Research On Critical Peak Pricing Mechanism And Performance Evaluation

Critical peak load(CPL)arises when the electricity demand is high,especially in summer and winter.It leads to the shortage of reserve capacity,compromising the security and stability of power system.Critical peak pricing(CPP)is an effective demand side management method to attack such problem;that is,it lifts the electricity price when CPLs arise so as to cut the load.The performance of CPP implementation is mainly decided by the policy formulation.With the promotion of smart grid and electricity market reform,there are new aspects in CPP policy formulation.Therefore,the research of CPP mechanism and performance evaluation has importance significance.In the thesis,firstly,the optimization of CPP policy based on load response model is expounded.The formulated CPP policy lifts the price at CPP time intervals and drops the off-peak price;besides,the electricity fee increase due to CPP is used for the purchase of interruptible loads at CPP time intervals to further cut the CPLs.The load response model is established based on load-price elasticity,load transfer rate,and load transfer potential.The objective of the optimization model is to minimize the maximum load on CPP day;and the constraints include the up and downtime limits of the interruptible loads,the electricity fee increase limit,and the electricity price adjustment limit.The simulation results indicate that the proposed method can provide a reference for the TOU-based CPP policy formulation.Then,the optimization of spot-price-based CPP policy is researched.The policy applies spot price on CPP day or CPP time intervals and sets a refund mechanism according to the individual load response performance.The spot price is made up of three components,that is,the generation,transmission,and distribution price.The generation and transmission price is calculated collectively using the model of dynamic optimal power flow with the objective function of minimizing the power generation and transmission cost.The distribution is set based on voltage grade.After the formulation of CPP policy,the load response is simulated based on the aforementioned load response model to check the effectiveness of the policy.The results indicate that the proposed method can provide a reference for CPP policy formulation in open electricity market.Finally,the performance evaluation is discussed from three aspects,that is,the load variation index analysis,clustering analysis,correlation analysis.For the first one,load variation indexes are proposed,including the CPP energy curtailment rate,the maximum daily load reduction rate,the load factor change rate,and the peak-valley differential factor change rate.Then,time series forecasting method is employed to calculate the indexes and their confidence intervals.For the second one,k-means clustering method is used to classify and grade the load response performance of different industries.For the last one,Pearson correlation coefficient is employed to analyze the linear correlations of an entity's CPP energy curtailment rate with its electric load composition and with its proportion of annual electricity cost to the total energy consumption cost.The results indicate that the proposed methods can objectively and effectively evaluate the performance of CPP policy.