Behavior In The Absence Of Active And Reactive Power Setpoints - SMA SUNNY CENTRAL 500CP XT User Manual

SMA Solar Technology AG
By supplying reactive power, the inverter performs voltage-stabilizing measures in the event of overvoltage or
undervoltage. The parameterization is carried out by means of a reactive power/voltage characteristic curve. The
characteristic curve can be configured flexibly by parameterization of the slopes, a type of deadband through two
voltage points, a hysteresis and the thresholds for activation.
Figure 39: Characteristic curve for reducing reactive power with deadband and hysteresis
The parameter Q-VArTmsSpnt determines the delay time which must elapse before the calculated reactive power
setpoint is actively used.
In order to prevent mutual interference of several systems with this function, the parameter Q-VArTmsVtg can be used
to set a delay time. This delay time defines how long a voltage change must be pending before a change in reactive
power feed-in is triggered. Consequently, control of the grid voltage at the grid feed-in point can be staggered across
several systems.
You can activate and deactivate the delay time by means of the parameter Q-EnaTmsVtg.
In addition, the parameter Q-VLockInW can be used to define a voltage at which reactive power control will be
activated after the time specified in parameter Q-VLockInTm has elapsed. If the voltage exceeds the threshold
defined in parameter Q-VLockOutW, the reactive power control will be deactivated once the time specified in
parameter Q-VLockOutTm has elapsed.

10.3.5 Behavior in the Absence of Active and Reactive Power Setpoints

In the event of failure of setpoints for active and reactive power control, the inverter is capable of bridging the gap in
two ways:
• Use of last default values received:
As long as the inverter does not receive any updated default values, it will use the last value received (when
setpoint takes place via communication) and the last valid mean value (when using analog setpoints).
• Use of substitute values:
As long as the inverter does not receive any updated default values, it will utilize the specified substitute values for
active power limitation, reactive power setpoint and displacement power factor. In this case, different substitute
values can be configured for feed-in operation and grid monitoring.
User Manual
10 Function Description
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