This document discusses various topics related to earthing design including:
1. Calculating the necessary cross-sectional area of conductors to carry grid fault current and prevent dangerous surface potentials.
2. Factors that influence surface current density such as soil resistivity, time to clear faults, and temperature limits.
3. Formulas to evaluate the cross-section of conductors based on mechanical and electrical requirements.
4. Techniques for measuring soil resistivity like taking readings in multiple directions to generate a polar curve and account for variability.
Earthing in a substation is important for safety. It involves connecting electrical equipment to earth at a uniform low potential to limit dangerous voltages under fault conditions. Key aspects of substation earthing design include soil resistivity testing, sizing the earth mat conductor based on fault current and duration, and ensuring step and touch potentials remain below safety limits. Proper earthing aims to provide protection to life and property against faults.
The document discusses the role of power cables in electrical power systems. It describes how cables are classified based on their application, such as for overhead transmission lines, power transmission, and underground cables. It also discusses factors that can cause trouble for cables, including mechanical activities, accessories, improper selection, overvoltages, and installation problems. Additionally, it covers the importance of earthing electrical systems and describes how well-designed earthing systems provide a safe return path for fault currents and minimize hazards.
The document discusses different types of grounding systems used in electrical installations. It describes six common grounding systems: equipment grounds, static grounds, system grounds, maintenance grounds, electronic grounds, and lightning grounds. It provides details on each type, including their objectives and how they are implemented. The document also discusses factors to consider when designing grounding systems and recommendations for proper grounding practices.
This document discusses earthing systems in mining operations and managing transfer voltage hazards. It presents options for bonding all systems commonly versus separating systems. It notes that separating earthing systems may be necessary when earth potential rise cannot be managed through common bonding alone. The document provides examples of how to set up separated power and lightning earthing systems and discusses factors like impedance earthed systems, screens, single point bonding, and controlling areas to mitigate hazards from different earth potentials.
The presentation deals with principles of protecting buildings/structures and and power systems from effects of lightning.It also deals with protecting the power systems from over voltages arising from lightning and switching.
The document discusses different types of earthing systems used in electrical installations. It provides details on:
- The purpose of earthing systems which is to provide protection from electric shocks and maintain safe voltages.
- Common types of earthing methods including plate, pipe, rod and strip earthing. It also discusses maintenance free earthing systems.
- Factors that determine good earthing including low resistance, corrosion resistance and ability to dissipate high fault currents.
- Causes of short circuits and how earthing provides protection during faults.
- Maximum earth resistance values that should be achieved for different electrical equipment.
At the outset we wish to thank you for the curtsey and excellent response from you and active interest in taking a comprehensive view of modern safe Lightning Protection / Earthing and the underlying scientific principles as we posted in our Linkedin Profile, which is for your ready reference.
There are several earthing configurations for electrical systems that have different safety, functionality and cost implications. The optimal configuration depends on factors like required safety levels, cost, potential electromagnetic compatibility issues and ability to continue operating after faults. Some configurations like TN-C-S provide a compromise between separate earthing, cost and electromagnetic compatibility. Expert analysis of voltage and current distributions for the specific environment is needed to select the best configuration.
Earthing in a substation is important for safety. It involves connecting electrical equipment to earth at a uniform low potential to limit dangerous voltages under fault conditions. Key aspects of substation earthing design include soil resistivity testing, sizing the earth mat conductor based on fault current and duration, and ensuring step and touch potentials remain below safety limits. Proper earthing aims to provide protection to life and property against faults.
The document discusses the role of power cables in electrical power systems. It describes how cables are classified based on their application, such as for overhead transmission lines, power transmission, and underground cables. It also discusses factors that can cause trouble for cables, including mechanical activities, accessories, improper selection, overvoltages, and installation problems. Additionally, it covers the importance of earthing electrical systems and describes how well-designed earthing systems provide a safe return path for fault currents and minimize hazards.
The document discusses different types of grounding systems used in electrical installations. It describes six common grounding systems: equipment grounds, static grounds, system grounds, maintenance grounds, electronic grounds, and lightning grounds. It provides details on each type, including their objectives and how they are implemented. The document also discusses factors to consider when designing grounding systems and recommendations for proper grounding practices.
