METHOD FOR DETERMINING DISTANCE TO PLACES OF DOUBLE EARTH FAULTS ON POWER LINES IN NETWORKS WITH LOW EARTH FAULT CURRENTS

摘要

FIELD: electric power industry.;SUBSTANCE: invention relates to the electric power industry and can be used to determine the locations of damage in case of double earth faults on one power transmission line of a 6-35 kV distribution network with low earth fault currents. The phase current and phase voltage are measured, the emergency mode associated with the occurrence of a double earth fault on the same line according to the growth of the phase currents of the damaged phases is determined, the mutual inductive resistance of the phases of the damaged power transmission line is considered. Along with the currents and voltages of the emergency mode, the currents and voltages of the pre-emergency normal mode are recorded. By the difference between the currents and voltages of the emergency and pre-emergency modes, the components of the purely emergency mode are obtained. The distance to the near place of damage and the far place of damage is calculated, providing a decrease in the influence of the current distribution of the branches and the load mode on the accuracy of calculations due to the use of currents and voltages of a purely emergency mode.;EFFECT: invention improves accuracy of determining the distance to ground faults on one power line by reducing the influence of the load and branches of power lines.;1 cl, 5 dwg