Study On The Situation Prediction And Active Defence Strategy Of The Distribution Network Under Ice Disaster Enviroment

Under the background of frequent occurrence of natural disasters caused by global climate change,the situation of the distribution network suffering from ice disasters has constantly occurring,which has seriously affected the society.It is of great practical significance to study the active defence method of the distribution network under the ice disasters.Therefore,the research of situation prediction and active defence method under the ice disaster environment has carried out.Firstly,the ice growth model of distribution network is analyzed.Considering the multi angle correction of the micro meteorological identification and real-time updating,the micro-topography,a fault probability improvement prediction model of the distribution network under ice disaster is put forward.The prediction accuracy of the fault probability can be effectively improved by accurately predicting the ice thickness.The case analysis shows that the prediction results are more accordant with the actual fault occurrence.Secondly,considering the situation awareness of the distribution network,the multi-source situation of grid structure,historical data,real-time operation,defence resources and real-time risk of power equipment are processed.The calculation method of the fault probability under the situation prejudgement based on typical situation index is proposed,which improves the visibility and accuracy of multi sources situation awareness.Combined with the revised prediction model of the fault probability,the situation prediction and weakness identification method of the distribution network under ice disaster is established,which significantly improves the ability of fault prediction and early warning in distribution network.Through the example analysis,it is proved that the method can identify the weakness more accurately,and the effect of situation prediction is better.Then,from the perspective of the dynamic intrusion of the ice disaster,the capacity of the disaster bearing and the response potential of demand,the whole process safety situation assessment index system including ice disaster current status,prediction state,distribution network disaster bearing state,defence resource capacity,ice melting and deicing capacity is established.The initial accident scenario set is determined according to the real-time fault prediction,and it is updated with the safety assessment results.So the scene reduction and optimization method is established to form a dynamic accident scenario set.The example analysis shows that the method can fully display the security situation level of the distribution network in Liaoning province during the ice disaster.Finally,the active defence evolution strategy of the distribution network is proposed considering the situation prejudgement.The strategy takes into account the constraints of power supply recoverability and transfer capacity under the special environment of ice disaster,as well as the constraints of limited resources and economic of strategies transfer.And the objective is to minimize the loss of load.By establishing the linkage mechanism between the power supply output,load transfer and load shedding,an active defence evolution strategy is established,which is coordinated by active island,transfer network and emergency island.From the two angles of horizontal and vertical,the directed evolution path from dynamic accident scenario to defence strategy is searched.And it realizes the coordinated control on locality and globality of the active defence strategy.It is proved by the example that the method can reasonably select the defence strategy,which can improve the power supply capacity of the distribution network and reduce the load loss.