This document discusses earthing systems in mining operations and managing transfer voltage hazards. It presents options for bonding all systems commonly versus separating systems. It notes that separating earthing systems may be necessary when earth potential rise cannot be managed through common bonding alone. The document provides examples of how to set up separated power and lightning earthing systems and discusses factors like impedance earthed systems, screens, single point bonding, and controlling areas to mitigate hazards from different earth potentials.
The presentation deals with principles of protecting buildings/structures and and power systems from effects of lightning.It also deals with protecting the power systems from over voltages arising from lightning and switching.
The document discusses different types of earthing systems used in electrical installations. It provides details on:
- The purpose of earthing systems which is to provide protection from electric shocks and maintain safe voltages.
- Common types of earthing methods including plate, pipe, rod and strip earthing. It also discusses maintenance free earthing systems.
- Factors that determine good earthing including low resistance, corrosion resistance and ability to dissipate high fault currents.
- Causes of short circuits and how earthing provides protection during faults.
- Maximum earth resistance values that should be achieved for different electrical equipment.
At the outset we wish to thank you for the curtsey and excellent response from you and active interest in taking a comprehensive view of modern safe Lightning Protection / Earthing and the underlying scientific principles as we posted in our Linkedin Profile, which is for your ready reference.
There are several earthing configurations for electrical systems that have different safety, functionality and cost implications. The optimal configuration depends on factors like required safety levels, cost, potential electromagnetic compatibility issues and ability to continue operating after faults. Some configurations like TN-C-S provide a compromise between separate earthing, cost and electromagnetic compatibility. Expert analysis of voltage and current distributions for the specific environment is needed to select the best configuration.
The document provides an introduction to electrical grounding practices for power systems. It discusses the primary goals of grounding for safety and protection. It also describes the different types of grounding systems used in industry, including ungrounded, solid ground, low resistance ground, and high resistance ground. Each system is characterized by its handling of faults, safety aspects, reliability and economics.
The document discusses earthing arrangements and protection against electric shock. It defines key terms like earthing, protective conductors, and fault conditions. It describes the three common earthing arrangements - TT, TN-S, and TN-C-S systems. For each system, it explains the wiring configuration and how fault currents flow. Protection methods like RCDs and their operation are also covered to prevent electric shock. Diagrams and formulas are provided to calculate touch voltages and ensure safety.
This document discusses earthing systems and the hazards of a broken neutral connection for a power transformer. It defines system earthing and equipment earthing, and explains that a broken neutral connection can cause overvoltage issues for the transformer and prevent protective relays from operating during a fault. The document also discusses the objectives and importance of proper earthing, including providing an alternative path for fault currents, ensuring safety from electric shocks, and maintaining system voltages. It provides examples of what can occur when a transformer's neutral connection to earth is broken.
Tank Grounding for safe operating conditions to ensure proper dissipation of transient electrical currents, static electricity, and lightning dispersion.
Successful operation of entire power system depends to a considerable extent on efficient and satisfactory performance of substations. Hence substations in general can be considered as heart of overall power system. In any substation, a well-designed grounding plays an important role. Since absence of safe and effective grounding system can result in mal-operation or non-operation of control and protective devices, grounding system design deserves considerable attention for all the substations. There are two primary functions of a safe earthing system. Firstly, ensure that a person who is in the vicinity of earthed facilities during a fault is not exposed to the possibility of a fatal electrical shock. Secondly, provide a low impedance path to earth for currents occurring under normal and fault conditions.The earthing conductors, composing the grid and connections to all equipment and structures, must possess sufficient thermal capacity to pass the highest fault current for the required time
The document defines and describes different types of overvoltages that can occur on power systems, including temporary, transient, lightning, and switching overvoltages. It explains that overvoltages are caused by both internal factors like switching and insulation failures, as well as external lightning strikes. The mechanism of lightning is then described in detail, including how charge separation in storm clouds leads to the formation of stepped leaders and streamers, completing an ionized conductive path between the cloud and earth.
