Technical Support

What are low resistance faults and high resistance faults

:2024-11-08 17:03:45:

Low resistance fault and high resistance fault are two common abnormal situations in cables, which are mainly distinguished based on the insulation resistance value of the cable fault point.

1. Low resistance fault

Low resistance fault refers to the occurrence of abnormally low resistance in a cable. Specifically, when the insulation resistance of the cable fault point drops below the characteristic impedance of the cable, or even the DC resistance approaches or is zero, this fault is called a low resistance fault or short circuit fault. The causes of low impedance faults can include cable short circuits, insulation moisture, and external substances entering the cable. When a short circuit occurs in a cable, the current will jump directly from one point to another, causing a decrease in resistance value. When the insulation of the cable becomes damp or external substances enter, it can also cause a decrease in resistance. Low impedance faults may cause issues such as excessive current and equipment damage. In terms of detection methods, low resistance faults can usually be detected through methods such as cable short-circuit testing.

2. High resistance fault

High resistance fault refers to the occurrence of abnormally high resistance in the cable. Specifically, when the insulation layer of the cable is damaged, resulting in a decrease in insulation resistance, but it is not close to zero, but between several hundred kiloohms and several megaohms, a high resistance fault occurs. This type of fault is different from low resistance faults, which refer to situations where the insulation resistance is close to zero. High impedance faults may be caused by various factors, including cable aging or damage, external object compression or damage to the cable, poor contact of cable joints, damage to cable insulation materials, and other external factors such as lightning strikes, environmental temperature changes, etc. High impedance faults may cause issues such as poor current flow and unstable voltage. In terms of detection methods, high impedance faults can be detected through methods such as cable impedance measurement.

Summary: Low resistance faults and high resistance faults are common resistance anomalies in cables, and they have some differences in definition, causes, effects, detection methods, and handling methods. Understanding these differences helps to more accurately diagnose and handle cable faults, ensuring the safe and stable operation of the power system. In practical applications, it is necessary to select appropriate testing methods and tools based on specific situations for fault detection and localization.

KST-700A2组合.jpg

The ZC-700A cable fault tester can be used to detect low resistance, high resistance, short circuit, open circuit, leakage faults, and flashover faults of various cables. It can accurately detect the fault point location, cable length, and cable burial path of underground cables. It has the characteristics of accurate testing, high level of intelligence, wide adaptability, stable performance, and lightweight portability. The instrument adopts a Chinese character system, high-definition display, and user-friendly interface.

Cable tracing and fault location are composed of a pathfinder, a locator, a T-probe, an A-frame, an earpiece, etc. This instrument is a specialized instrument for cable fault location testing, suitable for testing various cables with metal conductors (wire pairs, protective layers, shielding layers). Its main functions are to locate and test points of poor ground insulation, detect cable paths, and test cable burial depth.

Kvtester Electronics Technology Co.,Ltd. is a high-tech enterprise specializing in power testing, testing, research and development, production, and sales of testing equipment. It has been engaged in the electrical testing industry for many years, and its products are of high quality. We welcome customers to come and purchase. Service hotline: 0086-27-81778799, to learn more, visit the official website: www.kvtester.com

My Site © www.kvtester.com    Powered By Kvtester