Modelling and simulations of Power Generating Units

The model of the generating unit which is required to be used in simulations must reflect the measured electrical characteristics with sufficient accuracy given in different standards.

• • • Dynamic models: Developing of Root-Mean-Square models, the so called RMS Model
    • Quasi-steady-state models: Simplified model to determine the reactive power supplied in the normal operating mode. Depending on the complexities of the WTG system, this model can be included in the RMS model above
    • Electro-Magnetic-Transient model: Developing of the EMT Model
    • Harmonic model: Developing of equivalent Thevenin and Norton harmonic model
    • Building of Software interfaces: co-simulation studies with models or model blocks in different software using dll’s (e.g. MATLAB/Simulink, DigSilent/Power Factory, PSCAD and GH Bladed)
    • Validation of the models according to the modelling standards and the grid code:
  • 1. 1. Short circuit current capability of electrical devices within the wind farm
       2. Reactive power exchange and voltage stability
       3. Voltage- and current harmonic impact
       4. Low- and High Voltage Ride Through behavior – grid support during failures
       5. Primary Control – active power reaction during frequency deviations

Below a simple illustration of model boundaries and validity in the unit level is shown, using an example of a wind turbine generating unit as full converter concept (WTG Type 4b).