Overseas 220V 50 Hz Single Phase
- Thread starter gwpowell
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kwired
Electron manager
- Location
- NE Nebraska
It is generally the line to neutral voltage of a wye system. If you have a wye system that is 220 volts to neutral the 380 is line to line voltage, and all you likely have to do is connect your equipment from line to neutral.
(220 x 1.732 = 381)
(220 x 1.732 = 381)
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
I agree. I have several projects around the world that involve 380Y/220 volt distribution systems, and some with 400Y/230V. I don't know why you would need a transformer in this instance. What are you considering to be your primary voltage? Are you starting with something in the medium voltage range, perhaps 11kV or higher, and needing to step it down to 220V? If so, then you simply get a three phase transformer, as kwired has said.
UK, part of which is England, is nominally 400/230V. As is the Eurozone in the name of harmonisation....
I don't what the distribution system is in China. Where would the 380V be coming from? Why would you need to transform it to 220V since 220V already exists there?
broadgage
Senior Member
- Location
- London, England
Yes, 220 volt or 230 volt in most places that use it is derived from a 3 phase, 4 wire system with 220/230 volts from phase to neutral and 380/400 volts phase to phase.
No transformer is needed for 220/230 volt loads.
Some large 3 phase machines may have only a 3 phase 380 or 400 volt supply without a neutral, this is done simply to save on cable, since a 3 core cabe is cheaper than 4 core. Any small 220/230 volt loads within the machine such as control circuits would require a small step down transformer.
There are a few systems that are 3 phase, 3 wire, with 380/400 volts between phases, these are fairly rare, and would need a transformer for a 220 volt load.
Other systems exist that are 3 phase 4 wire with 400 volts between phase and neutral and 690 volts between phases, these are also fairly rare and would need a transformer for 220 volt loads.
No transformer is needed for 220/230 volt loads.
Some large 3 phase machines may have only a 3 phase 380 or 400 volt supply without a neutral, this is done simply to save on cable, since a 3 core cabe is cheaper than 4 core. Any small 220/230 volt loads within the machine such as control circuits would require a small step down transformer.
There are a few systems that are 3 phase, 3 wire, with 380/400 volts between phases, these are fairly rare, and would need a transformer for a 220 volt load.
Other systems exist that are 3 phase 4 wire with 400 volts between phase and neutral and 690 volts between phases, these are also fairly rare and would need a transformer for 220 volt loads.
mbrooke
Batteries Included
- Location
- United States
- Occupation
- Technician
Most of the time it is 230 volts phase to neutral derived from a 230/400 grY system. Most systems are like this. A few exceptions: Norway is ungrounded 230 volts and some older networks in Europe are 127/220 or 137/240Y with all loads phase to phase connected.
Tony S
Senior Member
- Location
- Resting under the Major Oak UK
Despite what the IET (Institute of Engineering & Technology) and the EU (European Union) harmonisation committee may say the distribution voltage in the UK is near 433/250V.
A standard DNO (utility) transformer will be 11/.433KV ?Y (Dyn11).
To change all the transformers just to satisfy a whim of the EU isn?t financially viable. Added to the cost there is the practicality of not being able to parallel various transformers in a district, during switching procedures. Another little problem is vast areas of the system are falling apart at the seams. Any current rise is going to cause major problems.
Before I retired I worked in the iron industry. Our accountant had read somewhere of the cost savings to be had from reducing the supply voltage. I got roped in to his madcap idea despite all my protests.
Over a period of a few weeks I used the four 20MVA 33/11KV transformer OLTC?s to lower the voltage to the mythical 400V from 433V. As the voltage got lower the problems grew. Motors tripping on O/L, lighting failing to strike, etc.
The upshot was the accountant had his backside kicked, I put the voltage back to normal.
A standard DNO (utility) transformer will be 11/.433KV ?Y (Dyn11).
To change all the transformers just to satisfy a whim of the EU isn?t financially viable. Added to the cost there is the practicality of not being able to parallel various transformers in a district, during switching procedures. Another little problem is vast areas of the system are falling apart at the seams. Any current rise is going to cause major problems.
Before I retired I worked in the iron industry. Our accountant had read somewhere of the cost savings to be had from reducing the supply voltage. I got roped in to his madcap idea despite all my protests.
Over a period of a few weeks I used the four 20MVA 33/11KV transformer OLTC?s to lower the voltage to the mythical 400V from 433V. As the voltage got lower the problems grew. Motors tripping on O/L, lighting failing to strike, etc.
