The Power Purchasing And Selling Electricity Strategy For The Power Retailer

A new round of reform in electric power system will focus on the power trading system and the power price,which will bring in competition in retail side.It will allow generation companies,power retailers and customers choose trading objects freely,which will change the situation of buying electricity from power grid companies,forming the patterns of multiple buyers and sellers.In this condition,the research on the electricity purchase and sale strategy of the power retailer is important for the healthy development of the electricity market and the safe operation of the power system.In order to guide customers consume power temperately and take full advantage of low-carbon energy,the price structure and level of state grid offering to customers should be optimizated and adjusted,and it should be provided with an optional price schedule.Then,this paper study and work out a pricing model optimization method,which is Aiming at establishing A price menu consisting of two-part tariff,capacity price and energy price of industrial users whose capacity at or above 315kVA.Firstly,the power transmission and distribution cost are allocated by using postage stamp method with customers' power consumption correction index.Secondly,the load characteristics indices of the customers on different voltage levels are analyzed.According to the economic principle of customers'electricity fees,the customer selections of basic price or capacity are pre-judged.Thirdly,the pre-judging conditions of the two-part tariff options are designed.Then,according to the conditions and the pre-judged results,a model of linear equations is established to calculate all kinds of alternative price schedule.Finally,the model is verified by real data set of a province.The results show that the model can not only ensure the recovery of total cost but also ensure that the price category of the pre-judged users is the most economical price.Electricity market is mainly composed of the forward contract electricity market and the power spot market.Electricity transaction in the forward contract electricity market is realized through the forward contract.However,in spot market,quotation is in short time,trading is real time and price fluctuates frequently.In this paper,the time sequence of the spot market price(load)is separated into two parts,the periodic component and the random component.By comparing ARMA,ARCH and GARCH three kinds of time series forecasting model,the GARCH model which considers the time varying variance is used to predict the random component,and the real-time electricity price(load)of the spot market will be determined in turn.Based on this,the purchase cost of the power retailer is analyzed in the spot market by hour and the power forward contract with optional parameters.Then,the Gauss error function is used to establish a market share function which is connected with sale price of the power purchaser.And,the arithmetic product of the market share and the predicted load is the transaction volume.Next,considering two purchasing ways of spot contract and forward contract,the purchasing portfolio optimization model of the power retailer is established,which regards profit maximization as the objective function and regards CVaR risk control as the constraint condition.At last,based on spot market price and its corresponding electricity consumption data of the nordpoolspot trading center,the model is solved.The result shows the degree of risk aversion will has impact on the purchasing decision of the power retailer.If the CVaR risk loss value that can be accepted is greater,the power retailer will tend to purchase electricity in the spot market.Conversely,they will prefer to buy electricity forward contracts to control the risk.It is completely consistent with the electricity market law,proving the rationality of the model.