345kv vs 500kv 5

[Mbrooke]

For areas where 345kv is sufficient for both capacity and distance, is there any advantage to using a 500kv bulk power network? Such as having higher Kv equipment but at a lower current rating, ie lines, cables, 550kv 2000amp 40ka breakers vs 362kv 3000amp 63ka breakers.


I know that is very broad question- like asking what ocean life or bacteria might evolve into billions of years from now- but any standing specifics or general facts that come to mind such as cost difference? I'm all ears.

 

[marks1080]

Parallel circuits don't have to run on the same towers. For smaller systems this will be common, but for large systems you can often run your parallel (double circuits) on different towers.

PRC - Thanks for the transformer information. Very interesting!

 

[bacon4life]

PRC-Thanks for the correction on second harmonics.


While NERC TPL-001-4 does have an additional performance Category of P7 for double circuit towers, Category P6 requires utilities to consider the loss of any two transmission lines. The difference between P6 and P7 is that P6 allows manual system adjustments between the two outages and P7 assumes the outages happen simultaneously.

Additionally, TPL-001-4 requires utility's to simulate extreme events including loss of all transmission lines on the a common right of way and then to evaluate possible actions to mitigate the consequences. There have certainly been instances within WECC of fires taking out multiple circuits on the same right-of-way.

On some tubular steel double circuit towers, it is challenging to work on one circuit while the other circuit is energized. On older lattice towers, there seems to be much more circuit to circuit clearance.