Optimal Capacitor Placement In Radial Distribution System Based On Simulated Annealing With Memory

The line loss ratio of transmission and distribution system in our country has maintained a high value over a long period of time, and distribution system has played an important role in it. Placing facilities for reactive power compensation can reduce network loss effectively as well as improve transmission capacity and regulate voltage profile. This dissertation works over the problem of optimal capacitor placement, which is to determine the number, locations, types and sizes of capacitors to be installed in a radial distribution system, and the control schemes of the capacitor at different load levels so as to minimize the energy cost plus the cost of capacitors installed in the system while the load constraints and operational constraints at different load levels are satisfied. Based on the summarizatin of previous work, this dissertation sets up a practical mathematic model and presents a improved simulated annealing with memory, which can achieve better solution than traditional simulated annealing.The characters of distribution system, the necessity and the content of research of optimal capacitor placement in distribution system is introduced and the background of this thesis at home and abroad is summarized in first chapter.In chapter two, the theory and superiority of reactive power compensation is analyzed and a practical mathematic model of optimal capacitor placement is set up.In chapter three, a back/forward sweeps based on branch loss for power flow is presents, which is credited with simple program, good numerical value stability, small EMS memory and rapid calculation.The conception of network loss sensitivity and is introduced in chapter four, which provides theoretical reference to reduce calculation amount for simulated annealing. How to achieve network loss sensitivity is also included in this chapter.In chapter five, the fundamental theory of simulated annealing is introduced andits improved algorithm--simulated annealing with memory is presents fordrawback of conditional algorithm.In chapter six, simulated annealing with memory is applied to the problem of optimal capacitor placement successfully. Improve algorithm is tested in IEEE 69 bus and IEEE 33 bus system and achieved satisfied solution. Furthermore, compared with conditional simulated annealing, improved algorithm can win better solution.