Algorithm for calculating influence of power transformer oil temperature change on the accuracy of allacoustic non-iterative partial discharge localization

Abstract

This article investigates the all-acoustic method for partial discharge localization in a power transformer. This method is based on mathematical model that uses multilateration with Time Difference of Arrival (TDOA) principle and non-itterative mathematical algorithm. In this model, it is assumed that acoustic signal propagates only through transformer oil and that the velocity of acoustic signal is constant. Acoustic signal velocity is largely dependent on transformer oil temperature meaning that oil temperature is also considered to be constant. In reality if we look from the perspective of physics, thermo dynamics of fluids, transformer construction etc. this approximation is enormous. Therefore, influence of power transformer oil temperature change (velocity of acoustic signal change) on the accuracy of this method is investigated. For that purpose special algorithm is designed and implemented in Visual C# programming language. Based on conducted simulations, further knowledge is gained about interaction between transformer oil temperature and placement of acoustic sensors. This interaction produced significant disparity in noniterative algorithm's accuracy for different sensor positions with oil temperature change. In order to fully take advantage of noticed interaction, certain steps for further research and development are proposed.

Keywords

• power transformer
• partial discharge
• oil temperature
• acoustic measurement
• elementary sensitivity
• input variables interaction
• sensor placement
• software