Определение значений граничных концентраций растворенных в масле газов методом минимального риска

Abstract

The article describes a method for determining the limit concentrations of gases dissolved in oil at which the minimal possible risk is achieved in case of making erroneous decisions. The limit concentrations of gases dissolved in oil are suggested to be determined by minimizing the average risk function for multidimensional distributions using the Nelder—Mead method. The average risk values accompanied by using the limit gas concentrations stipulated by the well-known international and national procedures are subjected to a comparative analysis. The effect the values of distribution law parameters, the flaw occurrence probabilities, and the erroneous decision cost ratios have on the limit concentration values is investigated. It has been revealed that the limit gas concentration values at which the minimal average risk is achieved are not constant, but vary depending on the values of gas distribution laws’ parameters for healthy transformers and for transformers containing developing flaws, on the values of erroneous decision costs, and on the probabilities of defective and flawless state of transformers. It follows from the above-mentioned findings that the limit gas concentration values at which the minimal risk is achieved should be determined taking into account the above-mentioned factors.