A New Optical Method of Partial Discharge Distant Positioning in GIS

Compared with traditional partial discharge(PD) detections, optical PD detection has significant advantages in anti-interference, intrinsic characterization and sensitivity in the particle discharge detection of Gas Insulted Switcher(GIS). Optical PD positioning is an efficient and economical positioning method which has a high practical value. In this paper, a new optical sensor array positioning system, consisted of three Silicon photomultipliers(SiPM) in different planes, is designed to locate the PD source in a distance. As the distance between SiPM and PD source increased, the PD source can be regard as a point light source, and the light illuminate to the SiPM is considered to be parallel light. In this circumstance, the radiant flux illuminating to the SiPM is proportional to the cosine of the angle between SiPM plane normal vector and the parallel light. Thus, we can use these characteristics to find the PD source. First, we verified that the quantitative relationship between SiPM output and the cosine of the angle between SiPM plane normal vector and the parallel light intensity. Second, we established nonlinear equations to find the approximately position of the PD source. The calculation of the equations show that there would be a 1cm acceptable positioning deviation with a 30cm distance between SiPM and PD source. The deviation is caused by reflection, measurement error, and some non-linear factor. Owing to its distinctive positioning mechanism, the optical PD positioning by SiPM has the advantages in sensitivity and low cost comparing with traditional positioning technology On the other hand, the problem of accuracy practical application of the system still need more research effort.