Power Systems Control and Stability

Introduction

This workshop has been designed to give plant operators, electricians, and field technicians and engineers a better appreciation of the role played by Power System Protection systems. An understanding of power systems along with correct management will increase your plant efficiency and performance as well as increasing safety for all concerned. The workshop is designed to provide excellent understanding on both a theoretical and practical level. The workshop starts at a basic level, to ease the engineer and technician into the perhaps forgotten art of studying, and provide a refresher to those who are more familiar with the basic topics covered. The workshop then moves onto more detailed applications. The workshop features an introduction covering the need for protection, fault types and their effects, simple calculations of short circuit currents, and system earthing. The workshop also includes some practical work, simple fault calculations, relay settings, and the checking of a current transformer magnetization curve.

Objectives

Participants attending this program will gain a detailed appreciation of the following:

• The need for protection
• An overview of power system fault analysis
• Protection fundamentals
• Relay transducers, both current and future
• System grounding principles
• Over current earth fault protection
• Coordination principles
• Transformer protection
• Generator protection
• Bus protection
• Motor protection
• Line and feeder protection
• Principles of relay application

Training Methodology

This is an interactive course. There will be open question and answer sessions, regular group exercises and activities, videos, case studies, and presentations on best practice. Participants will have the opportunity to share with the facilitator and other participants on what works well and not so well for them, as well as work on issues from their own organizations. The online course is conducted online using MS-Teams/ClickMeeting.

Who Should Attend?

• Electrical Engineers
• Project Engineers
• Design Engineers
• Instrumentation and Design Engineers
• Electrical Technicians
• Field Technicians
• Electricians
• Plant Operators

Course Outline

Need For Protection

• Selectivity, stability, sensitivity, speed, reliability, dependability, security

Fault Types & Their Effects

• Active, incipient, passive, transient, asymmetrical
• Phase & earth faults

Simple Calculation of Short                

Circuit Currents

• Revision of simple formulae
• Calculation of short circuit MVA & fault currents
• Worked examples

System Earthing

• Solid, impedance, touch potentials
• Effect of electric shock
• Earth leakage protection
• Protection System Components

Including Fuses

• History, construction & characteristics
• Energy let through & applications

Instrument Transformers

• Current transformers: construction, performance, specification, magnetization curves
• Voltage transformers: types, accuracy, connections

Circuit Breakers

• Purpose & duty, clearance times, types

Tripping Batteries

• Battery types, chargers, maintenance, D.C. circuitry

Relays

• Inverse definite minimum time (IDMT) relay
• Construction principles and setting
• Calculation of settings - practical examples
• New Era - modern numerical relays & future trends

Practical demonstrations and sessions

• Including simple fault calculations and relay settings

Co-Ordination by Time Grading

• Problems in applying IDMT relays

Low Voltage Networks

• Air & molded circuit breakers
• Construction and installation
• Protection tripping characteristics
• Selective co-ordination (current limiting, earth leakage protection, cascading)

Principles of Unit Protection

• Differential protection - basic principles

Feeder Protection

• Cables
• Pilot wire differential
• Overhead lines
• Distance protection (basic principles, characteristics, various schemes)

Transformer Protection

• Phase shift, magnetizing in-rush, inter-turn, core & tank faults
• Differential & restricted earth fault schemes
• Bucholz relay, oil & winding temperature
• Oil - testing & gas analysis

Switchgear (Busbar) Protection

• Requirements, zones, types
• Frame leakage
• Reverse blocking
• High, medium & low impedance schemes

Motor Protection

• Thermal overload, time constraints, early relays, starting & stalling conditions
• Unbalanced supply voltages, negative sequence currents, de-rating factors
•  Phase faults protection
•  Earth faults - core balance, residual stabilizing resistors

Generator Protection

• Stator & rotor faults
• Overload & over-voltage
• Reverse power, unbalanced loading
• Loss of excitation and synchronism
• Typical protection scheme for industrial generators

Overhead Line Protection

• Basic principles of the distance relay
• Tripping characteristics
• Application onto power lines
•  Effect of load current & arc resistance
• Various schemes using power line carrier

Management of Protection

• Routine & annual testing, investigation and performance assessment, upgrading