Moisture intrusion degree monitoring and evaluating method for power cable terminal

Abstract

The invention discloses a moisture intrusion degree monitoring and evaluating method for a power cable terminal. The method comprises the following steps: arranging a cable terminal moisture intrusioninspection device at a terminal part when a power distribution network cable is laid; and monitoring the internal humidity of the cable terminal by using an inspection device, and judging whether theinspection device continuously monitors the internal humidity of the cable terminal or evaluates the moisture intrusion degree of the cable terminal. The method has the beneficial effects that a moisture phenomenon of the urban power distribution network cable terminal can be efficiently, accurately and conveniently evaluated in real time, the problem of terminal explosion caused by moisture intrusion in the cable terminal is avoided, and reliable operation of the method is realized. The moisture intrusion degree of the power cable terminal can be evaluated, and a basis is provided for further exploring the internal insulation state of the cable terminal.

Description

technical field [0001] The invention relates to the field of cable terminal fault evaluation, in particular to a method for monitoring and evaluating the moisture intrusion degree of a power cable terminal. Background technique [0002] With the continuous expansion of modern city functions, power cables, as a power energy transmission facility with excellent electrical and mechanical properties, have been more and more widely used. In recent years, cross-linked polyethylene cables have become the most important application choice in urban construction. Since the insulation of cross-linked polyethylene cables is an extruded whole, this type of cable is famous for its waterproof and moisture-proof performance at the beginning of its investment. It has been favored by users, promoted vigorously and replaced the original line on a large scale, and people often ignore the work of preventing moisture intrusion, so that large areas of cross-linked polyethylene cables are soaked in...

AI Technical Summary

Problems solved by technology

With the prolongation of the operation time, the XLPE cables and terminals are gradually dampened due to moisture intrusion. After being eroded by moisture, a series of physical and chemical effects will occur under the action of a strong electric field, and "water branches" will be formed along the direction of the electric field in the insulation. The phenomenon of XLPE cable insulation is becoming more and more serious, leading to breakdown accidents of cable insulation. Experiments have shown that when the humidity of the operating environment reaches above 65%, the XLPE cable insulation material may form water tree defects, which seriously affects its insulation performance.

In addition, the intrusion of moisture will lead to serious corrosion of the shielding layer, which will also concentrate the electric field of the cable and terminal insulation, which will increase the contact resistance and cause serious heat generation, resulting in a sharp decline in the insulation performance of the cable.

[0003] At present, the methods for detecting and judging the moisture intrusion of power cable terminals laid in cable trenches are still relatively scarce. The detection methods currently widely used in the field are not aimed at moisture intrusion faults, and the detection effect is very poor, and the main research has not paid attention to This problem has caused great trouble to the safe and reliable operation of high-voltage cables in cities

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