Impact of switched voltages from electronic power converters on high voltage insulation systems and components

The growing deployment of power electronic converters (PECs) introduces fast, non-sinusoidal voltage waveforms that can alter partial discharge (PD) behaviour and insulation life compared to under pure AC. The existing literature is limited but points out potential severe consequences by applying such complex waveforms to electrical insulation. For sharp electrodes on pressboard in mineral oil and PEC substrates, PD inception voltage (PDIV) is reduced with increasing voltage rise time (dv/dt). In mica‑epoxy insulation for rotating machines (Type II) a less clear correlation between PDIV and dv/dt is found. Long‑term degradation studies show that when PDIV is lower under switched voltages, the time‑to‑breakdown also decreases. When