6 Electrical Connection
SMA Solar Technology AG
Operating manual
49
SI44M-80H-13-BE-en-15
Specifications for load-shedding configuration:
Load shedding in a multicluster system
One-level load shedding is integrated into the Multicluster-Box. The load-shedding contactor is controlled directly
by the master of the main cluster via communication with the Multicluster-Box. If you install an additional load-
shedding contactor in a multicluster system, it is controlled with a multifunction relay in the master of extension
cluster 1. Additional load-shedding contactors cannot be controlled by the main cluster.
Load-shedding contactors in a cluster
If you connect load-shedding contactors to the master, limited operation is possible in the event of a disturbance.
Slaves can control the load-shedding contactors less reliably in the event of a fault. In the event of a disturbance,
the slave may wait for confirmation from the master.
The following values are stored in the user interface of the Sunny Island for setting the load-shedding system. If you
connect load-shedding contactors, consider the effects in the system and comply with the instructions for use.
Value
System effects
Application
1-stage load-shedding
scheme (Load shedding
1)
If the Sunny Island has activated the load-shedding sys-
tem and then an external energy source is connected,
the load-shedding process is terminated immediately
(regardless of the battery's state of charge). The exter-
nal energy source is then supplying the loads. The bat-
tery is only charged with the excess energy.
• Works only in off-grid and
battery-backup systems
1‑stage load-shedding
scheme or first stage in
terms of two-stage load-
shedding schemes
(Load shedding 1)
Setting for 1-stage load-shedding scheme or the first
stage of a 2-stage load-shedding scheme. Load shed-
ding is only stopped when the battery has been suffi-
ciently charged. This setting affects the system behavior
regardless of whether an external energy source is
present.
• Suitable in systems for
increased self-consumption
(battery-storage systems)
Second stage in terms
of 2-stage load-shed-
ding scheme (Load
shedding 2)
Settings for second load-shedding contactor in terms of
a 2-stage load-shedding scheme. Load shedding is
only stopped when the battery has been sufficiently
charged.
• Suitable in off-grid systems,
battery-backup systems and
systems for increased self-
consumption
Load shedding in multi-
cluster system (Load
shedding 1)
In a multicluster system, this setting is intended for addi-
tional 1-stage load-shedding. When the battery state
of charge of a cluster falls below a set value, the load-
shedding process begins. The load shedding only ends
when the batteries of all clusters have reached the set
value of the battery state of charge. How long it takes
to reach this value depends on the battery technology
used and the selected battery capacity. If different bat-
tery technologies and different battery capacities are
combined in the clusters of a multicluster system, the
display values for the individual clusters may vary.
• Only for multicluster systems
Requirements:
☐ The technical requirements of the multifunction relay must be met (see Section 16, page 175).
Cable requirements:
☐ Conductor type: copper wire
☐ Conductor cross-section: 0.2 mm² to 2.5 mm²
