Unit certification and system certification

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The generation unit is the individual PV/storage inverter, the individual wind turbine or an individual CHP unit. These units belong to a specific type, which must have a so-called unit certificate in order to be approved for connection to the public grid. Unit manufacturers must therefore prove the grid conformity of a type by means of the unit certificate.

The generation system includes not only the installed generation units but also the park grid from the grid connection point (usually corresponds to the ownership boundary to the energy supplier) to the respective units, including cabling, transformers, protective devices and control systems. In order to obtain the grid connection and secure the remuneration, the system operator must present a system certificate that certifies the electrical properties and grid conformity of the entire system.

The certification of units and systems serves to integrate decentralized generation systems into the electricity grid. It is based on the so-called BDEW Medium Voltage Guideline 2008, which regulates the connection and parallel operation of energy generation systems on the medium-voltage grid. In conjunction with FGW TR 8, it is intended to ensure that wind turbines, combustion engines, photovoltaic systems and storage systems meet certain requirements for connection to the public electricity grid and can support the grid. The certification obligation not only applies to generation systems on the medium-voltage grid, but systems on the high-voltage and extra-high-voltage grid must also meet regulatory requirements. In addition to the certification of units and systems, there is also component certification, which verifies the electrical properties of system controllers, for example.

The issuing of certificates for units, systems and components is reserved for accredited bodies. The Deutsche Akkreditierungsstelle GmbH confirms the body’s competence in accordance with DIN EN ISO/IEC 17065 to carry out certifications and services in the field of network integration. The scope of accreditation is specified on the accreditation certificate.

The purpose of unit certification is to ensure that the manufactured units are actually suitable for operation on the medium, high and extra-high voltage grid. Before you as the operator can receive a system certificate for your generation system, the unit certificate must be available. One exception is the so-called individual verification procedure (read more about this here ).

As part of the system certification process, it is checked during the planning phase of a generation system whether the system meets the requirements for the electrical properties. If the planning documents are assessed positively, the system certificate is issued, which is a prerequisite for a permanent grid connection. The submission of a system certificate is mandatory for all decentralized energy generation systems with a connected load greater than 135 kW to medium-voltage grids.

We have illustrated the certification process for you in a short video:

The EZA Declaration of Conformity confirms the implementation of the properties of the system identified and assessed in the system certificate and concludes the certification process. In addition to an on-site assessment by M.O.E., the declaration of conformity includes a check of the settings on the units and proof of control and protection functions.

Individual components that are used in power generation systems, such as parking controllers, also have electrical properties that need to be verified. This not only facilitates system certification, but also provides the manufacturer of the components with a certificate of the properties and functions and thus proof of the quality of their product. You can find out more about this topic here.