Study On Voltage-Var Optimizing Real-time Control System In Local Power Grid

Under the present market economy condition, with the economic development and improvement of the living standards of the people, power quality and economic benefits have already become questions that power supply enterprises and power user have especially paid close attention to. The voltage is one of the important indexes of the power quality, power loss is an important technical and economic index of power supply enterprises, so it is the present focal point of work for power supply enterprises to improve voltage quality, decrease power loss. At present, the voltage is mainly adjusted by reactive power, there is no enough reactive power that will cause the system voltage to reduce insufficiently, the power consuming equipment can’t be fully utilized, a series of accidents of even causing the voltage to collapse etc., when there is reactive power surplus that will worsen the voltage, endanger the security of the system and equipment, too much reactive power reserved will waste unnecessary investment. Meanwhile, the power loss is reduced effectively by reactive power optimization and compensation. In a word, it is very essential to the power supply enterprises that the reactive power is optimized to guarantee voltage quality, reduce the power loss, so the research of voltage-var optimizing control system has got the extensive concern. The purpose of this paper is to study the relevant theories and technology of voltage-var optimizing real-time control system.This paper has proposed a kind of grid topological model that is of a general use to describe and record the structure of local power grid, one fast state estimate algorithm is utilized to estimate the state of the local power grid, a linear optimization model of reactive power is built and solved by prime-dual path-following method and reductive branch-bound method, and one voltage-var optimizing real-time control system is built based on supervisory control and data acquisition system (SCADA). This paper has finished the research of the following problems:1) The topological model of the local power grid: this thesis puts forward a device model for the local power grid based on the object oriented (OO), and a linked storage structure to record the topology structure of the local power grid. Meanwhile, the algorithms of changing the structure of the grid and searching the equipments of the grid are provided based on this grid topology.2) The state estimation of the local power grid:A fast method of parameter estimation is adopted based on information tree. After confirming the topological structure of the local power grid, choosing the proper information tree, the state information (voltage, active power and reactive power of both sides of the branch) are estimated layer by layer from inside to out.3) The modeling and calculation of voltage-var optimization: the model of the voltage-var optimization is built with the linear programming mode that is of a general use, and then, the linear model is solved by prime-dual path-following method and reductive branch-bound method synthetically and the feasible optimization output is got.4) The construction of voltage-var optimizing real-time control system in local power grid: in this paper, the optimization system is connected to the supervisory control and data acquisition system (SCADA) with UDP protocol (User Datagram Protocol), and then the control of voltage and reactive power in local power grid is realized by means of "four-remote" of SCADA.