Power System Transient Stability Analysis Via Second-order Non-uniform Kuramoto Model

As a large mount of renewable resource is successively integrating into powergrids, the transient stability issues of power systems become more severe than anytime before. In order to secure the operation of power systems, the stability state ofpower systems must be determined rapidly when a certain perturbation acts onpower systems.In recent years, a growing number of scholars specified in complexnetworks have noticed the similarity between the concept of frequencysynchronization of Kuramoto models and the concept of transient stability of powersystems.The latest research achievement on frequency synchronization ofsecond-oreder non-uniform Kuramoto model enables to reflect frequencysynchronization point’s trapping region by the parameters and states of system’sunderlying graph, which provides a way to resolve the proble of estimating theregion of attraction of disturbed system in direct methods.In this paper, the lastest frequency synchronization theory of second-ordernon-uniform Kuramot model is integrated into transient stability analysis byestablishing the correspondence between the second-order non-uniform Kuramotomodel and the network reduced power system model. Namely, a transient stabilitycriteria based on second-order non-uniform Kuramoto model frequencysynchronization theory is derived. The transient stability information of thedisturbed system can be obtained by comparing the state variables’1-demensionmapping value with trapping region’s1-demension mapping value of thedisturbance-canceling system. On this basis, a transient stability analysis method isput forward.For the case of faults occurring in power systems, the application of ourapproach to2machine3bus system, WSCC3machine9bus system, CIGRE7machine10bus system and IEEE6machine30bus system illustrate that the criticalfault clearing time algorithm based on second-order non-uniform Kuramoto modelfeatures concise format and fast computation speed, it can determine the transientstability of the system when a certain perturbation acts on as well as offer thestability margin of the disturbed system, which is of importance for practical use.For the case of power disturbance happening in systems’s buses, the example ofCIGRE7machine10bus systems demestrates that the approach based onsecond-order non-uniform Kuramoto model can quickly estimate the perturbation’scritical sustaining time which do not destroy system’s transient stability. Thoughcurrently this approach inevitably possesses some kind of conservatism, we havedefinite direction for future improvement. It will guarantee power systems safe and stable operation once this approach’s conservatism is over comed.This work was financially supported by the National Basic Research Programof China (973Program)(2012CB215201) and the National High TechnologyResearch and Development Program of China (863Program)(2011AA05A105).