Nova modelagem de máquina síncrona para estudos de fluxo de potência e fluxo de potência ótimo multifásicos em sistemas desequilibrados

Abstract

A new steady-state model to represent the synchronous machines, generators or motors, in phase-domain for unbalanced power flow studies is proposed. Also power and voltage controls, which can be applied to electrical machines, are modeled. Grounding of synchronous machines can be represented. The proposed machine model is implemented in a power flow and in an optimal power flow tools for unbalanced systems analysis. The optimal power flow can have as objectives the optimized generation cost, the minimization of the system electrical losses, including internal losses of the machines, or unbalance indices limitation. A method for limiting voltage and/or current unbalances, using shunt capacitor banks in the system nodes, is developed within the optimal power flow tool and is able to indicate in which phases the capacitors should be connected and its respective admittances. Unbalance indice values may be limited in accordance with current standards and equipment manufacturers' recommendations. Comparisons were made with PSCAD to validate the model and the proposed controls. IEEE test systems were used to compare traditional power flow models and the proposed model, which proved to be more accurate than traditional models in unbalanced situations. Analyzes considering different transformer configurations and grounding impedance of the SMs were performed. Voltage security, scalability and robustness analyzes were also performed.