The Research On Anti-TA Saturation Of Digital Busbar Protection

Busbar, one of the most important elements in electric Power System, Though the current differential protection principle that is the essential portion of busbar protection has been widely used in practice at present time, its accuracy is invariably reduced by current transformer (TA) saturation.By enlarging system capacity, the time constant of system is very large, which lead to the transient state process is extended. Thus the performance of the digital busbar protection to Anti-TA saturation is crucial to improve. The paper is arounded the problem of Anti-TA saturation,which mainly contains the following aspects: First,based on the analysis of TA saturation mechanics, common method of Anti-TA saturation at the present time are generalized; Then Each part of the digital busbar differential protection scheme is discussed respectively, a new digital busbar differential protection scheme based on the second voltage is analysed through using wavelet to make sure the in and out time of saturation . Finally, protection is blocked when foreign accident of busbar .The scheme is operated by using the model which is composed of the Simulink blocksets. Several simulation tests involving all kinds of fault situation are carried out through running the protection model in MATLAB development environment.