Improving the Availability of the Onitsha-New Haven 330kv Transmission Line Availability Using Adaptive PMU-Based Insulation Defect Detector

This thesis is aimed at improving the availability of the New Haven-Onitsha 330kV transmission line by using an adaptive PMU based insulation defect detecting and location scheme. The exposed nature of overhead power lines makes overhead power transmission lines very vulnerable to various kinds of faults. Insulation-related faults contribute reasonably to the number of faults experienced in overhead transmission lines. These faults cause outages in the network and reduce the availability of the transmission lines. Poor transmission line availability means long and frequent outages which imply that industrial and domestic consumers will have to run standby generators for longer times to sustain production and power-dependent domestic activities. The availability of the test transmission line was also evaluated over three years (2018 to 2020). Outage data obtained from TCN regional office Enugu was used for the evaluation. The performance of the proposed technique in enhancing line availability and reducing forced outage duration in the test transmission line was evaluated against the result of this characterization. Having established in the literature that insulation defect in transmission lines is characterized by the presence of partial discharge current pulse; a model of a three capacitor-based partial discharge current pulse generator was used to inject partial discharge current pulse into the test network in a controlled manner. A PMU based insulation defect detecting system was then modeled in Simulink to detect the insulation defect that will be introduced into the network. An ANN model that will make the PMU based insulation defect detection scheme intelligent was created, trained, and converted into a Simulink model. Developed models were then connected and simulated to determine the performance of the adaptive insulation defect detection system in detecting and locating insulation defects in the test transmission line. The impact of the use of an adaptive insulation defect detection system in preventing insulation-related faults and improving line availability (and reducing forced outage duration) was evaluated against the values obtained without the adaptive insulation defect detection system connected. Simulation results revealed that the proposed technique improved transmission line availability by 2.05% with respect to the network without the adaptive PMU based insulation defect detection scheme. It was concluded that an adaptive PMU based insulation defect detection scheme was effective in detecting and locating insulation defects in High Voltage transmission lines. It was also concluded that the adaptive detection scheme improved transmission line availability of the test network relative to the transmission line without the adaptive insulation defect detection scheme