Software development for power transformer condition evaluation using dissolved gas analysis methods; practical experience in Thailand

This paper proposes a software development for evaluating to actual condition of power transformers in Thailand´s transmission network. The Dissolved Gas Analysis (DGA) methods such as total dissolved combustible gas concentrations, total combustible gas, Rogers ratio, Dörnenburg ratio, as well as Duval triangle methods are applied to assess the actual condition of power transformer. All methods are developed by using Microsoft Excel and Visual Basic for Application (VBA) program for a simple usage with minimum cost of utility to evaluate actual condition of sampled insulating oil of transformer. The results are automatically generated and reported by the program to the user. The DGA sampling data of insulating oil of 126 power transformers are analyzed by all methods and compared to justify the actual conditions of power transformers. The results show that all methods identify in a consistence conditions while a proper maintenance can be suggested.