A Game Theoretical Approach To The Coalition Strategy Of Cascaded Hydropower Stations

In recent years, China is gradually accelerating the development process of hydropower.Along with the reform of the power market, it is becoming inevitable for cascadedhydropower stations to participant in electricity market. Thus the basin developmentcompanies need to optimalize their bidding strategies in competitive electricity market accordingto market rules, which is of great practial significance for upgrading the water resourceenergy construction and realizing sustainable development of river basins. Cascadedhydropower stations have special technical and economic characteristics. They have to becoordinate as a whole to schedule water resource while competing with each other. How tooptimize the water and power resources by bidding in market has always been the forefrontand hotspot of academic research. This thesis focuses on cascaded hydropower station’salliance strategy, coalition formation and stability referring to successful cases of foreignpower market with participation of hydropower and combining the national conditions ofChina. The conclusion provides a theory reference for cascaded hydropower stations’bidding strategy and can be considered as a police suggest on pricing reforming which aimsto equal price for the same electricity quality on the same power network.Hydropower stations which are belonged to the same investment entity tend tocoordinate naturally. They would rather bid cooperatively than individually on the target ofmaximize the profit of the coalition considering adequately water and power resourcerelations among stations. The coalition could exist as hydropower stations need unifiedmanagement even if hydropower stations belong to different investment entities. To explorethe outer condition and inner motivation of hydropower stations forming coalition, astatic game model is proposed firstly basing on the technological and economic charactersof electricity market place considering intricate relationships among hydropower stations.The model quantifies constraint of cost and demand functions. An extended Lagrangemultiplier method is adopted to resolve the model. The impacts of two clearing form,different and unified pricing, on profit of stations are compared by the simulation exampleas the outer condition of coalitions. Secondly, theory on the motivation of coalition forming is studied. The resolve conceptsincluding stable set, core and Shapley value are discussed mainly to analyze the stabilityand dynamics of coalitions. But those resolve concepts are all static and lack the effect onthe dynamics of coalitions. Coalitional game theory based on farsightedness is researchedon the base of the largest consistent set. The ultimated uncovered path is considered as thejudgment of coalition’s stability as cascaded hydropower stations’ alliance strategy relyingon history path.On the next section, the dynamic coalitional game model is proposed on the achievementof above static model and theory to analyze the coalition forming process in differentmarket places during repeatedly bidding. Three potential coalition contractures areconsidered. Once coalition forms, the stations bid as a whole, declaring unified price andtotal generate quality. The generate quality is dispatched cardinally in coalition to maximizethe coalition’s profit considering the relationship among stations. This model is solved bygenetic algorithm to provide the moving of cascaded hydropower stations coalition andultimate state.Finally, the dynamic model is updated by the method of forecasting opponent’s biddingprice, relaxing the assumption of complete information to be more practical. The classicalgray predict model GM(1,1) is improved to gain a more accuracy result. The predict modelis proved feasible on the test of NORD-POOL power market actual data and embeddedsuccessfully in the game model. The simulation result shows the varying of profit ofstations, which changes the reference of coalition structure in a incomplete informationsystem. So the cascaded hydropower station coalition stability is challenged.