Energy Concepts

Influence of decentralised electrical energy generation plants on energy quality

The aim of the project is to conduct a metrological study into the influence of wind energy on the quality of electrical energy, with subsequent assessment based on applicable connection criteria. The project partners will highlight problems that need to be considered in future assessment of decentralised energy generation plants and for connection approvals by network operators.



Decentralised energy generators, such as wind energy plants, are predominantly integrated into the public electricity supply. In addition to system stability, it is crucial to ensure the quality of the electrical supply. Due to increases in the output and number of decentralised generators, the problem of proliferation of voltage influences is taking on increased importance. 

In this context, the first section of this collaborative project involves developing calculation methods for assessing the proliferation of energy quality influences caused by decentralised plants. These methods for identifying critical frequencies and network nodes in terms of non-fundamental frequency voltage influences will then be verified in the laboratory. In the second section of the project, the partners will conduct experimental studies to describe the proliferation of harmonic components. The minimum mains supply quality will also be defined.


  • The data sheets for wind energy plants should be supplemented by additional measuring results to reflect the necessary factors for assessing the proliferation of fundamental frequency 'rapid' voltage influences.
  • Both monotonic and non-monotonic distributions were identified for the voltage level (local excessive resonance). In addition, the measurements confirmed the potential for identifying critical network nodes using the calculation method developed. The level quantities can be calculated in advance with a certain degree of accuracy.
  • The inductive and ohmic components of the cable can be determined for the fundamental oscillation, but in a higher frequency range above the 7th harmonic (350 Hz), the measured harmonic component values are subject to an excessively large error tolerance.
  • The calculation methods developed can be used as a basis for specialist software for calculating the proliferation of voltage influences.

Project Participants

Implementing Institution

Fachhochschule Oldenburg/Ostfriesland/Wilhelmshaven

Cooperation partner

GL Garrad Hassan Deutschland GmbH

More Project Informations

Project number:  0329855A

Project period:  1999 - 2002

Project region:  Germany (Lower Saxony)

Project contact:

Herr Prof. Dr. Diedrichs

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Source: German National Library of Science and Technology Hannover (TIB)