800 Vac LV Switchgear for Photovoltaic Electrical Distribution System

[faisalamir]

Dear Colleagues, 

I would like to have any reference related to 800 Vac LV Switchgear technical guidance for the Photovoltaic Energy solution within the Schneider portfolio

The new trend consists of designing a photovoltaic distribution network in 800 V AC instead of DC voltages with smaller string inverters close to the photovoltaic panels 

Any recommendation will be appreciated and it will helpful 

Thank you in advance 

Regards,

Faisal Amir Siregar-EAJ South Hub Execution Centre 

[PascalL]

Regarding your question, as soon as your exciding the voltage of 690/ in AC the switchgear offer is very few. There is a special offer in MTZ2 H10 able to run up to 1000V AC rated current 1000A. It is usually dedicated to miner or wind-power applications. And unfortunately I have no other proposal to do.

Best regards,

Pascal Lepretre.

[faisalamir]

Thank you for your reply, Yes, I had consulted regarding this requirement with Electra Team

for the MTZ2 breaker, unfortunately, no official performance @800Vac

However, through already existing tests and knowledge of the range Icu = 65kA – 800Vac is not a problem, can be covered through a DoC. For Ics, existing performance is 50kA – 800Vac 

Today we can cover Icu up to 36kA – 800Vac through a DoC on NSX400HB2

End of Q1, it planning to release NSX400K (maybe not worldwide but to be checked with LoB) with 1000Vac and 800Vac official ratings

[Gregoire_Brun · Accepted solution]

NSX 400 K is under progress to be launch soon  (comming month)

We could propose some other combination solution with NSX 400K + NS 630B/NS800 LB  if nedded to have performence highest than 36 kA at 800V

Contact me if needed.

[faisalamir]

Thank you @Gregoire_Brun for the information

Would you mind sharing the preliminary concept with a draft of a paper that can explain NSX 400 K and combination solution with NSX 400K + NS 630B/NS800 LB

Thank you in advance for your positive feedback

[jspher]

Hello everyone,

Photovoltaic cells generate direct current (DC) electricity. This DC electricity can be used to charge batteries that, in turn, power devices that use direct current electricity. And, the electric power from photovoltaic panels must be converted to alternating current by a power inverter if it is intended for delivery to a power grid. The inverter sits between the solar array and the grid, and may be a large stand-alone unit or may be a collection of small inverters attached to individual solar panels as an AC module.

[jeppe.damgaard]

Hello @Gregoire_Brun I was looking for solution that could be the one you are writing in this post. More and more it seems in large PV applications projects require more than 36kA at 800V. Solutions on market are not many and seems the limit is 36kA but some project is requiring higher value (in some case 50kA!!!). I read about your proposal NSX 400K + NS 630B/NS800 LB but I cannot realize how increase the kA value in this way. Can you explain better?

[Christian_Bach · Accepted solution]

Hello @jeppe.damgaard ,

My colleague Grégoire in out of office, so I reply on his behalf. The concept of having 2 limiting MCCBs in series is like cascading in a "standard" apllication.

The 2 breakers will help each other by increasing the arc voltage, thus increasing ultimate breaking performance.

Such kind of solution must be tested of course, depending on the needs. If you have requests you can come to me directly or @Gregoire_Brun, or you local customer care center. We will be happy to help.

Christian

[RHH-Eltechna · Accepted solution]

Hi @jeppe.damgaard ,

250A+ is not the level of amperage you normally try to cascade with. It does barely anything.
Using the NSX in this case what Gregoire is referring to is just an component that can probably withstand the kA, not lower it for other components.

You can cascade better with fuses/NSX from 160A and lower, preferably as low as possible. As lower the amperage the better the cascading.

I am not fully home within the lines of DC though. But that will come sooner or later with the current grid transformations/needs.

[Christian_Bach]

Hello @RHH-Eltechna ,

This is of course not something usual, but in such ultimate breaking performances it can actually answer the need. The "small" breaker makes the job in 99% of time, and the big one helps in case of very high SC.

Christian

[Peter_Hall]

Interesting conversation and something that we are seeing in the renewables sector quite often.

It seems like a trend in the renewables sector to think that by making the largest transformer possible is the cheapest solution. this obviously does not give any thought to the equipment or potential fault level on the system.

We have countered this by having to advise customers that they need to re-consider as the equipment required cannot handle the system fault level and they should put in multiple transformers.

Another interesting thing to consider is that the 800VAC MCCB's can only be fed from the top i.e. transformer supply to load. In this situation the supply could potentially come from both the transformer and/or the solar/battery supplies. It is not an unusual arrangement within the renewables sector, but something that needs to be considered when designing a system/equipment. 

[jeppe.damgaard]

Thank you @Christian_Bach for your feedback. It is more clear now but It is confusing me as solution. Main problem I see is that on not in Denmark now but somewhere (also in Europe) there are requests for single protection 50kA mccb but it seems nobody can offer this soluton now. bad thing is that we receive specifications asking for this protection but it seems not possible to provide a unique circuit braker, but customer write specification based on what?

Your solution needs to be tested for sure and it takes large space, don't seems the solution

[RHH-Eltechna]

I see and agree with your concerns @jeppe.damgaard .
Like @Peter_Hall also already put forward a bit.

Clients use so called ''advisors'' more and more often nowadays and these advisors often give recommendations that

are not necessary/needed or executable at all.

Papers full of copy+paste lines and/or information that is old or apprehended from who knows where.
The only thing we can do in such cases is correct and inform the client about what they want/are asking and what is really needed and/or executable for their installation.

[jeppe.damgaard]

Hi @RHH-Eltechna thank you for your answer. I try to push a little customer that ask us and according to him the prospective short circuit current is 42kA so not good a 36kA. Customer say that there is a product that is difficult to find and it seems is coming from Asia. Not sure the name of brand but it seems it is a mccb 800V (AC) 50kA of Icu. Possible?

I agree with you most time specification are asking too much kA than the required but this case seems customer made the calculation.

[Peter_Hall]

@jeppe.damgaard Probably LS Switchgear from Korea. They had a new range of MCCB's & ACB's showing at Hannover. As far as I'm aware they are not launched yet. There were of course a lot of Chinese companies showing 800VAC devices. Could be one of those? What backup though?

[jeppe.damgaard]

@Peter_Hall could be because it seems from Asia. According to material found online it could be also another brand called Nader that is seems from china. mccb seems declared 50kA 800V (AC). European manufavturers seems to have 36kA max.

Difficult to propose solutions with 2 mccb in series to reach same value.