DIgSILENT GmbH’s NAR-conformity Test Laboratory carries out measurements and tests on operational type 1 generation plant (type 1-PGU) according to the “individual verification procedure” detailed in FGW TG 3. With more than thirty years of experience gained in the international field of power plant and network measurement, DIgSILENT has initiated and decisively contributed to the “individual verification procedure” guidelines of the FGW. The current grid connection guidelines for high voltage and medium voltage refer to this procedure for generating plant for which unit certificates cannot be issued due to technical or economic reasons.

The DIgSILENT Test Laboratory for NAR-conformity is DIN EN ISO/IEC 17025 accredited. The accreditation is valid for the scope defined in the annex of the accreditation certificate D-PL-20970-01-00. The procedural aspects of the “individual verification procedure” were developed in close cooperation with the “TÜV SÜD Industrie Service GmbH” network compatibility certification centre. The joint development and work on the guidelines has resulted in a successful cooperation between the “TÜV SÜD Industrie Service” certification body and the DIgSILENT Test Laboratory. Under the leadership of the TÜV SÜD certification body and as a certified service provider, DIgSILENT offers a comprehensive service package for the implementation of the "individual verification procedure" for power plants with synchronous generators (type 1-EZE).

Our Services in Detail


  • Evaluation of the preliminary conformity assessment and the plant certificate C
  • Development of a measuring point plan to record all required signals of the generation units and all other signals of the power plant (including PoC, and the power plant controller).
  • Design of a measurement concept for the implementation of a consistent, virtual measuring system. This is based on the DIgSILENT PFM300-GCC Monitoring System for time-synchronous acquisition of generating unit and power plant signals at the measurement points.
  • Customised development of a measurement and test plan for the plant that is to be certified, in order to comprehensively implement measurements and tests required according to FGW TG 3, as well as additional tests according to the high and medium voltage grid connection requirements.
  • The DIgSILENT PFM300-GCC measuring system applied in this process is calibrated in-house before each use, according to DAkkS regulations. Optionally it can remain at the generating unit / power plant in order to efficiently meet the high and medium voltage grid connection requirements for fault recorder monitoring.
  • After completing the FGW TG 3 measurements, the DIgSILENT PFM300-GCC Measuring System can be connected via remote access for further monitoring and evaluation. The GCC functionality ensures that only NAR-conformity relevant records are considered.


Preliminary conformity assessment

  • Data collection to describe and evaluate the power plant
  • Assessment of available data and coordination with regard to the high and medium voltage grid connection requirements and the requirements of the network operator
  • Review of model data. Preparation and application of simulation models
  • Identification of all system characteristics according to the relevant grid code, within the preliminary conformity study
  • Coordinating support to constructors and grid operators in all relevant matters

Final conformity study

  • Creation of the definitive generating unit / power plant simulation models
  • Evaluation of power plant measurements carried out according to FGW TG 3
  • Simulation model validation according to FGW TG 4, based on measurement results
  • Identification of the final generating unit / power plant parameters


The "individual verification procedure" uses an extensive simulative approach. Based on our longstanding international experience, we create validated simulation models. These form the core of the "individual verification procedure".

  • Simulation models of complex combined cycle power plants with process steam or heating steam extraction and coordinated power frequency and compression controls
  • Simulation of complex steam power plants including ORC technologies
  • All types of hydropower plants with complex hydraulic systems
  • Internal combustion engines (gas and diesel engines)
  • Control equipment for turbines and internal combustion engines
  • Voltage regulators with excitation devices including Power System Stabilisers (PSS)
  • Plant controllers for the regulation of distributed active and reactive power, including the control of transformer tap-changers

Testing and Certification

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