With the development of smart grid construction, the application of power fiber is becoming more and more important. With the gradual deepening of the environmental governance work of overhead into the ground, the overhead weak wires will be gradually removed, and the overhead optical cable laying is difficult to carry out, and the laying of optical cables in 10 kV cable is not allowed. In order to meet the requirements of optical fiber coverage in power distribution network, new technologies and processes must be adopted. For a large number of power distribution network lines, ADSS optical cable is generally used as the laying technology.
The ADSS cable is exposed to snow, ice, rain, wind, lightning and other elements of the transmission line. As a nonmetallic material, ADSS cable has no electrical influence on the operation of interphase transmission lines. ADSS optical cable has strong low temperature resistance and environmental adaptability in the same type of aerial optical cable laid in interphase. In the state of no power outage installation operation, economic performance is more obvious; Because of the development of ADSS fast optical cable, electric power communication business becomes more convenient and can be an ideal choice. ADSS cable itself is very resistant to tension, its span is generally 100~800 m, the greater the span, the higher the price of the same type of product. At the bottom of the interphase laying, the bearing diamond with other transmission lines can not only ensure that other lines are not affected by interphase laying factors, but also will not cause visual deficiency.
The aerodynamic performance of ADSS cable should be considered in the design, which is mainly related to the line conditions, meteorological conditions and mechanical characteristics of the cable itself. Mechanical properties mainly include fiber number, cable diameter, cable weight, calculated breaking tension, allowable service tension, maximum allowable span, delivery standard length and elastic modulus, etc. Line conditions generally refer to line voltage, block distance, line corner and height difference.
ADSS cable connection and line length calculation is limited by the production and transportation conditions of the line and its own situation, the connection is carried out on the tensioning tower, and the joint needs about 5m at a time. ADSS optical fiber connector as little as possible in the point of view of signal transmission, optical signals through a joint will have different degrees of decay. When doing the middle connection box, usually in the ADSS cable to the ground, after completing optical fiber welding will again from the ground connector box fixed on the poles, to prevent theft, connector box fixed location should be appropriate to improve, to make joint after the rest of the fiber optic cable, should, according to the requirements of permissive bending radius should not less than the remaining cable rules do dish, fixed near the connector box.
The length of each cable can be calculated according to the catenary equation. When the suspension points at both ends are of equal height, the length is L= L + L3G2/24 /σ2 (1). σ is the cable stress; G is specific load of optical cable. In practice, the line length should be at least 2% longer than the line path based on general flat hill experience; Mountain line length is at least 4% longer than the path; About 6% in mountainous areas; From the perspective of construction, the line length of each ADSS cable should be considered in addition to the line length between poles and towers. From the perspective of construction, each ADSS cable should be conveniently connected with a section twice the full height of tensioning tower. Before welding the optical fiber, should be in the construction of traction force larger cable joint part cut, generally not less than 6 m, at the same time to consider the cable length, with tower base surface left about L0 m is more reasonable. Optical cable stripping should be first of all the two optical cable grounding in 4 ~ 5 m from the fusion point, under the guidance of the manufacturer's construction technical supervision of the specific process of optical fiber fusion. 1.2 Selecting the placement position of ADSS optical cable In the placement of optical cable, the general use of tension line machine, traction rope, wire frame, tractor and traction net with torsion retractor to complete the ADSS optical cable overhead work.
To maintain a certain tension, cable in the erection of the construction process generally maintain a certain tension, the tractor should be slow start, and gradually increase the speed steadily, to ensure that the smooth discharge. In cable routing corners meet or exceed 35 °, and the direction of the cable first hang hang point and the last point, the minimum diameter of pulley should be not less than 500 mm, hanging point is responsible for the support in the middle of the pulley should be greater than 400 mm in diameter, pulley groove diameter should be no greater than 1.2 times of cable diameter, depth should not be less than the radius of the fiber optic cable, to ensure that the cable will not slide items: There is a minimum vertical net distance between buildings, trees, etc., and overhead cable. The height of residential area should be 6m, the height of non-residential area should be 5m, and the crossing of 10 kV power line should be about 2m, the crossing of 35 kV power line should be kept at 7.5m, and the crossing of highway should be kept at 6m. ADSS cable construction process includes the wheel groove. In the process of installing optical cable, there are some matters needing attention: 1) do not arbitrarily change the position of the transition tool and pulley, if arbitrarily changed will change the induction electrodynamic force to aggravate the electrical corrosion. 2) The traction rope should be well arranged to ensure that the traction rope and ADSS cable firmly connected. 3) the wiring machine is installed at the starting point of a plate of optical cable and the tractor is installed at the end of a plate of optical cable, in the far position from the starting rod (tower) tension wiring machine, generally speaking, should ensure at least 4 times the height of the hanging point. 4) The traction rope should be laid first, then a certain tension should be applied, and check whether the traction rope and connection point are firm. 5) with the help of tension table, in the process of cable traction traction tension for real-time monitoring, to ensure that the operating tension of the cable is greater than the tension of the cable.