Selecting the DC Traction Network Critical Residual Resistance

The article addresses the development of a methodology for calculating the critical residual resistance of a DC traction network to identify the nature of contact system faults. It is noted that the correctly determined critical value of the quantity considered will help determine whether the contact system power outage is caused by a persistent short circuit fault or is caused by short-term factors (insulation surface flashover, momentary contact with oversized loads, etc.) and decide whether it is possible to re-energize the disconnected section. The features of determining the DC traction network critical residual resistance are considered taking into account the ground shunting effect, the rail circuit parameters, and the contact system supports grounding method. Formulas for determining the critical residual resistance for individual and group grounding of supports have been obtained. It is shown that, given an electric rolling stock in the controlled railway section with power and auxiliary circuits connected, the critical resistance should be selected taking into the traction load into account. The proposed methodology makes it possible to select, in a technically sound manner, the settings of test installations and improve the reliability of contact system monitoring devices and the trouble-free operation of electric railways.