Simulation and analysis of the energization of a distribution feeder with temporary protective grounding connected

This paper presents a study on the voltage and current levels to which workers are exposed during maintenance of a distribution network in the event of accidental re-energization. Simulations of the energization of a real distribution feeder, with temporary protective grounding connected were performed using ATPDraw software. Assuming that the temporary protective grounding was appropriately installed, several simulations were performed changing the system characteristics, such as feeder lengths, ground rod resistance and soil resistivity. Additionally, single-phase energization and the bracket grounding method were simulated. The voltage and current levels that the worker and the temporary protective grounding cables would be exposed were verified, as well as the voltages between the point where the temporary protective grounding was connected and the ground. The results demonstrate that in some accidental energization the current and voltage levels exceed the established safety limits for the workers. The IEEE 1048 standard, which provides guidelines for the application of temporary protective grounding in transmission and distribution lines, warns against the use of bracket grounding systems where single-phase energization could occur. However, the simulations indicate that voltages and currents exceeding safety limits can also occur during a three-phase energization.