(1) The cable manufacturer is required to use the protective layer outside the metal sheath of the AAC Cable when manufacturing the cable, and the aluminum sheathed cable must have polyethylene or PVC outer sheath.
2) When selecting the cable route, it is necessary to make full investigation, collect the soil data near the area where the line passes, and carry out chemical analysis, so as to judge the degree of soil and groundwater erosion. If necessary, measures should be taken, such as changing the route of the line, partially replacing the bad soil, or adding special protective measures, such as putting the cable through the corrosion-resistant pipe.
Prevent external damage and theft of facilities
Design and infrastructure stage
The setting of cable route, auxiliary equipment and facilities (ground grounding box, entrance and exit, ventilation Pavilion, etc.) shall be approved by the planning department. It should be avoided that the cable passage is adjacent to the thermal pipeline, flammable and explosive pipeline (oil and gas) and corrosive medium pipeline.
Note: it is a new clause. It is proposed that the route, auxiliary equipment and facilities should be approved by the planning department, and the requirements of avoiding the cable passage adjacent to thermal pipelines, flammable and explosive pipelines (oil and gas) and pipelines with corrosive media should be avoided.
It is difficult to understand the corrosion degree of the cable on the running cable line. In the area where the corrosion of the cable has been found or the leakage of some chemicals piled on the ACSR Cable line, the soil should be dug to check the cable, and the nearby soil should be chemically analyzed to determine the damage degree
2. Methods to prevent electrolytic corrosion
(1) strengthen the insulation between the metal sheath of the cable and the huge metal objects nearby.
(2) installation of drainage or forced drainage, polarity drainage equipment, cathode station, etc.
(3) for areas with serious electrolytic corrosion, shielding pipes should be installed.
stray current is related to the distribution of electrical track, the maintenance of joints and the layout of other underground metal pipelines. In order to protect the underground pipelines and communication cables, the departments of underground oil and gas pipelines and local communication cables sometimes adopt cathodic protection. Therefore, the cable operation Department must systematically measure the potential difference between the lead sheath and the earth and other pipelines, the stray current density of the lead sheath and the current density flowing into the earth, so as to accumulate data. When we know which area is in danger of corrosion, we should take preventive measures in time, and work together with relevant units to try to eliminate the source of stray current and do a good job of corrosion prevention.
the operation experience shows that when the current density from the cable metal sheath reaches the average value of one day and night, the metal sheath will be corroded. This paper introduces a method of measuring stray current density auxiliary electrode method,
the auxiliary electrode is made of a section of cable similar to the tested cable, and its length should be such that the contact surface between the electrode and the earth is not less than 500. Peel off the outer protective layer of the electrode surface, wipe off the armored surface, weld the connecting wire, and pour asphalt or other insulating materials on the solder joint insulation and both ends of the electrode.
In addition to cable corrosion, there are also corrosion phenomena such as metal bracket, metal hoop and grounding wire in cable channel.