摘要
传感器的直流漂移以及电网的3次、5次、7次谐波直接影响介质损耗角δ的测量精度。文中提出了一种梳状陷波器干扰抑制新方法。陷波器的零点位于单位圆,极点在非常靠近单位圆的径向方向上,传递函数在所设计的频点(直流、150 Hz、250 Hz、350 Hz)有超过140 dB的衰减,而对50 Hz无影响,在此基础上,让梳状陷波器输出与母线参考信号进行互相关计算,从而消除随机干扰带来的误差。现场测试表明,该方法的测量精度比传统方法有很大提高。
Measuring precision of dielectric loss tangent S is directly influenced by the transducer's direct current (DC) shift and the 3rd, 5th, 7th harmonic waves. The dielectric loss measurement based on the traditional Fourier transform can not avoid the influence of frequency leakage and rail fence effect. Thus a comb notch filter based new interference reduction method is proposed. The zeros of the notch filter lie on the unit circle, and the poles highly approach to the zeros' position in radial direction. It is desired to reject a very narrow frequency band leaving the rest of the spectrums little changed. The filter has more than 140 dB attenuation for the designed frequencies of DC, 150 Hz, 250 Hz and 350 Hz while signals of 50 Hz can easily pass through this filter without any distortion. Furthermore, output of the comb notch filter correlated with reference voltage can eliminate the Gaussian white noises. Field tests show that the precision of this method has excellent improvement more than traditional methods in the power equipment insulation on-line monitoring system.
出处
《电力系统自动化》
EI
CSCD
北大核心
2004年第3期67-70,共4页
Automation of Electric Power Systems
