Experiment on multiple voltage application for insulation reliability evaluation method with Weibull distribution

摘要

In the conaition settings of a power-frequency withstand voltage test for substation equipment, an approach based on insulation reliability evaluation using Weibull distribution is available. This can be done by either the "independence model" or "accumulation model" which have been proposed in order to handle the coexistence of multiple voltage levels, but there remains a problem of how to use these models. In the author's preceding research, the V-t characteristics of oil gaps were obtained by focusing on the presence of oil flows in oil-filled transformers as a parameter that influences the voltage application history. In this paper, results of insulation test with applying the same voltage multiple times are exhibited to clarifies the differences between the independence model and accumulation model, and evaluates the influences of voltage application history. These results present that the oil flow velocity, interval voltage and interval time weaken the influence of voltage application history. And the degree of influence with oil flow and interval voltage is evaluated.