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Grid Connection: Testing, Certification and Project Support for Energy Systems

Grid connection and component certification, measurement and testing services, as well as project support – TÜV NORD assists the energy sector with all aspects of grid integration for photovoltaic and wind power plants, wind farms, combined heat and power (CHP) units, and energy or battery storage systems.

Solar- und Windenergieanlagen in einer grünen Landschaft, Symbol für Sektorkopplung und nachhaltige Energievernetzung mit TÜV NORD.

TÜV NORD – Your Partner for Safe and Stable Energy Grids

The energy transition and the increasing share of decentralized power generation are fundamentally changing grid structures. As a result, photovoltaic systems, wind power plants, CHP units, and energy storage systems are subject to high requirements regarding grid stability, operational safety, and compliance with standards.

Since 2019, the current VDE application rules have been mandatory in Germany — including VDE-AR-N 4105 (low voltage), VDE-AR-N 4110 (medium voltage), as well as VDE-AR-N 4120 and 4130 for connections to high-voltage and extra-high-voltage grids. The NELEV (Ordinance on the Verification of Electrical Properties of Energy Systems) requires certificates for grid connection that implement the provisions of EU Regulation 2016/631 (“Requirements for Generators”).

Our services contribute to system stability and ensure that power generation plants, energy storage systems (e.g. battery storage or hybrid solutions), as well as grid components comply with all technical connection regulations. Important verifications such as the plant certificate enable operators to obtain operating approval on time and thereby secure feed-in remuneration.

In this environment, TÜV NORD is an accredited, manufacturer-independent partner with many years of experience. We support manufacturers, plant operators, energy suppliers, project developers, component manufacturers, and grid operators with practical, standards-compliant testing and certification procedures — from prototype testing and certification of individual units and components to the plant certificate (e.g. according to NELEV / VDE-AR-N 4110, 4120 and 4130) for generators and storage systems connected to medium-, high-, and extra-high-voltage grids.

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Together for Stable and Sustainable Energy Grids

We support the key stakeholders of the energy transition with our technical expertise — ensuring smooth grid connections, standards-compliant technology, and maximum efficiency.

  • Plant operators – Whether photovoltaic systems, wind farms, CHP plants, or energy storage systems: with a structured process, we support you in obtaining the plant certificate quickly, thereby securing both economical operation and grid stability.
  • Manufacturers – We help producers of inverters, CHP units, energy storage systems, and power generation controllers (EZA controllers) bring their products to market in a compliant and future-proof manner. Through inspections, testing, and certification, we ensure that devices can be reliably integrated into complex grid infrastructures.
  • Component manufacturers – We inspect, test, and certify your components to ensure they can be reliably integrated into complex grid infrastructures.

Together, we contribute to a strong and future-ready energy system.

Our Services at a Glance

  • Plant certification (A, B & C) for medium-, high- and extra-high-voltage grids
    VDE-AR-N 4110, VDE-AR-N 4120, VDE-AR-N 4130
  • Unit certification for generation units such as PV inverters, wind turbines, energy storage systems, Combined heat and power (CHP) units
  • Component certification (protection devices, power generation controllers (EZA controllers), voltage regulators)
  • Product certification in accordance with national and international grid codes

  • Voltage quality measurement & harmonic analysis
  • Protection testing and functional tests
  • Concept review & feasibility studies
  • Incident and fault analyses

  • Interdisciplinary consulting for grid expansion
  • Environmental and weak-point analyses
  • Plant safety & fire protection

  • Quality assurance and construction supervision

     

  • Standards and regulations for grid connection
  • International grid code requirements
  • Grid-supportive operation of generation plants
Grid Connection Certification: Safe and Efficient Implementation

For more than 15 years, TÜV NORD has been operating as an accredited certification body for Grid Code Compliance. With in-house laboratories for low- and medium-voltage testing and extensive international project experience, we support you through every phase – from individual components to complete plants.

