Partial Discharges in typical defects of power cable systems at variable test voltage frequency – fundamental and practical considerations

Testing energy cable systems often implies the necessity to drive large capacitive loads. A test voltage supply that generates testing voltages with service frequency (50/60 Hz) is then bulky and heavy because of the high demand of reactive power. In addition, the reactive power is sometimes difficult to obtain, especially under on-site conditions, where the energy supply for cable test systems is limited. A common solution is the use of resonant test systems that operate at variable testing voltage frequency to meet the resonant frequency. Another solution is to significantly lower the testing voltage frequency e.g. to 0,1 Hz in order to lower the demand of reactive power as well. In both cases the question arises, how the preferably performed measurement of partial discharges is…