What are the causes of errors in cable fault detector equipment?

While cable fault detectors offer a certain degree of convenience in cable fault detection, in practice, various uncertainties can lead to deviations in detection results. So, what are the causes of cable fault detector errors?

Cable Fault Detector

Human Error

Currently, cable fault detectors based on the traveling wave method primarily rely on testers to determine the distance to the fault by analyzing the fault detection waveform. User interpretation errors can sometimes lead to detection errors, often due to the tester's experience. These errors primarily stem from the application of the detection method, the test voltage level, wiring details, and the determination of waveform inflection points. This is a major reason why cable fault detection is more difficult than other electrical equipment faults. Due to the irregularities and complexity of cable fault detection waveforms, truly automatic fault location calculation is currently difficult.

Cable Fault Detector

Cable Error

This error is primarily caused by the propagation speed (V) of radio waves along the cable under test. The formula L = (U*T)/2 shows that the cable fault detection distance L is directly proportional to V. In cable fault detection, V is considered a constant, a relative concept, not an absolute value. Actual measurements and relevant data indicate that the transmission velocity V generally exhibits a relative error of ±2%. For example, the transmission velocity V of XLEP cable is approximately 172.3 m/s. There are two reasons for this error: First, the same type of cable produced by different manufacturers may exhibit errors due to factors such as production processes and ingredients. Second, cable insulation aging causes V to vary. Currently, there is no accurate data to explain this variation. Note: There may be inconsistencies between the marked length, actual length, and test length of the cable being tested.

Cable Fault Detector

Environmental Error

After a rough cable fault is detected, the distance along the cable is typically measured based on the detected distance data. However, due to adverse environmental conditions (such as rivers, ditches, buildings, etc.) and the winding nature of buried cables, accurate measurement is extremely difficult, and often only a very rough location can be determined. This error, also known as measurement error, is often an unpredictable source of error. Therefore, establishing and improving detailed power cable records is crucial, and digital management of pipeline networks using GIS will become even more essential in the future.

Cable Fault Detector

In addition to the aforementioned factors, cable fault detector errors can be caused by other factors, such as equipment failure. To avoid errors in cable fault detector detection, careful data analysis is required during testing.