The Operation Risk Analysis Method Of Cascade Hydropower In Medium And Long Electricity Market

The market-oriented operation of cascade hydropower stations should consider not only the bidding risk caused by electricity price,but also the contract performance risk caused by runoff.In the multi cycle and multi variety coordinated medium and long-term electricity market,how to describe the correlation and uncertainty of runoff,electricity price,electricity quantity and other variables,make trading decisions,arrange operation plans and measure related risks are the theoretical and practical challenges that need to be solved urgently by cascade hydropower stations.For this purpose,based on the research background of a hydropower rich provincial power market in Southwest China,this paper conducts in-depth research on the following four aspects:long-term dispatching risk analysis under the multi market environment,medium-term operation adjustment range control within the long-term operation framework,optimal bidding strategy for medium-term transaction within the long-term operation framework,and multi time scale market performance risk analysis.The main lines of this paper are as follows:(1)Risk analysis method for long term operation of cascade hydropower stations considering multi variable uncertainty.For allocating annual electricity resources in multi variety market,a risk analysis method for lon g term operation of cascade hydropower stations is proposed.First,a seasonal autoregressive integrated moving average(SARIMA)model is used to handle the time-varying and seasonal characteristics of inflow series by using a copula connect function to fit the joint distribution of the monthly inflow,the clearing price of the intra provincial market and the delivery volume of the inter provincial market.Then,uncertain chance-constrained programming is established.Finally,a developed particle swarm optimization(PSO)algorithm embedded in a Monte Carlo simulation is solved for hydropower operation policies,and the maximum revenue,resource allocation and scheduling strategy are obtained under the corresponding risk tolerance.(2)Medium term operation adjustment control method of cascade hydropower stations within the framework of long term operation.Based on the long-term framework of cascade hydropower stations obtained in the above section,aiming at solving the fluctuation range of runoff and market electricity price and formulating the medium-term operation range of cascade hydropower stations to meet different expected benefits,the control method of medium-term operation range of cascade hydropower stations is proposed.This method considers both the uncertainty of hydropower runoff and market price,establish a bilevel stochastic IGDT model for the main hydrologic and economic uncertainties in hydropower market participation.The lower level model solves the minimum robustness profit or maximum opportunity profit from power sale,and the upper level model solves the maximum robustness fluctuation range or minimum opportunity fluctuation range of the uncertain variables for different expected profits.Through the transformation,the equivalent single-layer model is obtained,and the deviation degree between runoff and market electricity price and the medium-term operation water level and output range are obtained.(3)Medium term trading decision making method of cascade hydropower stations considering the fluctuation range of multiple variables.The bidding strategy in the declaration stage is closely combined with the operation dispatching.Considering the risk of bidding failure in medium-term transaction,a mid-term market risk decision-making method for cascade hydropower stations is proposed,which considers two stages of bidding and operation.Using the information gap decision theory,the maximum deviation range between the daily runoff and the market clearing price in the robust model is obtained,and then a bidding strategy model considering the psychological factors of cascade hydropower operators is constructed by using the prospect theory.(4)Multi market performance risk analysis method of cascade hydropower stations considering settlement rules.Aiming at the problems of medium and long-term market transaction contract performance and whether to participate in the short-term market,the medium-term operation risk analysis method of cascade hydropower stations in multi cycle market is constructed.Copula Monte Carlo method is used to generate a combination scenario of daily runoff and clearing price of day ahead incremental trading,and enhanced elitist retention strategy genetic algorithm is used to calculate the generation income of all scenarios,and the corresponding CVaR value under a given confidence level is obtained.