变压器铁芯接地线上耦合VFTO信号的仿真研究  

Simulation Research of VFTO Signal Coupled on Transformer Core Earthing Conductor

作　　者：柯学志 李朝晖 KE Xuezhi;LI Zhaohui(School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;State Key Laboratory of Advanced Electromagnetic Engineering and Technology,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学土木与水利工程学院,武汉430074 [2]华中科技大学电气与电子工程学院强电磁工程与新技术国家重点实验室,武汉430074

出　　处：《高电压技术》2021年第11期3923-3931,共9页High Voltage Engineering

摘　　要：在对变压器铁芯接地信号(core earthing signals,CES)监测过程中,多次记录到侵入变压器的特快速暂态过电压(very fast transient overvoltage,VFTO)冲击脉冲,这为检测VFTO冲击提供了新途径。为了研究VFTO耦合至CES的途径,并分析CES中VFTO信号的特征,首先对VFTO的产生过程进行仿真分析;其次建立绕组的高频暂态混合模型,仿真分析VFTO在绕组内的传输模式;最后建立铁芯高频电容耦合模型,并与前面模型进行联合仿真,分析VFTO致使CES中产生VFTO脉冲的全过程,总结VFTO脉冲特征,初步建立VFTO脉冲的特征知识库。同时,还对某水电站隔离开关分闸过程进行对比仿真,仿真波形与实测波形基本一致。上述研究表明,VFTO在绕组上同时存在沿线传输和电容耦合两种传输模式。VFTO可通过绕组与铁芯之间、铁芯内部的电容耦合至CES,产生VFTO脉冲,这些脉冲在隔离刀闸分闸过程中呈现出幅值逐渐增大、分布逐渐稀疏的特征,而在合闸过程则完全相反。通过该研究,获知了VFTO耦合至CES的全过程,总结了CES中VFTO脉冲的关键特征,进而证明了利用CES检测VFTO冲击的可行性。During the monitoring of transformer core earthing signals(CES),very fast transient overvoltage(VFTO)impulses have been recorded many times,which provides a new way to detect the VFTO impulse.In order to research the way of VFTO coupling to CES,and to analyze the VFTO signal features in CES,firstly,the generation of VFTO is simulated and analyzed.Secondly,the high-frequency hybrid model of the winding is established,and the transmission process of VFTO in the winding is analyzed.Lastly,the core high-frequency capacitance model is established and united with the previous model for simulation to analyze the process of VFTO-pulse generation in CES.Moreover,the VFTO-pulse features are summarized and the VFTO-pulse knowledge is established.Meanwhile,a comparative analysis of the opening process of a disconnector in a hydropower station is carried out by simulation.The simulation waveform and the field recording waveform are basically the same.The above studies show that VFTO is transmitted along the line and coupled through the capacitances on the winding,and then coupled to CES through the capacitance between the winding and the iron core and inside the iron core to generate VFTO-pulses,which possess the characteristics of gradually increasing amplitude and gradually sparse distribution in the opening process of the disconnector,but they are completely opposite in the closing process.Through this study,the whole process of VFTO coupling to CES is obtained,the key characteristics of VFTO-pulse in CES are summarized,and then the feasibility of detecting VFTO impact by CES is proved.

关 键 词：特快速暂态过电压(VFTO) 电力变压器 铁芯接地信号(CES) VFTO检测 VFTO特征知识库 

分 类 号：TM41[电气工程—电器]