Common Technical Specifications Of OPGW cables

Technical specification formulation Researchers conducted field investigations and analyses on the OPGW down-lead operation failures that occurred in the cases. After actual case investigations and analyses and simulation experiments, many companies and relevant departments have formulated measures to rectify the OPGW technology. The main principles followed by these measures are: first, when the OPGW line is short-circuited or struck by lightning, it can ensure that the current can pass smoothly into the ground and cannot burn the OPGW cables; second, there should be no contact between the external body and the frame metal body, so as to eliminate the discharge risk between the OPGW external body and the frame metal. The main technical measures are as follows.

(1) Prevent water from penetrating into the protective iron pipe. In order to achieve the above goal, the pipe head should be sealed with a plugging cap and fireproof mud, and the diameter of the plugging cap here must be consistent with the aperture of the down-lead iron pipe, and some glass glue or foaming agent materials should be filled in the gap.

(2) When the OPGW enters the substation frame, the connection between the OPGW and the grounding grid connection point at the top of the substation frame must be connected with a grounding wire. For the grounding wire, it is necessary not only to ensure that its cross-sectional area is consistent with that of the OPGW, but also to ensure that the metal connection surface between the grounding wire and the grounding grid is flat, so as to ensure good conductivity after connection.

(3) At the appropriate position between the OPGW connection box and the first grounding point of the top OPGW, the OPGW should be reliably connected to the ground grounding grid (the grounding grid of the horizontal metal platform component of the frame) in the substation with a grounding wire. During the connection, the grounding cross-section is the same as the OPGW cross-section, and the surface at the connection point must be flat. After ensuring good conductivity, it is also possible to ensure that the OPGW has another reliable connection with the substation grounding grid.

(4) In the grounding wire with severe arc burn phenomenon, its effective contact area is very small. If there is no way to calculate the effective contact area data of the appropriate wire ear, it is necessary to use a wire ear with a large contact area.

(5) Due to the diversity of substation architecture types, the connection position of the grounding wire is also diverse. In this case, how to ensure the connection method of the OPGW grounding wire and the substation grounding grid has become a concern for technical workers and researchers.