Individual solutions for international requirements

Feed-In Management

It is important for the operators to know the current output data from the photovoltaic plants and to be able to manage the output from these plants as needed to keep the grid stable.

Solar-Log™ models are flexible systems to meet the different regulatory and operating requirements from individual countries and grid operators.

Limited feed-in power

For photovoltaic plants up to 30 kWp, plant operators in Germany can choice which type of power limits to use:

  • remote controlled power reductions
  • fixed reduction of 70 % based on the installed module output

Solar-Log™ offers two variants for the fixed reduction of 70% at the feed-in point.

Inverter feed-in power limits of X % of the module output

The reduction offers the following options for implementation.

  • The feed-in power from the inverter is directly limited to the fixed X % of the module output at the inverter.
  • The Solar-Log™ adjusts the inverters to X % of the module output to limit the feed-in power according to the regulation.
  • A yield loss of 3 to 5 percentage is to be expected with this regulation.

With Solar-Log™ PM+ devices, a feed-in cap for the inverters with allowances for self-consumption can be configured.

Remote controlled 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.

  • The current consumption of self-produced power in the household is also calculated.
  • The Solar-Log™ calculates the current amount of power being fed into the grid and the current amount of power being produced by the inverters.
  • Before the feed-in power (the difference between the current production and consumption) exceeds the maximum amount specified, Solar-Log™ limits the output from the inverters to the defined X %.
  • 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 Large Plants

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 2000 PM+ 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 PM Interface

It can help to implement complex requirements from grid operators. This is possible with a direct connection to telecontrol systems from select manufacturers. The implementation with a Solar-Log™ PM+ device is done via the TCP-based Modbus protocol. The command signals and response signals between the remote control technology and the Solar-Log 2000 PM+ are relayed back and forth without potential-free and analog interfaces. Combined with remote control technology, communication according to IEC 60870-C, 61850-5-101 and -104 can also be implemented.

Do you have any questions?

Your Contact Person

Technical Support

Solar-Log™ China
Zhejiang Rhea Energy Technology Co.Ltd
Room 149, Building 4, No. 20 Longtan Road, Cangqian Street, Yuhang District
311 121 Hangzhou
Telephone: +86 13812056089