On July 30, 2011, Qinghai Electric Power Research Institute adopted the 1200kV/8A UHV series resonance test system produced by Suzhou Huadian (the complete set of equipment includes: 320kW without partial discharge frequency conversion power supply, 320kVA without partial discharge excitation transformer, 300kV/8A×4 units High-voltage resonant reactor, 1200kV AC voltage divider) successfully conducted the AC withstand voltage test of GIS at the Qaidam 750kV substation of Qinghai-Tibet National Grid.