An Investigation of the Effects of Grid Frequency Fluctuation on Test Voltage Stability in High Q, Inductance Tuned High Voltage Series Resonant Test Circuits

Inductance tuned high voltage series resonant systems have been employed extensively in high voltage testing laboratories worldwide over the last 40 years as a means of dramatically reducing the input kVA demand when testing high capacitance loads. The high efficiency of modern high voltage test reactors and low dielectric losses associated with the test object insulation result in high voltage resonant circuit quality factor (Q) values that commonly exceed 100, and may exceed 200. An undesirable side effect of operating at such high quality factors is that the output voltage tuning characteristic becomes ultra-sensitive to even small fluctuations in the mains voltage frequency, making it more difficult to maintain the test voltage within the limits specified in international high voltage…