A brief discussion on the difficulty of locating power cable on-site faults

Due to the variability of power cable installation and use environments, coupled with the introduction of new materials for various cables and accessories, on-site fault location for power cables is becoming increasingly difficult.

The difficulty of on-site cable fault location is particularly evident in locating faults in directly buried power cable lines. While there are currently classic technical literature and advanced fault detectors for high-resistance faults in power cable lines, on-site use of professional cable fault locators can sometimes encounter difficult and challenging faults that are difficult to locate. For example, localized creepage and flashover faults on the J-edge surfaces of medium-voltage cross-linked power cable terminals and intermediate connectors, as well as metallic short-circuit faults, are often difficult or inadequate to accurately locate using professional cable fault locators.

For common cable faults, commercially available cable fault locators can typically locate the fault within minutes or hours. However, for complex and challenging faults, repeated testing with multiple cable fault detectors with different functions may be necessary, requiring rotational testing and verification of the location. These fault detectors primarily include various cable fault detectors designed and developed based on the bridge and waveform methods. This method can take several days or even longer to locate the fault. With luck, the fault point can be located, but with bad luck, it can remain undetermined.

In northern my country, the ground freezes in winter. When a direct-buried cable fails, the actual fault location and troubleshooting process can be quite arduous. First, the cable fault location instrument must be highly accurate. Secondly, personnel with a thorough understanding of the cable's actual routing are essential. Although some cable fault detection instruments now include cable path testers, the cooperation of on-site personnel with a general understanding of the cable's routing is still necessary to achieve high locating accuracy. In practice, troubleshooting cable faults often relies 30% on human intervention and 70% on machine assistance.

Currently, numerous manufacturers offer a wide variety of cable fault detection instruments, but none can actually locate all cable faults. In practice, these instruments are often only effective for locating one or a few types of faults, leaving some unresolved. Today's power users are eager to invest heavily in a fully functional, high-precision cable fault detector (including both coarse and fine positioning) to quickly and effectively resolve all practical cable faults. However, this is often difficult to find. While a wide variety of cable fault detectors are constantly being introduced to the market, field inspections still encounter technical difficulties that cannot be located using a cable fault detector. I believe this is primarily due to two factors: first, the continuous development and upgrading of various insulation, filling, and wrapping materials used in cables and their accessories has led to a constant change in cable fault types; second, the limited market demand for cable fault detectors and the scarcity of relevant R&D personnel have hindered the development of portable, high-precision, intelligent, and multifunctional cable fault detectors. I believe that with the advent of the smart grid era and the rapid advancement of cable fault detection technology, locating cable faults will become a simple and easy task.