The below questions have been raised by participants during the spotlight. Sungrow provided some of the answers during the session and followed up on the rest here in writing.
Please explain the connection to remote SCADA without going through central control PPC.
We use Ethernet/FO and router.
The anti-corrosion of the inverter is C5-I or C5-M?
C5-M
How much is the inverter health diagnosis annual fee?
≤ 5MW Free
> 5MW ≤ 10MW $ 199
> 11MW ≤ 50MW $ 189
> 51MW ≤ 100MW $ 179
> 101MW $ 169
What topology is implemented for the inverter? Are any electrolytic capacitors in it?
3-Level topology. Yes, electrolytic capacitors are included.
What is the planned maintenance interval for this inverter?
Once every year
Can this inverter sustain up to 50 degree Celsius?
Yes, at 50°C the maximum capacity amounts to 200 kVA.
Do you have a available sizing tool?
Not yet. It is planned for end of this year.
Is the specified failure rate of 0.3% per year or per lifetime?
0.3% is the failure rate per year.
Do you guarantee 0.3% failure rate?
No
What are the cut in temperature set points for cooling fans?
We do not have the exact code for the control of the fans. However, the temperature curve that we publish takes the fans and its control mechanism into consideration.
In one scenario are fuses mentioned, what is that?
The inverter design is fuse-free (as 2 strings per MPPT do not need fuses according to VDE 0100-712 / EN60363-7-712-2016). If you use 2-in1 design with y connectors you have to add fuses per Y connector.
What type of communication protocol is available and what are the compatibility details?
Our string inverters communicate with an open modbus protocol and thus are also compatible with external logger.
What about the harmonics generated at different loading of the inverters?
The harmonics are measured from order 1.5 to 178. In each order a measurement is done for 11 loading ratios (0%, 10%…100%). The inverter complies with all grid codes that include requirements for harmonics. We support our customers when it comes to certifying their plants by providing the harmonic data and providing a harmonic calculation based on the grid connection and the connected power.
Will the inverter give any info about fan failures?
Yes, the state of the fans is provided in the protocol and can be observed via monitoring.
What is an average price per watt?
2.5 USD ct/W
What is the price for the inverter in Euro/kW?
23 €/kW DDP
What are the suitabilities of the 250HX for roof-top projects?
It is suitable for rooftop projects, but originally built for utility projects. The SG110CX is also built for rooftop and additionally equipped with type 1 SPD on DC side (in some countries this is mandatory for rooftop inverters).
What is the maintenance required for the cooling fans?
No maintenance is required. Only in case of failure they need to be swapped.
For the anti-PID-function, do you need IT grounding system?
Yes
In countries where TN or TT is an obligation, does anti-PID work there?
In those cases customers can use the PID recovery function. The selection of which function you would like to use can be done in the parameter settings.
If we consider anti-PID-solution (not the recovery solution), would it be possible to take 0.6/1 kV cables?
In case of anti-PID, please use 1.8/3 kV cables.
If we use the recovery function, would it be necessary to take 1.8/3 kV cables?
Yes
At 85 degree, won’t you see already a thermal degrading and does one lose yield by this?
We do not have the exact code for the control of the fans. However, the temperature curve that we publish takes the fans and its control mechanism into consideration.
When do you recommend the central solution instead of the string inverter?
This depends on the project location as well as the O&M strategy. A more detailed study on string vs central we will discuss in an upcoming webinar.
What is the maximum cable size that is possible to connect from the inverter to this 6.3 MW PowerStation?
Multi-Core: 240mm², Single-Core: 300mm²
Do these inverters provide reactive power at night?
Yes
What is the maximum current per MPPT? What is maximum oversizing?
As a rule of thumb we recommend max 1.5, but it is also possible to go higher. In these cases we would check case by case and give approval.
Nominal output voltage is 33kV, can you provide for other output voltages e.g 20kV?
Yes
Do you provied energy yield as a temperature function graphics?
Not energy yield vs temperature, but max output power vs temperature.
What is the variation of the output voltage in % you can hold without disconnecting?
It complies with LVRT and HVRT requirements.
Can this inverter stay outside?
Yes, it has C5 and IP66.
Why does it have 800V AC and not 1000V AC?
800 Vac seems to become common practice. Also, more transformers have 0.8kV than 1 kV on LV side.
Does MTBF > 25 years mean that no inverter replacement is required?
MTBF is a common industrial calculation when it comes to approximate lifetime and failure rate. It does take the main parts of the unit into account. But of course, this remains an estimation and no binding promise.
The MTBF of 25 years, will the warranty of the inverter cover that?
No, the maximum warranty extension is 20 years.
In the warranty, you include on-site labour or a pay-hour per intervention?
During the warranty period we pay 180€ for the 1st inverter and 90€ for every additional for the replacement done by the customer.
IV curve scanning is free or need to purchase license?
IV curve scan is part of iSolarCloud
Is Sungrow sourcing their Europe demand from its India Bangalore factory?
No, our inverters for Europe are manufactured at our HQ in Hefei.
Is this IV curve scanning possible in Sungrow central inverters?
Not up to now.
Is any detoration of the hardware due to ageing?
There is no detoriation expected.
As now a days PV modules current increase from 9Amp to 12Amp, how to address two parallel strings in one MPPT input?
The maximum current per MPPT arises to 26A (software limitation only, it does not harm the inverter if current exceeds 26A). On the other hand the modules with higher currents go in hand with higher power. So most likely you can then receive a good DC/AC ratio without combining strings.
Is there a max DC/AC ratio allowed?
As a rule of thumb we recommend max 1.5, but it is also possible to go higher. In these cases we would check case by case and give approval.
What is the standard warranty period for this model?
5 years
What is the auxiliart power consumption for this model?
For cooling: < 200W, for control: < 20W
Is the inverter bi-directional, allowing for the integration of dc/dc converters and batteries? If not, is it in the R&D pipeline?
For the future yes, it will be possible to install batteries over DC/DC converter. CAN port for battery communication is already installed
With 24/7 PID-function in day-mode, you need an ungrounded transformer (IT system) correct?
For Anti-PID function (this doesn’t run 24/7, only when PV generator is working)
Who is your supplier for PPC?
Main supplier is Inaccess
Is your MV station certified according to IEC standards?
Yes
We are looking for higher block size .ex .10mw or 12mw. is it available?
In this case you would combine MVS stations.
Can we run Q@night and anti-PID operation at a time?
With a software update it will be possible to use both.
Is the Q regulation something that i can do on a single inverter?
Yes
Where can we get the list of most bankable inverters?
BloombergNEF Solar Module & Inverter Bankability