400Kv Equipment

[Mbrooke]

Does a standard for 400Kv nominal class equipment exist in North America? If I use 400Kv I must either use IEC equipment or 500Kv IEEE/ANSI equipment?

 

[marks1080]

Not that I've ever heard of. You're talking phase to phase right?

 

[Mbrooke]

Correct, phase to phase.

 

[scottf]

No, IEEE/ANSI does not have a 400 kV class. There is 345kV and then 500kV.

 

[Mbrooke]

Thanks What is set official the max operating voltage rating of 345kv equipment?

 

[magoo2]

362 kV or 5% over nominal. See ANSI C84.1.

 

[Mbrooke]

Thanks. And my research yields that there is no such thing is a 400kv (IEC) dead tank breaker?

 

[ScottyUK]

Gas insulated dead tank breakers certainly exist at 400kV, and well above. Siemens, ABB, Alstom (now GE Grid) all have dead tank designs.

 

[Mbrooke]

Just not in IEEE designs?

 

[ScottyUK]

Well, they're sold over here with IEC / EN certification, CE Marked and type approved by the big European utilties. They're quite possibly designed in Switzerland (ABB Hosag) or Germany (Siemens), regardless of the eventual market. 400kV is a standard transmission voltage in the UK.

 

[Mbrooke]

And most of the world The thing is in North America 400Kv is unheard of, its either 345 (362) kv or 500 (550) kv. No 420kv rated equipment. In the UK you have post and tube bus work in substations?

 

[ScottyUK]

We have a lot of legacy 275kV open terminal substations in the UK, but most newer substations at 275kV and 400kV are gas insulated because of the greatly reduced size. Retrofits of the legacy 275kV sites as they are uprated to 400kV also tend to install GIS.

 

[Mbrooke]

How does GIS compare to open bars? Id imagine its more in the long run?

 

[davidbeach]

If you have the land for Air Insulated, it will less expensive than GIS, but if you don't have/can't buy the land then GIS becomes the preferred option. We've used GIS at 115kV where we've needed more station than we have yard for.

 

[ScottyUK]

As David says - lack of space for 400kV gear, and precious little prospect of obtaining it. Elimination of the ancillary plant associated with legacy air blast gear is another attraction.

 

[Mbrooke]

You still holding on to them or replacing them with SF6?

 

[ScottyUK]

Air blast gear? The outdoor 275kV air blast breakers from the 1960's are being replaced with indoor 400kV GIS as the transmission voltage is increased.

 

[Mbrooke]

Yup, air blast. But the 132kv equipment is still remaining as open air bus?

 

[Mbrooke]

One request if I may, would anyone happen to have links to these 400Kv dead tank breakers? I keep looking but I am only finding live tank versions.

 

[FPelec]

Dead tank circuit breaker are quite uncommon in western Europe and, generally speaking, in the all the countries using 400 kV for power transmission.
Note that, due to the recent harmonization of IEC & ANSI/IEEE Standards for High-voltage Circuit-breakers, most EHV circuit breakers can be nowadays installed both in IEEE and IEC market areas.
As a consequence most producers have not developed a 420 kV class dead tank circuit breaker, as it should have a marginal market share.
However, ABB has recently launched a 420 kV class hybrid switchgear, which in its most simple declination consists in a dead tank circuit breaker. We have installed some of these in a similar fashion to dead tank circuit breakers.

https://library.e.abb.com/public/3c1693cf1d451352c1257aef00331444/PASS 420kV Flyer.pdf

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