Multi-period, Multi-contingency and Interval Optimal Power Flow for Dimensioning and Allocation of Spinning Reserve Ricardo Augusto Borba, Thelma Solange Piazza Fernandes Brazilian Archives of Biology and Technology, 2025 Due to their low environmental impact and decreasing costs, there has been significant growth in the use of renewable sources worldwide. However, their power generation fluctuates randomly, necessitating reliable energy supply methods. Spinning reserve can mitigate the risk of energy deficits during generation interruptions and line contingencies. It is therefore necessary to develop specific techniques for dispatching and scheduling energy, power and reserve, with a focus on attending to emergency situations, congestion of transmission lines and spinning reserve. In this context, the present work proposes a linear multi-period, multi-contingency and interval optimal power flow scheme, which can schedule the power dispatch of a hydrothermal system (including electrical and energetic restrictions) for a horizon of one day ahead, and is also capable of dimensioning and allocating the amounts of spinning reserve necessary to supply different situations involving the outflow of lines and balancing levels of renewable energy not supplied. In addition, as a strategy to incorporate the uncertainties inherent in the problem, interval mathematics is applied to the post-optimization problem; that is, after the deterministic optimization obtained based on the optimal power flow, ranges of uncertainties are added to some network parameters so that an optimal range of network operation can be determined. Results are presented for a system of 291 buses representing the south-southeast network of Brazil. The proposed methodology adequately sizes and allocates the necessary reserve to meet the most important contingencies affecting transmission.
INTERVAL MATHEMATICS APPLIED TO MULTIPERIOD OPTIMAL POWER FLOW Ricardo Augusto Borba, Thelma Solange Piazza Fernandes 2023 15th IEEE International Conference on Industry Applications Induscon 2023 Proceedings, 2023 The main tools for the operation and planning of electrical power systems are Power Flow (PF) and Optimal Power Flow (OPF). However, the analysis performed by these tools delivers deterministic values, that disregard uncertainties that occur in electrical systems. Such uncertainties are mainly caused by data error of lines, transformers, demand, and generation of alternative sources forecasting. A strategy to incorporate these uncertainties in the tools is through Interval Math (1M), which allows the inclusion of data intervals instead of single points. This strategy is performed only once, unlike probabilistic methods that run exhaustive simulations. Thus, the objective of this work is to incorporate 1M into a Multiperiod Optimal Power Flow (MOPF) to consider load and generation data uncertainties, after the deterministic optimization. The uncertainty ranges are added via Krawczyk Method, which determines an optimal interval of operation. The MOPF realizes the dispatch of power generation and reserve spinning along 24 hours of a hydro-thermal-wind system. The proposed method was compared with results obtained from traditional exhaustive simulations carried out with the southern Brazilian system with 33 Buses. The results obtained were close to the values of the random analysis, with uniformity.
Voltage regulation planning for distribution networks using multi-scenario three-phase optimal power flow Antonio Rubens Baran Junior, Thelma S. Piazza Fernandes, Ricardo Augusto Borba Energies, 2019 Active distribution networks must operate properly for different scenarios of load levels and distributed generation. An important operational requirement is to maintain the voltage profile within standard operating limits. To do this, this paper proposed a Multi-Scenario Three-Phase Optimal Power Flow (MTOPF) that plans the voltage regulation of unbalance and active distribution networks considering typical scenarios of operation. This MTOPF finds viable operation points by the optimal adjustments of voltage regulator taps and distribution transformer taps. The differentiating characteristic of this formulation is that in addition to the traditional tuning of voltage regulator taps of an active network applied for just one scenario of load and generation, it also performs the optimal adjustment of distribution transformer taps, which, once fixed, is able to meet the voltage limits of diverse operating situations. The optimization problem was solved by the primal-dual interior-point method and the formulation was tested using the IEEE 123-bus system.
