Field Investigation for Application of Existing FDS Based Moisture Diagnostic Tool for Power Transformer Insulation System

A power transformer is one of the most important and expensive type of equipment in the transmission and distribution network. Transformer insulation is subjected to various kind of stresses such as Thermal, Electrical, Mechanical, Ambient that reduces it's useful life. Thus, condition assessment and diagnostics techniques are very useful for improving the reliability of the network and service continuity. Various monitoring and diagnostics techniques are to be employed for amongst the purpose of which dielectric frequency domain spectroscopy (FDS) is leading technique to check the condition of transformer insulation which consists of oil, paper, pressboard. Moisture is the major culprit for degradation of transformer insulation. Frequency domain spectroscopy(FDS) is basically a non-invasive technique which is developed to identify the amount of moisture in transformer insulation. This paper provides overview of the FDS technique. it's practical application & field investigation.