Research Publications (Engineering and Built Environment)
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Item Investigation of voltage unbalance in low voltage electric power distribution network under steady state mode(IEEE, 2017-11) Taiwo, Ogunboyo Patrick; Tiako, Remy; Davidson, Innocent E.; Okafor, K.C.; Atimati, E.E.; Achumba,, I.E.© 2017 IEEE. With the ever increasing use of semiconductor devices and information technology (ICT) equipment in the industry's, homes and offices voltage quality are gaining meaningful attention to both industry and the electric utility. Poor voltage quality cause unusually large economic losses all over the world, since voltage quality problem is one of the major power quality disturbances. This report provides an investigative study on the typical 11/0.4 kV, low voltage electric power distribution network. The network was modelled with standard network parameters for low voltage typical electric power distribution network using MATLAB/Simulink Sim Power System tool box. Results obtained from simulation with distribution feeder length 0.5 km for unbalanced 3-phase loads are within the acceptable nominal voltage tolerance range of ± 5 % of the nominal voltage value at the customer's terminal. While this is admissible for customers close to the infeed terminal, it was established that an inadmissible poor voltage reaches the customers at the end of the distribution network for network lengths 0.8 km to 5 km. Voltages measured here were less than the standard allowable limit of 0.95 p.u, of nominal voltage value. The summary of the paper gives recommendations on effective methods for enhancing voltage profile and correcting the unbalanced voltage to an allowable standard.Item Effectiveness of dynamic voltage restorer in enhancing voltage profile in low voltage electric power distribution networks under normal mode operation(IEEE, 2017-11) Taiwo, Ogunboyo Patrick; Tiako, Remy; Davidson, Innocent E.; Okafor, K.C.; Atimati, E.E.; Achumba, I.E.© 2017 IEEE. This work addresses the compensation of power quality disturbance in electric power distribution network as a result of voltage variation and voltage unbalanced using one of the most effective power electronics based custom power controller known as Dynamic Voltage Restorer (DVR). DVR usually connected between the source voltage and the customer load. The new setup of DVR has been put forward using dqo controller and proportional integral (PI) controller method. The simulations are achieved using MATLAB/Simulink Sim Power System tool box. The simulation results attest to the effectiveness of the proposed DVR configuration in compensating the power quality problems in secondary distribution system. The simulation results runs are presented with different settings of parameter used in the model in order to help the validity of the function of DVR in enhancing the quality of power supply at customer side.Item Voltage profile enhancement in low voltage 11/0.4 kV electric power distribution network using dynamic voltage restorer under three phase balance load(IEEE, 2017-09) Taiwo, Ogunboyo Patrick; Tiako, Remy; Davidson, Innocent E.; Cornish, D.R.With the global trend of restructuring in electricity market, providing affordable, reliable and quality electric power by service providers to customers the end users of electric energy are of immerse concern. Several initiatives have been taken by utilities to improve power quality in low voltage electric power distribution network but the inadequate operation/performance of the conventional compensation devices to mitigate the poor power quality problems have prompted the use of custom power device such as the dynamic voltage restorer (DVR). Dynamic voltage restorer (DVR) is an advanced power electronics based compensation device which is series connected to the distribution network through boosting transformers. DVR aimed at improving the voltage profile, enhancing the reliability and good quality of power flows in low voltage electric power distribution networks. The DVR is a highly efficient device, the principle is based on the voltage source inverter (VSI) which injects the appropriate missing voltage in series with the system voltage to correct the voltage variations experienced in the distribution feeder lengths. The dependability, robustness and effectiveness of the DVR control and power scheme in respect of the response to voltage disturbances at normal mode operation of three phase balanced loads is presented using the MATLAB simulation results carried out in Power System Sim Tool box. The balance of the paper gives recommendations on effective methods for improving the voltage profile and reducing the voltage variation to an allowable standard.