Case Study: Live Path Detection of a 35kV Single-Core Cable

Ⅰ.Pre-Test Preparation

II. Principle Introduction

Audio signal induction method: An audio signal generator injects a current of a specific frequency into the cable, producing a corresponding magnetic field around it. This magnetic field is detected by a sensor coil and converted into an audible or visual signal via magnetoacoustic or magnetoelectric methods, allowing the cable path to be traced.

III.General Path

IV.Test results

As shown in the figure below, no interfering cables were present at the site. The detected path was clear, unique, and undisputed.

V. Test Summary

1. If multiple interfering cables are present at the site, eliminate them by observing the receiver's current value and the known approximate cable paths.

2. In this case, a live path search was performed on a 35kV single-core cable. Since one end was directly grounded and the other was protectively grounded, a direct loop could not be formed. Instead, a signal was applied to the cable to enable path detection, forming a loop through the direct ground and weakly shielded sections.