2026-03-30
On March 23, we received a mission to trace the route of a power cable:
A new transmission tower was being constructed outside the substation, necessitating the installation of a new 110 kV cable route leading into the facility. Prior to excavation, however, it was imperative to determine whether any existing cables lay within the designated digging zone.
One end of the existing cable terminated at a GIS switch inside the substation, while the other connected to a 110 kV tower located outside. Unfortunately, the tower's nameplate was illegible, making it impossible to identify which specific switch the cable corresponded to.
The cable itself was directly buried in the ground, spanning a distance of approximately 300 meters, and remained energized throughout the entire operation. Furthermore, the cable platform on the tower was situated at a considerable height, rendering standard signal coupling methods—typically used for such tasks—impractical.
The critical challenge was this: regarding the area slated for excavation, no one knew whether any cables lay beneath the surface—let alone their precise routing. It was, in every sense of the word, a true "blind test."
Faced with live-line operating conditions and the inability to establish a direct connection, we selected the XHGX507C pipeline locator. Inductive detection thus became the primary method employed for this mission.
This constitutes the most critical step in the entire detection process.
Two-Person Team: Utilizing the XHGX507C Pipeline Locator, one operator holds the transmitter while the other holds the receiver; maintaining a distance of approximately 10 to 20 meters between them, they move forward in parallel.
Directional Control: The orientation of the transmitter is aligned with the estimated direction of the pipeline, while the receiver's antenna is positioned perpendicular to the probable direction of the underground utility line.
Dynamic Tracking: As they move, the receiver operator continuously shifts the receiver back and forth to monitor signal fluctuations on the display screen in real time.
When a cable is present beneath the device, the receiver's signal strength increases significantly; the energy bar on the screen rises, accompanied by directional arrow prompts (left and right)—indicating that the receiver is approaching the position directly above the cable.
Continue to fine-tune the position until the receiver is situated precisely above the cable; at this point, the signal reaches its peak intensity. We then mark this specific spot on the ground.
If the receiver drifts away from the cable, the energy bar diminishes, and a single arrow appears on the screen, clearly indicating the direction in which the cable lies.
Proceeding in this manner—using two visible cable points as a starting reference—we systematically extend our detection outward across the excavation zone. By repeating the aforementioned procedure every ten to fifteen meters, the consecutively marked points form a continuous line, thereby gradually revealing the precise routing of the cable.
Through the collection of a series of signal points, we have successfully mapped out the complete trajectory of the cable as it extends outward from the known reference points in both directions.
The distribution of cables within the excavation zone has now been clearly defined: it is immediately apparent which areas contain cables and which areas do not. This result serves as a direct guide for formulating the safety protocols required for the subsequent cable-laying operations associated with the construction of the new transmission tower.
