Leandro Ramos de Araujo

A new heuristic reconfiguration algorithm for large distribution systems

Summary form only given. This paper presents a reconfiguration algorithm which is specially suited to large scale distribution systems. The algorithm uses a heuristic strategy that starts with the system in a meshed status, with all maneuverable switches closed. The choice of the switches to be opened is based on the calculation of the minimum total system losses, using a load-flow program. A refinement on this procedure, based on branch status exchange is described. The paper includes results and comparisons on test systems utilized in three classical papers published in the technical literature. Results obtained on a real large scale distribution system are also presented

High Impedance Fault Area Location in Distribution Systems Based on Current Zero Sequence Component

This paper presents a new methodology for detection and area location of high impedance faults (HIF) on unbalanced distribution systems. The method is called Quasi-Differential Zero Sequence Protection (PQDSZ) and it detects these faults by analyzing the current zero sequence rms value on a distribution feeder. The detection relies on a differential area, defined by two points of measurement. The data is sent to a control center, which analyzes the relation between the received currents and send an alarm if any problem is detected. A simulation system with the RTDS and real automation equipment is presented, in order to validate the PQDSZ.

Voltage Security Assessment on Unbalanced Multiphase Distribution Systems

This paper presents a multiphase continuation power flow (MCPF) methodology to perform voltage security analyses on unbalanced multiphase distribution systems. The proposed tool includes comprehensive models of most network components, and allows for explicit representation of neutral cables and grounding connections. The methodology has been validated through comparisons with a commercial software and with results available in the literature. Additional analyses are presented using the IEEE 4-bus, the Neutral-to-Earth (NEV) and the IEEE 8500 Test Systems. These systems have been developed to present several challenges to distribution systems analytical tools. In particular, the influence of the 3-phase transformer connections on the PV curves have been demonstrated and has been useful to stress the importance of a complete system representation.

A Fault Analysis Algorithm for Unbalanced Distribution Systems

This paper describes a new methodology for the fault analysis of a distribution electrical system, in which the phase imbalances, different types of loads, neutral cables, groundings and other inherent characteristics of distribution systems are taken into account. The proposed methodology is based on the currents injection method and can represent in a simple way several types of fault. In the results some cases are presented to show the efficiency of the proposed method.

Representation of Magnetic Coupling in Distribution System Feeders Using BW/FW

This letter presents a new method for representing the mutual coupling between feeders or sections of feeders in distribution systems using a backward/forward sweep method. Two distribution systems with magnetic coupling between the feeders are used to test the method and to show the impact of mutual coupling between feeders. Features of computational convergence are also analyzed.

A Study of Neutral Conductors and Grounding Impacts on the Load-Flow Solutions of Unbalanced Distribution Systems

This paper presents detailed analyses of unbalanced distribution systems with special attention to the multiple load-flow solutions in the presence of neutral conductors and neutral groundings. Some simple distribution systems and some IEEE Test Feeders are used for the identification of the problems and to perform sensitivity analyses to investigate attraction potentials towards solutions and cases of non-convergence.

Algorithm for the Analysis of Coordination of Protection for Distribution Systems

The selectivity and coordination of overcurrent relays is most commonly studied distribution systems protection. This paper proposes a method for detailed analysis of the overcurrent protection of distribution systems, in which the phase unbalances, neutral conductor and groundings are to be taken into account. All calculations are performed in a full three-phase methodology. The mathematical models of the main protective equipment and protective functions found in distribution systems were also developed. Two distribution systems were analyzed to verify the efficiency of the proposed methodology.

A Methodology for Optimization of Unbalanced Distribution Systems

A method for the optimization of three-phase electrical systems is proposed in this paper, the proposed method can be used in transmission, distribution and joint studies of transmission-distribution systems. The proposed methodology is based on the three-phase currents injection method and primal dual interior point method. This document presented the mathematical models of electric components, operative constraints and some objective functions. In the results some cases are presented to show the efficiency of the proposed method.

Evaluation of the impact of different neural network structure and data input on fault detection

This paper presents a methodology for detecting single-phase fault in medium voltage distribution systems using neural network. The impact of diverse types of neural network topologies and different inputs in the performance of the fault detection is assessed. The entries of the neural network are the electrical parameters of voltage and current, which could be phasor and / or non-phasor measurements. The proposed methodology aims to identify single-phase faults with an arc resistance ranging from 0 to 20 ohms, considering the variation of the system load.

A Method for Sizing of Industrial Electrical Systems using Genetic Algorithm

This work proposes an integrated computational tool to support the designer engineer during the elaboration of projects of industrial distribution networks during the conceptual and basic design, presenting the methodology for a technical and economic analysis of electrical systems applied to oil refineries.