A Novel Adaptive Impedance Estimation Framework for Real-Time Fault Location in the Nigerian Transmission Network Using Phasor Measurement Units

This research proposes and validates a novel adaptive impedance estimation framework for real-time fault location in the Nigerian 330kV and 132kV transmission network using phasor measurement unit data, constituting an original theoretical contribution to wide-area monitoring and fault location science for large-scale power systems in data-sparse environments. Accurate fault location in the Nigerian transmission network remains a major operational challenge due to the network's extensive geography, limited PMU deployment, and the time-varying line impedance characteristics introduced by the frequent thermal overloading and ageing conductor condition typical of Nigerian transmission infrastructure. The proposed framework is grounded in a novel adaptation of the distributed parameter line model that incorporates temperature-dependent impedance updates derived from real-time PMU measurements and ambient temperature data from Nigerian Meteorological Agency sensor networks. The theoretical contribution extends existing single-ended and double-ended fault location algorithms by introducing an online parameter adaptation mechanism that corrects systematic location errors arising from impedance uncertainty, demonstrated to reach 8 to 15 percent of line length in the Nigerian context without adaptation. The framework is validated through a combination of hardware-in-the-loop testing using a real-time digital simulator platform and field validation using actual PMU event records from seven TCN PMU installations. Validation results demonstrate fault location accuracy within 1.8 percent of line length across the tested scenarios, representing a threefold improvement over non-adaptive methods. The framework accommodates sparse PMU deployment through a novel observability extension algorithm. Keywords: fault location, phasor measurement unit, adaptive impedance, transmission network, Nigeria.