The Differential Protection Of Transformer Based On Time Difference Method And Fault Component

With the development of China's “the 13 th Five-Year Plan of electric power industry ” in planning and deployment, enhance the ability of the stability of power system security, and has become the important issue in the development of power industry in our country.As power safety accidents caused by the economic losses and social impact is more and more serious, further highlighted the significance of ensuring stable power.As a indispensable key hub of throughout the whole power network equipment, transformer, its running state directly affects the efficiency of the whole power network, its security problem is the key problem in power stable security.Based on the analysis of the principle of transformer differential protection equipment as well as the transformer differential protection refusing action and error action of the key factors- the unbalance current,Foucs on the unbalanced current and fault current recognition, this paper proposes a method based on fault component and time difference new transformer differential protection.The main research content is as follows:(1)For power transformer differential protection, one of the main protection in the overall composition and action criterion has carried on the theoretical research, analysis of obstacles to the implementation difficulties. Theoretical analysis of Common in transformer unbalanced current,And in allusion to the worst affected in unbalance current of excitation inrush current, respectively to study the forming mechanism,performance characteristics and the existing assessment method.(2)The fault component is used on transformer main protection depth profiling,The performance analysis in various fault cases,on the motion equation and the equation of braking under different fault is deduced and the action of complex electromagnetic environment of the characteristics.(3)Will have been mature in the line protection by using time difference method is introduced into transformer protection,Because the structure of the transformer core,Under the excitation current of iron core role unbalance current and fault current caused by the effect of fault has the time difference.In order to extract and identify the difference,This paper studies the different types of singular point sampling method,choose the most appropriate way to redefine the time different.(4)Based on the above study and put forward a kind of differential protection of transformer based on time difference method and fault component, Module with Matlab simulink power system blockset(PSB) on the no-load switching-in in fault and failure of the internal and external circumstances of simulation research, fully test the reliability of the new principle of differential protection, selectivity, sensitivity, and quick action.