UniversityafSalford,

ABSTRACT. This paper describes an optoelectronic system for detecting corona discharge in SF6 filled systems. Using the discharge detection sys-tern, investigations have been carried out to study the influence of various experimental parambters on the amount of detected corona light. It is shown that the measured irradiance due to corona depends upon the applied voltage level, gas pressure, the distance and angle between the corona source and the fibre optic light guide, and the radius, the material as well as surface properties of the electrodes. It is further shown that addition of nitrogen to SF6 significantly improves the corona light emission. The sen-sitivity of the detection system can be further improved by the use of fluorescent paint on the interior walls of the pressure vessel. 1