Research On Resilience Evaluation Method And Enhancing Strategy For Distribution Network Considering Micro-energy Grid Supporting Function

With global climate change,the occurrence of large-scale failures of power system caused by extreme natural disasters has become more frequent.It is of great value to introduce the concept of resilience to evaluate the ability of distribution network to reduce losses caused by faults under extreme disasters and to return to normal power supply status as soon as possible.With the continuous development of integrated energy technology,more and more micro-energy grids will be connected to the distribution network.The evaluation and enhancing of distribution network resilience need not only consider the satisfaction of the terminal multi-type energy demand,but also focus on the multi-energy complementary supporting function,especially most natural gas pipeline systems adopt buried design and have powerful resistance to surface disasters.In view of the above-mentioned new situation,the current research has not yet formed a scientific system solution,and it is difficult to achieve coordination between the micro-energy grid and distribution network in the whole process of dealing with disasters.To close this gap,this dissertation proposes a distribution network resilience evaluation method and a whole process emergency response strategy considering the micro-energy grid supporting function under typhoon disasters.The specific work is as follows:Firstly,combining with the system function curve of distribution network under extreme disaster,the distribution network resilience evaluation index is proposed from the perspective of terminal multi-type energy demand.Based on the structural reliability theory,the failure rate model of distribution network component is established.The system information entropy is utilized to screen failure scenario and a resilience evaluation process is proposed.Secondly,during the stage of distribution network defending and adapting to disasters,the micro-source mathematical models in the micro-energy grid are established.The rolling outage management scheme when micro-energy grid is in islanding state is raised,which considers the relevance among cool,heat and electric load as well as the influence of the remaining capacity in energy storage system on the next stage.A model solving method based on the improved particle swarm optimization algorithm is proposed.Thirdly,during the stage of fault recovery,a distribution network fault recovery model which considers the micro-energy grid supporting function is established,including the master-problem of raising fault repair plan and the sub-problem of formulating island division,load control and micro-source output scheme under each repair plan.Through iteration of the master-problem and sub-problem,the optimal fault recovery strategy is worked out.Lastly,an improved PG&E 69-node distribution network is verified as a case.The results show that the resilience enhancing strategy proposed in this dissertation can effectively enhance the distribution network resilience by using the micro-energy grid.And considering the coordination between two stages can also maximize the role of time-series components such as energy storage system.The results of the case verify the effectiveness of the resilience evaluation method and the practical value of the enhancing strategy,which have important guiding significance for the planning and operation of the distribution network in the future.