导线与地线工程

We're stringing the twin bundle ACSR conductor for Section 5 — 4.2 kilometers from Tower T-18 to Tower T-31. The tensioner is set up at T-18 and the puller at T-31. We have three crossings to manage: a highway at span 5-6, a 33 kV distribution line at span 7-8, and a river at span 10-11. I need your approval on the crossing protection before we start pulling.

Let's walk through each. The highway: have you installed the scaffold bridge with the net? I need to see the traffic management plan — road closures or lane restrictions coordinated with the highway authority. The 33 kV line: is it de-energized, or are we stringing over a live line? If live, the protection net must be earthed and we need minimum 3-meter clearance from the conductor to the net during stringing.

Highway crossing: scaffold bridge is in place, highway authority has approved the lane closure for tomorrow 9 AM to 3 PM. We have flagmen and warning signs deployed. The 33 kV line has been de-energized by the utility — outage confirmed from 8 AM to 6 PM tomorrow. I have the permit number. The river crossing doesn't require special protection — the towers are on both banks and the conductor clears the water by 22 meters at maximum sag.

Good. All three crossings check out. But I want a pre-start briefing with the entire stringing crew before we begin — cover the tension limits, communication protocol between the puller and tensioner operators, and the emergency stop procedure. Two-way radios for every team member on the ground. If the highway flagmen report any issue, we stop pulling immediately.

The conductor sagging for Section 3 is complete. I need to verify the sag before we clamp the conductors permanently. The ruling span for this section is 380 meters with a design sag of 6.2 meters at 25°C. Let's set up the theodolite at the observation point.

I'm measuring from Tower T-14 to Tower T-15. The equal-height method applies since both suspension points are at the same elevation. My reading shows the conductor is at 6.35 meters — that's 150 mm above design. We need to slack it slightly. It's currently 26°C, so the sag should actually be about 6.3 meters at this temperature. We're close but need a small adjustment.

Agreed. Let the tensioner slack by 50 mm and recheck. While we wait for that correction, let's discuss the OPGW splicing at Tower T-15. The optical fibers need to be spliced in the joint box — how many fibers and what's the splice loss target?

The OPGW has 24 single-mode fibers. We splice them in a dome-type closure mounted on the tower at about 8 meters height. Splice loss target is less than 0.05 dB per splice — we're using a fusion splicer with active core alignment. After splicing, we do an OTDR test from both ends to verify each fiber. The OTDR trace must be clean — no steps, no reflections above -35 dB. I'll provide the test report within 2 hours after completing the splicing.