the secondary of the potential transformer,shortening the wires,increasing the cross-sectional area of wires,minimizing the contact resistance,and reducing the secondary loads of the voltage transformer.