高压开关柜局部放电TEV信号传播衰减特性

高灵敏度状态感知是实现设备数字化运维的关键环节,也是实现设备状态分析与全生命周期管理的重要前提。局部放电暂态地电压(transient earth voltage,TEV)检测是实现开关柜绝缘状态感知的主要手段,其检测灵敏度受到放电类型与部位、检测位置的影响,目前缺乏系统研究。文中建立基于实测脉冲电流波形的时域有限差分法的电磁波仿真模型;分析局部放电脉冲电流波形上升沿时间、放电源位置及脉冲电流方向等因素对TEV幅值与衰减程度的影响;在实验室开展开关柜局部放电试验与TEV测量,得到影响TEV检测灵敏度的主要因素。结果表明,脉冲电流上升沿时间与放电源位置是影响开关柜局部放电信号幅值的主要因素。脉冲电流上升沿时间越长,TEV信号幅值越小,当2种脉冲电流波形上升沿时间相差10倍时,TEV幅值相差3.17~3.37倍;母排室局部放电的TEV衰减程度明显大于电缆室,前者衰减程度约为后者的9.5~10.0倍。该结论对检验TEV检测灵敏度具有参考价值。

Propagation and attenuation of TEV signals by partial discharge in high voltage switchgear

High sensitivity in condition monitoring is a key link in digital electrical equipment operation and maintenance,besides,it is also an important premise of status analysis and life cycle management. The partial discharge (PD) transient earth voltage (TEV) detection is the primary mean to insulation state perception of high voltage switchgear. The detection sensitivity of TEV method is affected by the type and location of the defect,the location of TEV detection. However,there is no systematic research on this subject by now. A finite difference time domain (FDTD) electromagnetic wave simulation model based on the measured pulse current waveform is established. The stuexplores the effects of factors such as the rise-up time of PD pulse current waveform,the position of discharge source,and the direction of pulse current on the amplitude and attenuation degree of TEV. A series of PD tests and TEV measurements are conducted in a laboratory setting to identify the primary factors influencing TEV detection sensitivity. The results reveal that both the rise-up time and spatial position of PD significantly affect the amplitude of the TEV signal. Specifically,the amplitude of the TEV signal exhibits a decreasing trend as the pulse current''s rise-up time increases. Notably,a tenfold increase in the rise-up time results in a decrease in TEV signal amplitude within the range of 3.17 to 3.37 times. Furthermore,the TEV signal''s attenuation degree in the busbar room compartment is approximately 9.5 to 10.0 times greater than that observed in the cable compartment. This conclusion has reference value for testing the sensitivity of TEV detection.