Investigating the assessment of insulation integrity using radiometric partial discharge measurement

Modern power systems require that power delivery components operating at very high voltages use the minimum amount of insulation necessary for reliable operation in view of economic considerations. The insulation is subject to a high electrical stress, so that partial discharge (PD) activity may initiate under normal working conditions in high voltage equipment that is aging or has flawed insulation, leading to further weakening of the insulation and eventually to complete. This paper studied RF PD pulses from six types of defects involving gaseous, liquid and solid in a substation environment. Results between corona signals and PD signals obtained from defects connected to a metallic structure show that the earth-path structure influent the RF frequency spectral analyses. It is useful for the further development of non-contact RF monitoring systems for detecting PDs and assessing electrical equipment, eventually contributing to improvements in the reliability of the electrical power supply.