Medium Voltage Power Systems

The backbone of many electric power systems is the medium voltage distribution system. Typically operating at voltages ranging from 2,400 to 34,500 Volts, voltage stress, corona, surges and protection of equipment all create unique challenges in design, equipment selection, operation and engineering.

This 16 hour training course by Jim Phillips, P.E. takes you through the fundamentals of medium voltage power systems including the components, equipment, design and operation problems as well as overcurrent protection, surge protection, insulation coordination and many other important aspects of medium voltage power systems.

Jim has developed this course based on almost four decades of extensive experience with industrial, commercial and utility power systems and standards development. He is not just another trainer reading a script.  Jim’s training is based on his insider’s view from being very active with many different standards committees which provides him with the unique perspective, literally from the inside. Coupled with his broad electrical power background, he loves sharing his experience and insider’s view with others.

One of the many topics that Jim discusses in this 2 day class is overcurrent relays and relay settings including determining the current transformer ratio, CT saturation calculations, determining overcurrent relay settings and calculating transformer differential relay settings. This class also includes many other topics such as surge protection, insulation coordination and more.


AGENDA - MEDIUM VOLTAGE POWER SYSTEMS

INTRODUCTION

Medium Voltage Systems, Voltage Ranges, Special Considerations

Failure Modes, Voltage Stress, Thermal Stress

MEDIUM VOLTAGE SAFETY

Electrocution at Low vs. Medium Voltage, Arc Flash Issues, Qualified Person,

Approach Boundaries

TYPES OF MEDIUM VOLTAGE SYSTEMS

Utility and Industrial One lines, Reliability Requirements, Overhead and Underground

Systems, Regulated Systems

MEDIUM VOLTAGE CABLE

Copper vs. Aluminum Design, Voltage Ratings

Insulation Ratings, 100%, 133%, 173% Insulation Levels, Shielding Requirements,

Electric Fields, Terminating MV Conductors, Orientation of Overhead Lines

MEDIUM VOLTAGE SUBSTATION TRANSFORMERS

Core and Coil Design, Aluminum and Copper Windings, Transformer Characteristics, Tank Construction, Loss Evaluation, Loss Calculations, Efficiency Calculations, Regulation

SPOT NETWORKS

Spot Network Design, Network Protectors, Network Protector Relay Operation, Directional Protection Requirements, Large Network Fault Currents

PARTIAL DISCHARGE

Corona, Surface Tracking, Voltage Stress, Sensing Partial Discharge, Component Failure

GROUNDING MEDIUM VOLTAGE SYSTEMS

Resistance Grounding, Solid Grounding, Ungrounded Delta Charging Current, Coefficient of Grounding Calculations, Effect of Ground Faults on Delta Voltage, Sizing Grounding Resistors, High Resistance Grounding vs. Low Resistance Grounding

OVERVIEW OF SYMMETRICAL COMPONENTS

Positive, Negative and Zero Sequence Impedance, Per Unit

Line-to-Ground Short Circuit Calculations

SURGE PROTECTION

Lightning and Switching Surges, Classes of Surge Arresters, Insulation Basic Impulse Level BIL , Basic Impluse Switching Insulation Level (BSL) Front of Wave (FOW), MCOV Ratings – (Maximum Continuous Operating Voltage) TOV – (Maximum Temporary Over Voltage Capability), Protective Characteristics, Surge Arrester Selection, Energy Capability, Effect of Grounding on Arrester Selection, Insulation Coordination, Protective Ratio and Protective Margin Calculations.

CURRENT TRANSFORMER APPLICATIONS

Ratings, Selection Process, Accuracy, Saturation, Excitation Curves, Burden,

Calculation, Momentary Ratings, CT Saturation Calculations for Performance

MEDIUM VOLTAGE CIRCUIT BREAKERS

Vacuum, Air, Oil, SF6 Designs, Symmetrical Interrupting Rating, K-Rated

Voltage Factor, Close and Latch Capability

OVERCURRENT RELAYS

Protective Relay Concepts, Selective Coordination Principles, ANSI Device Numbers i.e. 50, 51, 67, 32, 27, etc. Amp Tap, Time Dial, Instantaneous Setting  Relay Setting Calculations, Digital Relays, Electromechanical Relays, Time Margins, Coordination Between Devices

RECLOSERS

Application on Feeder Circuits, Recloser Settings, Continuous Current and Interrupting Ratings

MEDIUM VOLTAGE FUSES

Medium Voltage Switches, Load Rating, Expulsion vs. Current Limiting Fuse Characteristics, E and R Rated Fuses, Fuse Cutouts, ANSI Time Current Points

MEDIUM VOLTAGE PROTECTION CONCEPTS

Medium Voltage Protection, Relays, Circuit Breakers, R and E rated Fuses,

Short Circuit vs. Overcurrent Protection

DISTRIBUTION FEEDER PROTECTION

Protection with Fuses – 300%, Overcurrent Protection with Relays – 600%,

Short Circuit Damage Characteristics, Relay “Reach” for End of Line Faults

ROTATING MACHINERY PROTECTION

Protection Requirements, Generator Decrement Curves, Thermal Damage Curves, Reactive,

Capability Curves, Differential Protection, Protection Example Calculations

MEDIUM VOLTAGE MOTOR CONTROLLERS

Protection Requirements, Motor Management Relays, Circuit Breaker Protection, Relaying, Class R Rated Fuses

TRANSFORMER PROTECTION

ANSI C57 Transformer Thru Fault Curves, Impact of Transformer Winding Configuration,

Overview of Differential Protection, Inrush and Harmonic Restraint, Hands On Differential Relay Setting Calculation Problems and Calculation Worksheets.


Questions? Call us 800.874.8883 (U.S.) or email

Lessons

Instructor

About Jim Phillips

Jim Phillips

Instructor

• Founder: Brainfiller.com Electrical Power, Safety and Arc Flash Training • Associate Director: Electrical Safety UK Ltd. - Rotherham, England • Contributing Editor: Electrical Contractor Magazine • Author: Complete Guide to Performing an Arc Flash Hazard Study • B.S. Electrical Engineering • Registered Professional Engineer • Four Decades of Industrial and Utility Experience • Vice Chair: IEEE 1584 - IEEE Guide for Performing Arc Flash Hazard Calculations • TC Member: NFPA 70E - Electrical Safety in the Workplace • International Chair: IEC TC 78 Live Working Standards • Steering Committee – IEEE/NFPA Arc Flash Collaborative Research Project. E-mail: jphillips@brainfiller.com

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    CEU 1.6/PDH 16
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