The paper examines the variation of electrical variables during phase-to-ground faults on medium voltage electrical power lines with a grounded through a resistance neutral. The studies were performed with simulation models of a medium voltage electrical power line. The parameters under consideration have been the voltages and the currents in the transient and steady state operation of the line and more precisely their dependence on the variation of the arc resistance in the place of the fault and the distance from the fault to the supply source. Calculated, accordingly, is the overvoltage during the transient process, the maximum magnitude of the overvoltage and phase-to-earth fault current, the duration of the transient phase-to-ground fault current as well as the maximum magnitude of the overvoltage оn the neutral.