Setting One-Level Load Shedding
The basic procedure for changing operating parameters is explained in another section ( > Changing Operating Parameters).
One multifunction relay controls the load-shedding contactor depending on the state of charge of the battery.
Significance of the SOC thresholds:
When the state of charge of the battery reaches the lower SOC threshold, the multifunction relay opens the connected load-shedding contactor. The load-shedding contactor disconnects the loads from the stand-alone grid. When the state of charge of the battery reaches the upper SOC threshold during recharging, the multifunction relay closes the connected load-shedding contactor. The load-shedding contactor connects the loads to the stand-alone grid.
Procedure:
- Select Device > Load shedding 1 > Additional time range.
- Set the parameter Lmt value battery state of charge for start load shedding 1 to the lower SOC threshold.
- Set the parameter Lmt value battery state of charge for stop load shedding 1 to the upper SOC threshold. The upper SOC threshold must be at least 10 percentage points above the lower SOC threshold.
- Set the parameter Time load shedding 1 and the parameter Start time additional time range load shedding 1 each to the same value, e.g. to 00:00:00. This will switch the time-dependent load shedding off.
- If the loads are only to be reconnected when the set SOC threshold is reached, ensure that the parameter of the multifunction relay has been set to 1-stage load shedding or 1st stage with 2-stage load shedding ( > Setting the Functions of the Multifunction Relays).
- If the loads are to be supplied by an external energy source during recharging of the battery, perform the following steps:
Ensure that the parameter of the multifunction relay is set to 1-stage load shedding ( > Setting the Functions of the Multifunction Relays).
Ensure that the external energy source can supply the loads with sufficient power.
- If the off-grid system is a multicluster system, ensure that the parameter of the multifunction relay is set to Load shedding in Multicluster ( > Setting the Functions of the Multifunction Relays).