This paper presents a novel technique for diagnosing a turn-to-turn fault at the incipient level inside the power transformer winding using frequency response analysis (FRA). Utilizing lower frequency region of FRA in case of pre-fault and post fault conditions of transformer windings, the proposed technique determines the deviation in equivalent inductances. Based on the deviation, a location factor (<i>lf</i>) is derived, which indicates location of fault, by calculating accuracy factor (<i>x</i>) corresponding to each section of the winding. Thereafter, the extent of turn-to-turn fault and number of faulted turns are determined based on the accuracy factor of the faulted disk. The performance of the proposed technique has been validated through a simulation model as well as from two different laboratory-developed winding models and 400 kVA real filed transformer. The results designate that the developed technique is proficient to estimate location of turn-to-turn fault even when number of faulted turns are lower than 5% of the total turns. Its response remains immune against winding configurations and lead error encountered during measurement. Eventually, a comparative assessment of the proposed approach with various other approaches indicates its eminence in terms of turn-to-turn fault localization and estimation of fault extent and faulted turns.