Due to changes in the environment in which Power Cables are laid and the application of new materials for cables and their accessories in the cables, it is increasingly difficult to locate faults on the power cable site.
The difficulty of field cable fault location is mainly reflected in the fault location of directly buried power cable lines. At present, despite the relevant classic technical literature and advanced fault detectors, it is still available for high resistance faults in power cable lines. However, when using a professional cable fault locator to locate on site, sometimes you will encounter some special and difficult faults that cannot be located. For example, using a professional cable fault locator, part of the creepage flashover fault on the insulation surface of the medium voltage cross-linked power cable terminals and intermediate joints, and accurately determining the metal short-circuit fault, often appears powerless or powerless.
For common cable faults, you can use a cable fault locator purchased on the market to determine the location of the fault point within minutes or hours. However, when you encounter special difficult faults and the detection is not stable, you may need to call multiple cable fault detectors with different functions to repeat the test, and take turns to detect, locate, compare and confirm. The types of these fault devices mainly include various cable fault detectors designed, manufactured and developed based on the principles of bridging method and wave method. In this way, it may take several days or even longer to locate the fault. In this way, if you are lucky, you can determine the location of the fault point. If you are unlucky, the location of the fault point is still uncertain.
In northern China, the ground freezes in winter, and the directly buried cables fail at this time. The actual fault detection and handling process is actually a difficult task. First of all, the cable fault locator used must have high accuracy, and secondly, the corresponding personnel must have a clear understanding of the actual cable laying route. Although some cable fault detection instruments are now equipped with cable path testers, they must also be equipped with cable path testers. Only on-site personnel who understand the approximate laying path of the cable can cooperate to improve the positioning accuracy. The actual handling of cable faults sometimes depends on man-made three points and machine-made seven points.
At present, there are many manufacturers selling cable fault detection instruments on the market, and there are many types of detection instruments, but in fact, it is impossible to locate all cable faults. In actual use, the instrument usually can only effectively locate one or several types of faults, but still cannot do anything about some faults. The current electric power department hopes to spend a lot of money to purchase a universal cable fault tester with complete functions and high positioning accuracy (including rough and precise measurement points) to quickly and effectively solve all actual cable faults. But it’s actually hard to buy. There are various updated cable fault detectors on the market. However, the actual on-site inspection will still encounter some technical problems that cannot be located using the cable fault table. I think the reasons are mainly from two aspects: First, the various insulation, filling and wrapping materials used in the cable and its accessories are constantly being developed and updated, which leads to continuous changes in the types of cable failures. The other is that the market demand for cable fault detectors is limited, and related R&D personnel are scarce, resulting in a delay in the start of portable, high-precision, intelligent and multi-functional cable fault detectors. It is believed that with the advent of the smart grid era and the rapid development of Aerial Bundled Cable ASTM B231 Standard fault detection technology, the location of cable faults will become very simple and easy.