Distributed generators performance during short-circuits considering fault ride-through requirements / Desempenho de geradores distribuídos durante curtos-circuitos considerando requisitos de suportabilidade a afundamentos de tensão = : Distributed generators performance during short-circuits considering fault ride-through requirements

AUTOR(ES)

Rafael Schincariol da Silva

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

03/08/2012

RESUMO

The increase of distributed generation penetration in distribution systems not only helps to diversify the electrical matrix but also brings both technical and economic benefits. Yet, it also raises worries related to energy supply reliability. For wind power plants into the medium and high voltage networks there are the grid codes for "Fault Ride-Through" which stands that wind generators ought to ride a fault with voltage sag and, in some cases, provide reactive power for the terminal voltage restoration. However, implementing such requisites for low voltage connected generators is not a trivial task, as under great perturbations the distributed generators are required to be disconnected from the grid if an islanding situation occurs. Otherwise, people and equipment security would be at risk and the quality of the supplied power cannot be guaranteed. Besides, during short-circuits generators contribute to the increased fault currents along the grid and because of that the protection schemes should experience loss of selectivity and coordination. So, meeting the fault ride-through requirement demand a review of the anti-islanding schemes in order to permit generator islanding, as well as review the protection schemes to guarantee selectivity and coordination. Therefore, studies about the impacts of this initiative are necessary as well as the main generators behavior analysis under short-circuits. In this dissertation, a distribution network was analyzed through successive electromagnetic transient simulations. The behavior of three types of distributed generators under shortcircuits was investigated by stability studies, voltage sag characteristics and reactive power support. Synchronous generators showed to present the best capability to ride through temporary faults on the grid. The impacts on overcurrent protection of increased shortcircuit currents due to the distributed generators and impacts of not disconnecting the generators during islanding situations were also analyzed. The outcomes showed that keeping distributed generators connected might lead to problems on the protection selectivity and coordination and deteriorate the transient behavior of generators.

ASSUNTO(S)

geração distribuída de energia elétrica curtos-circuitos sistemas de energia elétrica - proteção sistemas de energia elétrica - estabilidade distributed generation of electricity short-circuit electric power systems electric power systems

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