Metodologias de controle de tensão com justiça de corte da geração fotovoltaica em redes de distribuição de baixa tensão

Abstract

The growing concern about climate change and global warming have motivated the current Energy Transition, which concerns the shift from fossil fuels to renewables energy sources (RES) in an effort to reduce CO2 emissions. This energy transition has driven the electrification of the economy, fostering significant growth in RES, particularly in photovoltaic solar energy. In this context, the decentralization of the electric sector has enabled the direct integration of these sources into Low Voltage Distribution Networks (LVDNs). However, the massive integration of Micro Photovoltaic Solar Generation (µPVSG) into these networks has caused reverse power flow, resulting in technical challenges such as overvoltage and thermal overload in their assets. Solutions, such as Volt-Watt Control (VWC) in Photovoltaic Inverters (PVIs), have proven effective in addressing voltagerelated issues. However, this control has led to an unfair distribution of active power among the PVIs during VWC operation, penalizing consumers located further from the distribution transformer. Additionally, stability issues related to the convergence in the dynamics of VWC, due to the slope of the Volt-Watt curve, have been considered in various studies. Therefore, this study presents a new methodology for adjusting Volt-Watt curves, ensuring the stability of VWC and simultaneously ensuring a fair power cut among PVIs. This approach is applied in two voltage control architectures, decentralized and centralized, respectively. In the first methodology, a linearized model of the network is used for Volt-Watt curve adjustment, employing local measurements at the connection points of the respective PVIs. In the second methodology, a voltage sensitivity matrix is used for the linearized model of the network when applying the Volt-Watt curve adjustment, where VWC parameters are coordinated in real-time, assisted by local measurements in the respective PVIs. The studies were conducted on a set of LVDNs and evaluated for effectiveness and fairness of power cuts quantitatively, using the Jain’s Fairness Index (JFI) as a metric. The results confirmed the effectiveness of the proposed control in mitigating voltage problems, acting fairly by equally exporting surplus energy to the grid, while ensuring controller stability. Additionally, penalties arising from the local dependence of PVIs in power cuts were eliminated compared to conventional VWC strategies.