Locating the Inter-turn Faults in Transformer Winding Using Reflection Function Measurement

Power transformers are one of the most important and expensive equipment in the electrical power system. Therefore, many efforts have been made to decrease their unplanned outage and downtime which are related to the type of the defect. Incipient inter-turn faults and mechanical winding failures are two common types of failure could result in winding destruction and even transformer explosion in sequence. Therefore, these winding defects should be detected in early stages before leading to interruption or high consequential costs. Frequency Response Analysis (FRA) is one of the methods that could detect most kind of the winding mechanical failures. Several contributions are attempted to localize these types of winding failures. Authors have already shown that a new method based on the measurement of a reflection coefficient function in frequency domain is a feasible method to localize the resistive fault between two disks of the winding. In this contribution, the reflection coefficient function is utilized to distinguish and localize the inter-turn faults like resistive and capacitive between two different disks as well as faults between disk and ground.