Service Restoration And Operation Optimization For Active Distribution Network Based On Network Observability

At present,the development and utilization of clean renewable energy has become a global consensus,but the efficient use of clean energy is still a global challenge and has become a rigid constraint to the rapid development of energy clean alternatives.Research shows that under the same network infrastructure conditions,the proportion of distributed generation(DG)that can be integrated with active management technology is three times that of passive management.Therefore,the active distribution network(ADN)technology has become the next commanding point for all countries to compete.ADN's salient feature is self-healing,not only can effectively resist multiple failures,improve disaster restoration capabilities,but also can improve the technical and economic levels of operation under normal operating conditions,and optimize power indicators.The key to self-healing is the full-scale measurement of ADN.Information acquisition needs to be further expanded and integrated on the basis of the original distribution network automation measurement content.For this reason,this article focuses on a number of problems of ADN self-healing,including measurement and configuration,disaster recovery,and operational optimization.It begins a series of scientific explorations and theoretical analysis.The main work and research results are as follows:1)The phasor measurement unit(PMU)applied to the distribution network can greatly improve the measurement level and provide reliable measurement data for ADN operation.In order to ensure the ADN observability and economics of PMU configuration,this paper proposes an optimization configuration model for the phasor measurement unit of the active distribution network considering N-1 faults,taking into account the zero injection node,measurement accuracy,the impact of branch N-1 faults and PMU equipment N-1 faults.And cooperate with the traditional measurement methods to further reduce the cost of ADN measurement configuration.The example analysis shows that the proposed model has good computational efficiency and reliable global convergence performance.2)Therefore,a service restoration model for active distribution network after disasters,which is a mixed integer programming model,was established.The objective of the model was restoring the maximum load through arranging reasonably DG outputs and operating a series of switches,forming microgrids including a single DG and its nearby load.The restoration satisfied the constraints,such as load characteristics,DG droop characteristics,power flow,network topology,DG output and voltage security,etc.This model was tested and validated by modified IEEE37 system.3)ADN has stronger power supply capacity and more flexible regulation than traditional distribution networks,and its load margin also has significant time-space characteristics.For this reason,this paper establishes an ADN operation-optimized mixed-integer programming model considering the load margin.This model takes the maximum load margin as the goal,taking into account load margin equilibrium distribution constraints,power flow constraints,topological constraints and voltage constraints,The limitation of difficult non-convex nonlinear calculations to converge is avoided.The proposed model was verified using a modified IEEE33 node system.