The ever-increasing renewable sources and advances in electric vehicle (EV) technology have persuaded many researchers to conduct various studies on power system design and operation in the areas of renewable energy and EV industries. Furthermore, pollution and environmental concerns have drawn the attention of the world community to the use of EV and wind renewable sources. In the present study, the optimal location and sizing of EV charging stations are determined in the distribution network and urban transportation network in the presence of wind resources with stochastic generation. By simultaneously considering the distribution and transportation networks, a bi-objective optimization problem is formulated. The EV trip success rate on daily basis is considered as an objective function of the problem and network costs as another objective function. The constraints of the urban network include traffic volume, path length, land price, and transportation network limitations, while distribution network constraints include losses, voltage/current constraints, and maximum loading capacity. The simulation results of the sample distribution and transportation networks based on the bi-objective genetic algorithm and MATLAB software confirm the correctness of the proposed method.

Insulation coordination studies are of great importance in power grid reliability. In this paper, a new method is proposed for modeling trapped charge sources (TCS) in switching transient studies. The TCS is used to take account of the voltage stored in line capacitors during reclosing operation after fault occurrence. The proposed model is designed based on the active filter concept, so it does not have the limitations of conventional TCS for simulating transient states in EMTP/ATPDraw. Given the natural frequencies of the transmission line to which the proposed TCS (PTCS) is connected, the PTCS injects the appropriate frequencies and eliminates voltage oscillations, which limit the use of TCS. To verify the efficiency of the PTCS, it is implemented in a real system with a shunt reactor, and the results are then compared with field measurements. A comparison of the results shows that the PTCS eliminates the voltage oscillations in the simulation before closing and provides a smooth voltage with the desired amplitude. Using the proposed model, the maximum line switching overvoltage is correctly calculated; this, in turn, results in a more accurate transmission line insulation design, which is technically and economically beneficial.