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Zero sequence voltage protection

        Zero sequence voltage is a three-phase line in a phase or two-phase ground generated, the size depends on the degree of grounding, metal grounding, non-metallic grounding, is the grounding resistance. Zero sequence power at the point of failure, the fault point of the zero sequence voltage is highest, the distance from the fault point in the system the lower the zero sequence voltage, dependinge and zero sequence of the degree of measurement (sometimes only one of them), so by detecting the two should not be normal The weight of the system, you can know the system out of the problem (especially when the single-phase ground zero sequence component). on the measurement point to the earth between the size of the impedance. When the system fails, the three phases become asymmetrical, then the decomposition of the amplitude of the negative sequenc.

       
  When a neutral point direct grounding system (also known as high current grounding system) occurs in the ground short circuit, there will be a large zero sequence current. Also in the neutral point is not directly grounded system (through the high impedance grounding system or by arc suppression coil grounding system) in the event of single-phase ground, it will produce zero sequence voltage.
       
  Zero sequence power at the point of failure, the fault point of the zero sequence voltage is highest, the distance from the fault point in the system the lower the zero sequence voltage, depending on the measurement point to the earth between the size of the impedance.
       
  The positive sequence, the negative sequence and the zero sequence are used to analyze the asymmetric components of the three phases into the symmetric components (positive and negative sequence) and the zero sequence components of the same direction in the system voltage and current asymmetry. As long as the three-phase system, you can break down the three components (a bit of the synthesis and decomposition of the force, but in many cases the value of a component is zero). For the ideal power system, because the three-phase symmetry, so the negative sequence and zero sequence component values ​​are zero (that is, we often say that the normal state only positive sequence component of the reasons). When the system fails, the three phases become asymmetrical, then the decomposition of the amplitude of the negative sequence and zero sequence of the degree of measurement (sometimes only one of them), so by detecting the two should not be normal The weight of the system, you can know the system out of the problem (especially when the single-phase ground zero sequence component).
       
  Zero sequence voltage is a three-phase line in a phase or two-phase ground generated, the size depends on the degree of grounding, metal grounding, non-metallic grounding, is the grounding resistance.
       
  Zero sequence current and zero sequence voltage distribution or substation in the background monitoring software is generally used as a fault signal to deal with, its normal value is zero, if there is a failure, the computer will automatically alarm.
 
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