international power systems 3

[don01]

I have been reading with interest the discussions on this site and my complements to all. Being from Australia where everbody wants to sell thier electrical goods i see a lot of gear with different voltage frquency etc etc

I think it would be interesting to see how many different systems there are
to start the Aust. system is uniform for the whole country for industry and domestic 415v 50hz 3 phase 4 wire
(star) with MEN earth and stake. domestic usually 240V 50hz 2 wire with MEN. Safety equipment 32v ac ( industry special)
Over head lines 3.3 kv and up. Really big users get HVAC if they have licenced switchers(people)
the applicable base standard is AS3000 + the usual myriad of others

I would be interested to get data on your systems.

Thanks Don

 

[jbartos]

USA power system mostly complies with ANSI/IEEE Standards (available on-line)
1. Residential is usually a single phase three wire system 240V/120V and neutral, 60Hz (120V is center tapped from a single phase transformer 240V)
2. Commercial is often 3x240V(open delta-two 1-phase overhead transformers)/120V, 60Hz
3. Industrial is often 480V/277V, 60Hz, 3phase. Occasionally, 440V/254V 3phase 60Hz
4. Power distribution is 4.16kV 60Hz 3phase, 13.8kV 60Hz 3phase, and higher voltage systems that vary; however, they comply with ANSI C84.1-1977

 

[don01]

jbartos
Thanks for that. I'm learning all the time. As a discussion only, Iwould never have imagined that centre tap transformers would be used for distribution. We do use auto changing tapped tranformers but only to trim those last % pionts.

Am I correct in thinking you have 240 and 120 at the domestic or is it just 120V?

Again thanks
Don

 

[jbartos]

Apparently, the 240V/120V, 60Hz, 1phase, 3wire system for the residential (mostly houses) power distribution is substantiated by its economy since more powerful loads, e.g. airconditioners, heaters, electric stoves, etc., may be powered by 240V, 60Hz, 1phase, and all smaller loads are powered by 120V, 60Hz, 1phase.
The commercial sector or mixed commercial-residential sector has either open delta 240V (3phase)/120V (1phase, center tapped), 60Hz, 4wire system good to power a reasonably sized 3phase motor load, or the 208V (delta)/120V (star), 60Hz, 3phase (appearing often in institutional sector, e.g. schools, public buildings, etc.) that can power larger loads (~3000A switchgear and buses). The ever power hungry institutional sector seems to prefer 480V/277V, 60Hz, 3phase with an additional transfomation level providing 480V/240V/120V or 480V/208V or 480V/120V, 60Hz, 3phase for smaller loads. This may be somewhat linked to or conditioned by a real estate size.

 

[don01]

Ahhh the mist clears I had visions of some pretty hefty switch gear if restricted to 120/240 v systems

It must be "interesting" to work on systems with so many options. Is the voltage supplied set by the consumer (read engineer/installer) or the supply company. Ours are set by regulation("law&quot & standards to only 240 1phase or 415 3phase (HVac by negotiation for reaallly big users (1.5 to 2 MW + ) my site 900A 415V,

thanks heaps

Is there any info on other systems from our other collegues ???

 

[koolkid]

Talking about international power systems, I need to know where I can get CE spec for power systems. I designed a power supply that needs to pass that kind of test.

 

[EEIre]

For info on CE etc see

http://www.cenelec.org/

http://europa.eu.int/comm/enterprise/newapproach/legislation/guide/legislation.htm

 

[Rodneywagr]

In Australian rural areas, there is also the single phase 480 V centre tapped system, (or is it 2 phase, 180 degrees apart?). The neutral is grounded, providing two supplies at 240 volts or one supply at 480 volts.

 

[jbartos]

Suggestion: Visit

http://www.iec.ch

for more info