What are the precautions for insulated overhead wires?

Insulated overhead conductors, suitable for places with many trees. For lines erected with bare conductors, there is a great contradiction between the erection and maintenance of the lines and the greening and forestry of the multi-tree areas. The use of insulated overhead conductors can reduce tree felling, protect the ecological environment, beautify the city, and reduce line grounding faults.
Insulated overhead conductors provide better protection against salt spray corrosion. And it is protected by an insulating layer, which can reduce the corrosion of the wire by the salt spray, delay the aging of the line, prolong the service life of the line, and reduce the lightning strike of the line. Even if there is lightning, the impact will be much smaller. Minefield For lines erected with bare conductors, the insulation of the lines will generally drop rapidly, which often leads to sudden grounding accidents. After replacing the insulated overhead conductors, the outage time for ground faults can be reduced.

What should be paid attention to in the construction of overhead insulated wires?

(1) The erection of insulated overhead wires should be carried out in dry weather, and the temperature should meet the requirements of the insulated wire manufacturer to avoid laying out construction in rainy and snowy weather. The insulated overhead wires shall not be dragged on the ground, towers, porcelain bottles or other objects when releasing the wires, in order to prevent damage to the wire insulation layer.
(2) Pay attention to the inspection of the mechanical strength of the insulated wire. In the design of distribution network of 10kV and below, due to its small span, if steel-cored aluminum stranded wire is used, generally as long as its rated load and economic current density meet the requirements, its mechanical strength can meet the requirements. However, since the overhead insulated wire does not have a steel core, if the span exceeds 60m, its mechanical strength should be checked, because the insulation layer of the insulated wire also bears the tension.

(3) Pay attention to the selection of branch drainage materials and the specification of parts. In order not to damage the insulation performance of the outer layer of insulated overhead conductors, insulation piercing clips are often used for branch drainage. However, in actual construction, due to the strict requirements on the construction process of the puncture wire clip, if the construction is improper, it will increase hidden danger points for the line and bury hidden dangers of accidents. Therefore, one should pay attention to the selection of qualified insulation piercing clips. The second is to strengthen the skills training of construction personnel, to construct in strict accordance with the technical requirements, to be equipped with qualified tools, and to ensure the reliable operation of insulated overhead conductors from the technical standards. The third is to strengthen the acceptance and operation monitoring of line equipment. During the acceptance, check the poles. During the operation, the inspection and infrared temperature measurement of the line should be strengthened to eliminate the troubles in the bud.
(4) Pay attention to installing a proper grounding ring on the line, and set up a corresponding grounding body. The places where the insulated overhead wires pass are also relatively densely populated places with many houses, and the ground at many poles has been hardened. In order to facilitate maintenance, a device for hanging the grounding wire must be reserved, and a grounding ring needs to be installed at a suitable position, usually one at 4~5 gears, and a grounding body is pre-buried under the corresponding pole, so that the grounding wire can be installed in the future maintenance. It is more convenient and reliable to ensure that the grounding resistance meets the requirements of the regulations. Grounding rings must be installed on both sides of the tie breaker, at the joints of branch rods, tension rods, and at the branch point wires that may reverse power transmission. In order to ensure the insulation performance of the line during normal operation, these grounding rings should be equipped with insulating covers when they are not overhauled.
(5) Pay attention to the protection of the insulating layer during construction. Insulation performance is an important indicator of overhead insulated wires, and special attention should be paid to the protection of the insulation layer during construction. When laying out the wire, the insulated wire shall not be dragged on the ground, towers, cross arms, insulators or other objects. Pay attention to the hooking of the insulated wire by trees to prevent damage to the insulation layer. If the insulating layer is inadvertently damaged, it is necessary to perform damage judgment and necessary repairs. If the damage depth of the insulating layer is 10% or more of the thickness of the insulating layer, insulation repair should be performed. It can be wound with insulating self-adhesive tape, and each circle of insulating self-adhesive tape is lapped by 1/2 of its width. After repairing, the thickness of the insulating self-adhesive tape is greater than the depth of insulation damage, and it is not less than two layers. It can also be covered by an insulating cover. Cover the damaged part of the insulating layer well, and wrap the opening part with insulating self-adhesive tape. Within a span, the damage to the insulation layer of a single insulated wire shall not be repaired more than three places.
(6) Pay attention to the balance of the load on the low-voltage overhead insulation line. One is to prevent the unbalanced heating of the wires from causing inconsistent sag and short-circuiting between wires. The second is to ensure the safety of the neutral line of the three-phase four-wire system. Otherwise, when the load of one phase is heavy, the excessive current of the neutral line may cause the neutral line to burn out, which will cause the user’s household appliances to burn out, and will also cause damage to personal equipment. threat to security.