Diagnostic Technique of a Switchboard by Frequency Analysis of Radiated Electromagnetic Wave

방사전자파의 주파수분석에 의한 배전반 진단기술

In this paper, we analyzed the frequency spectrum of radiated electromagnetic waves generated by series arc- and corona- discharges as a basic study to develop an online diagnostic technique for power facilities installed inside switchboards. To simulate corona and series arc discharges, an arc generator specified in UL1699 and a corona generator were fabricated. The experiment was carried out in an electromagnetic shielding room, and the measurement system consists of an Ultra Log Antenna and an EMI Test Receiver. The frequency spectrum exists in ranges from 30 to 500 [MHz] for series arc discharge and 30 [MHz] to 2 [GHz] depending on defects for corona discharge. The peak frequency of series arc discharge and corona were 40 [MHz], 80 [MHz] and 35 [MHz]~160 [MHz], respectively.