The paper is concerned with the issues of automated decision support system creation for integral assessment of electrical grid equipment technical state at power stations and substations for equipment operating efficiency improvement and repair cycles correction. The fundamental principles of developed system, based on artificial intelligence techniques comprising fuzzy logics and artificial neural networks methods which allow the system to be self-adjustment and self-training, are presented in the paper. Decision-support system validation in the context of 110 kV power transformer technical state assessment, based on chromatographic analysis data of gases dissolved in oil, is also presented in the paper.