METHOD FOR DETERMINING MAXIMAL OVERLOADS FOR ONE-PHASED ARC SHORT CIRCUITS ON GROUND IN NETWORKS WITH INSULATED NEUTRAL Russian patent published in 2006 - IPC G01R31/08 

FIELD: electric power engineering, possible use for determining overloads during one-phased arc short circuits on ground in distributive networks with insulated neutral.

SUBSTANCE: method includes performing artificial shorting of phase to ground on source bus during passage of phase voltage through zero value. Phase shorting is performed through resistor R₃ with resistance, appropriate to resistance of arc. Into short phase from current source current is injected, alternated in broad range and having constant amplitude. Components of industrial frequency in measured values of current and phase voltages are suppressed (filtered). At the moment of first voltages maximum on one of unlocked phases oscillations period T₁, amplitude and phase of injected current and voltage on shorted phase are determined. In accordance to expression (where C_p- phase capacity of network) active-inductive resistance Z is determined for contour at frequency decrement , and level of maximal overloads in network is

EFFECT: simplified method, improved effectiveness and speed of determining of maximal overload level.

4 dwg