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50 - LONG - Long-Term Programs


LONG 506 - Electric Substation Design and Electrical Protraction Systems (52 Weeks)

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Course Description

This program is designed to provide an introductory for the fundamentals of the electrical, civil, structural design issues of electric power substations. The program also it will address a complete variety of substation design subjects. It will also discuss application, installation, maintenance and testing issues related to low, medium and high-voltage switchgear and electrical circuit breaker equipment. Additionally the course will provide fundamentals on protection, relay design and protection schemes for transmission lines and transformers

Course Objectives

  • Understanding of substation technology and modern substation design practices
  • Understanding the importance of preventive maintenance check and servicing of the various types of circuit breakers
  • Implementing safe electrical systems of work and operations
  • Understanding the fundamentals of electrical power protection and applications
  • Recognizing the different fault types
  • Performing simple fault and design calculations
  • Understanding protection system components

Course Details/Schedule

Week 1

Electrical Substations, Power Systems, and Deregulation

  • Structure of the electric power system overview
  • Systems for distribution of power
  • Classifications
  • Equipment definitions
  • Design principles

Substation Project Chronology

  • Workflow and project sequence
  • Site identification and acquisition
  • Engineering design, drawings and documentation
  • Construction, testing and commissioning

Developing the Scope/Identifying the Constraints for the Overall Project

  • Safety
  • Power requirements
  • Site constraints
  • Atmospheric
  • Environmental community and societal influences

Costs and Schedules

  • Costs and financial analysis
  • Schedules and impacts

Site Grading Design

  • Substation grade types
  • Drainage and erosion protection
  • Oil spill containment

Foundations

  • Slab on grade and others
  • Design Techniques
  • Open air
  • Metal clad switchgear
  • Gas insulated subs/SF6

Bus Configurations & Conductor

  • Types of common configurations
  • Reliability criteria

Insulation

  • Insulation protection and shielding
  • Clearance
  • Surge arresters

Grounding

  • Need for grounding
  • Personnel safety
  • Hazardous potentials during faults

Structures

  • Materials
  • Design options and considerations
  • Finishes

Principle Equipment

  • General specifications and ratings
  • Transformers
  • Core, winding configuration
  • Tap changers
  • Specifications

Circuit Breakers/Switches

  • Design and purpose

Ancillary Equipment

  • Potential transformers
  • Current transformers

Substation Auxiliary Systems

  • Necessity
  • AC station power
  • DC and battery power

 

Week 2

Introduction - reasons for faults - and classification of faults

  • Distinction between load and fault current
  • Sources of short-circuit current
  • Introduction to fault calculations
  • Balanced and unbalanced faults

Overview of Power System Protection

  • Measurement - voltage and current transformers
  • Protective device characteristics
  • Types of protection systems
  • The role and importance of the circuit breaker in power systems

Overview of types of circuit breaker

  • Air-Break
  • Vacuum
  • Gas
  • Other related switching devices
  • The single-line diagram
  • Substation layouts

Air-break

  • Principles of arc extinction
  • D.C. circuit breaking
  • A.C. circuit breaking
  • Contacts and arc initiation
  • Arc chutes
  • Performance characteristics
  • General construction Principles

Vacuum

  • History – The early years
  • The vacuum arc – An overview
  • Current interruption in vacuum
  • Methods of keeping the arc diffuse
  • Current chopping – general implications
  • Vacuum interrupters in series
  • Design of vacuum switchgear
  • Maintenance and testing requirements

SF6 Gas

  • Properties of SF6
  • Principles of arc extinction
  • Features and construction
  • Mechanism principles
  • Insulation principles
  • Gas leak problems
  • Specific supervision requirements
  • Circuit power factor considerations
  • Maintenance and testing requirements

International Standards

  • Importance and relevance to specifications
  • ANSI and IEEE
  • IIEC and IEE

Circuit breakers and power system

  • Circuit breaker failure and the effects on power system operation
  • Circuit breaker inspection, testing and maintenance program
  • The Principles of modern substation control systems
  • Power circuit breaker maintenance

Importance of adequate maintenance

 

Maintenance of molded case circuit breakers

  • Frequency of maintenance
  • Routine maintenance tests

Maintenance of Iow-voltage circuit breakers

  • Frequency of maintenance
  • Maintenance procedures

Maintenance of medium-voltage circuit breakers

  • Frequency of maintenance
  • Safety practices
  • Maintenance procedures for medium-voltage air circuit breakers
  • Maintenance procedures for medium-voltage oil circuit breakers
  • Maintenance procedures for medium-voltage vacuum circuit breakers

