I didn’t want to make this thread about my bigger and more complex system.

For home / small business I figure Gennie:Rectifier for DC supply would allow smaller and less fancy Gennie, all of it automatic no bounces no ATS and virtually any battery inverter will cope without delving into layers of settings or whether it has a Gennie input.    Need a SOC trigger at say 30% and another signal at say 75% SOC and that is all.

Whether grid is off or comes back on, run that 45% at constant output Gennie very efficient.    Pick rectifier output size at the Gennie happy point, done

2 hours ago, macafrican said:

Atess sent people from China as they had several issues with replacing their PCB and firmware until things worked.

Atess did the job of painting a bad name all on their own!

Granted their support is not great & usually they will take close to 3 weeks to make it to your site. Hence a company like mine that understands the equipment & architecture that provide design, commissioning & post sales RMA support for customers locally & regionally. They prefer to leave the support up to the end supplier eg. ARB & the like. It usually doesn't amount to happy customers unfortunately. I actually think their support is geared up for installers rather than suppliers. The broken telephone is too great. 

 

2 hours ago, macafrican said:

early warning for people on 500kW bypass cabinet.   They ship with 1250A breakers so if you planned on 630A cables, dig an extra cable trunk now.   Mine also arrived ex factory with the PCB from the smaller one - think 350.   Several daughter board components replaced and several shielded cables replaced.

The 1250A breakers are documented & your supplier/ system designer should know this & provide MCCB protection of 630A externally as part of the system design. I know you provided a good RFP but technically that's not your issue to specify the protection equipment, that's job of the system design engineer. 

 

2 hours ago, macafrican said:

would be nice if there was a Watcher (me doing that manually now).    Give it general parameters/goals and then it will figure out that we could run 10kW cap today because solar forecast looks great.   When loadshed becomes an issue again, the watcher operates more carefully.

This is exactly what our in-house designed EMS carries out. It will run any host of automation requests based on your requirements. You don't need to baby sit anything.

2 hours ago, macafrican said:

The system generally DOES work.   It keeps within about 8% of my grid demand cap.  I set 90 they might do 95 over half hour measure, so I learnt I set to 86 if I really want 90.    Transfer during loadshed is now virtually not noticeable, which is wonderful.

I'm glad you found something that works. You have spent a small fortune on this system. 

I'm very sorry to say that if from the design stage your installation team did not know about simple equipment protection Vs what is installed on the Bypass cabinet, then I would say how the system doesn't operate & functions should be taken with a pinch of salt. I don't take a go at them as I don't know them neither do want to rubbish anyone's work without them having a say first. 

Found in the appendix of the manual of the ATESS Bypass cabinet...

4 hours ago, Steve87 said:

Found in the appendix of the manual of the ATESS Bypass cabinet...

@Steve87 I see that there is quite a big weight difference between the Bypass 250 and Bypass 500 for a doubling in power, do you know why there is such a big weight difference?

18 minutes ago, GerhardK83 said:

why there is such a big weight difference?

I think the Form factor of the 1250A MCCBs needs a larger physical cabinet and then you also have to now have thicker Busbars to handle the phases so this all adds up. So this weight all adds up. 

@GerhardK83 I think out of interest they using the 1250A MCCBs just to save on production costs. Having to order 5 different breaker sizes can be expensive. So they make it common across some of the higher kW models. The same can be said for the enclosure itself. Having a common model reduces your production costs significantly.

The more popular model is the PCS250 for various reason like the redundancy if specifying a 500kW plant as well as the transformer being built in. That's why it weighs more than all the models in the PCS range. 

Having been exposed to the ATESS equipment, all I can say is that it has been very well thought out from an engineering perspective & that the switchgear is quality. The UI and it's operation leaves much to the imagination. A Great machine, but a very tricky machine to understand the first time. An EMS or other 3rd party device is a must to optimise it & make understanding of the operation.

On 2024/09/26 at 8:22 PM, macafrican said:

As I have it, the rectifier is set up to present to the generator as a constant load being taken.

Is this rectifier designed to also present a reasonable power factor to the inverter? If it's a single phase generator and the rectifier is little more than four diodes, then the  power factor will be woeful, and that will cause a world of pain.

