German EEG §9 requires to reduce feed in power by DNO for all installations up from 7kVA in 4 steps 100/60/30/0%. (See Multiplus FW update v555) Older Installations before February 2025 receive a compensation pay for assumed power within this throttled time. New installations after Febraury 2025 are allowed to append compensated lifetime after the 20 years capital consumption allowance.
Anycase it is required to supervise the calculations of the annual bill received from DNO for the previous year. Therefore I tried to record the 4 throttle signals supplied by the DNOs ImSys/FNN-Box using a VRM custom widget. The only choice to record digital input devices seems “count”. This only records number of rising or falling edges. The requirements are to record up and downtime hours or at least the downtime state aggregated manually to compare with the invoice of previous year.
My Node Red solution for power limiting is here. It already works like expected. To trace a complete year, tools like VRM using visualisation and database seems to be prefered. Its simply to see the voltage level of inputs instead counts. Maybe I have to connect analog inputs in parallel to achieve this?
I trigger the function every hour with an inject node, but you can chose the frequency you want to log. Be careful though as a higher frequency will generate a lot of data.
To record the throttle times, log frequency of one minute seems appropriate. For one year, this will produce a file with over 500000 Ascii lines each one with absolute time stamp and 4 signal states. That data amount is clearly the job of a database server with sufficient mass storage hard disk rather than a low power Cerbo hardware
Aha.
Does it switch that often? I would just record changes and a timestamp.
I only see 16 or so switches changes there per input. How long was it running?
For the moment, the control device supplied by DNO is not connected. They like to see the functionality first to make sure the power limiting works like required by their rules.
I have no idea, how much they use those throttle signals. What I heard from some DNOs that they never used. In Bavaria they use always at sunshine weather. Assume the production will be throttled if electricity stock price is negative. This situation increases more and more and nobody will pay for feeding in additional PV energy why the DNO will switch this off.
On the other hand, using 4 relais is a stupid VDE rule adopted by all DNOs. Although the EEBUS club is already more than 10 years old, the LPP (limit power production) use case exists and adopted by VDE last year, my DNO claims he never heard from that protocol.
As the use of 4 relay contacts seems ancient, I going to try a 4 bit passive D/A converter to connect the signals to the 5Volt analog tank sensor input. Using the shown resistors, 5mA should give sufficient noise immunity to to recognize 4 power threshhold values in NodeRed. This occupies only one input at the Cerbo instead of 4 and hopefully the VRM widget is doing automatically what it should do.
This is a proposal by VDE from last year to use one of the remaining outputs for the new EnWG §14a what is the use case LPC limitation of power consumption. Obviously the DNO cannot change their existing devices and control signals needs to be same for everybody.
The Royal Air Force in 2nd world war already used remote controlled bombs with puls width controlled servos.
what has an Azon guided bomb to do with §9EEG or §14aEnWG?
Never, and I mean never, try to compare anything, especially with me, with the Nazi-regime.
My family was deported from Bohemia.
But, If your DNO still stays with the good old German Rundsteuerempfänger instead a real control-box and IMSys, than hope, that a Node-Red-Solution will be accepted. This is not manipulation free, a simple deletion of a single connection between the nodes would disable that. An issue with §9EEG as this is monitored, but for §14a the DNO can’t see if the load is coming from the kitchens-oven, or your HP.
Next time use your brain fist, before starting with Nazi comparsions.
I deleted my last 4 words but before and after, it remains still a comparison of signals and not of countries or ideologies.
The new and hardly available FNN-Steuerbox also works with 4 relais contacts. The danger of manipulation is that somebody else than the DNOs will control the power of all inverters in a country. Mark Elsberg already deleted some text in his “Blackout” novel written in 2012 about this to avoid giving instructions for cyber criminals. Thats also why the BSI as owner of the root certificates is somewhat dizzy. Even with direct coupled EEBUS to the inverter without using redundant control boxes and relays, manipulated inverters could give digital acknowledge while doing something else. Finally my efforts are simply the trial to log the remote controlled throttle commands using the widgets inside VRM.
