Study On Electro-Thermal Coordination Optimal Dispatching Aiming At Intermittent Energy Accommodation

Bonding with electro-thermal coupling law, the power system optimal dispatching based on electro-thermal coordination theory (ETC) synthesizes transmission line’s dynamic heat balance equation with grid’s power flow equation. This dispatching way measures transmission capacity directly by transmission line’s temperature, which utilizes thermal inertia effectively. Thus, transmission capacity and result of dispatching-decision are improved, making grids accommodate intermittent energy furthest, showing both theoretical and engineering prospect. But now the dispatching model doesn’t take transmission line’s dynamic environmental condition into consideration, which limits foresight of dispatching and goes against system’s security. Above all, further study on ETC optimal dispatching was carried out which aims at intermittent energy accommodation.Firstly, this dissertation analyzed transmission line’s heat exchange process during dispatching operation and expounds calculation methods of parameters in heat balance equation according to IEEE standards. And then calculation methods of transmission line’s ampacity was discussed by example of LGJ400/35 line. The influences of environmental temperature, sunlight intensity, wind speed, wind direction on transmission line’s ampacity were detailed analyzed.Secondly, this dissertation proposed a method of transmission line’s environmental meteorological short-term forecasting based on support vector machine (SVM). On the basis of principle of SVM was studied, the methods of meteorological data acquisition and the forecasting model’s parameter selection were offered. After using the sample data to construct the prediction model, the wind speed, sunlight intensity and wind direction in the future time were forecasted and the forecasting accuracy was analyzed. The conclusion indicates that the accuracy of wind speed, sunlight intensity and wind direction forecasting by SVM can meet the needs of engineering calculation and be used in following research of electro-thermal coordination advanced dispatching simulation.Finally, basing on electro-thermal coupling law, aiming at intermittent energy accommodation capability of power grid, combining transmission line’s environmental meteorological forecasting, the environmental meteorological parameters that does not change with time in traditional electro-thermal coordination advanced dispatching model are revised. Using a 4-node power system with intermittent energy generator as object, interior point method was utilized for verifying simulation results of advanced dispatching modified model in different weather conditions and intermittent energy outputs. The results were compared with the one of traditional model. The conclusion indicates that by forecasting the transmission line’s environmental meteorological conditions, the ETC advanced dispatching modified model proposed in this dissertation can further improve intermittent energy accommodation capability of power grid safely and reliably.