Maintenance of high-voltage circuit breakers

  • Frequency of inspections
  • External inspection guidelines
  • Internal inspection guidelines
  • Typical internal breaker problems
  • Influence of duty imposed

Maintenance of SF6 gas circuit breakers

  • Properties of SF6 (sulfur hexafluoride) gas
  • Handling nonfaulted SF6
  • Handling faulted SF6

Week 3

Power System Overview

  • Electrical distribution system
  • Reading single line diagrams
  • LV, MV AND HV equipment
  • Function and types of electrical switchgear
  • Basic circuit breaker design

Basics of Power System Protection

  • Need for protective apparatus
  • Basic requirements and components

Types of Faults and Short Circuit Current Calculations

  • The development of simple distribution systems
  • Faults-types, effects and calculations
  • Equivalent diagrams for reduction of system impedance
  • Calculation of short circuit MVA
  • Unbalanced faults and earth faults
  • Symmetrical components

System Earthing and Earth Fault Current

  • Phase and earth faults
  • Comparison of earthing methods
  • Protective earthing
  • Effect of electric shock on human beings
  • Sensitive earth leakage protection
  • System classification

Fuses and Circuit Breakers with Builtin Protection

  • Fuse operating characteristics, ratings and selection
  • Energy 'let through'
  • General rules of thumb
  • IS-limiter
  • Circuit breakers - types, purpose and arc quenching
  • Behavior under fault conditions
  • Protective relay-circuit breaker combination
  • Circuit breakers with in-built protection
  • Conventional and electronic releases

Instrument Transformers Transformer ratio and errors of ratio and phase angle

  • 'Class' of instrument transformers
  • Voltage and current transformers
  • Applications

Relays and Auxiliary Power Equipment

  • Principle of construction and operation of protective relays
  • Special focus on IDMTL relays
  • Factors influencing choice of plug setting
  • The new era in protection - microprocessor, static and traditional
  • Universal microprocessor overcurrent relay
  • Technical features of a modern microprocessor relay
  • Future of protection for distribution systems
  • The era of the IED
  • Substation automation
  • Communication capability
  • Need for reliable auxiliary power for protection systems
  • Batteries and battery chargers
  • Trip circuit supervision
  • Why breakers and contactors fail to trip
  • Capacity storage trip units

Protection Grading and Relay Coordination

  • Protection design parameters on MV and LV networks
  • Coordination - basis of selectivity
  • Current, time and earth fault grading
  • Time-current grading
  • Grading through IDMT protection relay
  • Coordination between secondary and primary circuits of transformers
  • Current transformers - coordination
  • Importance of settings and coordination curves

Unit Protection and Applications

  • Protective relay systems
  • Main, unit and back-up protection
  • Methods of obtaining selectivity
  • Differential protection
  • Machine, transformer and switchgear differential protection
  • Feeder pilot-wire protection
  • Time taken to clear faults
  • Unit protection systems - recommendations and advantages

Protection of Feeders and Lines

  • Over current and earth fault protection
  • Application of DMT/IDMT protections for radial feeders
  • Directional over current relays in line protection
  • DMT and IDMT schemes applied to large systems
  • Unit and impedance protection of lines
  • Use of carrier signals in line protections
  • Transient faults and use of auto reclosing as a means of reducing outage time
  • Auto-reclosing in circuits with customer-owned generation
  • Auto-reclosing relays for transmission and distribution lines

Protection of Transformers

  • Winding polarity
  • Transformer connections and magnetizing characteristics
  • In-rush current
  • Neutral earthing
  • On-load tap changers
  • Mismatch of current transformers
  • Types of faults
  • Differential protection
  • Restricted earth fault
  • HV overcurrent
  • Protection by gas sensing and pressure detection
  • Overloading

Protection of Rotating Machinery

  • Motor protection basics
  • Transient and steady state temperature rise
  • Thermal time constant
  • Motor current during start and stall conditions
  • Stalling of motors
  • Unbalanced supply voltages and rotor failures
  • Electrical faults in stator windings earth fault phase-phase faults
  • Typical protective settings for motors
  • An introduction to generator protection