Metering for ess

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Hi I have a quick question in regards of the ess metering. if we are to implement a real life ess to test the controllers, will the controller need to get the power data of the ess. I have noticed that when using the simulated ess, the ui will show the realtime power data(charge and discharge power) of the ess, not sure if these power reading will be used by the controller. thanks

would be great if there is a note showing the minimum data requirements of ess, pv inverter

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Hi Steve,

It depends on which controller you use, but I think most controllers won’t use the active power of the ess. They rather use values like SOC or capacity, of values from other devices, e.g. a grid meter.

For the minimum data requirements, you can simply check the enum ChannelId of the corresponding nature. For a Symmetric ESS for example, the values are here: https://github.com/OpenEMS/openems/blob/develop/io.openems.edge.ess.api/src/io/openems/edge/ess/api/SymmetricEss.java

For the PV Inverter, note that the ManagedSymmetricPvInverter (https://github.com/OpenEMS/openems/blob/develop/io.openems.edge.pvinverter.api/src/io/openems/edge/pvinverter/api/ManagedSymmetricPvInverter.java) extends the ElectricityMeter, so you need to fill its channels as well.

I hope my answer helps a bit.

Best regards,
Thomas

3

Sorry, I was plain wrong with my first statement. Indeed, many controllers need the power data to calculate the power setpoint.

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Hi Thomas,
thanks for the replay, really appreciate it! I guess if the there is an option for the ems to choose between the ess built-in power data registers or an outside standalone power meter, that would be great, not sure if it’s been implemented yet

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Hi Steve,

OpenEMS expects the ActivePower value to be set, and it is indeed used in a lot of places, so it should ideally match the actual AC-side power output of the ESS as accurately and quickly as possible.

If your “ESS” does not provide this data (which I doubt) you could of couse just place a meter there and write some logic in your ESS Component that copies the value of the Meter to the ESS. Just share your code if you need guidance on this.

Regards,
Stefan