Design and Experimental Research of Voltage Sensor for GIS

A prototype of coaxial capapcitive voltage sensor for 220 kV gas insulated switchgear (GIS), which makes full use of the axisymmetric feature of GIS's structure, is developed. The basic structure and working princple of the voltage sensor are presented, the problems that should be considered in the design of the voltage sensor such as the diameter, length and edge effect are described in details. The impacts of error factors, including processing technology, temperature and air tightness, on measured data are analyzed, and the compensating measures to improve the performannce of the voltage sensor, such as surface fitting and formula modification by software, are proposed. Testing results of the prototype show that traditional electromagnetic potential trasnformer can be substituted by coaxial capapcitive voltage sensor.