Grid-Tied, No Sell 3-phase with SMA Cluster Controller in Kenya

TMount

My system is currently:

( 1 ) SMA Tripower 20000TL-EE
( 88 ) Canadian Solar CS6P 255W panels

I also plan to purchase a SMA Cluster Controller, for reasons I will explain below. The documents I am referencing are:

http://files.sma.de/dl/18128/PWCMOD-DEN130211W.pdf

http://files.sma.de/dl/7418/ZE-PCM-TI-en-20.pdf

This system is going to be installed in Kenya, and I am using a EU model of the Tripower that is compatible with their grid. It is for a non-profit, and will help power a well, orphanage, and school. While there is a good chance we can talk the local utility into allowing us to net-meter, there is a small chance they will not allow us to push power back to the grid at all. If this is the case, I am trying to plan a backup solution without the addition of batteries where we can use the power from our 20kW system to assist the grid in powering loads during the day, but not sell or export back to the grid.

According to the above mentioned documents from the SMA Europe site, this is completely possible with the SMA Power Control Module, with the addition of (it is called various names in different versions of the above documents) a PLC + measurement device, a (radio) ripple control receiver, or an external signal generator.

My first call to SMA America the person that I got told me that what I was looking to achieve could absolutely be done using an SMA Cluster Controller. Further calls I made the mistake of sounding like this was going to be installed in the US, so they became much more vague as this does not seem to be supported or encouraged in the US at the moment.

My question is, does anyone have an idea how to get this working? The Power Control Module seems to be able to regulate the inverter to producing only a certain percentage of its total capacity, but needs external information for this. My guess is I need some kind of Modbus-capable monitoring device (recommendations?) that has a digital output that can connect to the SMA Cluster Controller, which would then translate the current into a % capacity, and send that to the Power Control Module which would inhibit/restrict the inverter.

Does anyone know if there is a recommended or well-tested method to do this? I'm having difficulty contacting the EU SMA without a serial number, and the American one is understandably hesitant. I know this would not be an ideal setup (wasted energy), but I need to at least have a backup plan if we cannot sell or export to the grid. One that does not involve the expense of 20kW+ worth of batteries.

Thank you!

tazil007

Re: Grid-Tied, No Sell 3-phase with SMA Cluster Controller in Kenya

Hi TMount

Am also looking at what to use as the device which reads power and translates this info (using 4 digital output) for the SMA cluster controller or power control module to limit inverter active/reactive power. This is only to prevent exporting to the grid and 100% self consumption in real time. Please do let me know if you find this missing device which can interface between measurement and controller.

Thanks

TMount wrote: »

My system is currently:

( 1 ) SMA Tripower 20000TL-EE
( 88 ) Canadian Solar CS6P 255W panels

I also plan to purchase a SMA Cluster Controller, for reasons I will explain below. The documents I am referencing are:

http://files.sma.de/dl/18128/PWCMOD-DEN130211W.pdf

http://files.sma.de/dl/7418/ZE-PCM-TI-en-20.pdf

This system is going to be installed in Kenya, and I am using a EU model of the Tripower that is compatible with their grid. It is for a non-profit, and will help power a well, orphanage, and school. While there is a good chance we can talk the local utility into allowing us to net-meter, there is a small chance they will not allow us to push power back to the grid at all. If this is the case, I am trying to plan a backup solution without the addition of batteries where we can use the power from our 20kW system to assist the grid in powering loads during the day, but not sell or export back to the grid.

According to the above mentioned documents from the SMA Europe site, this is completely possible with the SMA Power Control Module, with the addition of (it is called various names in different versions of the above documents) a PLC + measurement device, a (radio) ripple control receiver, or an external signal generator.

My first call to SMA America the person that I got told me that what I was looking to achieve could absolutely be done using an SMA Cluster Controller. Further calls I made the mistake of sounding like this was going to be installed in the US, so they became much more vague as this does not seem to be supported or encouraged in the US at the moment.

My question is, does anyone have an idea how to get this working? The Power Control Module seems to be able to regulate the inverter to producing only a certain percentage of its total capacity, but needs external information for this. My guess is I need some kind of Modbus-capable monitoring device (recommendations?) that has a digital output that can connect to the SMA Cluster Controller, which would then translate the current into a % capacity, and send that to the Power Control Module which would inhibit/restrict the inverter.

Does anyone know if there is a recommended or well-tested method to do this? I'm having difficulty contacting the EU SMA without a serial number, and the American one is understandably hesitant. I know this would not be an ideal setup (wasted energy), but I need to at least have a backup plan if we cannot sell or export to the grid. One that does not involve the expense of 20kW+ worth of batteries.

Thank you!

coke

Re: Grid-Tied, No Sell 3-phase with SMA Cluster Controller in Kenya

Hi,

I have the same questions for a system in Uganda.
I was also looking into the cluster controller and the pcm.

I think you only need either the cluster controller or the pcm and not both.
Each of them is the interface which communicates with the inverters and gives them the commands to regulate to power up or down.
But both of them need an input signal which tells them what to do. The PCM can only sense 4 digital Inputs.
The cluster controller can sense 4 digital inputs as well as two analog inputs for example among many others.

Here my pros and cons I found out about the two options:

Cluster Controller:
+ up to 75 STP at once
+ Speedwire connection (much faster)
+ analog input
+ Already equipped with ethernet port for sunny portal upload
+ stepless control ??? (not sure)
+ second analog input (reactive power control independant from normal power control)
- expensive

PCM:
- only predefined steps possible and no stepless controll
- needs 4 dig input signals which might be more work than one anlog signal
- only 5 inverters on one pcm
- needs 5 seconds to execute a new command (adjustable) (might be faster with the cc)
- no reactive power control independant from normal power control
+ cheap

I have just sent some clarifying questions to SMA Germany on wether it's possible with the cc to have stepless control and if the output (% inverter power) can be linked to the analog input signals).

