Study On Current Transformer Simulation Technology And Development Of Its Analysis&Evaluation Platform

With the rapid progress of the power construction, gird gradually developed into a gridof large-scale, complex structure and flexible operation mode. The protective currenttransformer performance has been put forward higher requirements because of the complexdiversity of its transient process. Transient current transformer saturation is one of the maincauses of differential protection maloperation, and differential protection is usually themain protection of power system, so that the maloperation may pose a serious hazard on thedevice itself and even the stable operation of the power system. Since many factors affectthe saturation of transformer, such as the short-circuit current level, the non-periodiccomponent size and the attenuation length, the amplitude\decay rate of the inrush currentand the load level, the current transformer core structure, material and the secondary loadimpedance. These factors are difficult to test through dynamic simulation one by one.Therefore, the study of the current transformer simulation technology, and the developmentof its analysis&evaluation platform for complex grid of electromagnetic transient haveimportant practical significance and engineering value for the reasonable selection ofcurrent transformer, and the proper assessment of its transient saturation characteristics.Development of current transformer analysis&evaluation platform is inseparable fromthe accurate modeling of its core characteristics. After comparison of the JA model and theLucas model which are both widely used in the field of the ferromagnetic materialmodeling, a higher accuracy model--JA model is chosen as current transformer simulationmodel. A novel method of identification of JA model parameters is proposed.Developed an analysis&evaluation platform of the current transformer based on theVB.NET. In order to simulate the complex electromagnetic transient of the power grid, aflexible configuration of generic system model is built, and the performance evaluation ofthe current transformer is given.The effectiveness of the current transformer platform analysis&evaluation platformrequires verification through dynamic simulation. By comparing the dynamic simulationresults and the simulation results, validated that the current transformer analysis&evaluation platform can accurately and efficiently simulate complex grid of transientcurrent transformer saturation characteristics. Analysis&evaluation platform played a good effect in the accident analysis which caused by the saturation of the currenttransformer.