The fault detection and analysis methods of power cables mainly include traditional fault finding methods and modern technology applications.
Traditional fault finding methods:
Bridge method and low-voltage pulse reflection method: These two methods were widely used before 1970 to test power cable faults.
Acoustic magnetic method and audio induction method: Used for pinpointing, that is, to determine the exact location of the fault point.
Fault locator method: Use a special fault locator to measure the electrical parameters of the cable, and determine the approximate location of the fault point by comparing the measurement results of the normal line and the fault line.
Thermal infrared detection method: Use an infrared imager to detect temperature anomalies on the surface of the cable. The fault point usually generates heat, which is displayed on the infrared image.
High-frequency pulse detection method: Use the propagation characteristics of high-frequency pulse signals in the cable to find the fault point.
Partial discharge detection method: The common partial discharge phenomenon in cable faults will cause the radiation of electromagnetic waves. The fault point can be located by detecting these electromagnetic waves.
Cable grounding detection method: By detecting the grounding resistance and current of the cable, determine whether there is a grounding fault, and further locate the fault point.
Modern technology applications:
Artificial neural network: A new information processing theory with good adaptability, self-organization and fault tolerance, providing a new way for cable fault distance measurement.
GPS traveling wave fault location: The global positioning system (GPS) is used for cable fault distance measurement, and the fault surge is located by the time difference between the two ends of the cable.
Distributed fiber optic temperature sensor (FODT): The fault distance is calculated by the injection time of the laser pulse and the arrival time difference of the reflected light, and the operation of the cable line is monitored at the same time.
These methods have their own characteristics and applicable scenarios. The selection of an appropriate method requires comprehensive consideration based on the specific situation, including fault type, cable type, detection accuracy and cost.