Small signal stability on power systems with high wind power penetration

Resumen

Wind speed natural variability and the way it affects both wind turbine stability behavior and entire power system, has taken many researchers to study electrical network stability with high wind power penetration and propose solutions to increase damping and improve grid stability. Hence, in this thesis, first of all state of art is analyzed, allowing to know novel solutions, methods, algorithms and computational tools developed. After that, a solution for small-signal instabilities is proposed, i.e. a new methodology for designing and tuning a power system stabilizer that increases signal damping and allows higher wind power penetration in power systems. Therefore, the main aim of this proposal is to design and tune a power system stabilizer PSS, to increase signal damping and improve small signal stability in power systems with high wind power penetration. The design depends on static and dynamic modeling and the simulation of a power system. This method requires a full steady-state and dynamic small-signal stability analysis, then here is developed an algorithm for high wind power penetration and finally as has been mentioned a new methodology and an algorithm to design and tuning the PSS required for the system. This work is organized on five parts as follows. Part I. Presents the state of art that help to find research needs nowadays. Here some authors claim for detailed analysis and more research on small-signal stability analysis on wind power systems. Centered on Small Signal Analysis, different wind turbines, its modeling and simulation is analyzed in deep. Part II Expose basics knowledge about wind turbine technologies, considering technical, social and economical aspects. Then some deep immersion was done on the modeling of specific wind turbine generators and its dynamic model and control. Kundur's stability theory is a clue on this analysis. Part III Contains a full chapter on wind turbines and wind power systems simulations validating actual problem. In this part, will be used Matlab Simulink and modal analysis with the power system analysis toolbox PSAT that uses modal analysis with great graphic results. Here is analyzed static and dynamic responses for small-signal instabilities for different scenarios created of wind power penetration, including wind speed variations, generated voltage variations and load demanded. Wind power penetration is analyzed herewith the use of different commercial turbines actually installed, where different aggregation levels are considered, yielding local and inter-area instabilities that are analyzed on detail. Part V Finally, to increase power system damping, here is proposed a PSS's tuning, presenting a new methodology with high level of wind penetration, based on modal response and getting deep on gains and time constants calculation. In addition, an algorithm to this process is presented here.