MODELING CONTROLLERS AND GENERATORS
In planning studies on the expansion of power systems, suitable models of controllers (voltage regulators and speed regulators) and generating units (turbines and generators) are needed.
Such models provided by manufacturers require validation field tests, confirming that the model represents the physical system properly. Standardized models of controllers can be used in studies and the parameters can be validated through field tests, however, it is possible to pick up a transfer function that does not fit the standard models.
After the field tests, the obtained curves can be compared with the simulated ones:
A survey of appropriate studies in mathematical models of power systems and field tests bring other benefits:
- Actual operating limits of the generator;
- Restrictions imposed by the excitation, turbine system, etc .;
- Adjustment detection of excitation limiters and PSS system;
- Coordination problems between the control system and the protective devices;
- Deficient operation of the unit (for example, the unit makes primary regulation, dead band frequency, voltage control for power factor, limiting restrictions, etc.).
Simulations can be run to evaluate the individual plant performance as well as the performance of the complete interconnected system. Through these studies, it is possible to analyze:
- Coordination of the protection of the generator within the limitation of the excitation system;
- Operational limits of the synchronous generator;
- Automatic Voltage Regulator (AVR) and Dynamic Limiters;
- Adjustments to the power system stabilizer;
- Adjustments to the compensator’s reactive voltage regulator;
- Unit control mode.