On-site testing of gas insulated substation with AC voltage

Experience has proven that the reliability of a GIS/GIL can be ensured by an on-site AC-testing after assembly combined with a sensitive partial discharge measurement. Either conventional 50/60 Hz transformer systems or resonant test systems with variable inductance as well as resonant test systems with variable frequency have been used to perform the GIS/GIL on-site testing. The paper describes the different HV test systems with their advantages and limitations and the applicable partial discharge measuring methods. The UHF PD measuring method is emphasised.