Generation of High-Voltage Oscillating Impulse Waveforms

Conventional tests for HV equipment include lightning and switching impulse test, both having unidirectional waveforms. However, transients in high-voltage networks, generated by switching operations, have also oscillating waveforms different of those produced by lightning storms, which are of exponential type. Most impulse generators are designed for the latter, so it is necessary to modify their configurations to achieve an oscillating behavior. This paper presents a design method for that modification, adding an oscillation to the initial time of the exponential waveform. The proposed modifications were implemented on an impulse generator and tested in a HV laboratory.