Case Studies

Control Your Power – Frequency Shift

System in co. Sligo consist of 4x200Ah lifepo4 batteries (10kWh usable capacity), 5kW Victron inverter charger, 3kW Fronius solar inverter with 11x285Wp Perlight modules and recently installed VAWT. James has also 30kWh capacity in his car.

Shortly speaking system is independent last 12 days. As you can see below energy consumption  is between 5 to 10 kWh per day. Only when load is higher than 5.5kW internal relay of victron multi connects to ESB grid supply.

Total energy consumption source break down:

Below solar and wind inverters on separate graphs. Notice last few windy days (I am writing this post right now 🙂 Ireland vs Englad in teli). It was sunny week ago but spring will be after this hopefully…

Solar (top) and wind (bottom) generation last 12 days

Maybe not the best wind spot in terms of average production as very  dependent to wind direction but turbine works well and when windy it makes energy day and night. (if windy from west  – recorded 5.3kW of power during storms from there !).

In windy day when battery full, we can plug in  electric car to charge at 3.7kW (how many times energy was converted at this stage ?) and discharge system a bit, but if you do not want to do it… just watch frequency shift “mechanism” working. Whenever battery gets to absorption voltage, we toping up battery gently so we do not need all the power from the turbine (can be 3am ) system could be exporting at this stage  but we playing with full off grid as after latest ESB investigation grid is being upgraded. (impedance was to high resulting in bad energy quality ).

Victron is increasing our micro grid  frequency…and wind and solar inverter have grid settings so messed up that is my own grid code 🙂 So whenever  GTI (grid tie inverter ) can see grid frequency going up, he is fast to reduce output to keep system in balance.

AC output frequency (island frequency) and battery state of charge (bottom)

Maybe not the safest solution for wind turbine as 4kW resistor heater kiks in at 530V DC rectifier output so at pretty high rpm… but works 🙂 heater didn’t melted yet and turbine is still there on 10m tower so enjoy!

VE configure frequency shift victron settings
ABB aurora manager TL wind inverter settings

Last graph below…  area under will be bigger than area above red ax. Note it is more efficient to use energy directly from wind and sun before it hits battery.

AC Output Power History
AC energy direction of flow (above ax demand below excess going to battery)

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