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2018-10-19 application rule

Technical Connection Rules for Medium-Voltage (VDE-AR-N 4110)

Renewable energy plants will sustain the medium voltage grid more strongly in future. The new Technical Connection Rules for Medium Voltage also define the requirements on storage systems.

The Forum Network Technology/Network Operation (FNN) in VDE, in the "Technical Connection Rules Medium Voltage" VDE-AR-N 4110 (TCR Medium Voltage) Code of Practice, defines for the first time  the requirements for storage systems at this voltage level. This allows manufacturers of these plants to receive technically binding standards in good time thereby enhancing grid and system in the long term.

The VDE Code of Practice specifies the Technical Connection Rules (TCR) for planning, erection, operation and modification of customer installations that are connected at the grid connection point to the medium voltage grid of a network operator. Customer installations include reference and power generating plants, storages and combined facilities of generation/demand/storage.

TCR Medium Voltage develops for the first time requirements of the European Network Code "Requirements for Generators" for Germany entered into force in 2016. Against this backdrop, the TCR demand expanded capabilities for fault ride-through of short voltage drops as well as provision of reactive power in newly erected power generating plants. These new requirements improve grid stability. Further innovations include:

  • Requirements on combined facilities of generation/demand/storage (producers and consumers)
  • Updated protection concepts
  • Requirements for emergency power generators in the medium voltage grid for the first time

The medium voltage grids in Germany increase massively in importance through addition of renewable energies in the course of energy transition. Apart from large wind farms, photovoltaic green field plants and biogas plants, an increasing number of storage systems are being connected. The medium voltage grid is operated with 50 Hertz mains frequency and nominal voltages between 1,000 and 60,000 volt.

The new Code of Practice is part of the VDE FNN activities to preparing the system toward increasing feed-in of renewable energy in line with energy transition. It replaces, among others, the guidelines " Power Generation Plants at the Medium Voltage Grid" as well as the "Technical Connection Conditions for Medium-High Voltage" of 2008.

Target Groups

  • Network operators
  • Generating plant operators
  • Plant construction companies
  • Components manufacturers

Benefit and Improvement

  • Expanded requirements for fault ride-through of short voltage drops as well as for providing reactive powers through decentralized power generating plants
  • Modifies the European Network Code "Requirements for Generators" for the first time
  • Defines the requirements on storage as well as combined facility of generation/demand/storage (producers and consumers)
  • Defines requirements on emergency power generators in the medium voltage grid for the first time
  • User-friendly rules and standards: TCR Medium Voltage replaces several old documents


An English version of the TCR Medium Voltage will be available in Q3 2019.

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