On-line Monitoring System of Ultra-high-frequency PD in Transformer Based on Virtual Instrument

An on-line monitoring system of ultra-high-frequency (UHF) PD was investigated for transformers in this paper. Based on envelope detection technique, the measure principle of UHF PD signals was analyzed, and the hardware of this system was developed. The software of this system, consisting of data acquisitionsquare data storagesquare signal display and graph analysis, was constructed using National Instruments´ Measurement Studio software. The PD of five discharge models was measured. Experimental results show that this system has wider band width, stronger ability of interference suppression, and higher stability, and can be useful for on-line monitoring of UHF PD in transformers.