Without flexibility, the power grid will become the bottleneck of the energy transition. We must optimise both consumption and generation.

Malte Berghaus

Expert for Grid Management, TÜV NORD

Keeping an Eye on Future Trends – Supported by Technical Expertise

The energy grids of the future will be intelligent, flexible and digitally interconnected. To make full use of these opportunities, grid connection projects must be aligned with upcoming requirements at an early stage.

Smart grids – Automated load and feed-in control enables efficient energy flow management, prevents grid overloads and increases feed-in capacity. This supports better integration of renewable energies and optimises utilisation of grid infrastructure.

Integration of energy storage into the power grid – in particular battery storage, which enhances grid stability, reduces grid charges through peak load management and ensures reliable energy supply even with fluctuating generation.

EU grid code-compliant connection – Implementation of the EU Grid Codes ensures harmonised grid connection across Europe, reduces interface issues in international projects and facilitates certification in multiple markets.

Digital testing processes – From continuous monitoring and automated data evaluation to remote testing of complex energy systems: digitalisation shortens testing and certification times, reduces costs and increases plant availability.

TÜV NORD supports these technological trends with practical testing methods, highest-precision measurement technology and in-depth knowledge of standards. In this way, we ensure that your photovoltaic (PV) installations, energy storage systems (e.g. battery storage, hybrid solutions), wind turbines and combined heat and power (CHP) systems meet both current and future grid requirements – efficiently, safely and reliably.

Current Regulations in Grid Connection

European and National Frameworks

  • EU Regulation 2016/631 (Requirements for Generators – RfG) – Harmonised European requirements for generation units regarding grid connection, operational behaviour and grid stability.
  • NELEV (German Ordinance on Demonstrating the Electrotechnical Properties of Energy Systems) – National supplementary provisions and verification procedures for the technical requirements under the RfG.

Technical Connection Rules by Voltage Level

  • VDE-AR-N 4100 – Technical rules for the connection of customer installations to the low-voltage grid (basic document).
  • VDE-AR-N 4105 – Technical connection rules for generation units connected to the low-voltage grid (up to 1 kV).
  • VDE-AR-N 4110 – Technical connection rules for generation units connected to the medium-voltage grid (1 kV to 60 kV).
  • VDE-AR-N 4120 – Technical connection rules for generation units connected to the high-voltage grid (60 kV to 220 kV).
  • VDE-AR-N 4130 – Technical connection rules for generation units connected to the extra-high-voltage grid (220 kV and above).

Supplementary Technical Guidelines and Verification Procedures

  • BDEW Medium-Voltage Guideline – Former standard, still partly applicable for existing installations.
  • FGW TR3 – Determination of electrical characteristics.
  • FGW TR4 – Modelling and validation for grid connection verification.
  • FGW TR8 – Certification of electrical characteristics.

TÜV NORD – A Strong Partner for Your Grid Connection

For more than 15 years, TÜV NORD has been operating as an accredited certification body for Grid Code Compliance. With our own low- and medium-voltage testing laboratories and extensive international project experience, we support you throughout all project phases — from individual components to complete power generation plants.

With our comprehensive service portfolio — ranging from the testing of individual components such as PV inverters, power generation controllers (EZA controllers), or protection devices to the certification of complex power generation systems — we provide efficient and transparent processes tailored precisely to the technical requirements of the energy industry.

Thanks to our international project experience and global network, we reliably support plant manufacturers, plant operators, project developers, grid operators, and component manufacturers — from the first prototype through to fully certified grid connection.

Your advantage: With TÜV NORD, you choose a partner that combines technical standards compliance, legal certainty, and practical solutions — both today and for the challenges of tomorrow’s energy grids.

Contact

Do you have questions about a safe grid connection? We support you from planning to commissioning.

TÜV NORD EnSys GmbH & Co. KG | Netze

gridcode@tuev-nord.de
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