Research On Active Decoupling Control Scheme Of Power System

With the development of UHV transmission technology,the safety and stability of power system is getting more attention while bringing huge economic benefits.How to block the propagation of faults in the grid and avoid the occurrence of large blackout accidents is a problem worthy of key consideration.Active splitting control is an effective means to avoid system collapse by splitting the grid into several isolated grids before losing synchronization.This paper mainly focuses on two aspects of splitting section and splitting time,and a complete control scheme is proposed with the following main work:Based on the basic idea of EEAC to quantitatively evaluate the transient stability of power system,analyze the criterion of system transient stability assessment and the calculation method of trajectory stability margin.The cause of out-of-step oscillations is analyzed from the mechanism,and compare the influence of traditional out-of-step splitting with active splitting on the stability of isolated grids from the perspective of the action time combining the calculation example,which provide the subsequent chapters with research premise and theoretical basis.To address the problem of selecting splitting sections,an active splitting selection scheme of “generator coherent grouping + partitioned cut-set search + section optimization”is proposed.Firstly,the generator disturbed trajectory is divided into two complementary groups based on EEAC theory;then all potential homogeneous sub-groups of the system are clustered according to the degree of trajectory non-homogeneity within the leading group;then the initial splitting section is obtained for each instability mode of the system respectively based on the breadth first search algorithm;finally,based on the heuristic variable neighborhood search algorithm,considering the degree of structural damage and power imbalance of the isolated grid,the splitting section is further optimized,and the effectiveness of the scheme is verified by combining a 39-nodes system example.For the problem of splitting time,an active splitting control scheme based on faultdriven is proposed.Based on the online mode calculation and cost analysis,match the active splitting section from the sections with pre-configured splitting devices,search for corresponding emergency control measures,and screen out faults that require active splitting control in the expected faults set,so as to formulate the corresponding decision table;then the periodically refreshed decision table is matched online based on real-time fault information;once the matching is successful,active splitting control and corresponding emergency control measures for the isolated grids are triggered immediately.Finally,combining the previous research results,based on the multi-agent technology,the architecture of active splitting control system is presented,and the effectiveness of the scheme is verified by simulation of a real grid case.