Research On Hierarchical Partition Optimizing Operation Of Active Distribution Network Under Multiple Time Scales

Active distribution network is a good way to solve the problem of voltage beyond the safety limitation,short circuit current increase,frequency instability and the reliability of power supply reduction in the current distribution network.Reasonable optimal operation and multi-source coordinated control method,can achieve the function of initiative decision-making,management and control in the operation process of active distribution network,and ensure the reliability of grid power supply and the economy of running.Therefore,there is great significance of flexible control under different scenarios to build the active distribution network operation control system and investigate the multi-layered coordination control method under multiple time scales.This paper mainly focuses on the optimal operation and control in the active distribution network.According to the features of the active distribution network and the multiple time scales demand analysis in the running process,three-layer operation control system is built,namely,target making layer,global optimization layer and regional autonomy layer from top to bottom.The establishment of the target decision-making system in the top layer,could flexibly optimize the goal under different scenarios of the distribution network,and achieve the function of initiative decision-making and control.Meanwhile,this also sets the new requirements for the operation control system frame.This paper starts from coordinate operation of active distribution network,and the techniques of the global optimization and the regional autonomy are investigated systematically.For the global optimization layer,this paper study the multi-objective optimization design method under the long time scale,and establish a multi-objective active-reactive power coordination optimization model of maximizing the utilization rate of Distributed Generation,maintaining a better voltage level and minimizing the transmission loss based on the coordinated complementation of the distributed energy resource and the reactive power compensation device from the view of operation control.An improved particle swarm algorithm is used to solve the model based on the particle classification processing and the feasibility of this method is validated in different scenarios.In order to eliminate the disturbance of the actual operation in active distribution network,regional autonomy layer needs to be real-timely calibrated,so the disturbance critical switching index is proposed to quantify the disturbance in the operation of the system,acting as the basis for the control of the active switch.At the same time,with the feeder control error to zero as the control target,the power adjustment strategy under short time scale is developed to achieve the non-differential control,and the feasibility of the strategy is validated in different scenarios.