Modelagem e simulação de sistemas de geração de energia eólica através de co-simulação

Abstract

The present masters thesis presents strategies for modeling and simulating wind energy generation systems by means of co-simulation techniques. Firstly, the wind energy conversion system (WECS), consisting of a wind turbine coupled to a permanent magnet synchronous generator (PMSG) through a gearbox and back-to-back two-level voltage-source-based power converters, is detailed. Operating modes for the given WECS are also discussed, along with their respective controllers. In order to establish steady-state operating conditions for wind farms, composed by several parallel-connected WECS, an improvement to the conventional load flow computation is proposed to include electric nodes that specifies only active power and power factor at a remote node. Results are shown for a wind farm AC medium-voltage collection system. Co-simulation techniques, in turn, allow complex and interconnected systems, such as the electric power systems, to be partitioned into smaller subsystems, where each subsystem can be modeled and simulated on its own. Furthermore, such a separation among subsystems allows one to use distinct modeling alternatives and solution algorithms, which may be more appropriate or efficient to each subsystem. From a computational viewpoint, partitioning larger systems into smaller interconnected subsystems also helps sharing the required computational effort among several computing processes and, consequently, mitigating computational bottlenecks often encountered in bulk power systems analysis. In this work, the co-simulation is attained by means of the FMI (Functional Mock-up Interface) standard, which aims at making models, developed for different simulations tools, compatible. As a consequence, the FMI standard permits encapsulating whole subsystems into a single FMU (Functional Mock-up Unit), which contains a machine-coded mathematical description of a model along with its numerical solver. As a by-product of the FMU encapsulation, provided by the FMI standard, is the protection of intellectual property, which can be vital for certain applications. The presented mathematical models are developed into Modelica language, whereas the co-simulation is implemented in Python with the aid of the message-passing parallel programming paradigm provided by the MPI (Message Passing Interface) standard.