Single-phase grounding leakage line selection method and device of industrial and mineral low-tension electrical network

Single-phase grounding leakage line selection method and device of industrial and mineral low-tension electrical network

  • CN 105,606,954 A
  • Filed: 11/16/2015
  • Published: 05/25/2016
  • Est. Priority Date: 11/16/2015
  • Status: Active Grant
First Claim
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1. an industrial and mineral low voltage electric network single-phase earthing electric leakage selection method, is characterized in that, comprises the following steps:

  • (1) take out fault from three phase network bus and judge starting resistor signal u0qWith residual voltage signal u0

    Fault judges starting resistor signal u0qAfter entering single-phase earth leakage route selection module, form square-wave signal U0Q, be used as zero sequenceThe enabling signal of first-harmonic multiple frequency phase method of discrimination;

    Residual voltage signal u0Enter after single-phase earth leakage route selection moduleForming pulsewidth is the initial voltage square-wave signal U that 0~

    180 degree changesOAWith initial voltage square-wave signal U0L, useUsing the basis signal as the processing of residual voltage signal frequency multiplication;

    U0q

    U0AAnd U0LSignal all enters zero sequence first-harmonic doublyFrequently phase judgment device;

    (2) U of the reflection three phase network dielectric level size of taking out from same section of bus of this three phase networkjySignal, UjySignal forms U after entering single-phase earth leakage route selection moduleJYSignal, moves as three phase network dielectric levelThe direct current detection signal of resistance value size;

    UJYSignal enters zero sequence first-harmonic multiple frequency phase discriminating gear;

    (3) respectively feed out the secondary side-draw of the zero sequence current mutual inductor circuit from same section of bus of this three phase networkGo out zero sequence current signal i0

    i0Signal enters and forms pulsewidth after single-phase earth leakage route selection module is between 0~

    170 degreeThe initial current square-wave signal I changingOAWith initial current square-wave signal IOL, as zero sequence current signal frequency multiplication placeThe basis signal of reason;

    Respectively feed out the I on circuit0AAnd I0LSignal all enters zero sequence first-harmonic multiple frequency phase discriminating gear;

    (4) the zero sequence first-harmonic multiple frequency phase decision rule of setting single-phase earthing leak current fault circuit;

         1) simultaneouslyBe the optional frequency U between 50HZ to 250HZ by zero-sequence fundamental voltage and zero sequence current signal frequency multiplication0BSignal andI0BSignal;

         2) residual voltage signal U0BTrailing edge must be positioned at zero sequence current signal I0BRising edge and declineBetween edge, and residual voltage signal U0BPulsewidth must be greater than zero sequence current signal I0BPulsewidth;

    Each branch roadZero-sequence current and residual voltage signal differentiate by above-mentioned two zero sequence first-harmonic multiple frequency phase decision rules;

    (5), when a certain while feeding out branch road generation single-phase earthing leak current fault, zero sequence first-harmonic multiple frequency phase is differentiated dressPut the zero sequence current signal that decision rule according to the rules butts up against on same three phase network each and feed out branch roadi0Carry out zero sequence first-harmonic multiple frequency phase and differentiate, non-fault branch if, zero sequence first-harmonic multiple frequency phase discriminating gearThe output of fault-free signal;

    Fault branch if, zero sequence first-harmonic multiple frequency phase discriminating gear output fault-signal,And carry out lamplight pointing fault branch and audible alarm by peripheral drive circuit, through single-chip microcomputer management systemCarry out Chinese character demonstration, combined network communication, print fault information;

    Simultaneously through drive circuit make fault branch move inTripping operation.

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