SMA SC 500CP XT - Manual (Page 97)

10.3.3.6 Reactive Power Setpoint 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 Description
< 2 mA Last valid mean value or 0 kVAr after
restart Signal is in the invalid range.
2 mA to 4 mA Qmax / underexcited The maximum amount of negatively excited reactive
power is fed in.
4 mA Qmax / underexcited Start point of the characteristic curve
The maximum amount of negatively excited reactive
power is fed in.
11.5 mA 0 kVAr Zero-crossing of the characteristic curve
No reactive power is fed in.
> 19 mA Qmax / overexcited End point of the characteristic curve
The maximum amount of positively excited reactive
power is fed in.
The analog value is converted to a setpoint for power limitation. Here, the parameter Qmax forms the end point of the
linear characteristic curve.
Figure 23: Limitation of the reactive power to the parameter Qmax
10.3.3.7 Reactive Power Setpoint via Displacement Power Factor cos φ: PFCnst Mode
The reactive power setpoint is set via the parameters PF‑PF and PF‑PFExt. The parameter PF‑PF indicates the
displacement power factor cos φ and the parameter PF‑PFExt indicates the degree of overexcitation or
underexcitation.
10 Function Description SMA Solar Technology AG
User Manual 97 SCCPXT-BA-E4-en-54