Strategy Of Voltage And Reactive Power Control On Global Optimization Control

With the development of economy and the improvement of people's living quality, the need of power supply is increasing quickly, as well as there is high requirement to the reliability and quality of power supply. Distribution network is an important part of power system directly facing consumers. Reactive power optimizing problem takes a super important role in protecting the secure operation of network and power supply.The electric quality is mainly reflected by the voltage, the power loss is technical and economic index of electric utility. The voltage quality had important influence to safe and economy of electric power system. To increase voltage qualified rate and decrease power network loss is the aim of global optimization control system of voltage and reactive power in regional power grid. It optimizes regional power grid, and achieves some special plans to regulate transformer tap changers and to put in-out parallel compensation capacitors.In this paper the complexity of voltage control in power system is discussed through the analysis of relationship between power system balanced states of voltage and reactive power. A mathematical modal is established by means of the theory of reactive power/voltage control in a substation. It proposed a new control strategy combination control strategy because of the research of disadvantages resulting from the traditional nine-zone diagram methods.Nine-zone theory is optimization of reactive power control strategy which takes the operating point whether is located the superior control area as the start control criterion; five-zone theory is one kind regulative strategy based on the movement effect, which adopts the criterion of operation quality distance and faces the voltage and reactive power control (VQC) installment; In view of the boundary blind area of five-zone theory lacks the explicit movement criterion, we introduce the criterion of put in-out capacitors.The discrete reactive power optimization algorithm of the entire power network is performed in main station system to minimize active power loss and keep bus voltage within allowable range according to 24 time segment data of the next day's active and reactive power of the low-voltage side of each substation and status information of switches. Based on these optimization results, the control setting values of voltage and reactive power subsystem in each substation can be obtained.According to the most superior limiting value curve designed, we judges each substation the operating point region and start up limits of reactive power and voltage based on nine-zone theory in the entire net transformer substation. The substations over limits were adjusted using VQC device by five-zone theory. We can not only reduce the operation of control variable, but also make sure the voltage quality and optimal power flow the whole network.