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In the event of a direct lightning strike to a protected building which is integrated with an electrical or electronic system installed on the roof such as roof-top PV system, dangerous arcing may occur between the external lightning protection system (LPS) and the conductive components of the electrical system. To prevent such side flashes, a minimum separation distance between the metallic components and the air termination system is required. Even though, IEC62305-3 Standard provides a formula to specify the necessary separation distance, so far there is no extensive study that has been done to evaluate the suitability of the application of equation to calculate the separation distance, specifically to the safety of electrical systems integrated into the roof top of building. In this study, a new computational method has been developed for calculation of the separation distance between an LPS and metallic components on the roof. In the proposed method which is based on the theoretical background of the IEC62305-3 Standard formula, the break down behavior of the gap geometry between the LPS and the metallic components for the applied voltage across the gap is analyzed. PSCAD software was used to model the LPS and the lightning strokes.

In an event of direct lightning strike to a protected building which is integrated with an electrical or electronic system installed on the roof such as roof-top PV system,dangerous sparking may occur between external lightning protection system (LPS) and conductive components of the electrical system. To prevent such side flashes, a minimum separation distance between the metallic components and air termination system is required. Even though, IEC62305-3 Standard provides a formula to specify the necessary separation distance, so far there is no extensive study that has been done to evaluate the suitability of the application of equation to calculate the separation distance,specifically to the safety of electrical systems integrated into the roof top of building. In this study, a new computational method has been developed for calculation of the separation distance between an LPS and metallic components on the roof. In the proposed method which is based on the theoretical background of the IEC62305-3 Standard formula, the break down behavior of the gap geometry between the LPS and metallic components for the applied voltage across the gap is analyzed. PSCAD software was used to model the LPS and the lightning strokes. Separation distance has been computed considering the voltage-time area of the induced voltage across the gap as rectangle, triangle and trapezium and the results have been compared with the one considering the voltage-time area of the real voltage wave shape. It has been observed that calculated result for separation distance considering the real voltage wave shape is lower than the results for assumed voltage wave shapes. Finally, the value of separation distance which is obtained by the proposed method has been compared to the value obtained by IEC62305-3 Standard formula. The comparison indicates almost 20% difference between the values of separation distances calculated by the proposed method and IEC62305-3 standard formula, whereas the proposed

In this paper a new evolutionary computing method based on imperialist competitive algorithm (ICA) is used for optimization of the reactive power in a wind farm. The output power and also the reactive power of wind farms are not constant due to the oscillation in wind speed. Reactive power optimization is known as an efficient way to have an improvement in power quality and also to reduce power loss. The conventional optimization algorithms have some drawbacks, such as slow convergence and premature. ICA as one of the newest optimization algorithm could be applied in order to optimization of the reactive power and overcomes the difficulties which are coming from the traditional methods. In this paper, the reactive power consumption of a wind turbine is optimized by using (ICA) method. To illustrate the application of the method, a wind farm with some uncertainties is provided. Finally the results of the ICA method are compared with the one of conventional method. Results show that the proposed reactive power optimization method is simple and effective.

In this paper a hybrid Genetic-Tabu Search Algorithm (GT) is used for tuning the elements of a PID controller which is applied in a Multi Area Load Frequency Control System (MA-LFC). If a large power imbalance is suddenly happened in a multi area power electric system, generation units and also consumer sides will be affected by the distortion in the energy balance between both two sides. This inequality is firstly handled by the kinetic energy of the system turning components, but, eventually, the frequency will change. Therefore, LFC is considered as one of the most challenging issues in power system control and operation. PID type controllers are conventional solutions for MA-LFC. The three parameters of the PID controllers have been adjusted traditionally. In this paper, a PID controller is applied for the MA-LFC problem and then its parts are modified by using GT method. To validate the application of the technique, a multi area network with some uncertainties is provided. Finally the results of the GT-PID controller are compared with the ones of GA optimized controllers. The simulation results show the success and the validity of the GT-PID controller in compare with the GA - PID controller.