Optimal load management in a low power off-grid wind-photovoltaic microhybrid system

The most significant problem is to balance between generation and consumption in power systems ranging from small to large scales. This may be done by daily load scheduling in small-scale systems using metaheuristic optimization techniques such as the GA, the PSO and the SA etc. In the case of an off-grid low power wind-photovoltaic hybrid system, it is expected to power the loads without shedding and this may require scheduling loads on the basis of power balance, continuously energizing loads and low operation cost as much as possible at each interval of in a day. The fact is that it is a complex optimization problem with several constraints and this problem should be solved 24 times for an hour time interval. Due to incapability of deterministic techniques the GA or similar techniques may be the best approach to solve this problem for optimal power management. The construction of objective function is considered to reduce operation cost and use stored energy in the micropower system consisting of a 1 kW wind turbine, 8 photovoltaic panels, a diesel generator and 4 gel batteries. The problem under consideration is solved by the GA for an hour time interval during a day. The results indicated that the balance between generation and consumption can mostly be maintained and operation cost and energy efficiency are improved with respect to an unscheduled case.