This document discusses methods for measuring ground resistance to ensure safe and effective grounding of electrical systems. It explains that ground resistance testing is important to verify a low-resistance path for fault currents. The most common method is the fall-of-potential test, which applies a known current through a test electrode and auxiliary electrode, then measures the voltage drop to calculate resistance. Proper spacing of electrodes is also important, as resistance readings are most accurate when the test and auxiliary electrodes are farther apart.
This document provides guidelines for designing an earth mat for a metro station. It discusses standards for earth mat design, the design procedure, and provides an example of a design for the Joka Station. The key steps in design include determining the fault current, selecting conductor size, and using software to model symmetrical or asymmetrical mat layouts based on space availability and soil properties. The example shows the proposed mat layout for Joka Station, simulation results verifying touch and step potentials are below safety limits, and demonstrating the effectiveness of the design.
This document discusses the basics of earthing systems. It begins by defining important terminology related to earthing. It then discusses the disadvantages of unearthed systems and the different types of earthing including system, equipment, and reference earthing. The document outlines the basic principles and methods of system earthing, including how fault currents flow. It provides details on the earthing schemes adopted in process plants, including the voltage levels and earthing methods used. Finally, it includes an earthing conductors schedule with requirements for equipment body and instrument earthing connections.
Substation lightning protection and earthing standard(august 2019)Mahesh Chandra Manav
Lightning protection and earthing systems are essential parts of transmission systems that constrain earth potentials and provide protection. They dissipate over voltages from lightning strikes. The document provides detailed design requirements for lightning protection systems, earthing systems, and their components. Key aspects addressed include lightning protection coverage, earthing of equipment, buildings and fences, jointing methods, and testing of joints.
POWER SYSTEM PROTECTION
Protection Devices and the Lightning,. protection,
Lightning protection, Introduction
Air Break Switches
Disconnect switches
Grounding switches
Current limiting reactors
Grounding transformers
Co-ordination of protective devices
Grounding of electrical installations
Electric shock
Lightning protection
Lightning Arrestor
This document summarizes types of lightning arresters, their classification, identification, standard ratings, and service conditions. There are three main types of arresters: expulsion, valve, and gapless metal-oxide. Arresters are classified into four classes based on their nominal discharge current and use: station, intermediate, distribution, and secondary. Arresters must be properly identified and can operate under normal conditions of temperature, radiation, altitude, and frequency, but may require special consideration under abnormal conditions.
Contents:-
#What is Grounding or Earthing?
#Symbol
#Earthing cable
#History
#How Earthing works?
#Difference between Earth & Neutral
#Importance of Earthing
#Components of earthing system
#Types of Earthing
This document discusses different types of earthing systems used in electrical installations. It defines earthing as connecting electrical equipment to the earth to provide a safe path for electric current. The main purposes of earthing are to protect humans and equipment from electric shocks. The document describes maintenance free earthing and conventional earthing methods. It also explains different earthing electrodes like plates, pipes, rods and strips that are buried underground to reduce earth resistance.
This document discusses various grounding techniques for electrical systems. It begins by comparing different grounding methods such as ungrounded, solidly grounded, and resistance grounded systems. It then focuses on high resistance grounding and describes how HRG limits fault currents while allowing systems to continue operating after ground faults. The document provides examples of applying HRG to generators, variable frequency drives, and paralleled power sources. It discusses component ratings, fault currents, harmonics, and coordination of protection devices for HRG systems.
Earthing is the process of connecting metallic electrical equipment to the earth using a low resistance wire. This serves several important purposes: to protect human life from electric shock by providing an alternative path for fault currents, to protect buildings and machinery under fault conditions, to safely dissipate lightning and short circuit currents, and to maintain a stable voltage for sensitive electronic equipment. Traditionally, earthing involved digging a pit and burying a metal plate or pipe surrounded by charcoal and salt, which required regular maintenance and watering.
Lightning protection and ground solutions for wireless networksComms Connect
This presentation discusses lightning protection and grounding solutions for wireless networks. It begins with some facts about lightning events, noting they produce currents up to 100,000 amperes and temperatures of 20,000 degrees Celsius. It then covers topics like step leaders, pulse wave shapes, annual flash rates, and the physics of the lightning strike. The presentation provides guidance on proper tower and equipment grounding techniques to mitigate lightning damage. It also reviews coaxial cable protections and surge arrestor products to safeguard network components.
