The invention discloses a
voltage class design method for a medium-
voltage direct-current AT type
traction power supply system, and the method comprises the steps: S1, determining a
system network parameter set according to a
train operation scene, building a
system equivalent circuit model, and initializing a
voltage class to be a minimum voltage class; s2, judging whether the voltage level is within a preset range, and if so, S3; otherwise, outputting a result; s3, calculating electrical parameters of the line based on
power flow analysis, and judging whether the
pantograph voltage is within a preset range, if so, S4; otherwise, S7; s4, judging whether the stray current and the steel rail potential are within a preset range or not, and if so, S5; otherwise, S7; s5, calculating the temperature of the wire, judging whether the temperature of the wire is within a preset range or not, and if so, S6; otherwise, S7; s6, calculating the total cost according to
economic analysis, and returning a result under the
current voltage grade; and S7, increasing the
current voltage grade according to a preset gradient, and returning to S2. The method has the effect that the voltage grade design of the medium-voltage direct-current
traction power supply system accessed by the direct-current AT is realized.