Research On Partitioning Of Secondary Voltage Control And Application Scheme Of Hierachical Voltage

Voltage stability is a vital item to research. The related researches are concentrated on the followings: voltage collapse mechanics, security index and measure to prevent voltage collapse. Hierachical voltage control is an effective method to avert voltage collapse, and the power system has a pyramidal structural, which is primary, secondary and tertiary control level. The tertiary level partitioning power system into some control areas, and do the global optimization of voltage and reactive power. The secondary level coordinates the primary control devices in various areas. The secondary level is an important segment of the hierachical voltage control level, and it is a connecting link between the proceeding and the following level. The paper researches the partitioning algorithm of the secondary voltage control. The primary level supplies the required reactive power through regulating generator uits and reactive-load compensation equipments.Automatic voltage control(AVC) which based on the hierachical voltage control is difined as follows: Through controlling of dispatching automation station, AVC perform the optimal closed loop control on the reactive-load compensation equipment of the same voltage level, so as to satisfy with the optimization of reactive flow under the security confinement and to obtain high-quality voltage and the minimum lost. Automatic voltage control(AVC) is considered as the highest stage of scheduling control development, and it can improve voltage profile and make full use of the EMS and VQC equipment. The main researches in this paper are as follows:(1) Present partitioning algorithm that based on threshold searching and dynamic scatter, the method is mainly based on the graph theory. The threshold in the voltage/var coupling matrix is searched, and the initial partition scheme is then obtained in which the areas are nearly decoupling with each other. This paper use dynamic scattering to improve and adjust the"movable node"(this paper call it critic point) which appear in the initial scheme, the stable and reasonable partitioning schemes thus are derived. This method is based on the structure of network, and eigenvalue calculation is not needed.(2) Present clustering algorithm based on principle of optimum number. Firstly, the sample point space of load is built, and the shortest distance clustering method is used to cluster the load bus. The clustering technique, such as entropy and cluster validity, is then used to derive the optimal clustering scheme and select the multiple pilot buses. This...