[villagetinker]

Originally Posted by BrianL

Within the United States, High-Voltage long distance lines are typically DC running anywhere from 100 kV to 800kV. It is not obvious as to the type of transmission used within Sumter County. The obversion that the large round ceramic insulators are 10 kV insulators is correct. So if you have 10 of these, it will be a 100 kV line; however, that doesn't determine if it's AC or DC. There are excellent reasons for DC in power transmission, you can read about them in wikipedia. If there are more than 4 ceramic insulators, the lines are unlikely to be 34.5 kV lines. Power line transmission is substantially different than local power distribution. The only way to really know the voltage of the lines would be to contact SECO, provided that the transmission lines going through the are even SECO lines. They would likely know the correct answer to the question regardless of the actual owner of the lines.

This is SO WRONG I do not know where to start, but here goes.
DC in the very few places it exists use TWO (2) sets of conductors, NOT 3, all of these lines are AC and are 3 phase. Those with ONE conductor per phase are 230 kV or less, those with two conductors per phase are typically 500 kV. I am not familiar with line designs for 345 kV AC so this would also be possibility for the lines with 2 conductors per phase.

As noted in the previous reply there are VERY FEW DC links in the US, and the few that exist are typically between the large east, west and Texas interconnects. DC links do not have frequency constraints and can control power flow through the inverters at each end.

As for those of you expressing concerns about living close to these lines, there have been many studies over the last few decades on this, with results indicating very low to NO effects.

Also, the one or 2 smaller conductors at the very top of the towers are 'static' or lightning protection lines and do not carry any voltage and very low current.

I found a map of these lines, and I was able to confirm they all terminate in AC only substations.

I was a senior staff engineer/scientist in the electric power industry with over 40 years experience, and 33 years of that in the design of these facilities.