Operating Reliability Analysis And Optimization Research Of Power System Considering Down Operating Reserve

Operating reserve(OR)has been considered as one of the most important resources for maintaining the power balance between generation and demand in power systems.However,as the penetration of renewable energy in power systems increasing largely,due to it is volatility and uncertainty,it is still a considerable challenge to schedule the generation and operating reserve of power systems in a reliable and economical way.Generally,OR can be divided into up OR and down OR according to the adjustment direction of power output.The up OR is utilized to provide an increased rate of generation and compensate for the deficit of production,which is conducive for improving power system operating reliability.In contrast,the down OR is used to provide a decreased rate of generation output without shutting down units,when there is a surplus of generation,which is conducive for enhancing the ability of power system to consume wind power.However,traditional operating reliability analysis of power systems mainly focuses on the up OR and neglects the effects of down SR on power system operating reliability and wind power consumption.This paper focuses on the researches about how the down OR can impact the operating reliability of power systems and the method to schedule the generation and OR of power systems while satisfying the operating reliability and wind curtailment requirements.The main content of this paper is as follows.1)The impact of down OR on the operating reliability of power systems has been studied.We proposed an operating reliability evaluation method considering the down OR.Firstly,the day-ahead unit commitement(UC)model is utilized to schedule the generation and oeprating reserve.Based on the scheduling results of UC model,the real-time economic dispatch(ED)model is utilized to re-dispatch the power system considering the uncertainty of load demand and random generation failures of generating units.Based on the re-dispatched results,the operating reliability of power sytems considering down OR is evaluated.2)Based on the multi-state models of load demand,wind generation and random failures of generating units,the expected energy not supplied(EENS)and the expected wind power curtailed(EWPC)criterions are established to schedule the operating reserves.The multistate model of generating units considering both the down OR and up OR is proposed in this paper.Compared with the two-state models of generating units,multi-state models are more conducive for effectively scheduling operating reserve.3)In order to schedule power systems economically,while satifying operating reliability and wind curtailment requirements,the day-ahead unit commitment(UC)model incorporating the EENS and EWPC criterions are proposed to pre-dispatch the power systems.The redispatch process for power systems during real-time operation considering random failures are presented,based on which the operating reliability of power systems is evaluated and the effectiveness of EENS criterion is verified.