Single-phase ground wire selecting equipment and method of neutral-point uneffect earthed system

A non-effective grounding, single-phase grounding technology, applied in fault location, protection against overcurrent, etc., can solve the problems of automatic single-phase grounding fault line selection, one empty, difficult signal detection, etc.

Inactive Publication Date: 2007-02-14
徐文远 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

From completely relying on the information of the fault current itself to artificially injecting signals for line selection, this is a change in thinking to solve the problem of single-phase grounding line selection in neutral point non-effectively grounded systems. The limitations of strength and characteristics make it very difficult to detect signals injected when the grounding resistance is large or for loads with serious power pollution
Therefore, although the line selection equipment manufactured according to the above-mentioned many principles is widely used in domestic distribution network systems, so far there is no line selection equipment with a line selection accuracy rate of more than 80%, especially for systems such as coal mines and oil fields. For serious loads, its automatic single-phase ground fault line selection is always an empty

Method used

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  • Single-phase ground wire selecting equipment and method of neutral-point uneffect earthed system
  • Single-phase ground wire selecting equipment and method of neutral-point uneffect earthed system
  • Single-phase ground wire selecting equipment and method of neutral-point uneffect earthed system

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Experimental program
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Effect test

Embodiment 1

[0069] Embodiment 1: Single-phase grounding line selection equipment for neutral point non-effectively grounded systems, mainly including a controllable short-circuiter and a short-circuit pulse detector; the controllable short-circuiter is connected between the neutral point and the ground, and the step-down transformer (or current-limiting inductance), voltage transformer, thyristor or a pair of opposite polarity thyristor group and thyristor firing angle controller; the short-circuit pulse detector is located at the exit of each outgoing line, mainly by signal acquisition and processing board composition.

[0070] The firing angle controller is equipped with a bus voltage input and multiple auxiliary input ports, the short-circuit pulse detector is equipped with a remote control output port, and there is a channel for simple data exchange between the firing angle controller and the short-circuit pulse detector .

[0071] The controllable short circuit is directly connected...

Embodiment 2

[0081] Embodiment 2: The structure and specific implementation method of the present invention are the same as Embodiment 1, the difference is that the controllable short-circuiter is directly connected between the neutral point of the transformer and the ground, and is connected in parallel with the arc suppression coil, such as Figure 4 shown.

Embodiment 3

[0082] Embodiment 3: The structure and specific implementation method of the present invention are the same as Embodiment 1, the difference is that the controllable short-circuit device is connected in series on the secondary side of the arc suppression coil or its PT, such as Figure 5 shown.

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Abstract

A method for selecting wire of single phase earthing in neutral point noneffective earthing system includes making instant short circuit between neutral point and ground at position near two ends voltage polarity from positive to negative over zero by short circuiter set between neutral point and ground when single phase earthing is occurred in neutral point noneffective earthing system and state is stabilized in order to generate a short circuit pulse current being used to judge earthing line through short circuit detector. The device for realizing said method is also disclosed.

Description

1. Technical field [0001] The invention relates to a single-phase grounding fault line selection technology for a neutral point ineffective grounding system of a distribution network, in particular to a single-phase grounding line selection device and method for a neutral point ineffective grounding system. 2. Background technology [0002] Most distribution networks in my country adopt the non-effective neutral point grounding operation mode. Since the power supply can still maintain the symmetry of the line voltage when a single-phase grounding occurs, and the fault current is small, it does not affect the continuous power supply to the load, so it is not necessary to immediately Tripping, the regulations stipulate that it can continue to run for 1 to 2 hours. However, with the increase of feeders and the widespread use of cables, the capacitive current will continue to increase. After a single-phase grounding operation for a long time, the fault will easily expand to two o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08H02H3/08
Inventor 徐文远朱珂
Owner 徐文远
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