For single phase, a proper rectifier has to have a boost stage with  a power factor correction chip, and then the voltage will need  to be transformed up or down via another DC->AC and then AC->DC stage. These latter can be high frequency square waves, obviating any power factor problems. But all those conversion stages makes for an expensive battery charger, especially at high power.

If the generator is three phase, then the ≈6% ripple can usually be handled with inductors. I'm rusty here, I suspect that the power factor is still pretty bad in this scenario.

On 2024/09/26 at 2:29 PM, BritishRacingGreen said:

I dont have field experience here, but I can assure you one thing that the battery is now a perfect filter component as far as the generator is concerned. It does not get better than this. Your lithium battery has got such a low source impedance that it will just suck up any surge that the load wishes to impose within design parameters of the system.  The generator is therefore abstracted from abrupt load variations. 

 

DC blending of sources are just the perfect way nature intended. 

I would actually suggest the opposite in that you set the rectifier to a voltage that is  lower than the inverter charger. This is maybe required as to not interfere with the transaction between bms and inverter. A pedantic bms or pedantic inverter might abort operation if the actual charge voltage is higher than that negotiated. But this I have not witnessed in practice. Maybe @Coulomb can give us his thoughts here. 

 

 

1 hour ago, Coulomb said:

Is this rectifier designed to also present a reasonable power factor to the inverter? If it's a single phase generator and the rectifier is little more than four diodes, then the  power factor will be woeful, and that will cause a world of pain.

For single phase, a proper rectifier has to have a boost stage with  a power factor correction chip, and then the voltage will need  to be transformed up or down via another DC->AC and then AC->DC stage. These latter can be high frequency square waves, obviating any power factor problems. But all those conversion stages makes for an expensive battery charger, especially at high power.

If the generator is three phase, then the ≈6% ripple can usually be handled with inductors. I'm rusty here, I suspect that the power factor is still pretty bad in this scenario.

Coulomb : as I have it there is no power factor ‘downstream’ of the rectifier as it is DC.     I am not sure as what good/bad power factor the rectifier presents to the generator on the upstream side, thought it would be 1 from perspective of the gennie.     After the DC level, the power factor are a function of my loads and inverter and impact of solar.    The financially relevant at the 11kV meter before my transformer is nowadays very good because I switched my old PFC back on after PCS presented 0.6 PF at 11kV level.

If generator is AC coupled, I normally have to relay PFC equipment off.     Going generator:rectifier:DC would mean I can leave my PFC on while generator runs.

 

21 hours ago, Steve87 said:

Granted their support is not great & usually they will take close to 3 weeks to make it to your site. Hence a company like mine that understands the equipment & architecture that provide design, commissioning & post sales RMA support for customers locally & regionally. They prefer to leave the support up to the end supplier eg. ARB & the like. It usually doesn't amount to happy customers unfortunately. I actually think their support is geared up for installers rather than suppliers. The broken telephone is too great. 

 

The 1250A breakers are documented & your supplier/ system designer should know this & provide MCCB protection of 630A externally as part of the system design. I know you provided a good RFP but technically that's not your issue to specify the protection equipment, that's job of the system design engineer. 

 

This is exactly what our in-house designed EMS carries out. It will run any host of automation requests based on your requirements. You don't need to baby sit anything.

I'm glad you found something that works. You have spent a small fortune on this system. 

I'm very sorry to say that if from the design stage your installation team did not know about simple equipment protection Vs what is installed on the Bypass cabinet, then I would say how the system doesn't operate & functions should be taken with a pinch of salt. I don't take a go at them as I don't know them neither do want to rubbish anyone's work without them having a say first. 

Steve, we started process in early 2023, the documentation then did not indicate 1250A breaker in 500kW bypass then (just like it incorrectly indicated not only the generator integration operation and the free space needed around isolation transformer but luckily my bunker could deal with that).   The RFP respondents were all large professional installers (over 200 professional electrical engineers including panel members on NRS) and all had to calculate and specify cables for distance between my LV room and my smartgrid bunker, for me to do the underground trunking in advance.