The document discusses different types of grounding or earthing systems for electrical equipment and power systems. It describes:
1) Equipment grounding, which connects the non-current carrying metal parts of electrical equipment to earth to protect against insulation failures.
2) System grounding, which connects parts of the electrical system like the neutral point of a star-connected system to earth.
3) Neutral grounding, a type of system grounding where the neutral point of a 3-phase system is connected to earth either directly or through a resistor or reactor. This provides safety benefits and allows faults to be isolated.
The document discusses the grounding design of the Kano Hydro Power Station in Nigeria. It provides background on the authors and Skipper Electrical. It then summarizes the key aspects of designing the grounding system, including measuring soil resistivity, calculating touch and step potentials, and following relevant safety standards and codes. The results of the initial grounding design are presented, but the final design had to be re-evaluated after excavation revealed much higher soil resistivity in some areas than initially measured. The final design ensures touch and step potentials are within safe limits across the power house and switchyard.
Lightning, Surge Protection & Earthing of Electrical & Electronic Systems in ...Living Online
Few topics generate as much controversy and argument as that of lightning and surge protection of electrical and electronic systems. Poor practices in earthing, and incorrect application and selection of lightning and surge protection devices can be the cause of continual and intermittent problems in a facility, often resulting in lost production and equipment failure.
This workshop looks at these issues from a fresh yet practical perspective and enables you to reduce expensive down time on your plant and equipment by the correct application of these principles. Essentially the workshop is broken down into the methods used to prevent lightning entering a facility such as dissipation arrays and those that divert surge energy away from sensitive equipment.
Dissipation systems are discussed with associated earthing systems. The unique properties of various surge protection devices are reviewed, enabling you to select the correct device suited to the application required. Earthing and surge protection for telecommunications and IT systems are examined in detail as well as the impact of lightning and simple techniques for minimising its impact.
MORE INFORMATION: http://www.idc-online.com/content/lightning-surge-protection-earthing-electrical-electronic-systems-industrial-networks-13?id=6987
Erico Eritech Lightning Protection - IEC62305 Earthing Design Guide.
ERICO’s proven experience in providing grounding and bonding systems, including ground rods, ground enhancement material and signal reference grids, provides for the safe dissipation of energy.
Erico System 1000 - ESE Standard System
The ERITECH® SI Series encompasses three air terminal models and accessories that are designed to comply with the requirements of the French NFC17-102 and Spanish UNE-21186 Standards.
Erico System 2000 - Conventional Protection
ERICO offers the System 2000 series of air terminals, downconductors and fittings in accordance with Australian-AS1768, British-BS6651, Singaporean-CP33, European-IEC and USA-NFPA780 Standards.
Erico System 3000 - Enhanced Protection System
ERICO's System 3000 is a technically advanced lightning protection system. The unique features of this system allow optimum performance, flexibility of design, and overall cost-effective installation.
Example kitchen ventilation calculationwilliammana
This document provides calculations for kitchen ventilation requirements. It determines that a mobile hot cabinet appliance area requires 662.5 CFM of exhaust and additional makeup air is needed from the surrounding hood area, totaling 984 CFM required. A 1200 CFM kitchen exhaust fan and 960 CFM makeup fan are selected to meet the calculated needs. Technical specifications are also provided for the selected fans.
The document provides an introduction to electrical grounding practices for power systems. It discusses the primary goals of grounding for safety and protection. It also describes the different types of grounding systems used in industry, including ungrounded, solid ground, low resistance ground, and high resistance ground. Each system is characterized by its handling of faults, safety aspects, reliability and economics.
The document discusses earthing arrangements and protection against electric shock. It defines key terms like earthing, protective conductors, and fault conditions. It describes the three common earthing arrangements - TT, TN-S, and TN-C-S systems. For each system, it explains the wiring configuration and how fault currents flow. Protection methods like RCDs and their operation are also covered to prevent electric shock. Diagrams and formulas are provided to calculate touch voltages and ensure safety.
This document discusses earthing systems and the hazards of a broken neutral connection for a power transformer. It defines system earthing and equipment earthing, and explains that a broken neutral connection can cause overvoltage issues for the transformer and prevent protective relays from operating during a fault. The document also discusses the objectives and importance of proper earthing, including providing an alternative path for fault currents, ensuring safety from electric shocks, and maintaining system voltages. It provides examples of what can occur when a transformer's neutral connection to earth is broken.
