I have recently been asked to provide Field support for a number of commercial sites countrywide...I would like to share & document what my experiences are & also share with the community the goods the bads & the uglys about the installation work on these installs. I have really been fortunate to have such opportunities & when one starts to digest what is rapidly happening in the Commercial solar space in SA one starts to see that it's not all that different from the residential market. 

I must put out a disclaimer that I am a consultant on these sites & just assist with commissioning of the plant & providing Field support. I will not disclose the parties involved for their own security of equipment privacy etc. 

I will share on this thread the common equipment types of the two main brands on this thread rather than to make new threads each time. I often feel like a kid in a toy store when I see these plants produce power for the first time.

Enjoy the solar pawn....

Can we please have some numbers? Storage size, kW etc?

This particular site has 150kW Inverting power (3 x HPS50 in parallel), 400kWh Lithium BESS (2 x 200/160HV Freedom Won) and 200kW of Trina Solar PV attached. Also has 2 x GenSets ( 850kVA Volvo and 250kVA Perkins).

Base load on avg is 90kW. So their requirement was to have 4 hrs of backup power then to rely on the Gensets to start and carry the load and charge the batteries then continue the cycle. Massive Diesel savings as well as savings due to the large PV Array. 

They will also feed into the Grid once approval has been acquired. This site is also a 24 hrs operation and the load is critical so cannot afford an unplanned outage of any kind.

A lot more sites to follow...

Edited May 3, 20242 yr by Steve87

I have been struggling to find good purpose in SA for a Grid tied system mainly because our grid can at times be so unstable. But finally I have found a very good use case for it & that involves a Micro Grid scenario. 

The PCS models as well as the HPS models support the use of a Grid tied inverter to AC couple with it. The main advantage is that Grid tie inverter can use up to 12 strings & rated at a good value per string. The labels marked INV are for a Grid tied inverter. 

As can be seen with the pic of the PCS250 that has solar edge Grid tie inverters are being used. The Grid tie inverter traditionally will island and switch off during a grid outage. However, the PCS or HPS AC output creates a Grid for the PV to stay on for . 

 

I am 9 months into a fairly large Atess system (500kW battery inverter plus 600kWh battery and 625kW solar).     We had some issues of reality vs promises but solved most of these outside the system - eg power factor correction you will want to keep your old PFC as Atess is terrible at it.     Main hurdle that now remains is Atess generator integration.

 

our primary paybacks are (1) capping grid as we have extortionate peak kVA fees so to save R100k (per month) by avoiding the few times a month when loads are 300+ and solar is small, we cap grid at 80-100;   And (2)  not running diesel - have not since September even stage 6;  and then (3) increasing solar self-consumption by only exporting if battery 100%.   We’ll later get smarter and cap grid even more in advance of most days we export midday, but first want to walk before dancing.   Any event, the scenario exists where it pays me to run the Scania gennie for a couple of hours when battery is low, to avoid extra R100k a month in peak demand fees.

 

the standard Atess approach to generator integration is terrible.     Manual says can run grid and gennie parallel : that is an admitted lie, it cannot.    The contactors they use to switch grid and generator also cause huge spikes at begin and at end.    Plan was run gennie from 25% battery SOC to 75% SOC and then cut gennie.   Unbelievably, while generator runs, Atess cannot dynamically change battery charge rate based on gennie plus solar minus house loads.   We also have to trick solar to run with gennie, from outside of system as Atess cannot.

 

so two options.   Expensive route is Gennie:Rectifier:Battery, probably run Gennie at fixed output of 200/250kW to keep new cables and rectifier investment to a sane number.      Other route is with the right controller, sync the gennie to the house loadbars being supplied through bypass cabinet, again running Scania fixed output say 350kW.   So this way Atess does not even know about gennie, it just suddenly sees very reduced house loads (or potentially negative house loads), but for rest it continues taking throttled grid, fullspeed solar and throws any excess at battery.   Risk here is we MUST cut gennie immediately if inverter goes off.    Fast CB is there for that.

 

has anybody done something similar and can share war stories please?

Edited May 27, 20242 yr by macafrican

Additional battery added here. Was just a backup system. But will get the MPPT exercised regularly in a few weeks. 

1 hour ago, Steve87 said:

Additional battery added here. Was just a backup system. But will get the MPPT exercised regularly in a few weeks. 

Nice 80kwh@454v what size pv array are you planning?👌

Hi @TaliaB, they are roof limited as well as Cable limited. Looking at around 180 PV modules. Main incomer is only 100A. Their plan was to add panels to this HPS50 & then grid tie with the rest of the space. If we send power past the meter in export it will be consumed elsewhere because this is deep within the sub distribution. But the 100A breaker & cable size feed unfortunately is the deal breaker. 

 

On 2024/05/10 at 11:26 PM, Steve87 said:

I have been struggling to find good purpose in SA for a Grid tied system mainly because our grid can at times be so unstable. But finally I have found a very good use case for it & that involves a Micro Grid scenario. 

The PCS models as well as the HPS models support the use of a Grid tied inverter to AC couple with it. The main advantage is that Grid tie inverter can use up to 12 strings & rated at a good value per string. The labels marked INV are for a Grid tied inverter. 

As can be seen with the pic of the PCS250 that has solar edge Grid tie inverters are being used. The Grid tie inverter traditionally will island and switch off during a grid outage. However, the PCS or HPS AC output creates a Grid for the PV to stay on for . 

 

On 2024/05/10 at 11:26 PM, Steve87 said:

I have been struggling to find good purpose in SA for a Grid tied system mainly because our grid can at times be so unstable. But finally I have found a very good use case for it & that involves a Micro Grid scenario. 

The PCS models as well as the HPS models support the use of a Grid tied inverter to AC couple with it. The main advantage is that Grid tie inverter can use up to 12 strings & rated at a good value per string. The labels marked INV are for a Grid tied inverter. 

As can be seen with the pic of the PCS250 that has solar edge Grid tie inverters are being used. The Grid tie inverter traditionally will island and switch off during a grid outage. However, the PCS or HPS AC output creates a Grid for the PV to stay on for . 

 

What controller was used between the Grid-Tied Inverter and the ATESS PCS/ Bypass Cabinet? Are there any External RS485 Modbus energy meters & CT's needed for control of the Grid-Ties by the 3rd Party app?

How is the System holding up in terms of functioning in an OFF-Grid scenario? (batteries charged up with excess power from the Grid-Tied inverters when avaiable?)

Hi Brad, you have accessed it well. In order to create a Micro Grid ie. Have Grid tie inverters connected to the load output of Large Hybrid inverters you need an Energy meter to carry out the Measurements of what the Grid ties and or Load is doing. That Energy meter allows us to via Modbus send production throttle commands to the Grid tie inverters. I have used most brands and they operate on the same principles. When the Grid ties produce more than the load, the power is exported into the LOAD port into the inverter. The inverter will suck up that energy into the battery and charge up. When we reach 95% we Throttle the Grid ties to follow the load only (Zero Export). We have successfully added our EMS controller into many of these control scenarios with very good results.

Please send me a PM if you want to discuss further or have a project requirement. This is a niche market and there are probably a handful of operators and EMS creators that can achieve this. I'm proud to say my company is one of them. Further to that of the handful only 4 of these companies are local and once again proud to be one of the local EMS producers finding solutions for large Commercial Solar Plants ...