ECN Forum Forums Technical Discussion Electrical Theory and Applications 900kV Too Spooky?

There are several 1,000kV {one megavolt} DC lines in routine service on the North American continent. The upper end for 60Hz is generally 1,200kV AC (UHV class) but not considered technically [and economically} practical.

For 60Hz, the functional maximum in IEEE Standard 1312 is 800kV {3ø} with a nominal rating of 765kV (EHV class - includes 345 and 500 kV).