Modeling of the Induced Voltage in a Disconnected Grounded Conductor of a Three-Phase Power Line

Disconnection of a conductor from a three-phase line causes induction of electrostatic potential in it by the other non-disconnected phase conductors. Such a situation can be dangerous if the conductor is not grounded on both sides, since any contact with it can be related to dangerously high values of the contact voltages. The permissible contact voltage is considered to be the highest value of the voltage that can be applied indefinitely under certain conditions.This creates the necessity to study the resistance of the ground. The paper presents the methodology and the obtained mathematical models for determining the value of the grounding resistance of a disconnected conductor in a three-phase power line, for which the contact voltage is safe, by taking into account the potentials, induced by the non-disconnected phase conductors. Power lines with nominal voltages of 20kV and 110 kV have been considered. The mathematical models have been obtained by implementing the experimental design techniques.