Resistance lowering device and method for a power cable high-resistance fault point

A power cable, high-resistance fault technology, applied in the field of power cables, can solve the problems of low-resistance at the fault point, short equipment life, low efficiency, etc., and achieve the effect of shortening the time of low-resistance, low cost, and cost reduction

Active Publication Date: 2016-07-27
西安宇铭电物理技术有限责任公司 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Existing equipment uses high-voltage pulse equipment to repeatedly break down the fault point and carbonize it by injecting pulse current. This method usually takes more than 30 minutes to achieve low resistance at the fault point, with low efficiency and short equipment life.

Method used

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  • Resistance lowering device and method for a power cable high-resistance fault point
  • Resistance lowering device and method for a power cable high-resistance fault point

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] This embodiment is a device and method for reducing the resistance of a high-resistance fault point of a power cable. The schematic diagram of the discharge circuit is as follows figure 1 shown. After confirming the high-resistance fault of the 10kV XLPE power cable, the device and method of the present invention are used to reduce the resistance of the high-resistance fault point of the power cable. Adjust the charging voltage of the adjustable constant voltage / constant current power supply to +100V; adjust the ball gap and the single high voltage pulse generator to output a positive polarity pulse high voltage of 12kV. The pulse high voltage propagates forward along the cable. When the high-resistance fault point of the power cable reaches the breakdown voltage, the adjustable constant voltage / constant current power supply outputs 10A DC current to the fault point, and the high-resistance fault point of the faulty cable is about 10s Burned through, showing a low resi...

Embodiment 2

[0055] This embodiment is a device and method for reducing the resistance of a high-resistance fault point of a power cable. The schematic diagram of the discharge circuit is as follows figure 1 shown. After confirming the high-resistance fault of the 35kV XLPE power cable, the device and method of the present invention are used to reduce the resistance of the high-resistance fault point of the power cable. Adjust the charging voltage of the adjustable constant voltage / constant current power supply to +200V; adjust the ball gap and the single high voltage pulse generator to output a positive polarity pulse high voltage of 40kV. Pulse high voltage propagates forward along the cable. When the high-resistance fault point of the power cable reaches the breakdown voltage, the adjustable constant voltage / constant current power supply outputs 20A DC current to the fault point. Burned through, showing a low resistance state.

Embodiment 3

[0057] This embodiment is a device and method for reducing the resistance of a high-resistance fault point of a power cable. The schematic diagram of the discharge circuit is as follows figure 1 shown. After confirming the high-resistance fault of the 40kV XLPE power cable, the device and method of the present invention are used to reduce the resistance of the high-resistance fault point of the power cable. Adjust the charging voltage of the adjustable constant voltage / constant current power supply to +300V; adjust the ball gap and the single high voltage pulse generator to output a positive polarity pulse high voltage of 50kV. Pulse high voltage propagates forward along the cable. When the high-resistance fault point of the power cable reaches the breakdown voltage, the adjustable constant voltage / constant current power supply outputs 30A DC current to the fault point. Burned through, showing a low resistance state.

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PUM

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Abstract

The invention discloses a resistance lowering device and method for the power cable high-resistance fault point.The resistance lowering device comprises a high-voltage pulse generating part and a direct-current arc maintaining part, wherein the high-voltage pulse generating part and the direct-current arc maintaining part are in parallel.The high-voltage pulse generating part is connected with the direct-current arc maintaining part through a sphere gap, a magnetic switch and a silicon stack; when the resistance lowering device for the power cable high-resistance fault point operates, pulse voltage is firstly output, and a direct current for keeping arc burning is finally output.When the resistance lowering device for the power cable high-resistance fault point operates, a high-voltage pulse firstly acts on a high-resistance fault point of a cable, after the high-resistance fault point of the cable is broken down by the high-voltage pulse and arc discharging is carried out, resistance is decreased to be close to a short circuit, and the direct-current arc maintaining part provides the direct current for the high-resistance fault point to keep arc burning till the high-resistance fault point is subjected to resistance lowering.According to the resistance lowering device and method, under the condition that the power cable is not damaged, main insulation of the cable of the high-resistance fault point can be partly carbonized within ten more seconds to dozens of seconds, and resistance to ground of the fault point is subjected to resistance lowering.

Description

technical field [0001] The invention belongs to the technical field of power cables, in particular to a device and method for reducing the resistance of a high-resistance fault point of a power cable. Background technique [0002] The single-phase grounding insulation faults of widely used XLPE power cables can be mainly divided into cable body faults and cable head faults. The main body fault is manifested as a high-resistance type and a low-resistance type at the fault point. When the resistance of the fault point of the power cable is low, the low-voltage pulse reflection method is generally used, that is, a low-voltage pulse is injected at any end of the fault cable, and the time interval between the pulse and the reflected wave is measured, so as to roughly obtain the length of the fault point from the measuring end; When the resistance of the fault point of the power cable is high, the low-voltage pulse has no obvious reflection at the fault point. The ground resistan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/083
Inventor 吴红延王维黄易之薛军白晓斌常江
Owner 西安宇铭电物理技术有限责任公司
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