Navegando por Assunto "Photovoltaic generator"

Agora exibindo 1 - 2 de 2

Acesso aberto (Open Access)
Controle local de potência reativa em geradores fotovoltaicos para a melhoria da regulação de tensão em redes de distribuição
(Universidade Federal do Pará, 2017-03-31) SOUZA, Vanderson Carvalho de; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
This dissertation addresses the major operational problems faced by distribution network operators due to the high integration of photovoltaic (PV) generators, such as overvoltages, excessive tap counts and voltage regulator runaway condition. The overvoltage problem in distribution networks may be caused by significant active power injection from PV generation. Additionally, the rapid and significant variations in PV generator active power associated with cloud transients result in an increase of voltage regulator tap counts, adversely affecting the useful life of that device. Also, when the direction of the power flow is reversed due to PV generator active power injection, the voltage regulator can fail to control voltage at the regulated bus and reach lowest or highest tap limit (runaway condition). This dissertation proposes a local reactive power control for PV inverters to alleviate such problems. The proposed control is evaluated using measurement data from the real rooftop PV system in the city of Belém and dynamic simulations on a single MV feeder with a PV solar plant.
Acesso aberto (Open Access)
Impacto de geradores conectados via inversores na coordenação da proteção em redes de distribuição de energia elétrica
(Universidade Federal do Pará, 2017-08-11) CORDEIRO, Murillo Augusto de Melo; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
Despite its many benefits, the Distributed Generation (DG) can adversely affect some aspects related to the operation performance of electrical power systems, especially a no so deeply explored point: the interaction between the protection systems and inverter-based power generation units. In this dissertation, the impact of inverter-based DGs units on the fuse-recloser coordination schemes used in distribution networks is thoroughly studied. The simulations were conducted using the software package DIgSILENT Power Factory through several single-phase and three-phase short circuits along the distribution network, considering different fault locations, penetration levels of DGs, operating conditions, and other aspects that impact over the protection miscoordination in an IEEE real test distribution system of 34 busbars. The contribution to the short-circuit current of inverter-based generators is also investigated through simulations on electromagnetic transients models available in the software. The simulation results shows that significant inverter-based DG penetration levels on distribution feeders increase the short-circuit current that passes through the fuse and make it operate faster than the recloser in a fault condition, leading to loss of fuse-recloser coordination in a time frame base. A general discussion of the results is performed, identifying some recommended corrective actions that should be considered in order to maintain the coordination and selectivity between the distribution system protection devices located throughout the network.