The influence of current transformer saturation on the longitudinal differential protection of transmission lines

摘要

This paper explains the algorithm for the longitudinal differential protection of transmission lines. In case of current transformer saturation, conventional stabilization is insufficient for avoiding an unnecessary protection tripping. Such a problem may occur due to a fault outside the protected zone of the transmission line. In such cases, additional stabilization ought to be implemented as well. The paper presents simulations of various potential faults, and offers a comparison of relay operation with and without additional stabilization.