Autotransformer

About: Autotransformer is a research topic. Over the lifetime, 5457 publications have been published within this topic receiving 51807 citations.

Distribution system modeling and analysis

Abstract: Introduction to Distribution Systems The Distribution System Distribution Substations Radial Feeders Distribution Feeder Map Distribution Feeder Electrical Characteristics Summary The Nature of Loads Definitions Individual Customer Load Distribution Transformer Loading Feeder Load Summary Approximate Method of Analysis Voltage Drop Line Impedance K Factors Uniformly Distributed Loads Lumping Loads in Geometric Configurations Summary References Series Impedance of Overhead and Underground Lines Series Impedance of Overhead Lines Series Impedance of Underground Lines Series Impedances of Parallel Lines Summary References Shunt Admittance of Overhead and Underground Lines General Voltage Drop Equation Overhead Lines Concentric Neutral Cable Underground Lines Tape-Shielded Cable Underground Lines Sequence Admittance The Shunt Admittance of Parallel Underground Lines Summary References Distribution System Line Models Exact Line Segment Model The Modified Line Model The Approximate Line Segment Model The General Matrices for Parallel Lines Summary References Voltage Regulation Standard Voltage Ratings Two-Winding Transformer Theory Two-Winding Autotransformer Step-Voltage Regulators Summary References Three-Phase Transformer Models Introduction Generalized Matrices The Delta-Grounded Wye Step-Down Connection The Ungrounded Wye-Delta Step-Down Connection The Grounded Wye--Grounded Wye Connection The Delta-Delta Connection Open Wye--Open Delta Thevenin Equivalent Circuit Summary Load Models Wye Connected Loads Delta Connected Loads Two-Phase and Single-Phase Loads Shunt Capacitors The Three-Phase Induction Machine Summary References Distribution Feeder Analysis Power-Flow Analysis Short-Circuit Studies Summary References Center-Tapped Transformers and Secondaries Center-Tapped Single-Phase Transformer Model Ungrounded Wye-Delta Transformer Bank Leading Open Wye--Open Delta Transformer Connection Lagging Open Wye--Open Delta Connection Four-Wire Secondary Putting It All Together Summary Reference Appendix A Appendix B Index

Effects of eddy currents in transformer windings

Abstract: The effects of eddy currents in transformer windings are considered, and a method is derived for calculating the variation of winding resistance and leakage inductance with frequency for transformers with single-layer, multilayer and sectionalised windings. The method consists in dividing the winding into portions, calculating the d.c. resistances and d.c. leakage inductances of each of these portions, and then multiplying the d.c. values by appropriate factors to obtain the corresponding a.c. values. These a.c. values are then referred to, say, the primary winding and summed to give the total winding resistance and leakage inductance of the transformer. Formulas are derived and quoted for calculating the d.c. resistances and leakage inductances of the winding portions. Theoretical expressions are derived for the variation with frequency etc. of the factors by which the d.c. values must be multiplied to obtain the corresponding a.c. values. These expressions are presented in the form of graphs, permitting the factors to be read as required.

