Manufacturers – Network connection

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Certification of manufacturers of generation units

Certification of manufacturers of generation units, such as for example PV inverters, converters, wind turbines, energy storage units, internal combustion engines, cogeneration plants and ORC equipment.

Unit certification is the first step towards network connection. The requirements for generation plants are placed on the network connection point, therefore these requirements have to be transferred to the generation units.

Unit certificate – Required for all generation units

A unit certificate is required for all generation units which are part of generation plants which are connected to the medium voltage network at a connection point. This certificate does not depend on the nominal capacity of the units. In the case of plants with a capacity greater than 1 MVA and at a distance to the connection point of more than 2 km, the unit certificate must be submitted to the plant certifier.

TÜV NORD CERT provides the following unit and component services for component manufacturers at home and abroad:

  • Certification of generation units (cogeneration plants, internal combustion engines, photovoltaic power inverters, wind turbines)
  • Certification of components for generation units and generation plants
  • Measurement of generation units and/or components using a network simulation model (synthetic network) or an LVRT container
  • Prototype verification for wind turbines
  • Testing and evaluation according to harmonised standards for CE marking according to the directives of the European Community (EC Directives)
  • Analysis of foreign network connection guidelines (Grid Codes)
  • Evaluation of the single-fault safety of protective devices
  • Determination of the efficiency, for example, of inverters or uninterruptible power supplies (UPS)
  • Life cycle analysis through determination of failure probabilities and failure rates
  • Attestation of possible participation in reserve power mechanisms based on the ability to black-start cogeneration plants
  • Especially for cogeneration plants: BAFA accreditation (certified values)
  • Testing of smart meters (product certification)

Scope of assessment for Unit Certification

Some of the requirements for the network connection point must be fulfilled by the generation unit. The requirements for the generation unit are analysed and then calculated, assessed and, if appropriate, certified. This means that the scope of assessment covers all the points of the generation plant (see plant certification).

Offer phase


Inquiry with TÜV NORD CERT
  • Consolidation of the subject matter of the quote and the order
  • Tender preparation



Commissioning of TÜV NORD CERT

  • Order confirmation
  • Written confirmation of the commissioning


Order phase
  • Kick-off Meeting (project schedule and required documents)
  • Submission of the required documents

  • Conformity assessment
  • Issue of the assessment report
  • Model validation
  • Issue of the validation report
  • Factory surveillance and monitoring
  • Issue of the unit certificate
  • Submission of the unit certificate to the plant certifier and/or
  • network operator depending on the size of the plant and the distance to the connection point

Following this, agreement may be reached regarding recognition of the measuring results for other product families.