Débora Rosana Ribeiro Penido

Three-Phase Power Flow Based on Four-Conductor Current Injection Method for Unbalanced Distribution Networks

This work presents a new formulation for the power flow problem, with explicit representation of the neutral conductor and grounding. This methodology has been named the four-conductor current injection method (FCIM). The Newton-Raphson method is applied to solve the set of nonlinear current injection equations that are derived using phase coordinates, and the complex variables are written in rectangular form. The proposed algorithm can be used to analyze both balanced and unbalanced systems, meshed or radial, with controls and distributed generation, and is shown to be very efficient and robust for large scale systems.

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.

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.

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.

A Method to Reduce the Negative Sequence Current in Electrical Equipments

A multiphase optimal power flow method for limiting unbalances of currents in equipments using reactive compensation is proposed in this paper. The equipment modeling is based on current injection method in rectangular coordinates. The method was implemented and the proposed computational tool was developed with Matlab® and Lingo® softwares. This document presents the mathematical models of electrical components, operative constraints and some objective functions. Some cases are presented to show the efficiency of the proposed method.

Power-flow analysis of the IEEE8500-Node Test Feeder using the Current Injection Method

The Distribution Systems Analysis Sub-Committee has been organizing Test Cases to provide benchmarks and challenging real cases for power systems analysis programs. The present panel summary discusses the results obtained with the application of the Current Injection Method to solve the IEEE 8500 - Node Test Feeder proposed by R. Dugan. This system is based on a real large-scale Distribution System, and includes several relevant features of practical networks, such as single-and unbalanced multi-phase feeders, neutral conductors, unbalanced loads and voltage controllers, among others.