Improving the Operating Parameters of the 300 kV AC Test System

The High Voltage Test Laboratory in CVVOZEPowerLab is equipped with a Haefely Hipotronics HV Test Transformer HHT7300-300T5-760. This test system is used for withstand voltage, breakdown voltage tests and diagnostics of dielectrics - measurement of partial discharges and electronic bridge measurement up to 300 kV. Unfortunately, the system produces output voltage with high value of harmonic distortion, mainly in the condition of low output load. Higher harmonics in the output test voltage make it impossible to carry out accurate withstand tests and affects the measurement accuracy of the dissipation factor and the operation of the PD system. These problems were solved for last 5 years and currently are found several partial solutions. In this paper are described several basic concepts used to improve the operating parameters of the 300 kV AC source.