Q At Night; No Q At Night: Off Mode; Q At Night With Operation Command Via Modbus Protocol: Varctlcom Mode; Q At Night With Absolute Value: Varcnst Mode - SMA SUNNY CENTRAL 500CP XT User Manual

10 Function Description

10.3.4 Q at Night

10.3.4.1 No Q at Night: Off Mode

The reactive power setpoint is limited to 0 kVAr. This setpoint cannot be controlled.

10.3.4.2 Q at Night with Operation Command via Modbus Protocol: VArCtlCom Mode

The reactive power setpoint is received by the communication unit and transmitted to the inverter. The setpoint is
transmitted as a percentage value and converted to kVAr in the device. If the inverter has not received any signal for
five minutes, the error message Q-VArModFailStt will be displayed.

10.3.4.3 Q at Night with Absolute Value: VArCnst Mode

The reactive power setpoint is set via the parameter QoDQ-VAr. The parameter QoDQ-VAr is permitted to be within
the range from ‒QoDQmax to +QoDQmax.

10.3.4.4 Q at Night as a Percentage of the Nominal Power: VArCnstNom Mode

The parameter QoDQ-VArNom is used to set the reactive power setpoint in %. The parameter QoDQ-VArNom
refers to Pmax. If the calculated amount of reactive power exceeds the predefined value of QoDQmax, it will be
limited to QoDQmax. If the calculated amount of reactive power falls below the predefined value of ‒QoDQmax, it
will be limited to ‒QoDQmax.

10.3.4.5 Q at Night via Standard Signal: VArCnstNomAnIn Mode

The reactive power setpoint is set at the input terminals for the setpoints via an analog signal. This is usually
implemented by a ripple control signal. The analog value is converted into a reactive power setpoint. The electrical
current strength of the connected signal determines the setpoint. The analog measured values must be between
4 mA and 19 mA. If the analog signal is less than 2 mA, an error message will be displayed in the instantaneous value
Q‑VArModFailStt.
Signal Power limit
< 2 mA Last valid mean value or 0 kVAr after
restart
2 mA to 4 mA
−QoDQmax / underexcited
4 mA
−QoDQmax / underexcited
11.5 mA 0 kVAr
> 19 mA +QoDQmax / overexcited
102 SCCPXT-E7-BA-en-58
Description
Signal is in the invalid range.
The maximum amount of negatively excited reactive
power is fed in.
Start point of the characteristic curve
The maximum amount of negatively excited reactive
power is fed in.
Zero-crossing of the characteristic curve
No reactive power is fed in.
End point of the characteristic curve
The maximum amount of positively excited reactive
power is fed in.
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