Measurement of partial discharge point in power transformer using crosscorrelation

상호상관을 이용한 변압기내의 부분방전 위치측정

This paper describes an effort to develop a microcomputer-based parameter identification system for three phase and two phase brushless DC motor. Back EMF equation is derived from back EMF waveform of three phase and two phase brushless DC motor. In this paper, a new identification algorithm for the brushless DC motor parameters by Pasek's technique is de veloped. It is found that Pasek's equation is valid for the brushless DC motor, too. The results obtained clearly shows that it is possible to implement the identification system for the determination of the brushless DC motor parameters. To minimize errors due to the ripple component in the measured armature current, dlgital averaging filter is employed. The whole identification process of signal generation, measuring, parameter determination is fully automated. The use of the pmpased method in the parameter identification system shows that the averaged current curve is in excellent agreement with the estimated current curve. Therefore, this close agreement conf i i the validity of this technique.

전력 수요가 증가함에 따라 전력용 변압기의 용량이 커지고, 따라서 변압기사고의 파급효과가 커지게 된다. 본 논문은 전력용 변압기의 절연 열화에 의한 사고를 예방진단하기 위한 부분방전의 초음파 측정 기술을 응용하여, 초음파-초음파 측정법에 대한 부분방전점의 위치검출법을 연구하였다. 정확도를 높이기 위해 상호상관함수를 이용할 것을 제안하였으며 모의변압기에서 실험한 결과 만족할 만한 결과를 얻었다.