AN INVESTIGATION INTO POWER QUALITY-BASED REINFORCEMENTS AND COSTS FOR SELECTED ELECTRICITY DISTRIBUTION NETWORKS

Abstract

The study aims to provide adequate power quality-based reinforcements for typical electricity distribution networks with the proliferation of non-linear loads and to determine its cost implication to the utility and the electricity users. In this study, a simulation approach was used in the analysis and reinforcements of IEEE 33-bus and Ajilosun 43-bus feeder networks using NEPLAN software. The load flow and harmonic flow module of NEPLAN software was used to investigate the voltage profile and harmonic distortion levels in the distribution networks. The results obtained showed that 81% and 86% of the 11 kV buses of the IEEE 33-Bus and Ajilosun 43-Bus distribution networks respectively violated the specified ± 5% voltage deviation limit while 53% and 79% of the 11 kV buses of the IEEE 33-Bus and Ajilosun 43-Bus distribution networks respectively violated the specified 5% harmonic distortion limits specified in the IEEE 519 standard. Hybrid optimization techniques that combine the Genetic Algorithm (GA) and Direct Search method were used in the sizing and location of capacitor bank and passive harmonic filters to achieve optimal values for the voltage profile and voltage Total Harmonic Distortion THDV level at the load buses. The obtained results showed that the voltage profile of the 11 kV load buses improved significantly to the range of 10.69 kV (97.19%) to 11.43 kV (103.88%) and 10.64 kV (96.73%) to 11.03 kV (100.27%) for the IEEE 33-bus 43-bus and Ajilosun 43-bus distribution network feeders respectively. The THDV propagation on the 11 kV network was reduced to the range of 2.13% to 3.18% for the IEEE 33-Bus network and 2.99% to 4.46% for Ajilosun 43-Bus feeder network. The investment cost analysis for the implementation of these reinforcements was estimated to determine the economic feasibility of the reinforcements’ investment. The estimated cost of reinforcements based on different reinforcement investment cost options was in the range of 35.19 million Naira to 53.81 million Naira and 48 million Naira to 138.81 million Naira for the IEEE 33-Bus and Ajilosun 43-Bus distribution networks respectively. A reinforcement billing charge of up to ₦20/kWh of energy consumption resulted in a payback period of within two years for the different reinforcement investment cost options for the IEEE 33-bus and Ajilosun 43-bus distribution networks. The study showed that the investment in power quality-based reinforcements of the distribution networks achieved good quality operating parameters and the costs recoverable within two years based on selected tariff on energy consumption.