Adaptação do modelo genérico WECC de aerogeradores para estudos de transitórios eletromecânicos para atendimento aos requisitos regulatórios do Operador Nacional do Sistema Elétrico no Brasil

Abstract

The increase in wind farms with frequency converters and the consequent reduction in conventional power generation plants have contributed to the decrease in inertia of electrical power systems (EPS), bringing new challenges to the stability of electrical systems. Stability studies of power systems with generation plants connected to the grid by electronic converters demand great computational effort. To circumvent computational limitations for medium and large SEP analysis, as well as issues related to trade secrecy of wind turbine manufacturers’ proprietary models, the Western Electric Coordinating Council (WECC) developed non-proprietary generic wind turbine models . This work proposes an adaptation in the WECC generic models, with adjustments in the controls and parameterizations, necessary for electromechanical stability studies according to the regulatory criteria of the National Electric System Operator (ONS) in Brazil. The objective of this work is to demonstrate that the generic model adapted from the WECC wind turbine is able to satisfactorily respond to frequency and voltage deviations in the network external to the wind farm. The evaluation of the response of the adapted WECC model is carried out in the IEEE 5-bus test system, and then a case study is carried out in a sub-region of the National Interconnected System (SIN) corresponding to the state of Ceará, to verify the stability of system frequency. The equivalent system was obtained from the SIN models provided by the Energy Research Company (EPE), using tools developed in Python to select the buses of interest and active power injections or equivalent loads at the borders. The simulations of this work were evaluated situations with and without the participation of wind farms in frequency control. In the case studies analyzed, it was found that the stability of the system can be compromised in the event of a major disturbance when wind farms do not participate in frequency control. The simulation results show that wind farms with the adapted model are able to contribute to the control of the SEP frequency in cases of frequency deviations and their response corresponds to the requirements of the ONS Grid Procedures. In addition, the adapted model also correctly supports the specified time for momentary voltage variations of different magnitudes, which allows its use in large scale systems.