The Impact of the Modelling Depth of Mechanical and Electrical Sub-Models on the Simulated Electrical Properties of Wind Turbines
Abdul Baseer, Georg Jacobs, Markus Müllner, Daniel von den Hoff, Christoph Mülder, Uwe Jassmann, Ralf Schelenz, Dirk Abel; Conference for Wind Power Drives 2019 : Conference Proceedings, Pages 3-11
As the share of wind energy increases, it is critical that the requirements defined by the grid operator are fulfilled before connection to the grid is established. Nowadays, the measurements required for the certification of a wind turbine’s electrical properties are run in the field. This is time consuming and costly, due to limited accessibility and the fact that natural factors, such as wind speed, cannot be defined freely and consequently tests are not reproducible.
The certification procedure includes mechanical, structural and electrical requirements for the behaviour of the wind turbine in case of normal and fault operation. The required tests for such a certification are described in the FGW Technical Guideline 3 (TR3 - Determination of the electrical characteristics of generating units and installations at medium, high and extra high voltage grids [FGW16]).
For the simulation approach of such an electrical certification on a system test bench no qualified statements concerning the necessary modelling fidelities for the different test cases are known. Therefore, in this paper models with different modelling depth and their impact on the simulation results are analysed with respect to the representation of the wind turbine’s electrical properties. Consequently giving a recommendation on future modelling.
A holistic wind turbine model is built up, consisting of aeroelastic, mechanic and electric models. The mechanical elements, from the rotor blades to the generator, are modelled with SIMPACK by means of multibody simulation (mbs). The mbs model is connected with the aerodynamic and electrical sub-models in SIMULINK. The aim of this paper is to analyse the impact of the differently detailed models of the mechanical system on the properties relevant for the electrical properties of the wind turbine.
To define the sub-model’s level of detail they are successively refined with a variety of fidelity levels. The rotor blades are represented by rigid blades and can be refined up to elastic blades using modal based reduction with different number of eigenmodes. In the second step, the drivetrain model is refined from a single mass to a three-mass-oscillator. The different levels of detail are compared with respect to their impact on the electrical properties.