: Distributed Generations (DGs) have a productive capacity of tens of kilowatts to several megawatts, which are used to produce electrical energy at close proximity to consumers, which of the types of DGs can be named solar cells and Photovoltaics (PVs), fuel cells, micro turbines, wind power plants, and etc. If such kinds of power plants are connected to the network in optimal places, they will have several positive effects on the system, such as reducing network losses, improving the voltage profile, and increasing network reliability. The lack of optimal placement of DGs in the network will increase the costs of energy production and losses in transmission lines. Therefore, it is necessary to optimize the location of such DGs in the network so that the number of DGs, installation locations, and their capacity are determined to which the maximum reduction in network losses occurs. Besides, by applying an appropriate objective function, the evolutionary algorithm can find the optimal location of renewable units with respect to the constraints of the issue. In this paper, the Genetic Algorithm (GA) and the Particle Swarm Optimization (PSO) algorithm are used to address the placement of wind and photovoltaic generators simultaneously in two states: With and without considering the effects of greenhouse gas emission. In this regard, first, an analytical method for optimal DG (wind and PV) placement is presented, then, the proposed approach is applied over a real study case, and the simulation carried out using the MATLAB program; hence, the placement problem was solved using GA and PSO and implemented in the IEEE 33-bus radial distribution system. The obtained results were compared and analyzed. The results of the simulation show the improvement of the voltage profile and the reduction of losses in the network.

Due to the growing use of Renewable Energy Sources (RES) in many countries, the need for an accurate and detailed analysis from the technical and economic view point seems to be necessary. Power Quality (PQ) can also be another considerable matter that needs to be carefully evaluated. In this regards, in this article, an analytical and detailed approach is presented to evaluate the technical and economic performance of the strategy for PQ changes. In addition, an optimization-based PQ change strategy is presented to provide a distinct PQ in integrated grids with renewable generations. The proposed strategy is based on the assessment of financial losses due to changes in the quality of power and the cost estimation of various reduction approaches and repayment solutions. This approach presents various customer requirements and various levels of PQ in the power grid. In order to evaluate the performance of the proposed method, the effectiveness of the presented model has been utilised in an actual case study, and the results have been obtained and analysed. The results of the simulation provide both technical and financial advantages to obtain optimal change strategy.