Tank Grounding for safe operating conditions to ensure proper dissipation of transient electrical currents, static electricity, and lightning dispersion.
Successful operation of entire power system depends to a considerable extent on efficient and satisfactory performance of substations. Hence substations in general can be considered as heart of overall power system. In any substation, a well-designed grounding plays an important role. Since absence of safe and effective grounding system can result in mal-operation or non-operation of control and protective devices, grounding system design deserves considerable attention for all the substations. There are two primary functions of a safe earthing system. Firstly, ensure that a person who is in the vicinity of earthed facilities during a fault is not exposed to the possibility of a fatal electrical shock. Secondly, provide a low impedance path to earth for currents occurring under normal and fault conditions.The earthing conductors, composing the grid and connections to all equipment and structures, must possess sufficient thermal capacity to pass the highest fault current for the required time
The document defines and describes different types of overvoltages that can occur on power systems, including temporary, transient, lightning, and switching overvoltages. It explains that overvoltages are caused by both internal factors like switching and insulation failures, as well as external lightning strikes. The mechanism of lightning is then described in detail, including how charge separation in storm clouds leads to the formation of stepped leaders and streamers, completing an ionized conductive path between the cloud and earth.
This document discusses methods for measuring ground resistance to ensure safe and effective grounding of electrical systems. It explains that ground resistance testing is important to verify a low-resistance path for fault currents. The most common method is the fall-of-potential test, which applies a known current through a test electrode and auxiliary electrode, then measures the voltage drop to calculate resistance. Proper spacing of electrodes is also important, as resistance readings are most accurate when the test and auxiliary electrodes are farther apart.
This document provides guidelines for designing an earth mat for a metro station. It discusses standards for earth mat design, the design procedure, and provides an example of a design for the Joka Station. The key steps in design include determining the fault current, selecting conductor size, and using software to model symmetrical or asymmetrical mat layouts based on space availability and soil properties. The example shows the proposed mat layout for Joka Station, simulation results verifying touch and step potentials are below safety limits, and demonstrating the effectiveness of the design.
This document discusses the basics of earthing systems. It begins by defining important terminology related to earthing. It then discusses the disadvantages of unearthed systems and the different types of earthing including system, equipment, and reference earthing. The document outlines the basic principles and methods of system earthing, including how fault currents flow. It provides details on the earthing schemes adopted in process plants, including the voltage levels and earthing methods used. Finally, it includes an earthing conductors schedule with requirements for equipment body and instrument earthing connections.
Substation lightning protection and earthing standard(august 2019)Mahesh Chandra Manav
Lightning protection and earthing systems are essential parts of transmission systems that constrain earth potentials and provide protection. They dissipate over voltages from lightning strikes. The document provides detailed design requirements for lightning protection systems, earthing systems, and their components. Key aspects addressed include lightning protection coverage, earthing of equipment, buildings and fences, jointing methods, and testing of joints.
POWER SYSTEM PROTECTION
Protection Devices and the Lightning,. protection,
Lightning protection, Introduction
Air Break Switches
Disconnect switches
Grounding switches
Current limiting reactors
Grounding transformers
Co-ordination of protective devices
Grounding of electrical installations
Electric shock
Lightning protection
Lightning Arrestor
This document summarizes types of lightning arresters, their classification, identification, standard ratings, and service conditions. There are three main types of arresters: expulsion, valve, and gapless metal-oxide. Arresters are classified into four classes based on their nominal discharge current and use: station, intermediate, distribution, and secondary. Arresters must be properly identified and can operate under normal conditions of temperature, radiation, altitude, and frequency, but may require special consideration under abnormal conditions.
Contents:-
#What is Grounding or Earthing?
#Symbol
#Earthing cable
#History
#How Earthing works?
#Difference between Earth & Neutral
#Importance of Earthing
#Components of earthing system
#Types of Earthing
This document discusses different types of earthing systems used in electrical installations. It defines earthing as connecting electrical equipment to the earth to provide a safe path for electric current. The main purposes of earthing are to protect humans and equipment from electric shocks. The document describes maintenance free earthing and conventional earthing methods. It also explains different earthing electrodes like plates, pipes, rods and strips that are buried underground to reduce earth resistance.
