Optimal Reserve Modelling In Regional Interconnected Power System

With the rapid development of economy in China, the electric load goes upquickly, and the installed capacity is relatively insufficient. As a result, theshortage of electric power, which is occured all over the country, restrictseconomic development and leads to great loss and negative society effect. Onthe other hand, stable operation of the regional interconnected power system isinfluenced by inadequate reserve capacity. Therefore, it is necessary to keepenough and reasonable reserve capacity in regional interconnected powersystem.This thesis analyses reserve capacity of power system in some conditions. Anovel model called optimal reserve capacity (ORC) is presented, which consists ofminimum reserve capacity of the interconnected regional power system meeting theoperating constraints. The optimal reserve capacity comprises instant reserve, tenminutes spinning reserve and ten minutes non-spinning reserve.This thesis places emphasis on derivative real power increment equation of thetie lines and derivative the connected expression between offset frequency andoptimal reserve capacity.According to the complex characteristics of the problem, the adaptive immunegenetic algorithm (AIGA) is used to calculate the optimal reserve capacity, takinginto sufficient account offset frequency, load fluctuation and security reliabilityconstraints of the regional interconnected power system. The proposed method hasbeen validated on three independent power systems and a regional interconnected power system via AC and DC tie lines. The results of simulation can obtain flexibleoptimal reserve capacity in per hour of a day.The results of three independent power systems show that with thedevelopment of installed capacity, and scale of transmission and distribution ofpower system, the optimal reserve capacity occupying the biggest load ratioreduces gradually by 0.395%～9.366%.The results of regional interconnected power system show that when theregional power systems are interconnected, the optimal reserve capacity canreduce to some extent. The reserve capacity of regional interconnected powersystem can reduce by 1.034%～1.858% compared to each independent powersystem reserve capacity. It is helpful to save the cost and improve the operationeconomy of regional interconnected power system to a certain extent. Alongwith the sudden increment of load in the regional interconnected power system,the optimal reserve capacity is increasing, but the increase rate is small. Inother words, sudden increment of load in the regional interconnected powersystem causes the minimum reserve capacity to be decreased, the maximumreserve capacity constant, and the average reserve capacity to be decreased.Specifically speaking, when sudden increment load for the daily maximum loadreaches to 9.132%, the minimum reserve capacity decreases 36.531%; themaximum reserve capacity remains the same as the previous value of848.4968MW; the average reserve capacity increases 0.7968%; the flexiblereserve capacity is 2.974%～10.810%, reducing 0.987%～2.139%; the totaloptimal reserve capacity increases by 108.64MW compared to forecasted loadsof regional interconnected power system.The simulation and comparative analysis show that the proposed model isreasonable and the proposed method is feasible.