The Control Strategy For Optimization Of Voltage And Reactive Power In Substation

The reactive power optimization in power system is one of the most important means to improve the voltage quality, reduce net loss, and ensure security, stability and economic operation of system.Based on the in-depth understanding of status of reactive power optimization of voltage in power system, this paper analyzes the regulation theory and control strategy in the substation reactive power optimization of voltage, especially the widely used "nine-area map" control strategy. In the nine-area map, the sequence of regulation in means of changing the transformer tap and switching capacitor has a great influence on the control effects. It will produce the regional oscillation phenomenon if coordinate improperly. In the conditions of more heated load change, it will make over operation of equipments so as to reducing their useful life, even if no outbreak of the regional oscillation phenomenon.Based on the principle of nine-area map and from the load forecast, this paper studies control strategy in the substation reactive power optimization of voltage. According to the history data of substation load, artificial neural network technology is selected to forecast short-term load in substations. Sub-program is formulated by the principles of volume changes on the power of the next 24 hours based on the assumption of that the law of the next load with a daily repeat. And then sub-program is formulated according to the discrete minimum principle finally. According to the time as an option in the typical load transformer tap position and the number of capacitor banks, the sequence of equipment movement is changed in order to prevent the occurrence of oscillation loop. With the period of maximum load and minimum load, the correctness of sub-program is tested. In the device pre-program implementation process, the original proposal is turned or developed the new programs.The application of 35kV distribution system in the region of Hohhot demonstrates that substation reactive power optimization control strategy based on load forecasting can improve the quality of power supply and the power factor of transformer substation on the high-voltage side. It can also reduce the number of transformer tap movement, with better social and economic benefits.