Analysis of Multi-Spectral Signal in GIS and Comparing with Electrical Signals

Multi-Spectral test is common methods in power facility monitoring. A high sensitive ultraviolet (UV) PD test facility has been set up for real size 145kV GIS tube. To install the UV sensor on GIS, an observation module for the sensor has been designed with qualified electric field distribution which is calculated by finite element method. This paper gives the results of UV detector for PD optical signal on samples of tip defects and floating defects, and comparing with conventional impulse current test and UHF method. In addition, the influence of electrode potentials on tip defects and signal distances on floating defects are investigated with applied voltage varying from 0 to 110kV, and propagation distances varying from 0 to 1.6m. Test results show that the UV PD impulses are clearly influenced by the defect patterns which are in accordance with the electrical signals; the tip electrode at high potential radiates stronger UV signals as voltage increasing and breaks down at 110kV, while the one at low potential radiates no signal with voltage changing; the features of decreasing UV impulse numbers with increasing distances are also discussed, which may help for detector arrangement and defects recognition.