Electromagnetic Transient Modeling and Application Test of Current Transformer

• Main Authors: Yu Hsiang Chuang, 莊佑翔
• Other Authors: W. N. Chang
• Format: Others
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/32181886416783245352

碩士 === 長庚大學 === 電機工程學研究所 === 97 === This thesis proposes the electromagnetic transient modeling and application test of CT. First of all, this thesis constructs a CT characteristic analysis model in the EMTP. Effects of DC and AC saturations of CTs are simulated. The results from the simulation show the importance of the saturation characteristics of CTs in protections. Secondly, applying differential protection relays to a three-phase transformer is introduced. The influences of the CT saturations on differential protection relay are also mentioned. And then, this thesis establishes a simulation system for a three-phase transformer differential protection. Two faults, internal fault and external fault, are set in the simulation. With the CT saturation, the simulation results indeed cause measurement errors which may induce mis-operation of differential protection relay. Finally, this thesis constructs a hardware measurement system for transient high current test of CT. The measurement system can observe the characteristics of CT responses under transient high current impacts. At the same time, in order to verify the precision of the CT model with saturation effects built in the EMTP, the simulation results are compared to those from the measurement system. The result of this thesis can provide useful reference for relay settings with CTs.