System Earthing and Protective Earthing In Utilities and Industrial Electrical Networks

Introduction

Few topics generate as much controversy and argument as that of grounding or earthling as it is called in some countries and the associated topics of lighting and surge protection of electrical and electronics systems. Any engineering dealing with power supply networks needs to understand the basic principles of grounding system design and its role in ensuring the safety of equipment and personnel. A correct understanding of the basic principles involved will help him/her to avoid mistakes in grounding system design, mistakes that could lead to expensive failures and long downtime. In this training, we will demystify the concepts of grounding as applicable to utility networks and industrial plant distribution systems as well as their associated control equipment. In fact, a lot of myths have been built around this subject, although it is quite a simple one when approached from basic principles. Our endeavor will therefore be to explain the fundamentals of grounding, which we hope will enable you to gain a correct perspective of the subject and give him the knowledge needed to solve real-life grounding problems. Essentially this training is broken down into system grounding, protective grounding and

Surge/noise protection of power and electronics systems normally found in distribution networks. A brief introduction to the design of substation grounding has been included Detailed information on ground electrodes introduction to the design of substation grounding has been included. Detailed information on ground electrodes and measurement of ground resistance is also available.

Objectives

Upon the successful completion of this course, each participant will be able to:-

• Learn the basic principles of grounding of electrical systems
• The function of the power system grounding and the various options available
• Fundamental principles in the design of grounding systems in substations
• How to solve static electricity-related hazards by grounding and bonding

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 swell 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?

• Instrumentation and Control Engineers
• Consulting Engineers
• Electrical Engineers
• Project Engineers
• Maintenance Engineers
• Power System Protection and Control Engineers
• Building Service Designers
• Data Systems Planners and Managers
• Electrical and Instrumentation Technicians

Course Outline

Day 1: Overview

• Basics of grounding
• Bonding
• Role of grounding in lightning protection
• Ground electrodes and factors affecting their efficiency
• Grounding issues in outdoor substations
• Grounding for static charges
• Surge Protection
• Importance of grounding in mitigation of noise in sensitive circuits
• Importance of Local Codes

Day 2: Power Supply System Grounding

• Types of System grounding
• Ungrounded systems
• Solidly grounded systems
• Impedance grounding using neutral reactor
• Resonant grounding using neutral reactor
• Impedance grounding through neutral resistance
• Classification of supply systems based on grounding
• Point of grounding
• Other challenges

Protective Grounding

• Electric shock, its cause, and effects
• Direct and indirect contact
• Touch and step potential
• Role of protective grounding in minimizing the shock hazards
• Equipotential bonding
• Protective grounding conductors and installation
• Ground fault protection
• System classification based on system/protective grounding

Day 4: Ground Electrode Systems

• Soil resistance and factors affecting soil resistivity
• Measurement of soil resistivity
• The resistance of ground electrode and distribution of resistance in surrounding soil layers
• Electrode current capacity
• Ground electrode configurations
• Parallel electrodes
• Parallel electrodes
• Ground electrode resistance measurement
• Chemical electrodes
• Concrete encased electrodes and splicing methods
• Corrosion of buried electrodes
• Grounding system maintenance

Day 4: Substation Grounding Design

• Grounding practices
• Basic design approach
• Calculating the ground fault current
• The ground potential rise in HV systems
• Grounding design in LV and MV substations/installations
• Grounding grid design for HV/EHV substations - A step-by-step approach
• Introduction to a 2-layer soil model
• Transferred potential and ways of avoiding
• Points needing special attention in substation grounding design and for GIS equipment
• Design of substations containing converter equipment feeding to HVDC transmission systems
• Ensuring effective substation grounding - Important aspects

Static Electricity and Protection

• What is static electricity and how is it generated?
• Examples of static charge build-up and its dangers
• The energy of spark due to static electricity
• Ways of controlling the static build-up
• Risk assessment and preventive measures

Day 5: Grounding for Lightning Protection of Buildings and Structures

• The physics of lightning
• The lightning incidence in different landmasses
• Lightning strike probability
• Lightning protection
• Planning for protection and decision factors
• An improved approach to lightning protection and non-conventional systems
• Effect of lightning strikes on electrical installations

Surges and Surge Protection

• Surges, their causes, and mitigation
• The ways by which surges couple into electrical circuits
• Bonding of grounding systems
• The basic principle of surge protection and commonly used surge protection devices
• Graded surge protection
• Selecting appropriate surge protective devices and their positioning in a system
• Importance of correct grounding practices for sensitive equipment
• Other ways and devices for mitigating surge problems
• Comparative merits of different types of SPDs for sensitive equipment
• Hybrid surge protective devices
• Surge protection of telemetry and data communication systems

Electrical Noise and Mitigation

• Definition of electrical noise
• How are sensitive circuits affected?
• Noise categories
• Noise from power electrical equipment
• Noise coupling into signal circuits
• Noise mitigation measures
• Role of proper grounding in reducing noise
• Noise control by proper grounding of UPS derived supplies