The demand of electricity is soaring rapidly. Distributed genera-tion (DG) is one of the most suitable alternatives to fulfill this swellingdemand of energy. DG is a small scale generation which is directly in-stalled in the distribution network or at load centre. Optimal allocationof DG is a vital factor in improving the voltage profile of the system andin reduction of total power losses. In this article, a detailed study of threedifferent methods for DG allocation and sizing has been discussed. Thefirst method is based on Newton Raphson load flow based technique todeduce the optimal location of DG in two different IEEE bus systems inMATLAB software. The next methodology is based on particle swarmoptimization (PSO) technique where a multi-objective function is beingminimized. The objective function has been modified and PSO has beenimplemented to attain optimal size and location of DG unit. The thirdmethod considered is based on human opinion dynamics evolution-ary multi-objective optimization technique which is used to obtain thebest possible size and location of DG unit in IEEE 14 and IEEE 30 bussystems. The human opinion dynamics method shows superiority inminimizing the size and location muti-objective function, over the othermethods considered herein.