不同负载条件下CVT 过电压监测装置频率响应特性分析

Analysis on Frequency Response Characteristics for CVT Over-voltage Monitoring Device under Different Load Conditions

过电压的准确测量对保证电网的安全稳定运行具有重要意义。为此,对不同负载条件下基于电容式电压互感器(CVT)的过电压监测装置的频率响应特性进行了实际测试分析,研究了不含内置低压电容和含有内置低压电容情况下负载变化对频率响应特性的影响。研究结果表明:对于不含内置低压电容的情况,当CVT二次侧空载或额定负载时,得到的频率特性大致相同,但当负载较重时,频率特性与额定负载情况下差异较大;当含有内置低压电容时,内置低压电容的存在几乎不对CVT不同负载情况下的频率特性产生影响,且额定负载和空载情况也对内置低压电容高压侧频率特性影响较小。

The accurate measurement of over-voltage is very important to ensure the safety and stability of power grid.There-fore,the frequency response characteristics of over-voltage monitoring device employing capacitor voltage transformer(CVT)under different load conditions are tested and analyzed,and the effect of load change on frequency response characteristics without and with interior low-voltage capacitor is studied.The results show that:for the case without interior low-voltage capacitor,when the secondary side of CVT at no-load or rated load,the frequency characteristics are roughly the same,but when the load is heavy,the frequency characteristics are greatly different from the situation under rated load.When there is an interior low-voltage capacitor,the presence of interior low-voltage capacitor has almost no effect on the frequency character-istics of CVT under different load conditions,and there is also little effect on the frequency characteristics in high-voltage side of interior low-voltage capacitor under rated load and no-load conditions.