Distribution System Modeling and Analysis

For decades, distribution engineers did not have the sophisticated tools developed for analyzing transmission systems-often they had only their instincts. Things have changed, and we now have computer programs that allow engineers to simulate, analyze, and optimize distribution systems. Powerful as these programs are, however, without a real understanding of the operating characteristics of a distribution system, engineers using the programs can easily make serious errors in their designs and operating procedures. Distribution System Modeling and Analysis helps prevent those errors. It gives readers a basic understanding of the modeling and operating characteristics of the major components of a distribution system. One by one, the author develops and analyzes each component as a stand-alone element, then puts them all together to analyze a distribution system comprising the various shunt and series devices for power-flow and short-circuit studies. He includes the derivation of all models and includes many numerical examples that demonstrate applying the models to solve typical problems. This is the first book dedicated to distribution systems that is truly modern, covers computer applications, and gives a thorough grounding in modeling and analysis techniques. Assuming a basic foundation in transformers, electric machines, transmission lines, and symmetrical components, it serves as both a text for upper-level electrical engineering studies and as an essential reference for practicing engineers.

Table of Contents:
INTRODUCTION TO DISTRIBUTION SYSTEMSMajor Components of a Power System The Distribution System Distribution Substations Radial Feeders Distribution Feeder Map Distribution Feeder Electrical Characteristics THE NATURE OF LOADS Definitions Individual Customer Load Distribution Transformer Loading Feeder LoadLoad Allocation APPROXIMATE METHODS OF ANALYSIS Voltage Drop Line Impedance "K" Factors Uniformly Distributed Loads Lumping Loads in Geometric Configurations SERIES IMPEDANCE OF OVERHEAD AND UNDERGROUND LINESDevelopment of the modified Carson's equations Series Impedence of Overhead Lines Series Impedence of Underground LinesSummary SHUNT ADMITTANCE OF OVERHEAD AND UNDERGROUND LINES The General Voltage Drop Equation Overhead Lines Concentric Neutral Cable Underground Lines Tape Shielded Cable Underground Lines Sequence AdmittanceSummary DISTRIBUTION SYSTEM LINE MODELS Exact Line Segment Model The Modified Line segment Segment Model The Approximate Line Segment Model VOLTAGE REGULATION OF VOLTAGES Standard Voltage Ratings Two-Winding Transformer Theory The Two-Winding Autotransformer Step-Type Voltage Regulators Models Connections THREE-PHASE TRANSFORMER MODELS Generalized Matrices for all Standard Three-Phase Connections The Delta-Grounded Wye Step-Down Connection The Undergounded Wye-Delta Step-Down Connection The Grounded Wye-Grounded Wye Connection The Delta-Delta Connection The Open Wye-Open Delta Connection Thevenin Equivalent Circuit Summary LOAD MODELS Wye and Delta -Connected Loads Delta-Connected Loads Two-Phase and Single-Phase Loads Shunt Capacitors The Three-Phase Induction MotorSummary DISTRIBUTION FEEDER ANALYSIS Power-Flow Studies Short-Circuit StudiesSummary APPENDICES Conductor Data Tables Concentric Neutral Cable Data Tape Shielded 15 kV Cable Data Each chapter also contains a summary and exercises.