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.

SECO is a distribution company, not a transmission company, so they may know. The govt ruled to prevent vertical integration of the industry. FP&L is the assumed generation company. However, the utility industry is classified as a CNI industry. Critical National Infrastructure and as such, certain physical properties are only on a need to know basis, even within the company.

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.

Grandma was right
 

Like my Grandma said, "You fool, don't stick your tongue on that!"

There are no DC power lines. The reason for AC power lines is that there is resistance in the wires and the further the voltage travels the more power is lost (the voltage is lowered) to the resistance, therefore the AC is put through a transformer to bring the voltage back to the original voltage. Back when Edison and Westinghouse powered two different cities, one with AC (Westinghouse) and DC (Edison) they found out that AC was the more practical current to use because the DC would lose its value the farther away it was from the Generator.

Sorry that was Tesla not Westinghouse. I believe that he started Westinghouse and Edison started GE.

I can hear the guys kissing at the Coleman prison

Not many remember that movie… Michael Keaton was great!

Read VillageTinkers reply, there are a few, long distance, and we have at least one in the NE from Canada, the substation is in the town next to us, and the transmission corridor is adjacent to my parents' house. and its confirmed DC from Canada from the engineers in my company who built the receiving end distribution station of the Quebec hydro electric supply into the NE.

so its not a black and white There are no DC power lines. And I tried to connect with the transmission engineers in my company on Friday, but they were out of the office for the day.

but i still love the discussions here as its a perfect display of human behavior and biases in action.

The top wire is called “shield” the duplex conductors are called “double circuits”. Probably 475 lines. Kv has oddball multiples.