Real Time Measurement of Average Winding Resistances of Transformers

Abstract

The monitoring of transformers that are expensive equipment of power systems is the one of important issues. Transformer monitoring systems are usually used in order to detect failures, to determine the lifetime, to measure losses and to monitor winding temperatures. One of the important parameters that can be utilized for this aim is the winding resistances of transformer. Therefore, in this work, a novel method for monitoring the winding resistances of transformer is presented. The method is developed with help of equivalent circuit and power equations of transformer. In computations, voltages and currents at the both sides of transformers are used. Thus, it is provided to monitor the average winding resistance of transformer in real time. Not only the method can be applied to single-phase transformer, but also can be used in three-phase transformers with star-star or delta-star connection. In the paper, firstly, mathematical background of the method is introduced. Then, results of simulations done in Matlab environment and experiments are presented. Simulations and experimental works have demonstrated the validity of the method evidently.

Keywords

• Single-phase transformer
• Three-phase transformer
• Average winding resistance
• Real time monitoring