Centralized Volt/Var Control In Distribution Network Based On Fuzzy Theory & Expert System

Voltage and reactive power (volt/var) control is an important issue related to voltage stability, voltage quality and economical operation of power systems. Volt/var control problem is a typical non-linear problem with discrete variable, multi-constraints, and it's usually affected by the features of interaction and dynamic of power system. Hence, the volt/var control problem hasn't got satisfied resolutions for a long time. A centralized volt/var control method based on strategies is proposed in thesis to meet the practical demands of regional network.The thesis makes a brief overview of the history and current status of the research on volt/var control and points out the disadvantages of the traditional methods. With the improvement of the automation of power system and the development of the reform of power market, it's possible and necessary to perform the centralized volt/var control of regional network.The principles, architectures and features of the fuzzy control theory and expert system are discussed in detail. The combination of the two artificial methods is introduced, which can reserve the ability of dealing with uncertainty as well as can make full use of the synthetical decision-making capacity. The design progress of the volt/var control system based on fuzzy theory and expert system in a substation is dissertated as an example, and its control effects are verified by simulation. The volt/var control method based on fuzzy theory and expert system is extended to regional network. The control system is consisted of volt/var fuzzy control module and volt/var expert system decision-making module. In the method, Volt/var optimal mathematical computation of the regional network isn't adopted. Instead, each substation is regulated by matching rules in fuzzy control module and expert system decision-making module to achieve the volt/var control goals of the whole network. The principle, control progress and rule base are discussed particularly, and the control effects is compared with the effects of traditional methods.The functional requirements and technical qualifications of system software are proposed, and the general flow is expatiated, and part of the software is programmed.