Performance Enhancement of Grid-Connected Distribution Networks with Maximum Penetration of Optimally Allocated Distributed Generation Under Annual Load Variation

The integration of distributed generations (DGs) to the distribution networks is increasing day by day to reduce the pressure of rising load demand. The excessive penetration of the DGs at improper locations leads to performance deterioration in terms of higher losses, over-voltages, poor voltage stability and changes in fault levels. Thus, in this paper, the DGs' optimal location, size and power factor, capable of satisfying maximum load demand, are obtained in distribution networks using performance indices related to power loss, voltage stability, short-circuit current deviation and substation power intake. The optimisation is performed using particle swarm optimization and chaotic particle swarm optimisation algorithms considering the voltage and current constraints. A new voltage stability index that remains unaffected by radial or mesh flow of current in the network is proposed to quantify the voltage stability of the system. The short-circuit current deviation index is formulated to decrease the deviations in fault level, so the existing protective devices, with minimum or no changes in their settings, protect the system having DGs. The minimisation of the substation power index causes an increase in penetration of the DGs. The optimal power factor of the DGs gives better loss reduction. The proposed methodology is also applied to obtain optimal penetration of the DGs at their optimal locations for each hour of 96-h load profile representing the load curve of four seasons of a year. The methodology is tested on 33-node and 69-node distribution systems in both radial and mesh configurations.