Research Of Reactive Power Optimization & Control In The Distribution Network

The distribution network is located at the end of the electric power network with general features such as scattered load, great power fluctuation, long power supply radius, low power factor and inadequacte reactive power, in which the power loss and voltage loss are great. For the reactive power optimization, the voltage quality of the loads will be promoted, and the power loss decreased, and the economy benefits of the power supply companies increased. This thesis mainly focuses on the algorithms of the reactive power optimization in the distribution network, and software is developed based on the algorithms, and control modes are studied. The main contents are as follows:1. The contents and characteristics of the reactive power optimization are analyzed. A mathematical model with minimized power loss and good voltage profiles is adopted. The present algorithms, software and control modes are analyzed and summarized.2. In order to improve the global convergence and individual diversity, the niche technology is introduced into the genetic algorithm (niche genetic algorithm, NGA). NGA is used in the reactive power optimization. Aimed to the characteristics of the reactive power in the distribution network, some improvements have made in coding, ending criteria and distance criteria of individuals. IEEE 30 system and other systems are employed to test the algorithm. The result shows that the improved NGA has good performance in maintaining the diversity of the individuals, improving the searching efficiency and having good optimization result.3. Software is developed for the reactive power optimization in the distribution network. The system can manage the high, medium, low voltage distribution network unified, and realize the systematic integration of voltage and reactive power analysis, reactive power programming, reactive power control and reports with high integration and performance. The system has been used in two real networks, which shows its perfect functions and strong practicability.4. A tertiary distributed voltage & Q control mode adapted to the distribution network is provided. Using the improved NGA, four-remote controls in dispatching automation, and VQC developed in technic, the voltage and reactive power can be controlled in the whole distribution network, and the comprehensive target of good voltage profiles and minimized power loss can be realized by this mode.