Power System Dispatch And Its Resilience Enhancement During Extreme Weather Events

With the global climate change,the frequency and intensity of extreme weather are getting higher,which is likely to cause large-scale power outages.Hence,the threat of extreme weather to the safe operation of the power system is gradually increasing.Aiming to reduce the impact of extreme weather on the power system and enhance the ability of the power system to resist and recover,it is necessary to increase the resilience of the power system to extreme weather events.With the power system resilience as the background,this thesis studies the dispatching and resilience promotion process of the power system under extreme weather events.By analyzing the spatial-temporal characteristics of the impact of extreme weather events on the power system,an proactive dispatch strategy during extreme weather is developed.An modified resilience assessment metric is proposed to test its resilience improvement effect,and a reference for resilience improvement measures is given.Firstly,the impact of extreme weather events on power system components is analyzed,and the failure probability of system components under extreme weather extents is evaluated.The time and space characteristics of extreme weather are described by the hazard factor and duration model,and the vulnerability model of the component is established based on the Monte Carlo simulation method,and then the mapping relationship between the failure probability of the component and the intensity of the extreme weather is clear.The analysis of typhoon case verifies the effectiveness of this failure probability assessment model,which lays the foundation for the subsequent study of the impact of extreme weather events on the power system.Secondly,considering the spatial-temporal distribution characteristics of the impact of extreme weather on the power system,a proactive power system dispatch strategy under events extreme weather is proposed.Aiming to analyze the spatial-temporal impact of extreme weather on the power system,the topological state transition of the system under the events is abstracted as a Markov chain,and the regional network of the affected power system is rasterized.Furthermore,based on the semi-Markov decision process,a proactive dispatch model is established,which comprehensively considers the recovery process of components and the vulnerability of weak nodes,and reschedules the power system flow in advance on the extreme weather trajectory.Then two cases under ice disaster and typhoon weather are analyzed respectively.The results show that the proposed model could describe the sequential decision process considering the weather uncertainty,and has a good forward-looking and load-reducing effect.The proposed proactive dispatch method has certain engineering practicality for the operation process of power system under extreme weather events.Finally,aiming to test the superiority of the proactive dispatch model in the improvement of power system resilience,an modified resilience assessment metric considering the spatialtemporal characteristics is proposed.Comprehensively considering the duration of extreme weather and failure scenarios,the traditional resilience assessment metric is modified,and the specific resilience assessment process is given.Furthermore,the resilience of the two systems responded by the proactive dispatch model and the traditional dispatch model respectively is compared and evaluated,and the resilience promotion effectiveness of the proactive dispatch model is verified.Then,based on the modified resilience metric,specific measures to improve the power system resilience are proposed and tested from the perspective of planning and operation.From the above,the proposed resilience assessment metric has certain guiding significance for the selection and test of resilience improvement measures.