This document discusses various grounding techniques for electrical systems. It begins by comparing different grounding methods such as ungrounded, solidly grounded, and resistance grounded systems. It then focuses on high resistance grounding and describes how HRG limits fault currents while allowing systems to continue operating after ground faults. The document provides examples of applying HRG to generators, variable frequency drives, and paralleled power sources. It discusses component ratings, fault currents, harmonics, and coordination of protection devices for HRG systems.
Earthing is the process of connecting metallic electrical equipment to the earth using a low resistance wire. This serves several important purposes: to protect human life from electric shock by providing an alternative path for fault currents, to protect buildings and machinery under fault conditions, to safely dissipate lightning and short circuit currents, and to maintain a stable voltage for sensitive electronic equipment. Traditionally, earthing involved digging a pit and burying a metal plate or pipe surrounded by charcoal and salt, which required regular maintenance and watering.
Lightning protection and ground solutions for wireless networksComms Connect
This presentation discusses lightning protection and grounding solutions for wireless networks. It begins with some facts about lightning events, noting they produce currents up to 100,000 amperes and temperatures of 20,000 degrees Celsius. It then covers topics like step leaders, pulse wave shapes, annual flash rates, and the physics of the lightning strike. The presentation provides guidance on proper tower and equipment grounding techniques to mitigate lightning damage. It also reviews coaxial cable protections and surge arrestor products to safeguard network components.
The document discusses different types of grounding or earthing systems for electrical equipment and power systems. It describes:
1) Equipment grounding, which connects the non-current carrying metal parts of electrical equipment to earth to protect against insulation failures.
2) System grounding, which connects parts of the electrical system like the neutral point of a star-connected system to earth.
3) Neutral grounding, a type of system grounding where the neutral point of a 3-phase system is connected to earth either directly or through a resistor or reactor. This provides safety benefits and allows faults to be isolated.
The document discusses the grounding design of the Kano Hydro Power Station in Nigeria. It provides background on the authors and Skipper Electrical. It then summarizes the key aspects of designing the grounding system, including measuring soil resistivity, calculating touch and step potentials, and following relevant safety standards and codes. The results of the initial grounding design are presented, but the final design had to be re-evaluated after excavation revealed much higher soil resistivity in some areas than initially measured. The final design ensures touch and step potentials are within safe limits across the power house and switchyard.
Lightning, Surge Protection & Earthing of Electrical & Electronic Systems in ...Living Online
Few topics generate as much controversy and argument as that of lightning and surge protection of electrical and electronic systems. Poor practices in earthing, and incorrect application and selection of lightning and surge protection devices can be the cause of continual and intermittent problems in a facility, often resulting in lost production and equipment failure.
This workshop looks at these issues from a fresh yet practical perspective and enables you to reduce expensive down time on your plant and equipment by the correct application of these principles. Essentially the workshop is broken down into the methods used to prevent lightning entering a facility such as dissipation arrays and those that divert surge energy away from sensitive equipment.
Dissipation systems are discussed with associated earthing systems. The unique properties of various surge protection devices are reviewed, enabling you to select the correct device suited to the application required. Earthing and surge protection for telecommunications and IT systems are examined in detail as well as the impact of lightning and simple techniques for minimising its impact.
MORE INFORMATION: http://www.idc-online.com/content/lightning-surge-protection-earthing-electrical-electronic-systems-industrial-networks-13?id=6987
Erico Eritech Lightning Protection - IEC62305 Earthing Design Guide.
ERICO’s proven experience in providing grounding and bonding systems, including ground rods, ground enhancement material and signal reference grids, provides for the safe dissipation of energy.
Erico System 1000 - ESE Standard System
The ERITECH® SI Series encompasses three air terminal models and accessories that are designed to comply with the requirements of the French NFC17-102 and Spanish UNE-21186 Standards.
Erico System 2000 - Conventional Protection
ERICO offers the System 2000 series of air terminals, downconductors and fittings in accordance with Australian-AS1768, British-BS6651, Singaporean-CP33, European-IEC and USA-NFPA780 Standards.
