Research On Power And Communication Fault Repair Of Distribution Network Under Extreme Events

In recent years,extreme events including extreme natural disasters such as typhoons,ice and snow,earthquakes,and malicious man-made cyber attacks have occurred frequently,resulting in large-scale power outages in the power system,resulting in huge economic losses.The resilience of the grid is defined as the ability of the system to resist various extreme hazards,withstand the consequences of an initial failure,and quickly return to a normal operating state.Compared with the power transmission system,the distribution network is located at the end of the power grid,which has a weaker ability to cope with fault disturbances and is closely related to the user’s load.Therefore,in the face of the frequent occurrence of extreme disasters,how to effectively improve the elasticity of the distribution network is one of the key issues to be solved urgently in its development.In extreme events,after large-scale failures,the distributed generation(DG)connected to the distribution network can provide strong support for the normal power supply of partial loads,making a breakthrough in the measures to improve the flexibility of the distribution network..At the same time,with the development of information and communication technology,the distribution network has gradually evolved into a distribution network cyber-physical fusion system with deep integration of information and power.The distribution network communication system gives the distribution network more flexible and efficient fault response measures,but the power system The degree of dependence on the communication system is also deepening.If a large number of communication system failures occur,the recovery of the power system will be affected.This paper studies the repair of power faults and communication faults in the distribution network under extreme events.The main research work is as follows:1)Multi-fault repair of distribution network without considering the influence of communication.Firstly,based on the distribution network elasticity index considering the importance of load,the main measures to improve the elasticity of the fault recovery stage are analyzed.The frame reconstruction restores part of the load in the non-faulty area,and then determines the repair sequence of the faulty components and repairs them through the faulty component repair objective function.Finally,the effectiveness of the proposed method is verified by taking the IEEE33 node distribution network as an example.2)A collaborative repair method for power-communication faults in distribution network is proposed for resilience improvement.The structure of the distribution network communication system is analyzed,and a collaborative repair method for distribution network power-communication faults oriented to the improvement of elasticity is proposed.First,determine the urgency of the optical fiber fault and repair the emergency optical fiber fault.According to the repair priority indicators,the power failures and emergency mobile base station faults in each area are repaired in turn.Finally,the non-emergency optical fiber and mobile base station failures are repaired;on this basis,the power-communication fault collaborative repair GUI software of the distribution network is developed.A modified IEEE33 node distribution network power-communication system example is used to verify the effectiveness of the proposed distribution network power-communication fault collaborative repair method.3)A differentiated step-by-step repair method for power-communication faults in active distribution networks is proposed.Based on the analysis of the communication system structure of the active distribution network,a differentiated step-by-step repair method for power-communication faults in the active distribution network is proposed.First,the active distribution network is divided into multiple areas based on the optical fiber network Convert non-observable power elements into observable power elements,and calculate the load recovery rate of each area;secondly,through the differentiated repair method of power and communication faults in the area,repair power and communication faults that can bring load recovery value,and recoverable areas.For the communication failure of the observability of the internal nodes,the above operations are performed region by region according to the load recovery rate of each region;finally,the non-emergency communication failures that cannot bring the value of observability recovery and load recovery in each region are repaired.Finally,an example of IEEE33 node power-communication system is used to verify the effectiveness of the proposed differential and step-by-step repair method for power-communication faults in active distribution networks.4)A conversion-based unified repair method for active distribution network power-communication faults is proposed.Firstly,the typhoon fault probability model of the distribution network is analyzed,and the fault scenarios under extreme events are generated,and the influence of the communication system on the fault recovery is analyzed based on the information blind area.The unified fault repair method of conversion and emergency repair team task allocation: update the located fault set and the location of the emergency repair team,calculate the converted value of the load recovery value of the known power and communication faults,and then solve the faultoriented resilience index including the converted value of the load recovery value.And the optimization objective function of the failure recovery time,to assign the task of the repair team.Finally,the IEEE 33 node distribution network system is taken as an example to verify that the proposed method can effectively improve the flexibility of active distribution network.