Study On Short-term Optimal Operation And Automatic Generation Control Of Cascade Hydro System

With the deregulation of the electric power industry, the electricity market is beinggradually formed, the generator sells its energy with completive bidding, and its optimalscheduling objective is changing, therefore, the independent operation of the hydropowersystem is possible, and which is not merely an accessory service to the power system anylonger. Extraordinary, in the cascade hydropower system, because of the variability of theobjective and the complicated hydraulic and electric relationship among the cascadehydro power stations, the new field of research is come forth. As we know, the short-termoptimal scheduling of the cascade hydropower plants is important to the whole powersystem, therefore, in this paper, based on short-time optimal scheduling of Three Gorgesand the cascade Automatic Generation Control (AGC), the optimal scheduling model andits algorithm are studied and the scheme of Three Gorges (TG) AGC is presentedaccording to the actual projects of the AGC and the DSS of the TG cascade generationscheduling. The major research work is outlines as follows: Firstly, the research field is established after reviewing the new researchachievements by the domestic and international researchers in the field of short-termoptimal operation of cascade hydro system in recent years, and the key field andshortcoming of which are described. And then, the optimal algorithms and theirapplications in optimal scheduling field are evaluated. In chapter 2, the basic parameters of cascade station, including characteristic of units,water level and water head, water delays and so on, are analyzed in details. And a schemeis brought forward which calculates the real-time operating water head of plant by aiterative means. To satisfy the needs of various operating tasks, the choice of optimalprinciple of the cascade short- term optimal scheduling is thoroughly analyzed, and a newoptimal objective is put forward, which considers the cascade generation together withthe station storied energy in the end operation period. In order to decrease the dimensionsof the problem during the calculation, a scheme of Lagarage algorithm is presented andsome improved methods to Dynamic Programming (DP) are introduced. In chapter 3, two models, the cascade generation scheduling when given the totalwater consumptions volume and cascade load optimal dispatching, are founded. Whenthe shipping constraints are subject to the cascade generation scheduling, the unsteady IIIflow calculation of the riverway should be taken into consideration. Four schemes, whichcoordinate the cascade power station generation and shipping, are given, and adistributing parameters model considering the shipping constraints is presented, which iscalculated based on the system decomposition and coordination. Then, a new method,based on the frame of DP and linear interpolation, is introduced in order to reduce thesize and improve the compute efficiency. Finally, to meet the electricity systemrequirement to peak shaving, the optimal peak shaving model of cascade is described. As we know, the real-time operation of the cascade hydro power station is realizedthrough the cascade AGC. In chapter 4, the control mode of power system AGC, theconcept of Area Error Control (AEC) and the development of the control strategy of thetie-line, are introduced. Then, the power station AGC is described. On the base of which,the necessity to realize the cascade AGC is pointed out. In this paper, taking the TGcascade hydropower station as example, the basic frame, control scheme, basic functionand so on of the TG AGC are presented and the delamination control solution isestablished, and the active power station dispatching data flow of the TG station is given.As to the regulation to the unit, a new grads load dispatching scheme is introducedtogether with the unit's load regulating strategy. Finally, the concept of DynamicOptimizing Operat...