THE DISTANCE DETERMINIG METHOD OF THE SINGLE-PHASE EARTH FAULT IN ELECTRIC DISTRIBUTION NETWORKS

摘要

The invention relates to the electrical power sector protective relaying and automation, used for determining the location of earth fault in power line networks with isolated neutral and compensated neutral. For determining the distance from the busbar till the single-phase earth fault, then an emergency mode measured in the damaged phase voltage U PH, damaged phase I PH and undamaged phases I FL currents, zero sequence current I 0 as well as a current in transformer neutral I TR, but pre-fault (load) mode synchronized time points measured undamaged phase currents I L, at which damaged the line resistance Z LF from busbar to the lesion site F is proportion to the distance determined by the expressions:I F = I 0 + I FL - I L , unRF = Real (U PH / IF ) ,where: I FL and RF are the current and the transition resistance in lesion place; RGR is grounding circuit resistance for transformer neutral ; K0 is zero sequence current compensation quotient.