Current Transformer Characteristic Evaluation System Design

This thesis focuses on the analysis and comparison of existing mathematic models for current transformer and the design of CT Characteristic Evaluation System. The main work is as follows:In chapter 1, the principle, characteristics and technical difficulties of the relay protection are introduced. And the significance of designing Characteristic Evaluation System is discussed.In chapter 2, the characteristics of existing CT models are analyzed. The secondary load models for CT and the factors impacting the transient characteristics of CT are also discussed.In chapter 3, the CT Characteristic Evaluation System based on Lucas Model is introduced. The system contains the followings:(1) Modeling the CT mathematic model according to the principle of Lucas Model.(2) Designing the experiments to get the parameters of CT.(3) Analyzing the data from above experiments to calculate the parameters of CT.(4) Analyzing the characteristics of CT, including the steady-state behaviors, transient characteristics and the influence on relay protection performances.The CT Characteristic Evaluation System design described in this thesis needs less experimental devices than traditional experimental methods and avoids the errors caused by experimental devices. Further more, because the design is based on the electromagnetic transient simulation method, the calculation results of CT characteristics are more reasonable.