As measuring device I thought of something like this:

A C350 M2M control device to read from the Universal measuring devices UMG 103 with connected voltage and current sensors.
This would measure and calculate the current load capacity and give out an analog signal based on the PV capacity. For example 4mA=0% up to 20mA=100%.

The calculation would be simply %PV=Consumption/PV capacity. This could be done for reactive power as well.

mraza.majeed

Re: Grid-Tied, No Sell 3-phase with SMA Cluster Controller in Kenya

Hi,
Did you hear anything from SMA about your query?
I want to use the same system as you have described here in Pakistan and I want to know whether it is feasible or not and how you did all this. Please get back to me at your earliest. I'd appreciate your help.
Thank you.

coke wrote: »

Hi,

I have the same questions for a system in Uganda.
I was also looking into the cluster controller and the pcm.

I think you only need either the cluster controller or the pcm and not both.
Each of them is the interface which communicates with the inverters and gives them the commands to regulate to power up or down.
But both of them need an input signal which tells them what to do. The PCM can only sense 4 digital Inputs.
The cluster controller can sense 4 digital inputs as well as two analog inputs for example among many others.

Here my pros and cons I found out about the two options:

Cluster Controller:
+ up to 75 STP at once
+ Speedwire connection (much faster)
+ analog input
+ Already equipped with ethernet port for sunny portal upload
+ stepless control ??? (not sure)
+ second analog input (reactive power control independant from normal power control)
- expensive

PCM:
- only predefined steps possible and no stepless controll
- needs 4 dig input signals which might be more work than one anlog signal
- only 5 inverters on one pcm
- needs 5 seconds to execute a new command (adjustable) (might be faster with the cc)
- no reactive power control independant from normal power control
+ cheap

I have just sent some clarifying questions to SMA Germany on wether it's possible with the cc to have stepless control and if the output (% inverter power) can be linked to the analog input signals).

As measuring device I thought of something like this:

A C350 M2M control device to read from the Universal measuring devices UMG 103 with connected voltage and current sensors.
This would measure and calculate the current load capacity and give out an analog signal based on the PV capacity. For example 4mA=0% up to 20mA=100%.

The calculation would be simply %PV=Consumption/PV capacity. This could be done for reactive power as well.

jwrgorman

Re: Grid-Tied, No Sell 3-phase with SMA Cluster Controller in Kenya

Yes, this exists. We have the unit called the PicoGrid ZX (for Zero Export).

http://www.picogrid.com/products/zero-export-picogrid-zx/

It is small embedded computer that runs a Java OSGi based application that connects to a variety of equipment simultaneously, and drives the PCM on the string of SMA inverters based on the measurements of a Modbus-enabled kWh meter. We support a few different meters including Schneider, and have implemented a 5-Tripower 100kW system in New Zealand. Works great, very affordable and point and click to setup like an internet router, but much more powerful.

We also incorporate backup logic in the PLC that actually drives the SMA 4-wire signals (16-bit with full disconnect option), which will take over if there is no "heartbeat" maintained with our PicoGrid unit which manages the solar based on load. So there is redundancy, enterprise level logic, remote management and firmware upgrades, and certificate based authentication and encryption with our cloud based server, that handles the visualization and other services, also all Java OSGi.

If anyone is interested, it is also based on a 100% open-source development platform called SolarNetwork and supports Outback, Morningstar, Enasolar, Xantrex and other solar devices and metering equipment, switches and more. You can see more on technical details on Github and test it out as well, runs on a variety of embedded hardware such as Raspberry Pi etc.

I'd be happy to answer any questions, but we see a big need for this logic in regions where there is high-priced electricity on diesel-based grids, as it won't export but will chop out what it can from your grid-based usage during the day, with no batteries needed. The Pacific Region is an example, but I am sure that Africa could also see some good implementations.

Thanks, John









Let me know

coke

Re: Grid-Tied, No Sell 3-phase with SMA Cluster Controller in Kenya

Hi,

SMA is curently not having any device which can make this, but there will be a smaller version of the current cluster controller which will have this function as well as an update for the sunny home manager which will also have this function.

Until then I am using third party solution from companies which normally offer power plant controllers and such things. They know the inverter protocols very well and can even work with diesel and grid tied systems.

tazil007 wrote: »

Hi TMount

Am also looking at what to use as the device which reads power and translates this info (using 4 digital output) for the SMA cluster controller or power control module to limit inverter active/reactive power. This is only to prevent exporting to the grid and 100% self consumption in real time. Please do let me know if you find this missing device which can interface between measurement and controller.

Thanks

jwrgorman

Re: Grid-Tied, No Sell 3-phase with SMA Cluster Controller in Kenya

coke wrote: »

SMA is curently not having any device which can make this, but there will be a smaller version of the current cluster controller which will have this function as well as an update for the sunny home manager which will also have this function.

If anyone has a Raspberry Pi, a USB-to-485 adapter, a USB-to-232 adapter, and a PLC that can drive four 12VDC coils/contactors, you can get this functionality with SolarNetwork - the components download, install and execute on the unit over a browser, and it's point and click configuration. This is like an app-store for energy management devices:

http://www.solarnetwork.net/pluginFramework.php

you can add multiple SMAs, multiple kWh meters, etc. it's all open-source.