Vestnik MGTU (Dec 2023)
The single phase-to-ground fault location calculation method based on limited information on the distribution of zero-sequence voltages on the tree-structured feeder
Abstract
One of the key goals in the overhead power lines at the isolated neutral system 6–10–35 kV is topographic search area limitation for a single phase-to-ground (SPG) fault. This will ensure reliability improvement warranty and continuity of power supply. No fault founded in time can lead to failure of electrical equipment. Faults can initiate a ground fire in dry-weather period, which requires preventive shutdown of power lines with subsequent economic damage to power supply organizations. The paper proposes the use of emergency mode parameters, namely, zero-sequence voltages, in order to determine the faults locations in a calculated way. The need for additional installation of measuring voltage transformers at terminal substations is associated with some financial costs. In this regard, the possibility of their limited use is being considered. It has been shown that in this case the emergency section can be localized with accuracy down to the tap if there are no measuring voltage transformers on it. To calculate the SPG location, a mathematical model of lines with distributed parameters has been used. Signals at higher harmonics (HH) generated in the electrical network by arc faults, are considered useful. Full-scale experiments show the HH presence also during electrical contacts of wires with metal structures. The high frequency of the signal causes a significant change in voltage along the length of the line, which increases the accuracy of calculations. The use of zero sequence voltages promotes detuning from the influence of substation load. An algorithm has been developed for performing calculations to determine the location/area with a ground protection zone on a tree-structure feeder.
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