Setting Two-Level Load Shedding

The basic procedure for changing operating parameters is explained in another section ( > Changing Operating Parameters).

2 multifunction relays control 2 load-shedding contactors depending on the state of charge of the battery.

Significance of the SOC thresholds:

Two lower and two upper SOC thresholds are available for each interval for controlling the load-shedding contactors. The load-shedding contactors disconnect the loads from the utility grid if the states of charge are as follows:

  • When the state of charge of the battery reaches the first lower SOC threshold, the multifunction relay opens the connected load-shedding contactor for the first level of load shedding. The load-shedding contactor disconnects those loads from the utility grid that are to be disconnected for the first level.

  • When the state of charge of the battery reaches the second lower SOC threshold, the multifunction relay opens the connected load-shedding contactor for the second level of load shedding. The load-shedding contactor disconnects the remaining loads from the utility grid.

  • When the state of charge of the battery reaches the second upper SOC threshold during recharging, the multifunction relay closes the connected load-shedding contactor for the second level of load shedding. The load-shedding contactor connects those loads to the utility grid that were disconnected for the second level.

  • When the state of charge of the battery reaches the first upper SOC threshold during recharging, the multifunction relay closes the connected load-shedding contactor for the first level of load shedding. The load-shedding contactor connects those loads, which were disconnected for the first level, to the utility grid. All loads are connected to the utility grid.

Procedure:

  • Set the first stage of load shedding.

  • Set the second stage of load shedding.

Set the first stage of load shedding

  1. Select Device > Load shedding 1 > Additional time range.
  2. Set the parameter Lmt value battery state of charge for start load shedding 1 to the lower SOC threshold.
  3. Set the parameter Lmt value battery state of charge for stop load shedding 1 to the upper SOC threshold.
  4. 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.
  5. 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).

Setting the second stage of load shedding

  1. Select Device > Load shedding 2.
  2. Set the parameter Lmt value battery state of charge for start load shedding 2 to the lower SOC threshold.
  3. Set the parameter Limit battery state of charge for stop load shedding 2 in add time range to the upper SOC threshold.
  4. Select Device > Load shedding 2 > Additional time range.
  5. Set the parameter Time load shedding 2 and the parameter Start time additional time range load shedding 2 each to the same value, e.g. to 00:00:00. This will switch the time-dependent load shedding off.
  6. Ensure that the parameter of the multifunction relay has been set to 1st stage with 2-stage load shedding ( > Setting the Functions of the Multifunction Relays).
    Setting One-Level Load Shedding
    Setting Time-Dependent One-Level Load Shedding