Ramp rate limiter (with HEMS)

Description

To avoid rapid changes in the active power and reactive power output, the Ramp rate limiter option allows the power generating system to follow a defined ramp rate to increase or decrease the active power output after receiving a new setpoint from the grid operator/third party.

Functions

The option ramp rate limiter is available for active and reactive power control. The ramp rate limiter is applied to the grid operator / third-party setpoint. The following options are available:

Active power

Generally, the ramp rate limiter always applies to setpoints. In the mode PV-self consumption, internal constant setpoints are applied. As those setpoints are constant and not changing the ramp rate limiter has no effect. In the band-shaving mode, the ramp rate limiter has an effect because the internally generated setpoints are changing with time.

In closed loop mode operation during a setpoint change, the correction value always jumps to the measured actual power production to prevent the system delays in adapting the power.

Ramp rate limiter for active power.png — Ramp rate limiter for active power

Ramp rate limiter toggle	Activate the ramp rate limiter via the user interface.
Ramp up	The ramp rate configured for ramp up only applies to the new setpoint from the grid operator / third party if it increases the active power output.
Ramp up/ramp down	Define separate ramp rates (Ramp rate (ramp-up) and Ramp rate (ramp-down)) for increasing and reducing the active power output.
Soft start	A soft start ramp rate will be used if the active power at the point of common coupling is ≤ 0 W. The ramp rate is valid until the new setpoint is reached. Example: Active power is 0 W and the setpoint is 0% Setpoint changes from 0% to 100% Soft start is active until a setpoint of 100% is reached. e.g. for ramp rate 1%/s = for 100 s the Soft start ramp rate is active
Configuration of ramp rates	The ramp rate can be configured via the user interface.

Reactive power

Ramp rate limiter toggle	The ramp rate can be configured via the user interface.
Ramp up	The ramp rate configured for the ramp rate applies to the new setpoint from the grid operator.

Examples

	Setpoint grid operator input signal	Output signal
Ramp rate limiter off
Ramp up
Ramp up/ramp down
Soft start