【摘要】 为了对开关柜等电气设备中产生的局部放电进行检测和模式识别,研制了一种用于局部放电检测的Ddot探头,并搭建了三种典型的局部放电实验模型,采用该探头和脉冲电流法同时对局部放电进行测量,通过比较两者信号之间的幅值能量关系,验证了探头的可靠性。此外还研究了不同距离下的局放信号频谱图,分析了信号高低频分量衰减与其传播距离之间的关系。试验结果表明:(1)D-dot信号能很好的反应局部放电的相位分布;(2)局部放电D-dot信号幅值与脉冲电压峰峰值呈线性关系,信号能量与脉冲电压峰峰值呈二次相关,且针对不同放电模型比例系数有较大差别,可依此进行局放源放电类型分类;(3)D-dot信号中高频部分随距离增加衰减很快,只在短距离(10 cm)内能够测得,低频部分衰减缓慢,在1m范围内基本无衰减。更多还原

【Abstract】 In order to do online monitoring and pattern recognition for partial discharge generated in electrical equipments such as switchgear and so on,a kind of D-dot probe used for the detection of PD is designed in this paper.Three typical models of partial discharge are set up and the PD signal is measured by the probe and impulse current method at the same time. The probe’s reliability is verified by comparing the relationship of amplitude energy between PD signal and impulse current method. What’s more,the relationship between signal attenuation of high-low frequency component and the radiation distance is researched,and the relationship between high and low frequency component attenuation of signal and its propagation distance is analyzed. The conclusions are as follows:( 1) The phase distribution of PD pulse can be well reflected by the D-dot probe.( 2) There is a linear relationship between the amplitude of D-dot signal and the peak-to-peak value( VPP) of impulse voltage. Meantime,there is a square relationship of VPP of impulse voltage and the cumulative energy of D-dot signal. The scale factors vary from one PD model to the others,so the PD types can be differentiated.( 3) The high frequency components of D-dot PD signals attenuate quickly as the radiation distance increases,and it can be measured only within 10 cm,while the low frequency components attenuate slowly,and it has no attenuation within 1 m.更多还原