CVT一次隔离开关操作对变压器过励磁保护影响的研究

电容式电压互感器(CVT Capacitor Voltage Transformer)含有电容和非线性电感元件,当一次隔离开关操作时可能引起二次电压异常,影响变电站继电保护装置的正常运行,甚至引起主变过励磁保护误动作。运用ATP建立CVT及其所运行的变电站的等值电路模型,仿真计算一次侧隔离开关操作过程中CVT二次电压情况。比较影响二次侧电压的主要因素,分析在CVT一次侧隔离开关操作过程中主变过励磁保护误动作的原因。正常操作不会引起主变过励磁保护误动作。

Influence of CVT Primary-Side Isolator Operation on Over-Excitation Protection of Transformer

Capacitor voltage transformer(CVT) contains capacitors and nonlinear inductances,so primary-side isolator operation may cause abnormal secondary voltage to influences normal operation of relay devices in substation,or even to lead misoperations of over-excitation protection for main transformers.This paper establishes equivalent circuits models of CVT and the substation via ATP,and simulates CVT secondary voltage as primary-side isolator operates for determining the main factors which impact the amplitude of secondary voltage,and determining the reasons for misoperating over-excitation protection of main transformers.The result shows that misoperation of over-excitation protection for main transformers will not happen in normal operation.