The Research On Voltage And Reactive Power Optimized Control In Distributed Power System

In voltage-reactive power optimization, with the pursuit of the minimization of system losses and higher electric power quality, the restrict of the equipment operations number during a specific time period is often not considered, so some equipment may be operated frequently and the number of operated equipment in each optimization can be quite high. The equipment duration and system operation quality are not comprehensively optimized in this manner.In this paper, a new voltage-reactive power optimization method, which considers the equipment operational cost and confines the number of operated equipment in each optimization, is introduced. The system losses, endurance of equipment and operated times could be calculated optimally and comprehensively.By the result of load forecasting, the pre-optimization is made for a whole day (e.g. 24 time-points, i.e. 24 optimizations) in conventional voltage-reactive power optimization method . In the pre-optimization, not only the number of equipment operation at one point of time but also the number of operations during a whole day can be calculated. So in real-time control, inertia factors are introduced when equipment are operated too frequenctly within a whole day. With the utilization of such factors, the number of operations can be reasonably distributed among the whole day, and the violation of operating limits can be avoided.Furthermore, the hybrid optimal strategy is introduced and improved: introducing sensitivity to guide the searching course, in order to reduce the blindness of search; coding based on range of value corresponding equipment operation, to avoid invalid search; adopting variable cross over and mutation rate, to adapt it to the requirement of the searching progress; making dynamic variation of searching population, to ensure the optimization quality while accelerate the searching course; adopting the membership degree of fuzzy logic to objective function, to take into account the load status and to realize the counter voltage adjustment.The proposed algorithm has been used in real-time control of voltage-reactive power in a regional power network system and are of high practicability, good adaptability and fast speed.