Study On A Kind Of Novel Differential Protection Criterion Of Transformer

Power transformer is a very important and widely used equipment. Have it had fault, it will greatly affect the reliability and regular running of the power system. In order to keep the transformer safely running and avoid fault expand, installing sensible,fast,reliable and good selectivity protection device according to the fault it may occur is quite important.In view of the numerous benefits of digital relaying in terms of economics, performance, reliability, flexibility and system interaction, significant efforts have been made in the development of digital relaying algorithms. In this thesis, a series of criterions of differential protection of transformer are developed and analyzed, compared and then conclusions are written at the end of the thesis. The work including:1． A survey and a comparative analysis of various algorithms introduced for digital differential protection of three-phase transformers;2．A kind of novel trigger criterions applied in the main criterion of fault component differential protection is analyzed , compared with other trigger criterions;3．New criterion of stable differential protection with new characteristic curve is put forward, and moreover its reliability and sensitivity are analyzed;4．A kind of differential protection criterions based on fault component of three-phase transformers is analyzed , tested by simulation data; 5．A whole configuration scheme of digital differential protection including compensate mode is explained, and the performances for protection criterions is analyzed .The paper gains the bankroll of national fund of natural science, whose item is "Research of transformer's new theory based on non-linear excitation spur track"(item NO.50277012)。...