Abstract:

Due to the asymmetry of the traction load,there is a problem in the calculation of the measured impedance when the line distance protection on the grid side cooperates with the traction transformer,which brings the puzzle to the setting calculation personnel whether the distance protection can avoid the faults on low side of the traction transformer.The influence of traction substation on distance protection is analyzed.The analysis models of single-phase Ii traction transformer,V/v wiring traction transformer and V/x wiring traction transformer are built.The measurement impedance correction scheme of the grid side distance protection after low side of the traction transformer being faulty is analyzed.The setting calculation suggestions for the distance protection are provided.

Key words: traction transformer, distance protection, measured impedance, setting calculation