Power Loss Minimization of Distribution Network using Different Grid Strategies

Power losses in electrical power systems especially, distribution systems, occur due to several environmental and technical factors. Transmission & Distribution line losses are normally 17% and 50% respectively. These losses are due to the inappropriate size of the conductor, long distribution lines, low power factor, overloading of lines etc. The power losses cause economic loss and reduce the system's reliability. The reliability of electrical power systems can be improved by decreasing network power loss and by improving the voltage profile. In radial distribution systems, power loss can also be minimized through Distributed Generation (DG) system placement. In this thesis, three different grid strategies including real power sharing, reactive power injection and transformer tap changing are discussed and used to minimize line losses. These three proposed grid strategies have been implemented using a power flow study based on Newton-Raphson (NR) and Genetic Algorithm (GA). To minimize line losses, both methods have been used for each grid strategy. The used test system in this research work is the IEEE-30 bus radial distribution system. Results obtained after simulation of each grid strategy using NR and GA shows that real load sharing is reliable with respect to minimization of line loss as compared to reactive power injection and transformer tap changing grid strategy. Comparative analysis has been performed between GA and NR for each grid strategy, results show that Genetic Algorithm is more reliable and efficient for loss minimization as compared to Newton-Raphson. In the base case for optimum power flow solution using genetic algorithm and Newton-Raphson, real line losses are 9.481475MW and 17.557MW respectively. So, GA is preferable for each proposed grid strategy to minimize line losses than NR.