TANZANIA - Avoid sagging in distribution power cables

[GianDevergy]

Good afternoon,
we are Devergy, a utility installing solar microgrids in rural areas of developing countries.
We have an issue with the cables that we currently purchase in Tanzania.

Problem:
When we install the aerial distribution lines, after some time, the cables between two poles, sags under its own weight, and the intense sun, reducing the the clearance from the ground.

Current material used:
We currently use PVC insulated cables, with a 2x1.5mm2 copper stranded conductor (see picture). These cables are manufactured according to our specifications, hence we can request design changes. We distribute 24V DC electricity.

Solutions:
- Use a support metal wire between the two poles (anybody knows the engineering name for it?)
- Request the cable manufacturer
-- to add a metal support wire inside the cable itself
-- to replace the PVC outer jacket with another insulation jacket (e.g. XLPE or EPR)

Any take on the solutions described above? any good solution you'd like to suggest?

Best
GC

 

[magoo2]

Look up spacer cable. These installations use a steel messenger cable to support the other conductors.

 

[HamburgerHelper]

24 V? How does losses not become a big issue?

 

[crshears]

Unless the quantities of power being delivered are teensy weensy ones, maybe it's not just weight and the intense sun but the I squared R losses that are generating oodles of heat and excessively warming the conductors...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[roydm]

The proper name is Catenary wire, sometimes called messenger wire

Is the wire Hard Drawn?
Since it's low Voltage and insulated why don't you just run it on the ground

 

[waross]

Try a neutral supported cable.
Link
Link

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jghrist]

Self-supporting aerial cable. See

http://okonite.com/SSAC Brochure PDF.pdf

The micro grid must be pretty micro. 1.5 mm2 cable will only handle about 5A, or 120 watts at 24 vdc.

 

[LionelHutz]

Since that is a custom cable, I would investigate adding a small steel braided cable inside the jacket with the other conductors. You would then use that steel cable to fasten this cable up at each pole and it wouldn't stretch which would keep it from sagging.

 

[HCBFlash]

This is a misapplication of the shown cable, and for whatever reason you're not giving us an accurate description of the application, and not giving us the distance between supports, the length of the actual installed conductors, or any details of the terminations. You cannot and do not distribute power at 24v, using 1.5mm2 conductors, between separated buildings and equipment. We know that. If you continue attempting to do so, all your systems will fail shortly, as overcurrent and ordinary environmental issues repeatedly develop. The people here can do the math. Even if your objective is to light up a neighborhood by giving each residence only a single 50 lumen LED light, your transmission losses will be far higher than your utilization. We all design for higher expectations and standards than that. We understand the viewpoint that "alt" systems and solutions are actually viable in remote and other "ignored" micro communities and cultures, but "alt" will not provide things that make something out of nothing, or thrive on their own waste. I hope I don't come across as unduly harsh, or as representative of "the engineering establishment". A single post of 4 words or less could have directly answered your condensed question, but the 8 responses (so far) show that we read your entire post.

.


Me wrong? I'm just fine-tuning my sarcasm!