Actual German Grid code for MV and HV is compound by two Standards that can be certified together although there are two more grid code standard for LV and VHV, this article is focus on the most required service for Germany.

• VDE-AR-N 4110:2018-11. Technical requirements for the connection and operation of customer installations to the medium voltage network (TCR medium voltage), and
• VDE-AR-N 4120:2018-11. Technical requirements for the connection and operation of customer installations to the high voltage network (TCR high voltage)

The full process goes through testing, simulation and certification method described in

• TG 3 – Determination of the Electrical Characteristics of Power Generating Units and systems, Storage Systems as well for their Components in medium-, high- and extra-high voltage grids. Rev 25.,
• TG 4 – Demands on Modelling and Validating Simulation Models of the Electrical characteristics of Power Generating Units and Systems, Storage Systems as well as for their Components. Rev 9. And
• TG 8 – Certification of the Electrical Characteristics of Power Generating Units, Systems and Storage Systems as well as for their Components to the Grid. Rev 9

This process itself includes the following requirements analysis in terms of testing:

After a full certification process, what models can I include as variant models?

The measurement results obtained for the power generating unit concerned are permitted to be transferred in full or in parts to other power generating units provided that

• The execution and the control technology relevant for the electrical properties including the software used are technically equivalent in these power generating units; and that
• The results for the minimum and maximum power variants are available or that, alternatively, the rated apparent power of the power generating unit to be certified is between 1/√10-times and two times the rated apparent power (for Type-2 installations) of the surveyed power generating unit.

Additional test requirements

• Grid Quality test (Harmonics, interharmonics high frequency components, flickers and switching operation)

Additional simulation requirements

• Evaluation of simulation model of each variant model
• Plausibility test for each variant model

What will be requested for a product to be installed in Germany?

Certification Companies for power plants on German territory could ask for the grid quality test of any of the units indicated in the certificate as variant models if it is going to be installed on the power plant. Although this is a market standard requirement and is not written on the official standard, it’s something needed to have access to the German market nowadays. The criteria for the “additional test requirement” shall be indicated by the testing laboratory and approved by the Certification Companies for power plants on German territory.

Standard also requires a certified unit based on tests and validated and simulated models. This involves a full simulation process on each variant model, including plausibility tests, in order to include such model on the certificate.

Summing up, Certification Companies for power plants on German territory will request a certificate which include test report, particular grid quality test of the unit/units to be installed on the power plant, Simulation report and plausibility test of the unit/units to be installed on the power plant, and the certificate of the unit according Standard.