مرکز منطقه ای اطلاع رساني علوم و فناوري - An Optimum Design Strategy for Substation Earthing System with Considering Seasonal Variation of Earth Resistivity via Faure Sequenced Genetic Algorithms

Abstract :

The grounding substation system shall guarantee the safety for the living beings in case of a grounding fault in the power system in all seasons. It should ensure the safe, reliable and stability operation of power system. The optimal design of the grounding system is based on the actual soil models. On the other hand, the soil resistivity and soil model vary in rainy, frozen or dry seasons. The soil layer having low or high resistivity, which is formed in those situations, effects the safety performance of the grounding system. As long as the soil resistivity changes, the soil model as well as the step and touch voltages on the soil surface, the grounding resistance of grounding system and hence, the GPR changes. Thus, related to seasonal changes, the grounding system originally designed to provide the safety might itself become a hazard for the living beings and the power system safety. Therefore, the effects of seasonal factors must be taken into consideration as well as the safety conditions in the design of grounding grid. In this paper, grounding grid by considering the seasonal affects is designed. The design is performed via Genetic Algorithms using the Faure sequence as the initial population. The seasonal affects are studied systematically in the safety of grounding system. In this design, we obtained the safety and cost-effectiveness criteria related to the seasonal factors.