A Quadratic Objective Function Model And Algorithm Of Voltage Reactive Power Control

The voltage/var control of power system can efficiently minimize the real power losses and improve voltage profiles, so that the yearly running charge will be reduced and the quality of power energy can be increased. As a result, it is in great necessity for us to study the scheme of voltage/var control. The study is very important for the economic operation and the reliability of electric power system.This paper synthetically analyzes the status and the problems exist in voltage/var control field. The traditional mathematical model and algorithm are discussed and their characters are analyzed. The traditional voltage/var control mainly bring into effect by nine-area diagram, which is implemented by the reactive equipment of the transformer substation. The objective function is the local voltage optimization. They don't consider the influence of the local reactive power modification to the voltage of the other nodes in the electric network. It doesn't make full use of the equipment to accomplish the synthetical optimization control. According to the characteristics and problem of voltage/var control, a new wide-area voltage/var control algorithm is proposed in this paper. The new method based on the initial power flow of the electric network. The influence each other of the different nodes during the reactive power modification are considered in the new algorithm. Based on the mathematic relationship of the nodal impedance matrix and the nodal voltage .. nodal current, the mathematic relationship between the control variable and the status variable is presented. At the same time ,the quadratic function Expression formula of the voltage restriction is presented. And the quadratic function mathematic model is given. The objective function is the minimization of the network loss in the whole electric network. A new control scheme is proposed. And the implement flow of the algorithm is introduced in detail. The process to realize the new algorithm with MATLAB is presented in detail.At the end of this dissertation, the proposed mathematical model and algorithm are applied to a 5-bus system and the IEEE 30-bus system. The results are satisfactory. Compared with traditional voltage/var control algorithm, the correctness and efficiency of the proposed method are confirmed by the numerical simulations. This, control approach is a advanced way and it is worth to study more and utilize.