Parametric sensitivity analysis of longitudinal and transverse differential protections applied to double circuit transmission lines

In this paper, it is presented the performance evaluation of both longitudinal and transverse differential protection functions applied to double circuit transmission lines. In order to do so, a wide variety of faults were simulated in a 230 kV/60 Hz double circuit line 200 km long using the software ATP/ATPDraw. The performances of the protection functions were evaluated by using parametric sensitivity analysis, thereby only one parameter value changes at a time, providing a more comprehensive understanding of the relationship between each parameter and the performance of the algorithms. By the analysis of the obtained results, one can verify that the transverse or cross-differential function is immune to variation of fault resistance and system loading, but it is sensitive to fault location and source strength. On the other hand, the longitudinal differential protection is quite sensitive to all of them, and it may loss sensitivity depending on the value of system loading and fault resistance, as well.