Research on Purchasing Portfolio Strategies of Large Consumers with the Interruptible Load

With the policy of large consumers´ direct- purchasing, large consumers can manage its risk of power purchase through direct-purchasing market and spot markets. This paper takes the semi-absolute deviation as risk measurement index, establishes an optimal model of multiple market purchasing portfolio strategy to get the minimum expected power purchase cost while the interruptible load contract is taken into account. By using mixed integer linear programming method, the proportions in the direct- purchasing market, day-ahead spot market, self- provided power plant and interruptible load are calculated and the impact of the interruptible load and its details about the threshold price and compensating factor on power purchase decision is analyzed. The results show that the proposed model can effectively reflect the risks; interruptible load and direct-purchasing market can reduce the risk of power purchase efficiently. With the increase of threshold price and decrease of compensation factor, the effect of reducing transaction risk by interruptible contracts weakens gradually.