Insulation characteristics of XLPE cables and their accessories for high frequency voltage with PWM inverter

A step voltage waveform is applied, by an inverter in which high frequencies are superimposed on the basic commercial frequency, to feeding cables and their accessories that supply a power source to the propulsion coils of a MAGLEV system. The authors devised electrical testing equipment that can output such PWM waveforms, and they investigated the effect such waveforms have on the insulation properties of XLPE power cables and their accessories, the breakdown characteristics of the model and long-term characteristics. As a result, it was learned that the insulation breakdown depends on the voltage waveform peak value, and that the long-term characteristics are determined by the basic frequency. This knowledge will be useful for the rational insulation design of feeding cable systems.<
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