Transformer Practical Turn-to-Turn Fault Detection Performance using Negative Sequence and Space Vector-Based Methods

Transformer turn-to-turn fault (TTF) is one of the most difficult failures to detect. The negative sequence percentage differential current (NSPD) and extended park vectors approach (EPVA) are the two most promising methods for detection of the TTF inception. In this paper, in order to evaluate the performance of these methods, various experimental tests are carried out to detect the TTF initiation on the winding of the transformer under different operating conditions such as: no-load operation, when an external fault or an open conductor fault is also occurred. The results show that the setting of the proper thresholds plays the main role in the reliable and secure performance of NSPD and EPVA-based methods. Moreover, the experimental results verify that the selection of a fixed threshold for these detection methods can be very difficult. Even if the adjustment of the fixed threshold is possible, it may endanger the reliable and secure performance of the related protection methods.