GIS reliability statistics show that the most common electrical failure is characterized by a partial discharge occurring before the complete breakdown.The paper summarizes the present GIS partial discharge testing techniques and their characteristics

especially the application of the UHF method for partial discharge on-line monitoring

mainly focusing on the placement of the internal UHF sensors and its application effect.Combined with the development trend of China Southern Power Grid

the paper also points out the problem like GIS partial discharge monitoring system not matching well with the other on-line monitoring system and several systems running in parallel.And therefore

it suggests both the partial discharge monitoring system and its major on-line monitoring system should be developed by the same supplier.