Method for finding low voltage cable ground fault point using a safe ac power supply

By using a safe AC power supply combined with various measurement methods and tools, the problem of difficult location of low-voltage cable grounding faults has been solved, achieving fast, safe, and flexible fault location. It is suitable for low-voltage cable grounding fault detection in TN-S street light power supply systems.

CN122109712APending Publication Date: 2026-05-29JINJIANG YIZHONG LIGHTING DEV CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
JINJIANG YIZHONG LIGHTING DEV CO LTD
Filing Date
2026-03-03
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Existing technologies make it difficult to quickly and safely locate grounding faults in low-voltage cables, especially outdoor low-voltage cables. Traditional detection methods suffer from low accuracy, slow speed, and the potential for equipment damage and safety violations if operated improperly.

Method used

By using a safe AC power supply combined with various measurement methods and tools, and by measuring the current in each phase circuit and the principle of current change, the grounding fault point of the low-voltage cable is located. This includes applying voltage to the control cabinet outlet, using a portable clamp meter or the two-way method to disconnect the cable head, and using a self-resetting fuse to determine the location of the fault point.

Benefits of technology

It enables safe and rapid location of low-voltage cable grounding faults, avoids the need to disassemble cable joints, improves search efficiency, ensures operational safety and flexibility, and is suitable for different site requirements.

✦ Generated by Eureka AI based on patent content.

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    Figure CN122109712A_ABST
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Abstract

The application discloses a method for searching for a low-voltage cable grounding fault point by using a safe alternating power supply, and the method takes a TN-S street lamp power supply system as a research object. A power supply cable PE line is connected with a power distribution cabinet body grounding end and the inner wall of each lamp pole. Each lamp pole is connected with a street lamp foundation and connected with the ground through a grounding electrode. After a branch leakage protection device acts, a 0.5A self-resetting fuse is connected in series at one end of the safe alternating power supply, and connected to the power supply cable A, B, C and N phase respectively. After mA meter is connected in series at the other end, the safe alternating power supply is clamped on the power supply cable PE line grounding bus. When a fault phase cable occurs grounding short circuit, the grounding resistance containing the power supply cable resistance and the grounding system resistance is connected in series in the loop. The low-voltage cable grounding fault point can be searched for by the loop alternating current mutation, the safe and rapid positioning of the low-voltage cable grounding fault point can be realized, and the limitation of the traditional detection method is effectively solved.
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