What should be considered for ADSS cable suspension points?
(1) The ADSS optical cable "dances" with the high-voltage power line, and its surface is required to be able to withstand the test of high-voltage and strong electric field environment for a long time in addition to being resistant to ultraviolet radiation like ordinary optical cables.
(2) The capacitive coupling between the optical cable and the high-voltage phase line and the ground will generate different spatial potentials on the surface of the optical cable. Under the action of the meteorological environment such as rain, snow, frost, and dust, the surface of the optical cable will be burned and form electrical traces.
(3) Over time, the outer sheath is aged and damaged. From the outside to the inside, the spinning yarn is aged and the mechanical properties are reduced, which may eventually lead to the breakage of the optical cable.
(4) In order to minimize the burn of ADSS optical cable caused by electrical traces, it should be calculated by professional software. According to the established coordinate system, the phase line coordinates of the tower, the phase line diameter, the type of ground wire, the voltage level of the line, etc., can be obtained. An induced electric field distribution map, according to which the specific hanging point of the optical cable on the tower can be determined (the hanging point that meets the requirements of the electric field strength can be divided into three types: high, medium and low hanging points, high hanging points are generally difficult to construct, The operation and management are inconvenient; while the low hanging point has some problems in terms of the safe distance to the ground, and is prone to theft incidents, the middle hanging point is generally used), the electric field strength at this point should be the smallest or relatively small, and meet the requirements of the optical cable outside. Requirements for the tracking resistance rating of the sheath.
(5) Hanging point selection Considering the daily maintenance of ADSS optical cable and the possible economic losses caused by power failure during installation, the ideal installation position of ADSS optical cable on the iron tower is below the phase line; If the safety distance of the object is required, it can be considered to install the optical cable on the top of the phase line. The position of the hanging point should be calculated through the calculation that no contact between the optical cable and the phase wire or the ground wire is allowed during installation or under various environmental load conditions; at the same time, consideration must be given to avoid the risk of sparks at the supporting point of the optical cable. ADSS optical cables are generally hung around high-voltage power conductors. High voltage and strong electromagnetic fields act on the optical cables for a long time, which may cause electrical tracking on the surface of the optical cables, and even burn out the optical cables in severe cases. Therefore, the above two requirements are met. It is necessary to verify whether the field strength of the hanging point conforms to the design specification, that is, to ensure that there is as small a space electric field as possible at the hanging point of the optical cable. For the selection of long-span optical cable hanging points, it is also necessary to verify the strength of the tower.
