Analysis of TEV Caused by Partial Discharge of Typical Faults in HV Switchgear

The transient voltage between the metal enclosure of HV switchgear and the earth caused by partial discharge(PD) is named transient earth voltage(TEV),which can be used for efficient PD on-line detection.However,the application of TEV is limited to its average amplitude because of lack of effective characteristic information for routine fault recognition.In order to detect PD in HV switchgear more effectively and distinguish fault types more accurately,the authors designed a TEV sensor and a TEV detection system for HV switchgear,and used the TEV detection system to record the TEV information corresponding to three typical PD models in HV switchgears.Thus,the TEV statistical maps and scatter diagrams corresponding to the PD of three typical faults were obtained.The results indicate that the bandwidth of the TEV sensor is 5 kHz to 80 MHz,and it has excellent response to PD pulse signals.TEV can be used for detecting the features of various faults,and the TEV scatter diagrams corresponding to three typical fault models are obviously different.Since the TEV signals corresponding to three typical PD models show significant differences,TEV can be applied to recognition of fault type in HV switchgear.