Advancements in power electronics to higher power levels and faster switching times allow new machine and systems designs, but also create higher stresses on electric machinery insulation. High performance, pulse-width modulated (PWM) inverters are now available for medium voltage drive systems, and are being considered by the U.S. Navy as they move to the “all-electric” ship. If this process is to be successful, a necessary component will be to understand the impact of partial discharge (PD) generation on electric drive systems.; Out of the many PD influencing parameters, voltage level, voltage rise-time; switching frequency, and temperature were chosen to be investigated with regards to their influence on PD generation in a comprehensive research project in the Motor Systems Research Facility (MSRF) at Oregon State University (OSU). The tests were performed on representative propulsion coils employing two different 4160 V insulation systems and were evaluated by both an optical and electrical PD detection method.; A highly flexible test configuration was developed, capable of adjusting each of the four test parameters independently over a wide range of appropriate values. The developed test program enabled the analysis of the influence of the parameters on the generation of PD, as well as an evaluation of the test coils and PD instrumentation used.; It is concluded that, as expected, voltage level is the most significant parameter affecting PD production. However, there is a surprising interdependence of rise-time and pulse-width that requires further investigation. Multiple-cycling tests are seen as appropriate to determine the effect of temperature.; Based on the subjective nature of the findings from the test program an improved PD instrument is proposed, which would increase the capabilities and objectivity of the PD detection process.
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