RESEARCH OF PARTIAL DISCHARGE REGISTRATION EFFECTIVENESS USING HFCT SENSOR
The paper describes research on HFCT sensor effectiveness for PD measurement. It can be assessed only based on HFCT initial and secondary signals analysis. A secondary signal can be recorded easily. Initial signal direct registration is inappropriate. Thus, it was measured and recorded using resistive elements. PD signals were registered by HFCT and resistive sensors using a commercial portable diagnostic device and oscilloscope. The commercial device showed mostly similar signal forms except for the pulses’ magnitude. The resistive sensor showed about 27% higher pulses magnitude than the HFCT sensor for the same calibration pulses. Besides, the resistive sensor registered a larger amount of pulses but PD power was higher using the HFCT sensor. Calibration pulses trapezoidal integration showed that 3 nC pulses have an integrative value between 0 and 4 nC. Calibration pulses obtained using an oscilloscope sufficiently differ from pulses obtained using a commercial device. This difference is explained by circuit solutions of measuring tools. Besides, registered using oscilloscope pulses have much larger apparent charge values spread. PRPD patterns obtained using HFCT and resistive sensors have similar pulse distributions. The resistive sensor allowed for recording much more pulses. Nevertheless, HFCT sensor registered PDs had a larger power. Thus, the HFCT sensor is an effective tool for partial discharge registration.