Voltage/Reactive Power Control In The Substation Based On Load Forecasting And Adaptive Ant Colony Optimization

One basic condition to guarantee the voltage quality is that the voltage at the user end near the rated value and the reactive power balance on the spot. As an important component of the power system, the substation always dispatch the shunt capacitors and on-load tap changers to regulate the voltage and the reactive power, thus can increase the qualified rate of the voltage, reduce the reactive power loss and make the power grids not only satisfy the power supply quality but also operate economically. So voltage and reactive power control in the substation is of great significance.Voltage/reactive power control in the substation based on load forecasting and AACA (adaptive ant colony algorithm) is proposed in this paper, which is to determine one-day 24 hours'optimal control schedule of the on-load tap of the transformer and switch condition of the shunt capacitors on. Firstly, a model which adopts short term load forecasting based on combined use of FCM clustering and support vector regression is built. Hourly loads of a main transformer and its primary bus voltage are forecasted in a day. Then mathematical model of substation reactive power/voltage control is constructed. With the consideration of secondary voltage, reactive power and daily switching times of capacitors and taps, an objective function with penalty factor is adopted and the optimal control schedule of voltage and reactive power control in a substation is reached by using AACA. Because of forecasting reactive load at first, the trend of reactive power can be known in advance, thus blindly and deficient adjusting can be avoided. The calculation of the example indicates that the proposed strategy is more effective than general methods, and it can improve the security and economy of power system operation.Because of the influence of unexpected incidents, the load forecasting may be inaccurate, the global optimization strategy should be abandoned. In allusion to this problem, reactive power/voltage real-time control based on AACA is proposed in this paper. Real-time adjustment can be carried out hourly using this strategy, thus can assure the real-time voltage, reactive power and the adjustment times of transformer tap and capacitors synthetically optimal. The simulation result shows that this strategy has good real-time regulating ability.This paper makes voltage/reactive power control simulation of Balitai and Limindao step-down substation which have 220kV three winding transformers. The voltage of low side has been treated as main control object, and at the same time the balance of reactive power and the voltage qualification of middle side has been considered in three winding transformer step-down stations. Large amount of simulations show that the satisfaction degree of voltage and reactive power has been greatly improved which is far better than former locale manual regulation. In order to assure the reactive power balance on the spot and avoid reactive power over compensation phenomenon as possible as we can, the shunt capacitor bank's configuration of Limindao substation is discussed in this paper.