Electric power distribution system engineering

Abstract: Distribution System Planning and Automation Introduction Distribution System Planning Factors Affecting System Planning Present Distribution System Planning Techniques Distribution System Planning Models Distribution System Planning in the Future Future Nature of Distribution Planning The Central Role of the Computer in Distribution Planning Impact of Dispersed Storage and Generation Distribution System Automation Summary and Conclusions References Load Characteristics Basic Definitions The Relationship Between the Load and Loss Factors Maximum Diversified Demand Load Forecasting Load Management Rate Structure Problems References Application of Distribution Transformers Introduction Types of Distribution Transformers Regulation Transformer Efficiency Terminal or Lead Markings Transformer Polarity Distribution Transformer Loading Guides Equivalent Circuits of a Transformer Single-Phase Transformer Connections Three-Phase Connections Three-Phase Transformers The T or Scott Connection The Autotransformer The Booster Transformers Amorphous Metal Distribution Transformers Problems References Design of Subtransmission Lines and Distribution Substations Introduction Subtransmission Distribution Substations Substation Bus Schemes Substation Location The Rating of a Distribution Substation General Case: Substation Service Area with n Primary Feeders Comparison of the Four-and Six-Feeder Patterns Derivation of the K Constant Substation Application Curves Interpretation of the Percent Voltage Drop Formula Supervisory Data and Data Acquisition Advanced SCADA Concepts Advanced Developments for Integrated Substation Automation Capability of Facilities Substation Grounding Transformer Classification Problems References Design Considerations of Primary Systems Introduction Radial-Type Primary Feeder Loop-Type Primary Feeder Primary Network Primary-Feeder Voltage Levels Primary-Feeder Loading Tie Lines Distribution Feeder Exit: Rectangular-Type Development Radial-Type Development Radial Feeders with Uniformly Distributed Load Radial Feeders with Nonuniformly Distributed Load Application of the A,B,C,D General Circuit Constants to Radial Feeders The Design of Radial Primary Distribution Systems Primary System Costs Problems References Design Considerations of Secondary Systems Introduction Secondary Voltage Levels The Present Design Practice Secondary Banking The Secondary Networks Spot Networks Economic Design of Secondaries Unbalanced Load and Voltages Secondary System Costs Problems References Voltage Drop and Power Loss Calculations Three-Phase Balanced Primary Lines Nonthree-Phase Primary Lines Four-Wire Multigrounded Common Neutral Distribution System Percent Power (or Copper) Loss A Method to Analyze Distribution Costs Economic Analysis of Equipment Losses Problems References Application of Capacitors to Distribution Systems Basic Definitions Power Capacitors Effects of Series and Shunt Capacitors Power Factor Correction Application of Capacitors Economic Justification for Capacitors A Practical Procedure to Determine the Best Capacitor Location A Mathematical Procedure to Determine the Optimum Capacitor Allocation Capacitor Tank Rupture Considerations Dynamic Behavior of Distribution Systems Problems References Distribution System Voltage Regulation Basic Definitions Quality of Service and Voltage Standards Voltage Control Feeder Voltage Regulators Line-Drop Compensation Distribution Capacitor Automation Voltage Fluctuations Problems References Distribution System Protection Basic Definitions Overcurrent Protection Devices Objective of Distribution System Protection Coordination of Protective Devices Fuse-to-Fuse Coordination Recloser-to-Recloser Coordination Recloser-to-Fuse Coordination Recloser-to-Substation Transformer High-Side Fuse Coordination Fuse-to-Circuit-Breaker Coordination Recloser-to-Circuit-Breaker Coordination Fault Current Calculations Fault Current Calculations in Per Units Secondary System Fault Current Calculations High-Impedance Faults Lightning Protection Insulators Problems References Distribution System Reliability Basic Definitions National Electric Reliability Council Appropriate Levels of Distribution Reliability Basic Reliability Concepts and Mathematics Series Systems Parallel Systems Series and Parallel Combinations Markov Processes Development of the State Transition Model to Determine the Steady-State Probabilities Distribution Reliability Indices Sustained Interruption Indices Other Indices (Momentary) Load-and Energy-Based Indices Usage of Reliability Indices Benefits of Reliability Modeling in System Performance Economics of Reliability Assessment Problems References Electric Power Quality Basic Definitions Definition of Electric Power Quality Classification of Power Quality Types of Disturbances Measurements of Electric Power Quality Power in Passive Elements Harmonic Distortion Limits Effects of Harmonics Sources of Harmonics Derating Transformers Neutral Conductor Overloading Capacitor Banks and PF Correction Short-Circuit Capacity or MVA Bus Voltage Rise and Resonance Harmonic Amplification Resonance Harmonic Control Solutions Harmonic Filter Design Load Modeling In The Presence Of Harmonics Problems References Appendix A: Impedance Tables for Lines, Transformers, and Underground Cables Appendix B: Graphic Symbols Used in Distribution System Design Appendix C: Glossary for Distribution System Terminology Appendix D: The Per-Unit System Notation Answers to Selected Problems Index

Voltage rise: the big issue when connecting embedded generation to long 11 kV overhead lines

Abstract: There has been much interest in embedding small generators deep within distribution systems. The steady-state voltage rise resulting from the connection of these generators can be a major obstacle to their connection at the lower voltage levels. This article summarises the results of some generic studies, explaining this voltage rise issue and how it may be overcome. Methods discussed to counteract voltage rise are primary substation voltage reduction, reactive power import, autotransformers installation, conductor upgrading, and generation constraints.

Toroidal low-field reactive gas source

Abstract: An apparatus for dissociating gases includes a plasma chamber that may be formed from a metallic material and a transformer having a magnetic core surrounding a portion of the plasma chamber and having a primary winding. The apparatus also includes one or more switching semiconductor devices that are directly coupled to a voltage supply and that have an output coupled to the primary winding of the transformer. The one or more switching semiconductor devices drive current in the primary winding that induces a potential inside the chamber that forms a plasma which completes a secondary circuit of the transformer.