I have an off grid system i support that has AC coupled Fronius, Pylontech batteries and DC coupled water turbine and ACTHOR power diverters running in frequency mode.
The system operates as expected so no actual issues with the set up or equipment.
The issue i need to solve is that there is a large air to water heat pump that provides Domestic hot water, underfloor heating in the winter and pool heating in the summer. The Heat Pump uses a Panasonic outdoor unit, and its not happy when the frequency goes high. It errors out and has to be reset. Help from Panasonic is non existent as the outdoor unit is fitted to a third party specialist hot water tank (Polar Enegi)
My research into standards tells me that grid frequency tolerance for electrical appliances is 5% for my county, and many others. So for a 50hz grid, 52.5. As the system is running the default Victron PV assistant settings, we are seeing 52.7. I think this is the issue as the heat pump only trips at the top end of the frequency range.
Im going to take the PV Inverter “off” set point in both the PV assistant, and the Fronius AC coupled inverters back to 52.2. But before i travel to site and change settings, does any one know, or can Victron Tech support shed light on why, if most standards for electrical equipment are 5% on hz, why the default settings Victron and Fronius settled on is outside of the 5%.
Has anyone else come across this, other than clocks running fast?
Various manufacturers of grid coupled PV systems - where this started - ended up by using anything from 51 - 52 Hz to shut the inverter power down to 0%. One thing that they did have in common, was that a shift of +2.5Hz or more would result in a shutdown and disconnection. This is all for off grid systems, as frequency shift for a utility operator has far too much inertia to overcome.
Most inverters are programmable by the end user to a custom standard, as long as there is more than 0.5Hz between 100% and 0%. So it should be possible to configure your system to start curtailing at 50.5Hz, and get to zero at 51.5Hz (or less) This should keep your heat pump happy.
The ACTORS (there are two of them ) ramp up the water heating from 50.1 to 100% at 51.1, so my plan was have the inverters ramping back from 51.2 to 52.2, with disconnect at 52.5.
Your replay further reinforces my question to Victron i guess is, if most inverters are off and disconnected at 52.5, why dose the default PV inverter settings have the ramp to 0 at 52.7, and the off/disconnect at 53, both of which setting are out side 5% for a 50hz network…
in fact, i may have just discovered the answer myself, 5% on a 60hz network is 63!
Would like someone from Victron to confirm, but i will make the changes next week.