System Earthing & Protective Earthing in Utilities & Industrial Electrical Networks
System Earthing & Protective Earthing in Utilities & Industrial Electrical Networks
OBJECTIVES
- Principles, design, testing and maintenance of earthing for systems and equipment
- Nature of different types of electrical faults related to earthing problems
- Hazards and safety precautions associated with earthing
- Electrical safety requirements and procedures
- Understanding of electrical fault protection systems
- Practices to mitigate earthing problems in electrical networks and industrial installations
WHO SHOULD ATTEND?
- Designers, Engineers and Technicians from Distribution Companies and Power Utilities, Engineering Professionals in Electricity Supply Industry, Petrochemical Companies, Buildings and Service Managers who have to deal with the aspect of electrical and industrial power system protection, control and operation.
- Participants need no specific requirements other than good understanding of electricity and magnetism and some relevant experience.
COURSE OUTLINE
Day 1 – Introduction, General Principles and Requirements of Earthing
- Course overview, objectives, methodology, expectations and input from participants (experience and current responsibilities)
- Overview of power systems and components
- The distribution system and network configurations
- Basic safety requirements and devices in power distribution
- Electrical hazards
- Electrical shock
- Electrical fires
- Short revision of electrical principles, definitions, glossary and common terms
- Reasons for earthing, system earthing, equipment earthing
- Overview: of common causes of power equipment failure
- Work in the vicinity of electric and magnetic fields
- Approach to HV electrical apparatus
- Occupational health & safety (OH&S) requirements
- Installation safety requirements and regulations
- Safety related maintenance and environmental considerations
- Safety requirements for special equipment
- Personal protective equipment.
- Case studies and workshop discussion session
Day 2 – Theory and Principles of Earthing
- Earthing principles, basic requirements
- System earthing, equipment earthing, safety earth, signal earth
- Functional earth layout, practical low-frequency earthing
- Hardware earthing
- Earth loops, common impedance coupling
- Objectives of site earthing, categories of earthing
- Neutral earthing, protective earth
- Coordinating earthing within a control system
- The well earthed building, earthing coordination,
- Importance of low resistance earthing
- Earthing electrodes
- Trench earth vs driven rods vs foundation reinforcing steel
- Steps for designing earthing systems for structures
- Case studies and workshop discussion session
Day 3 – Equipment Earthing and Electromagnetic Shielding
- Basic principles
- Circuit return coupling
- Earth plane induced feedback
- Interference coupling
- Earthing practices for low frequency equipment
- Earthing practices for equipment containing both low frequency and high frequency.
- Basic shielding principles
- Definition of protection zones
- Shield impedance
- Low frequency shielding
- High frequency shielding
- Shielding materials
- Shield design criteria
- Cables shielding
- Importance of good bonding, recommended practices for effective bonding
- Case studies and workshop discussion session
Day 4 – Power Substation Earthing and Safety Requirements
- Purpose of substation earthing
- MV and LV network arrangements
- Earth potential rise
- Protective conductors
- Earth electrodes
- Electrode resistance
- Connection of services
- Grid and mesh potentials
- Potential gradient areas of common types of electrodes
- Multiple electrodes
- Measurement of soil resistance and electrode resistance
- Protective earthing devices
- Earth leakage circuit breakers
- Nature and effects of electric shock
- Protection against electric shock
- Protection against overcurrent and short-circuit current
- Common electric hazards
- High voltage areas
- Overloaded circuits
- Damaged cords, bare connectors
- Long and tall objects
- Mobile equipment
- Standing water
- Switching and tagging
- Protecting workers from arcs
- Safety testing procedures
- Unintentional energizing of circuits
- Field scenario: switching and tagging, field testing and grounding
- Case studies and workshop discussion session
Day 5 – Earthing for Protection against Lightning and Electrostatic Discharge
- Physics of lightning
- Electrical surges due to lightning
- Lightning current waveform
- Voltage and current surges due to lightning
- Direct and indirect surges due to lightning strikes
- Induced surges due to adjacent lightning strikes
- Avoiding side flashes
- Effect of earth impedance
- Lightning damage
- Lightning protection techniques for electricity supply
- Lightning protection of computer and communication equipment and systems
- Lightning protection for buildings
- Protection against electrostatic discharges (ESD)
- Damage to equipment and systems caused by ESD
- Protective techniques and devices against ESD
- Examples, case studies and workshop discussion session