The upshot was the accountant had his backside kicked, I put the voltage back to normal.
Well said that man. I've posted here and elsewhere a number of times that the harmonisation was a fudge.
And the changed wire colours for the phase an act of utter madness.
Can you imagine the bureaucracy that the EU would need to organise a pish up in a brewery...........
Tony S
Senior Member
- Location
- Resting under the Major Oak UK
The annoying thing is practicing electricians are basing calculations on a fictitious value.
You know as well as I, the DNO?s will never reduce the voltage. I?m just waiting for the EU to declare 380V as the ?new? standard voltage so we fit in with Belgium.
It is possible to reduce the voltage at the 33/11KV stage, but as I found out, it?s fraught with problems.
I did get mixed up with a 400KVA voltage optimisation transformer recently (who said I was retired). The O/P was 380V, the plant was having nothing but trouble. The ?management? just wouldn?t have it that there expensive new toy was causing the problems so I walked away.
I checked up on the optimisation transformer, it was marketed as ?cutting edge technology?, I found it in an 80 year old text book.
You know as well as I, the DNO?s will never reduce the voltage. I?m just waiting for the EU to declare 380V as the ?new? standard voltage so we fit in with Belgium.
It is possible to reduce the voltage at the 33/11KV stage, but as I found out, it?s fraught with problems.
I did get mixed up with a 400KVA voltage optimisation transformer recently (who said I was retired). The O/P was 380V, the plant was having nothing but trouble. The ?management? just wouldn?t have it that there expensive new toy was causing the problems so I walked away.
I checked up on the optimisation transformer, it was marketed as ?cutting edge technology?, I found it in an 80 year old text book.
Tony S
Senior Member
- Location
- Resting under the Major Oak UK
Just noticed, in place of the delta symbol in my post there's a ?
I'm just going to try something to see what works and what doesn't.
? ? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ? ? ^ ? ? ? ? ? ? ? ? ? ~ ?
Not a lot.
I'm just going to try something to see what works and what doesn't.
? ? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ? ? ^ ? ? ? ? ? ? ? ? ? ~ ?
Not a lot.
- Occupation
- Licensed Electrician
Finally, someone that speaks my langue.
Tony S
Senior Member
- Location
- Resting under the Major Oak UK
Sorry to resurrect this topic again. I found these photographs lurking around on my PC.
They should blow the myth of 230V out of the water.
They should blow the myth of 230V out of the water.
I was under the impression that the EU harmonization was to take the countries that used 380/220V & the ones that were 415/240V like the UK & France & harmonize them all to 400/230V with no real change in the supply voltages, they were all within the allowable range then please correct me if wrong. 
mbrooke
Batteries Included
- Location
- United States
- Occupation
- Technician
Sorry to resurrect this topic again. I found these photographs lurking around on my PC.
They should blow the myth of 230V out of the water.
No, don't sweat it
And thanks you for the pictures, well worth it! This is really neat stuff. Judging by the looks of it the phase to ground voltage was 250 if the phase was 433. Im guessing that the primary voltage was indeed 11kv as to have a 433 volt output to compensate for voltage drop on large networks? My understanding is that unlike an American transformer that will feed between 1 to 7 customers these feed several hundred? I was under the impression that the EU harmonization was to take the countries that used 380/220V & the ones that were 415/240V like the UK & France & harmonize them all to 400/230V with no real change in the supply voltages, they were all within the allowable range then please correct me if wrong.
My understanding, and by all means I shouldn't be commenting since at least 2 hear know this better than I:ashamed:, is that supply networks are still the same voltage. Main land UK is still closer to 240 (actual average supply voltage is 242.5?) while Eastern Europe is still 220. Appliances with the CE mark are now labeled with 230 volts, but all that's changed are tolerances. To change everything would cost to much. Of course that's my understanding.
IMO, I think the harmonization was a bad idea. At least harmonize everything to 240 volts since in theory its harder to lower the voltage of a network than to raise it (assuming actual infrastructure work takes place). Plus 240 volts is better than 230 volts voltage drop wise but a 10 volt difference isn't to much to be worried about.
Related to than and the txfr pics here are a couple of waveforms that verify what you said.
One cycle and several cycles of our domestic supply taken about a couple of years ago.
The calculated Vrms is 249.77V
The rather flattened top indicates the presence of harmonics, mainly 3rd and 5th in this case.
As I said, that's on the domestic supply at home but I've measured similar on the 11kV supply to pumping stations and such places.
The aggregate effect of all these blooming electronic gadgets!
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