Transmission expansion planning (TEP) refers to specifying the place, time, and number of new transmission lines that should be established, so that given the network available, one can fulfill the potential demand of the power system in the future in terms of both operation and economic aspects (given the system constraints). Nevertheless, TEP is intrinsically a large-scale, mixed integer, nonlinear, and non-convex problem, which basically has several local optima. Solving this problem is very difficult and its computation is very time-consuming. To solve such a problem, a powerful optimization method is needed. In this paper, to solve the TEP problem, a new optimization algorithm called bacterial foraging optimization algorithm (BFOA) has been used. The proposed method has been studied on a 6-bus network for different scenarios, with the results indicating efficiency of BFOA. Manuscript profile

Today, reduction of losses and operational costs is considered an important issue in power systems. Demand response program causes diminished consumption during peak hours and thus increased reliability and reduced costs. Reconfiguration of distribution networks are among the practical methods in reducing losses and costs as well as improving the voltage profile. In this paper, the reconfiguration of distribution networks is performed considering demand response potential and in the presence of distribution generated (DG) sources using a new optimization algorithm called mine blast optimization algorithm (MBA). For this purpose, reducing losses, improving voltage profile, and lowering operational costs of the network are also taken into account as objective function. The proposed method is applied on 33-bus radial network. Simulation has been performed using MATLAB software. Manuscript profile

Strike of lightnings with sea, due to the high conductivity of salty water creates more extreme electromagnetic fields in comparison with lightnings in land. This paper deals with analysis and simulation of electromagnetic fields resulting from lightning in the proximity of a watercraft in sea and its effect on the equipment on the watercraft. The magnitude of electric and magnetic fields is first calculated using Uman integral equations to calculate the electric field resulting from a limited current channel on a perfect conductor. To solve the field integrals, dual precision exponential model was used for the lightning’s current. Due to limitations of the solution of field integrals, parametric analysis is difficult. For this reason, the lightning channel and watercraft model was simulated in Maxwell software and the obtained fields were compared with the results of integral solution. Considering the closeness of integral and simulation results, with alteration of the peak lightning current and its distance off the watercraft, the field sensitivity to these variables was measured and the results of parametric analysis have been presented for different parts of the watercraft. Manuscript profile

This paper deals with modeling and investigating transient overvoltage resulting from lightning in medium voltage grid and transferring it to low-voltage grid inside watercraft during berthing and connection of the grid in the coast. Lightning wave transfer through distribution transformer has been considered taking high-frequency model of transformer into account for passage of impulse wave. The effect of high-frequency model obtained from the transformer has been compared and validated using capacitive π model using previous measurements. The effect of different quantities of the system for connecting coast power to the watercraft including length of the connection cable, the loads on the watercraft network, type of loads, and effect of transformers’ secondary on the watercraft was examined on the level of transient overvoltage on low-voltage loads. Determining the primary and secondary overvoltage levels of transformers allows for specifying the protective level of arrestors for insulator protection coordination. This protective level, which has been obtained from IEEE lightning arrestor selection guideline, has been employed to determine the suitable values of the lightning arrestor for coast to watercraft power connection system. Manuscript profile