Voltage regulation and grid connection fallback
React to high grid voltage, and decide how the grid limits change when a device stops communicating.
→ Overview
This chapter covers two modes that protect the site rather than save money:
- Voltage regulation switches the strategy to separate limits and a separate goal while the grid voltage is too high, for example to stop export so the PV inverters do not trip on over-voltage.
- Grid connection fallback raises or lowers the grid limits and fuse values while a chosen device of the strategy is offline.
Each strategy can have one of each.
1 Voltage regulation
When it is active
The strategy reads the voltage of each phase from its measuring devices (the grid meter). Voltage regulation:
- starts when the highest of the three phase voltages rises above Activate above grid voltage;
- stays on until the highest phase voltage falls below Activate above grid voltage minus Deactivation threshold.
With the defaults, 250 V and 5 V, it starts above 250 V and ends below 245 V. If the strategy measures no voltage, Voltage regulation never starts.
While Voltage regulation is active, its values win over Negative price, every Schedule entry and the Default mode. Only an active AI energy manager time slot can still replace its goal and grid limits.
Add voltage regulation
Parameters
| Parameter | What it does | Unit / default |
|---|---|---|
| Export limit | Maximum export while the voltage is too high. A low value reduces PV feed-in, which lowers the voltage at the connection point. | kW · 0 |
| Goal | Goal during over-voltage: Maximize production, Self-consumption, Maximize consumption or Peak shaving. | Self-consumption |
| Import limit | Maximum import during over-voltage. | kW · 5 |
| Activate above grid voltage | Voltage regulation starts when the highest phase voltage is above this value. | V · 250 |
| Deactivation threshold | Hysteresis. Voltage regulation ends only when the highest phase voltage is below Activate above grid voltage minus this value. Example from the tooltip: 250 V and 5 V end the mode below 245 V. | V · 5 |
| Advanced settings | Battery, PV, EVSE and HVAC settings during over-voltage. They work as in the Default mode, see Optimization modes, goals and limits. | — |
| Confirm | Closes the editor and adds or updates the Voltage regulation row. Nothing is saved yet. | — |
Voltage regulation reacts at the strategy's regulation speed and depends on the grid meter. Set Activate above grid voltage below the inverters' own over-voltage trip level, and keep their built-in protection settings as required by the grid operator.
Saving Settings → Grid with this strategy selected replaces the Export limit and Import limit of Voltage regulation with the site values. Check them again after you save the grid settings. See Grid settings.
While Voltage regulation is active, Optimization on the strategy's Last measurements tab shows
Over-voltage protection.
2 Grid connection fallback
What happens when a device stops communicating
The strategy reacts to offline devices in two ways.
Fallback to safe values. When a measuring device of the strategy (a grid meter in the Measurement devices and strategies column of Included items) goes offline and it has no fallback entry, the strategy no longer knows the power at the grid connection. It switches to safe values:
- the battery is no longer steered by the goal;
- PV is limited to the PV Fallback power;
- EV chargers are limited to the EVSE Fallback power;
- heat pumps are set to the HVAC Fallback setpoint.
The fallback values are set on the strategy's Details tab. See Strategy details: grid, EVSE, PV and HVAC.
Fallback entries. With Grid connection fallback you list devices and say how the grid limits change while each of them is offline. While a listed device is offline, its entry's values are added to or subtracted from the strategy's import limit, export limit and fuse values. If several listed devices are offline, all their entries apply.
Example: the heat pump stops communicating, so the controller can no longer turn it down. An entry for the heat pump with Decrease limits and an import value equal to its rated power keeps that power free for it, and the other devices draw less.
In both cases Fallback to safe values on the strategy's Last measurements tab shows ON.
Add a fallback entry
Parameters
| Parameter | What it does | Unit / default |
|---|---|---|
| Device | The device to watch. The list contains the devices of this strategy (see Included items); devices that already have an entry are not offered. | — |
| Action type | Increase limits adds the values below to the limits while the device is offline. Decrease limits subtracts them; the import and export limits never drop below the mode's minimum and the fuse values never below 0 A. | Increase limits / Decrease limits · Decrease limits |
| Export power active limit [kW] | Change of the export limit while the device is offline. Empty = no change. | kW · empty · min. 0, step 0.1 |
| Import power active limit [kW] | Change of the import limit while the device is offline. Empty = no change. | kW · empty · min. 0, step 0.1 |
| Fuse L1 [A], Fuse L2 [A], Fuse L3 [A] | Change of the fuse value of each phase while the device is offline. Empty = no change. | A · empty · min. 0, step 1 |
| Bin icon (in the row) | Removes the entry from the editor. | — |
| Add | Adds a row for the next device of the strategy. Greyed out when every device already has an entry. | — |
| Confirm | Closes the editor and adds or updates the Grid connection fallback row. Nothing is saved yet. | — |
If you add an entry for a measuring device such as the main grid meter, the strategy does not switch to safe values when that meter goes offline. It keeps regulating with the changed limits, without a valid measurement of the grid connection. This can overload the main fuses or exceed the export limit. Add measuring devices only if you are sure the site stays safe, and use Decrease limits for them.
Increase limits raises the import or export limit and the fuse values above what is set for the site. Make sure the raised values are still within the grid connection agreement and the installed main fuses.
How it works with other modes
The fallback entries change the limits of whichever mode is in effect, including an AI energy manager slot or a Flexibility activation. A grid operator limit received over the EEBUS connector is applied after the fallback entries, so a fallback entry can never raise the site above it.
3 Checklist
- The strategy measures phase voltages, so Voltage regulation can start.
- Activate above grid voltage is below the inverters' over-voltage trip level.
- Deactivation threshold is large enough to avoid frequent switching (5 V or more).
- Voltage regulation limits are still correct after the last save of Settings → Grid.
- Fallback power and Fallback setpoint on the Details tab are safe for the site.
- Fallback entries exist only for devices whose outage changes the allowed grid limits; the main grid meter has none unless agreed.
- Increased limits stay within the grid connection and the main fuses.
- Save was clicked.