Individual Solutions for International Requirements

Solar-Log™ Feed-In Management

In the next few years, there will be new requirements for grid stability in all countries that have a certain amount of power produced from decentralized sources to stabilize the power grid on critical days with limited sunshine.

The Solar-Log™ devices already cover the entire range of requirements for power management and provide a solution for every plant size.

Limited feed-in (x %)

A key function is to limit the feed into the grid. In Germany, plants with less than 30 kWp are required by law to have feed-in power limit of 70 % or to use remote control power limitations.

  • This means that the Solar-Log™ records the consumption onsite and calculates this with the inverter production.
  • Solar-Log™ ensures that the feed-in limit is not exceeded and that the amount self-consumption is maximized.
  • The limit can be set to any percentage such as 50% or 60% or even to 0% (only self-consumption, no feed-in).

Reduction with the calculation of self-consumption

With this innovative solution, the loss that results from the X % reduction can be minimized and implemented as follows.

  • To carry out this function, only current consumption needs to be measured.
  • The Solar-Log™ calculates the amount of consumption and the current inverter production.
  • If the difference between the current production and consumption exceeds, for example, 70% of the module’s power output, the output from the inverters is reduced accordingly.
  • This function can be also be used to define additional percentage reductions.

Please note, an additional external meter is needed to implement this function.

Simplified Feed-in Management

The German Renewable Energy Act (EEG) requires "simplified feed-in management" for plants up to 100 kWp and can be impletement in the following ways.

  • The signals to reduce active power are generally sent via a Ripple Control Receiver.
  • The Solar-Log™ PM+ product line comes with an additional interface for potential-free contacts.
  • Up to 2 ripple control receivers can be connected to this interface, one for power reduction and one for reactive power control.

Simple feed-in management can also implement the “remote controlled with the calculation of self-consumption” function. To carry out this function, the Solar-Log™ only needs a special power meter to measure the current self-consumption in the house.

Managing PV Plants in the Medium Voltage Network

The power grid management for photovoltaic plants (production plants) in the medium voltage network
 Plants larger than 100 kWp in the medium voltage network often have advanced requirements.

  • Control of the photovoltaic plant has to be guaranteed.
  • Information on the current amount of feed-in power has to be available.
  • Remote control technology with various commands and response signals is usually used for the communication with the grid control center.

What advantages does this type of communication offer

This technology allows bi-directional communication between the the telecontrol system and grid operator. The signals are transmitted between the telecontrol system and Solar-Log Base via I/O Box(es) with the PM package. The Solar-Log™ I/O Box can receive and send a wide range of signals from various grid operators. Depending on which value has to be transmitted to the grid operator, a measurement of transformer voltage with the Solar-Log™ Utility Meter is required.

Special Technical Requirements

Controlling active power and regulating reactive power represents a special technical challenge. Grid operators rely on various solutions here.

  • Control of voltage-dependent reactive power via the Q(U) function.
  • Reactive power control at the feeding point.

Both options can be implemented in combination with the Solar-Log™ Utility Meter. Other functions such as the fixed value cos phi shift factor or performance related cos phi functions can be implemented without additional measurements.

Modbus TCP Powermanagement (PM) Interface

Complex grid operator requirements can be implemented by using telecontrol systems that are directly connected to the Solar-Log™ via the TCP-based Modbus protocol. With this set up, the command signals and response signals between the remote control technology and the Solar-Log 1900 PM+ and 2000 PM+ are relayed back and forth via the protocol without potential-free and analog interfaces. This direct connection with remote control technology can implement communication according to IEC 60870-C, 61850-5-101 and -104.

Feed-in Management with Solar-Log™ Networks

The Solar-Log Base are linked together with an Ethernet connection to implement feed-in management at larger plants. This linking over the network allows control signals from Ripple Control Receivers to be interchanged.

  • The grid operator’s signals are received by the Solar-Log Base 2000 (master) and distributed to the connected inverters via the Solar-Log Base 2000 (slaves).
  • The master can be connected to up to nine slaves in this setup.
  • Linking the Solar-Log™ devices together over the network helps to implement complex requirements (several plant parts, feeding points and inverters from several manufacturers).

Do you have any questions?

Your Contact Person

Technical Support - Projects

Solar-Log GmbH
Fuhrmannstr. 9
72351 Geislingen-Binsdorf
Telephone: +49 (0)7428 / 4089-300