应用电站设备宽频特性的过电压在线监测装置

Online Over-voltage Monitoring Device Applying the Wide Frequency Characteristics of the Equipments in the Substation

过电压的监测和分析对现代电力供电系统有极其重要的意义。通过分析比较国内外现有过电压在线监测装置的特点,提出了一种新型的利用设备宽频传输特性的过电压在线监测方法,其原理是将电压互感器(TV)、二次电缆和分压器等二次设备看作相互级联的二端口网络,通过有理函数逼近建立了其传输参数模型;基于该模型,可由二次设备输出端口的电压信号,应用离散Fourier变换反演计算得到TV高压端口即高压母线上的过电压信号。同时应用该方法设计了在线监测装置的硬件结构电路,开发了软件运行程序,在实验室搭建了该过电压监测装置并建立了该装置的整体计算模型,计算结果与实测数据的比较验证了监测方法和监测装置的可行性和有效性。

Several typical overvoltage on-line monitoring devices in China and abroad are analyzed and compared in detail,and a new method for over-voltage on-line monitoring based on wide frequency transmission parameters of the device is proposed.This method establishes a model by taking the potential transformer（TV）,secondary cables and voltage divider as several two-port networks in cascade using their transmission parameters by means of rational function approximation.Adoption of this model can derive the over-voltage waveform of the high-voltage port of the TV from output voltage signals of the secondary device by means of discrete Fourier transform.Based on the principle,the hardware circuit of the monitoring system is devised and the software program of the system is designed.The over-voltage on-line monitoring system and the two-port transmission parameters model of the online over-voltage monitoring system are established based on the frequency domain measurements.The comparison between the calculated results and measured data verify the feasibility and validity of this method.