A Study on the Estimation of Twisted Pair Insulation Lifetime under Repetitive Pulse Voltage

In response to environmental demands, inverter-driven motors are increasingly used in industry and mobility. This has raised expectations for higher motor performance and reliability. Recent advances in power electronics have led to higher frequency and faster slew rates of inverter output pulse voltages. As a result, insulation degradation due to inverter surges has become a concern. These surges, caused by impedance mismatches at motor terminals, can trigger PD (partial discharge) within insulation materials. PD can degrade insulation and eventually lead to breakdown. To improve the reliability of inverter-driven motors, understanding PD characteristics and insulation lifetime under repetitive surge voltages is important. This paper proposes a computational algorithm to estimate insulation lifetime under repetitive surge voltages. The algorithm is based on experimental results under AC voltage. The estimated insulation lifetime of twisted pair samples was compared with experimental data, confirming the algorithm's validity.