基于CVT电路模型的谐波还原方法研究  

Research on Harmonic Restoration Method Based on CVT Circuit Model

作　　者：郭树永[1] 江海 戴甲水 郝良收 胡广富 朱豪帅 GUO Shuyong;JIANG Hai;DAI Jiashui;HAO Liangshou;HU Guangfu;ZHU Haoshuai(EHV Power Transmission Company Tianshengqiao Branch,China Southern Power Grid,Guizhou Xingyi 562400,China;Laboratory of Power Transmission Equipment Technology,Chongqing University,Chongqing 400044,China)

机构地区：[1]中国南方电网公司超高压输电公司天生桥局,贵州兴义562400 [2]重庆大学输变电装备技术全国重点实验室,重庆400044

出　　处：《高压电器》2025年第1期129-135,共7页High Voltage Apparatus

基　　金：中国南方电网有限责任公司创新项目(CGYKJXM20220055)。

摘　　要：电容式电压互感器(CVT)是电力系统中重要的电压状态监测设备,其在测量工频电压时具有较高精度。但是当电力系统中发生次同步谐振等复杂工况时,CVT中间变压器的铁心将会发生饱和,CVT的电压传输特性将会随铁心电感的改变而改变,进而导致CVT在测量谐波时的测量误差增大。现有的基于电压传输特性的谐波测量方法难以在电压传输特性发生变化时动态计算CVT谐波。因此,文中搭建了计及中间变压器铁心饱和特性和杂散电容的CVT电路模型,通过逆向求解该模型,实现谐波的精准还原,最后对35 kV CVT进行谐波仿真验证,结果表明,与传统电压传递系数法相比,文中提出的谐波还原方法将谐波分量误差由94.6%降至7.1%,能够准确地计算出中间变压器铁心处于非线性状态时一次侧电压的实际谐波分量。Capacitive voltage transformer(CVT)is an important equipment for voltage state monitoring of power sys⁃tem and has higher accuracy in the measurement of power frequency voltage.However,the core of intermediate trans⁃former of the CVT will be saturated in case of sub⁃synchronous resonance in power system.The voltage transfer char⁃acteristic of CVT can change with variation of inductance of core,resulting in the increase of measurement error of the CVT in the measurement of the harmonics.The existing harmonic measurement method based on voltage transfer characteristic has no way to dynamically calculate harmonic components of CVT in the course of variation of voltage transfer characteristic.Therefore,the CVT circuit model taking into account the core saturation characteristics and stray capacitance is set up in this paper.The accurate restoration of the harmonic is achieved by reversely solving the model.Finally,the harmonic simulation verification of 35 kV CVT is performed.The result shows that compared with the traditional voltage transfer coefficient method,the harmonic restoration method proposed in this paper can make the harmonic component error be reduced from 94.6%to 7.1%,which can accurately calculate the actual harmonic components of the primary side voltage when the core of intermediate transformer is at nonlinear state.

关 键 词：电容式电压互感器 谐波测量 逆向求解 杂散电容 

分 类 号：TM451.2[电气工程—电器]