Calculation of Distributed Grounding Devices in Networks of Different Voltage Classes

In the event of breaks in phase and neutral conductors in networks of various voltage classes, it is possible to temporarily maintain the functionality of the electrical network instead of disconnecting its damaged section. This can be achieved through the use of incomplete-phase network operating modes, in which grounding devices will provide the function of a neutral or phase conductor. The article examines the existing regulatory requirements for the values of grounding device resistances in accordance with the Regulations for Electrical Installations. The theoretical principles for calculating distributed grounding devices are described, and equivalent circuits of the electrical network for a grounding device, which is a lattice structure as a special case of distributed grounding devices, are given. A formula has been empirically derived, using which it is possible to calculate the resistance of distributed grounding devices ensuring the use of a two-sided single-phase ground fault mode. Using the obtained formula, the dependences of the resistance of distributed grounding devices on the distance between them were plotted for different values of soil resistivity. The dependences of the resistance of distributed grounding devices and the intact phase were also derived for different values of the grounding device electrode length for different designs of overhead line wires. Experimental studies were carried out to verify the obtained results of theoretical studies, from which it has been determined that the degree to which the results of theoretical and experimental data on the resistance of distributed grounding devices agree with each other ranges from 78 to 93%.