50Hz 230 volt power in a 60Hz world

[Electric-Light]

I figure y'all are the right people to ask. Not that you've ever been asked this before, but because I'm sure this will be an interesting discussion.

We have a growing amount of 50Hz 230 volt power (single phase of a 230/400 volt system) that's being produced at the office. Right now it is all being turned into heat courtesy of a rather large dump load.

The way things are wired right now, there is a several KW 50Hz power supply that is providing a grid reference to what I think is a 2 or 3KW solar array that is powering 50Hz microinverters. The microinverters are back-feeding the supply, which has its output paralleled with the dump load. So, if the sun isn't shining, the dump load is turning most of that 50Hz power into heat. And if the sun is shining, even more of it is turned into heat.

What are the code issues that might be associated with actually =doing= something useful with that power?

You should be able to experimentally run 265v rated PTAC heat-pump(designed to run on 277v single phase circuit) . It would be a great exercise to see if the inverter can handle the rigor of motor starting.

Since 277/60 = 4.61 and 230/50 = 4.6, the motor gets a good V/Hz match. The BTU capacity would be reduced because compressor slows down. If the RTC(timer) on the unit uses line frequency, then, that function would be useless, because it would clock every hour as 5/6 of an hour.

Japanese spec refrigeration equipment are often 50/60Hz rated, but have two BTU ratings, one for 50Hz, one for 60Hz. Capacity is reduced at 50Hz for the aforementioned reason.

If the PTAC is setup like a window A/C and connected with cordsets, it would be laboratory test load that happens to need access to outdoor air.

 

[Besoeker]

Why do you keep talking about DC power that doesn't exist?

That part of my post was in response to your specific point:

But so far you're convincing me that PV isn't your area of expertise.

Photovoltaic cells produce a DC output.

 

[Besoeker]

The 50Hz system would be 380/220V, 3 phase.

Nominally 400/230V these days in the "harmonised EU zone.

 

[tallgirl]

That part of my post was in response to your specific point:

Photovoltaic cells produce a DC output.

Yes, they sure do. But had you read the earliest posts, you'd know that the power output from the system on the roof is 230 volts at 50Hz AC.

 

[tallgirl]

You should be able to experimentally run 265v rated PTAC heat-pump(designed to run on 277v single phase circuit) . It would be a great exercise to see if the inverter can handle the rigor of motor starting.

Since 277/60 = 4.61 and 230/50 = 4.6, the motor gets a good V/Hz match. The BTU capacity would be reduced because compressor slows down. If the RTC(timer) on the unit uses line frequency, then, that function would be useless, because it would clock every hour as 5/6 of an hour.

Japanese spec refrigeration equipment are often 50/60Hz rated, but have two BTU ratings, one for 50Hz, one for 60Hz. Capacity is reduced at 50Hz for the aforementioned reason.

If the PTAC is setup like a window A/C and connected with cordsets, it would be laboratory test load that happens to need access to outdoor air.

Thanks! I'll take a look into this a bit more.

 

[weressl]

Not in Mexico, they have a 127/220 volt WYE and even use the same receptacles we use for the 127 volts although I thought it was 60hz like us?:?

Just checked with a few international voltage charts, and yes Mexico is 127/220 Wye and they also use 277/480 with a frequency of 60hz for both

Monaco uses a 127/220 WYE at 50hz as does Morocco and the Netherlands Antilles to name a few, the rest can be found HERE

Focus: the granite cutter is from I-T-A-L-Y not M-E-X-I-C-O:lol:

There is a variance but the overwhelming majority is as I described.

 

[Besoeker]

Yes, they sure do.

You mentioned PV, not I.

But had you read the earliest posts, you'd know that the power output from the system on the roof is 230 volts at 50Hz AC.

Had you read my post#33 you would have seen this:

The 50Hz is what you are generating and want to load if I understand you correctly.

 

[weressl]

Nominally 400/230V these days in the "harmonised EU zone.

So the utilization voltage is the 380/220, right? Or did they raise the range to disallow some of the voltage drop?

 

[Besoeker]

So the utilization voltage is the 380/220, right? Or did they raise the range to disallow some of the voltage drop?

As far as I'm aware, we don't differentiate between supply voltage and utilisation voltage in the way that you do with say 480/460.

