Reactive Power Control

Generating and electricity-drawing plants must provide reactive power to support the utility grid. By providing reactive power, voltage changes in the utility grid are kept within acceptable limits. The dimensioning of the generating plant with regard to the required reactive power provision at the grid-connection point is the responsibility of the PV system operator. The grid operator specifies the reactive power mode and the parameters to be set. The grid operator typically has different demands for generating and electricity-drawing plants. Accordingly, the process can be activated and adjusted for active power consumption (consumption) regardless of the process for active power output (grid feed-in).

The settings or the configuration are configured in the user interface of the System Manager (e.g. SMA Data Manager or Sunny Tripower X 25).

In connection with an energy meter, an SMA System Manager takes over closed-loop control at the point of interconnection and can control or regulate subordinate inverters. The System Manager also takes over system monitoring and communication to the Sunny Portal powered by ennexOS.

Additional information on the different reactive power modes and the associated parameters can be found under the following link: Technical Information "SMA GRID GUARD 10.0 - Grid Management Services via Inverter and System Controller" and at www.SMA-Solar.com.

System configuration with System Manager as per VDE-AR-N-4105

The VDE-AR-N-4105 requires using inverter terminals as the reference point for grid management services. The commissioning wizard of the SMA System Manager is designed to help you configure the reactive power control in accordance with VDE-AR-N-4110. The VDE-AR-N-4110 requires using the point of interconnection as the reference point for grid management services. It is therefore not possible to use the commissioning wizard and the grid management service configuration wizard to configure the reactive power control of systems in the low-voltage grid in accordance with VDE-AR-N-4105. Detailed information on the proper procedure for configuration can be found under following link: Technical Information "Commissioning and configuration of reactive power control of systems in the low-voltage grid in accordance with VDE-AR-N-4105" and at www.SMA-Solar.com.

Specifics for different measurement and fulfillment locations for active and reactive power requirements

Application: System control with two measuring devices and SMA Data Manager M

Requirement: Open-loop or closed-loop control of the reactive power, based on the pure generating power.

Requirements:

  • An active power measurement at the point of interconnection

  • A reactive power measurement at the common connection point of the (PV) inverters

Currently, the open-loop control and closed-loop control module of the ennexOS-based system control can only use a single measuring device as reference measurement for all operating modes usable.

In order to still be able to fulfill the specifications above, a compatible measuring device (Janitza UMG 604-Pro) is installed on both measuring points. One measuring device is subordinated to the other. The superordinate measuring device forwards its own measured values as well as the values of the subordinate device to the System Manager (SMA Data Manager M / L). This means that the active power measurements from the point of interconnection and the reactive power measurements from the generating system are available to the system controller.

15302995212

System Overview

For further information on this, refer to the Technical Information "SMA Data Manager M / L - System control with two measuring devices - Reactive power control Q(V) for PV systems in medium-voltage systems" and at www.SMA-Solar.com.

    Active power limitation with the SMA Data Manager M
    SMA Dynamic Power Control