SMA SC 500HE-US - Manual (Page 42)

8 Reactive Power Regulation SMA America, LLC
42 SC500HEUS-eng-BE-BUS120320 Operating Manual
8.1.5 "VArCnst" Procedure
The parameter "Q-VAr" is used to set the reactive power target value in kVAr. For this purpose, the
parameter "Q-VAr" must be in the range of "‒Qmax" to "+Qmax".
8.1.6 "VArCnstNom" Procedure
The parameter "Q-VArNom" is used to set the reactive power target value in percent. The parameter
"Q-VArNom" refers to "Pmax". If the calculated amount of reactive power exceeds the predefined
value "Qmax", the power will be limited to "Qmax". If the calculated amount of reactive power falls
below the predefined value "‒Qmax", the power will be limited to "‒Qmax".
8.1.7 "VArCnstNomAnIn" Procedure
The reactive power target value is set at the input terminals using an analog signal for specifying the
target value (see the the inverter installation manual). This is usually implemented by a ripple control
receiver.
The analog value is converted into a reactive power target value. The electrical current strength of the
connected signal determines the target value.
The analog measured values must be between 4 mA and 19 mA. If the analog signal is less than
2 mA, the error message will be displayed in the instantaneous value "Q-VArModFailStt".
Parameter used Q-VAr
Parameter used Q-VArNom
Signal Power limit Explanation
< 2 mA Last valid value or 0 kVAr after
restart Signal is in the invalid range.
2 mA … 4 mA − Pmax The maximum amount of negatively
excited reactive power is fed in.
4 mA − Pmax Starting point of the curve
Maximum amount of negatively excited
reactive power is fed in.
11.5 mA 0 kVAr Zero-crossing of the curve
No reactive power is fed in.
> 19 mA +Pmax End point of the curve
Maximum amount of positively excited
reactive power is fed in.