The harmonisation was a fudge to accommodate the range of voltages in use in the EU zone by relaxing tolerances.
Just another cross we have to bear.....

 

[weressl]

Yes, they sure do. But had you read the earliest posts, you'd know that the power output from the system on the roof is 230 volts at 50Hz AC.

Produced from what faw gawdsake?:dunce:

 

[SolarPro]

FWIW: These are listed ac modules, which are covered in NEC 690.6. The Code requirements that apply to dc circuits to do not apply to ac modules; see 690.6(A). Both the Code and the equipment standards consider the dc wiring to be internal to the listed device.

So yes, there is a dc source. But the output of the listed device is ac.

 

[Electric-Light]

So the utilization voltage is the 380/220, right? Or did they raise the range to disallow some of the voltage drop?

There were 415Y/240, 400Y/230, and 380Y/220. EU harmonization led to nominal of 400Y/230

As far as I'm aware, it was all on paper and no actual changes were made to the system.

220 countries permitted 230v -10%/+6% 240 countries 230v +10%/-6%... on paper. Something like that

 

[weressl]

FWIW: These are listed ac modules, which are covered in NEC 690.6. The Code requirements that apply to dc circuits to do not apply to ac modules; see 690.6(A). Both the Code and the equipment standards consider the dc wiring to be internal to the listed device.

So yes, there is a dc source. But the output of the listed device is ac.

The point is that the AC is synthetized from DC.

 

[kwired]

As far as I'm aware, we don't differentiate between supply voltage and utilisation voltage in the way that you do with say 480/460.

The harmonisation was a fudge to accommodate the range of voltages in use in the EU zone by relaxing tolerances.
Just another cross we have to bear.....

I usually do not either. 220, 230, 240, 250 - are all the same system IMO. If "208" is mentioned, then I think of a different system, but actual voltage may be as low as maybe 195, or as high as 220, but around here will usually be near 215.

 

[ggunn]

The point is that the AC is synthesized from DC.

I think the point is that although that is true, she cannot get at the DC because it is converted to AC at the modules. There is no DC bus.

 

[kwired]

I think the point is that although that is true, she cannot get at the DC because it is converted to AC at the modules. There is no DC bus.

Besoker, had solution for this way back in post #4, rectify it, then convert back to whatever is needed.

 

[Besoeker]

Besoker, had solution for this way back in post #4, rectify it, then convert back to whatever is needed.

Yes, simple and been done. Yet ignored.

 

[ggunn]

Besoker, had solution for this way back in post #4, rectify it, then convert back to whatever is needed.

Understood. It looked to me like some folks were advising her to tap the DC directly, but since it's a microinverter/AC module situation, there is no way for her to get at the DC. OTOH, it looked to me like she was trying to come up with a bidirectional solution so the the 50Hz inverter could somehow synch up with the 60Hz line, and I don't know of any way to do that.

 

[BillK-AZ]

This thread seems to be not considering the basic problem. The 50 Hz micro inverters are grid tie and will not operate without a stable 50 Hz grid. Therefore one can not simply rectify the outputs and use the DC energy usefully.

What is needed is a 50 Hz source stable enough for the micro inverters to connect, then some method of soaking up the excess power as inverters start putting out power so that the 50 Hz source is not damaged by excessive backfeed and stays stable like a utility. Not your normal piece of equipment.

One possibility I see is a 50 Hz standalone sinewave inverter for reference and a series of binary switched loads that are controlled by measuring the output of all of the micro inverters under test, calculating on a cycle by cycle basis the load needed to soak up the PV generated power plus some from the reference inverter, and switching on/off loads as necessary to continue to present a pseudo grid. Loads could be 25W/50W/100W/200W/400W/800W etc. so that a small number of loads will cover a wide range.

The 'Loads' could be power factor corrected power supplies that could charge a large battery and that energy could be converted to 60 Hz to utilize the energy.

 

[Besoeker]

This thread seems to be not considering the basic problem. The 50 Hz micro inverters are grid tie and will not operate without a stable 50 Hz grid.

From post #1:

We have a growing amount of 50Hz 230 volt power (single phase of a 230/400 volt system) that's being produced at the office. Right now it is all being turned into heat courtesy of a rather large dump load.

A dump load doesn't sound like grid tied.