HIGH voltage power converters.

[Ian Stirling]

How do you go about converting 200KVDC at 1000 amps into AC?

Is it as 'simple' as series/parallel bridge arrangement of 200*50 IGBT/fets,
running at a few Khz?

I suppose development work would involve serious projectile shielding,
as well as the normal equipment.

I suppose with several thousand devices in a converter, you'd have to
take into account that failures may happen, and cope with them without
shutting down.

 

[mike]

How do you go about converting 200KVDC at 1000 amps into AC?

Is it as 'simple' as series/parallel bridge arrangement of 200*50 IGBT/fets,
running at a few Khz?

I suppose development work would involve serious projectile shielding,
as well as the normal equipment.

I suppose with several thousand devices in a converter, you'd have to
take into account that failures may happen, and cope with them without
shutting down.

There's some interesting stuff on bpa.gov.
The constructed 800-kilovolt (kV) d-c line interconnects the northern
converter station at Celilo, Oregon, with the Sylmar Terminal Station
near Los Angeles, California.

What's your application? I can't imagine anyone with access to that
kind of power wouldn't already be in the power transmission business.
mike

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[Ian Stirling]

There's some interesting stuff on bpa.gov.
The constructed 800-kilovolt (kV) d-c line interconnects the northern
converter station at Celilo, Oregon, with the Sylmar Terminal Station
near Los Angeles, California.

What's your application? I can't imagine anyone with access to that
kind of power wouldn't already be in the power transmission business.

Idle curiosity.
Not actually considering hooking up to the lines

 

[Ralph & Diane Barone]

How do you go about converting 200KVDC at 1000 amps into AC?

Is it as 'simple' as series/parallel bridge arrangement of 200*50 IGBT/fets,
running at a few Khz?

I suppose development work would involve serious projectile shielding,
as well as the normal equipment.

I suppose with several thousand devices in a converter, you'd have to
take into account that failures may happen, and cope with them without
shutting down.

Search on abb.com for HVDC light...

 

[Frithiof Andreas Jensen]

Typically they use MANY series-connected "hockey-puck" (some of those are
8-9" dia, 3-4" thick) SCR's or GTO's,m usually optically triggered

I learned of such a, nameless to protect the guilty, link blowing six SCR
stack including fuses because of one of those Tantalum Capacitor Time Bombs
that were popular in 1980's equipment going off in the ground-side trigger
unit. '

The person replacing the fuses got 1.5 Kg of Silver out of it for his
"collection" (those fuses are BIG)!

 

[budgie]

How do you go about converting 200KVDC at 1000 amps into AC?

Rotary (motor-alternator) converter?

 

[Rene Tschaggelar]

Rotary (motor-alternator) converter?

Even bigger motors (many MW) don't operate on voltages
much above 20kV or so. You don't want arcs on the collector.

Rene

 

[Terry Given]

Idle curiosity.
Not actually considering hooking up to the lines

Jos Arillaga at Canterbury University, NZ, has written numerous papers on
(and built many) HV inverters. These are typically used to convert AC-DC and
back again for HVDC links - necessary for long distance power transmission.
Typically they use MANY series-connected "hockey-puck" (some of those are
8-9" dia, 3-4" thick) SCR's or GTO's,m usually optically triggered
(transmission line behaviour is an issue when your semiconductor stack is 3m
high . Failure mode (unless excess energy flows, vaporising the part -
quite common!) is short-circuit, so using N+M devices in series for N*Vrated
volts allows up to M devices to fail before servicing is required. For
Megavolt inverters these stacks are physically HUGE - I recall a picture of
an indian MVDC link rectifier, it was an a4 page, and a man standing in
front was about 1-2cm tall......so it was about a 5-6 storey building in
size.

Canterbury university has a 1.5MVDC psu for testing this sort of stuff - now
THATS a cool toy.

 

[Terry Given]

I learned of such a, nameless to protect the guilty, link blowing six SCR
stack including fuses because of one of those Tantalum Capacitor Time Bombs
that were popular in 1980's equipment going off in the ground-side trigger
unit. '

early tants were shite, and the failure mode/behaviour wasnt well known -
consequently lots of people operated them near their rated voltage, where
lifetime is dramatically reduced. They have improved a lot, but they still
dont stack up (usually cost wise) whenever I go to use them....

The person replacing the fuses got 1.5 Kg of Silver out of it for his
"collection" (those fuses are BIG)!

Yeah, one of our tech's at PDL used to scavenge silver out of the "little"
fuses we used in 20kW - 1MW drives......

 

[Terry Given]

Even bigger motors (many MW) don't operate on voltages
much above 20kV or so. You don't want arcs on the collector.

Rene

thats kinda the key - at 200kV you'll need some pretty impressive isolation
for a winding, and any "gap" in say a rotating device is going to have to be
extremely large to prevent arcing.....this used to be done with
ignitrons/thyratrons etc.

 

[Dave Cole]

How do you go about converting 200KVDC at 1000 amps into AC?

Is it as 'simple' as series/parallel bridge arrangement of 200*50 IGBT/fets,
running at a few Khz?

I suppose development work would involve serious projectile shielding,
as well as the normal equipment.

I suppose with several thousand devices in a converter, you'd have to
take into account that failures may happen, and cope with them without
shutting down.

Or you could use 300 * 1000 Hp synchronized MG sets with hot-swappable
backup/alternate/spares. Just imagine the auxiliary and cooling systems
needed. Good sized building even w/o offices/maintenance/spare parts
warehousing, etc. ;-)
DC

 

[Graham Holloway]

Or you could use 300 * 1000 Hp synchronized MG sets with hot-swappable
backup/alternate/spares. Just imagine the auxiliary and cooling systems
needed. Good sized building even w/o offices/maintenance/spare parts
warehousing, etc. ;-)
DC

Pay a visit to the Aldington converter station in Kent, and they can show
you how they convert 3 phase high voltage to 400KV ( at around 4000A)for
export to France or back the other way and feed the national grid. They
have this cavernous room with stacks of opto-isolated SCR bricks all driven
from a small rack of electronics.

Graham Holloway

 

[Ian Stirling]

Pay a visit to the Aldington converter station in Kent, and they can show
you how they convert 3 phase high voltage to 400KV ( at around 4000A)for
export to France or back the other way and feed the national grid. They
have this cavernous room with stacks of opto-isolated SCR bricks all driven
from a small rack of electronics.

Thanks everyone.
It is a bit far, as I'm at the other end of the country.

 

[Tim Shoppa]

Even bigger motors (many MW) don't operate on voltages
much above 20kV or so. You don't want arcs on the collector.

But there *are* electrostatic motors. I've seen toy models, and
scaling them up to a quarter-million horsepower is surely an
"exercise left to the student".

Tim.

 

[Terry Given]

Or you could use 300 * 1000 Hp synchronized MG sets with hot-swappable
backup/alternate/spares. Just imagine the auxiliary and cooling systems
needed. Good sized building even w/o offices/maintenance/spare parts
warehousing, etc. ;-)
DC

LASCRs are the way to go - light activated SCRs. drive with fibre optics.
have many more devices in series than required, when one fails it goes
short-circuit so the whole thing keeps operating.

Terry