Fluxo de potência intervalar para sistemas de distribuição multifásicos baseado no método da injeção de correntes trifásico

Abstract

The incorporation of uncertainties in the power flow problem in medium voltage systems represents a contemporary challenge due to the advent of new technologies that allow the insertion of new types of loads and renewable sources with high variability. Within this complex scenario, it is urgent to develop methods that represent distribution networks with all their peculiarities such as predominantly radial topology, existence of mutual impedances, unbalanced phase conductors, representation of the neutral and grounding impedances. Due to the lack of studies that address uncertainties in networks with such complexity, this work proposes a methodological collection based on interval power flow using current injection equations applied in distribution systems, assuming uncertainties about load and generation values. In the first proposed approach, an interval power flow calculation method is developed to analyze the insertion of distributed generation in active distribution networks with single-phase representation. In this context, the impact of distributed generation and their models are investigated by calculating the sensibility of voltages obtained by the interval power flow and the IEEE 18-bar active system is used as case study for conducting simulations and comparative analysis. The second developed methodology - and the main contribution of this work - presents the Interval Three-Phase Current Injection Method, a novel approach that consists of calculating the interval power flow applied to the Three-Phase Current Injection Method for multiphase systems. The main contribution of this thesis is based on the use of interval extensions and the application of the angular rotation technique. The implementation of these strategies to improve interval solutions made the calculations more assertive and reduced the overestimation, problem faced when the simple application of conventional interval arithmetic occurs in the calculation of three-phase power flow. Before the published works arising from this research, there was no reference in the literature that dealt with the development of FPI methods based on traditional interval arithmetic through current injection equations in multiphase systems. The obtained solutions are consistent with Monte Carlo simulations, which is a widely deterministic method used in interval analysis, and its application has a relatively higher computational time, depending on parameters such as convergence tolerance and number of simulations, which will be carefully evaluated during this document. Additionally, both methodologies are useful for operation studies and planning of unbalanced power distribution systems, representing a viable tool for calculating the impact of uncertain input data on the power flow envolving the three-phase and the neutral voltages, also known as Neutral to Earth Voltages