Research On Risk Assessment And Control Of Wenzhou Power Grid Considering Extreme Weather

With the continuous development and progress of society,the demand for electricity is increasing day by day,and the requirements for power quality are constantly improving.The ever-expanding scale of the grid and the increasingly complex grid structure make the dispatching and operation tasks more arduous and increase the risks in the grid.As a technical support platform in the operation of Wenzhou power grid,the current dispatching method and dispatching information system of Wenzhou Electric Power Regulation Center have been difficult to meet the growing demand.In addition,in recent years,the frequent occurrence of natural disasters in Wenzhou has caused a non-negligible impact on the normal operation of the power system,especially typhoons,heavy rains and lightning on the power grid.Therefore,it is necessary to build a set of risk assessment and control systems,improve the risk management and control capabilities of Wenzhou power grid in daily and extreme weather,and improve the intelligence and automation of dispatch and operation.To this end,the following research was carried out in this paper:(1)In view of the three extreme weathers with the highest frequency of typhoons,heavy rainstorms and lightning in Wenzhou,a model of equipment failure rate under the action of corresponding weather is established to quantify the impact of extreme weather on equipment downtime.(2)Propose a risk assessment system that takes into account extreme weather.First,design a risk probability rating criterion based on historical statistics.Secondly,combined with the actual situation and relevant regulations of Wenzhou Power Grid,seven types of risk severity level standards were designed.Finally,from the perspectives of normal weather and extreme weather,the risk rating strategy is designed: under normal weather,deterministic risk assessment is used,and only the severity is considered to classify the risk;in extreme weather,a probabilistic risk assessment is added,and the risk probability and risk severity are comprehensively considered to achieve both conservative assessment and accurate assessment.(3)Aiming at the problem of low solving efficiency of SCOPF model,a SCOPF model based on the power flow transfer relationship and a reduction method are studied.Firstly,the active power flow transfer relationship before and after the fault is established,and the fault state SCPF model is described by the ground state branch active power flow,and then the model is reduced by selecting the monitoring branch and filtering fault state constraint methods,simplifying the power grid model under fault state and improving the calculation efficiency.In addition,a grid load transfer method based on global search is proposed,which is used to quickly generate load transfer schemes in multiple scenarios and provide auxiliary decision support for operators.(4)From the four aspects of risk information integration,risk identification,risk assessment and risk control,the power grid risk assessment and control system is designed,and it is realized and applied in the Wenzhou power grid.The research and development of the system is introduced from the functional modules,system architecture and interface effects.