Erico System 3000 - Enhanced Protection System
ERICO's System 3000 is a technically advanced lightning protection system. The unique features of this system allow optimum performance, flexibility of design, and overall cost-effective installation.
Example kitchen ventilation calculationwilliammana
This document provides calculations for kitchen ventilation requirements. It determines that a mobile hot cabinet appliance area requires 662.5 CFM of exhaust and additional makeup air is needed from the surrounding hood area, totaling 984 CFM required. A 1200 CFM kitchen exhaust fan and 960 CFM makeup fan are selected to meet the calculated needs. Technical specifications are also provided for the selected fans.
This is a great guide to surge protection from Hager and if you would like Hager Surge Protection fitted to your Bypass Switches Input for mains one or two please call us on 0800 978 8988 or email sales@criticalpowersupplies.co.uk
Critical Power Supplies provide a range of surge protection kits that can be fitted to any of our bypass switches or consumer units to meet Amendment 1 of the 17th Edition.
The surge protection devices in the kit offer type 2 protection to the BS EN 61643 standard, to ensure conformity with the current edition of BS 7671.
Amendment 1 of the 17th Edition requires electricians to conduct a risk assessment of properties to see if they require surge protection.
When you consider that many homes have a lot of sensitive electronic equipment, such as TVs, Hi-Fis, PCs and printers that would be adversely affected by a voltage surge, then the need for such devices increases.
Transient overvoltages are not just caused by a direct lightning strike, a nearby strike, within a kilometre, can cause substantial damage. Other causes can be fluctuations in the power supply or from equipment such as microwaves or showers being switched.
Our surge protection kit can prevent the spread of overvoltages in electrical installations and protect the equipment connected to it. It is characterised by an 8/20us current wave.
To gain a greateer understanding of Surge Protection and our Surge Protection Kit & Devices download a copy of our Guide to Surge Protection Devices.
This document provides guidelines for designing an earth mat for a metro station. It discusses standards for earth mat design, the design procedure, and provides an example of a design for the Joka Station. The key steps in design include determining the fault current, selecting conductor size, and using software to model symmetrical or asymmetrical mat layouts based on space availability and soil properties. The example shows the proposed mat layout for Joka Station, simulation results verifying safe touch and step voltages, and low equipment grounding resistance and ground potential rise.
This document provides information about kitchen ventilation systems. It discusses the types of buildings that require kitchen ventilation such as hotels, restaurants, hospitals, etc. It covers the design of kitchen ventilation systems including components like exhaust hoods, exhaust fans, ductwork, filters and makeup air systems. The document provides guidelines for calculating exhaust air flow rates based on the type of cooking equipment. It also discusses best practices for installation and maintenance of kitchen ventilation systems for effective capture and removal of heat, effluents and grease from commercial kitchens.
This document provides information about earthing systems including their purposes, specifications, types, and maintenance. The key points are:
1) Earthing systems are used to protect lives and equipment from electrical shock by providing a safe path for currents to travel and ensuring conductive parts do not reach dangerous potentials.
2) Recommended earth resistance values vary based on the equipment, with substations requiring lower values like 0.5-2 ohms and individual devices like poles needing 5-10 ohms.
3) Common earthing types include pipe, plate, strip, and rod systems, with factors like soil conditions determining which type is best. Pipe earthing using galvanized iron pipes 10 feet long is very
Stone columns are a versatile ground improvement technique used since the 1950s. They involve compacting coarse aggregate in columns in the ground to reinforce, densify and drain weak soils. Stone columns can improve bearing capacity, stability, reduce settlements and mitigate liquefaction. They work by transferring loads around them to stiffer columns, accelerating consolidation. Installation methods include ramming and vibro-replacement. Case studies show stone column embankments experience less settlement than untreated ground. In summary, stone columns are an effective ground improvement technique to strengthen weak soils.
- Electrical earthing provides a safe path for lightning and fault currents to protect humans and equipment.
- There are different types of earthing for different applications like LV systems, lighting, telecoms, and computers.
- Earthing can provide either Class I or Class II protection against electric shock.
- Factors that affect earth impedance include soil type and moisture, weather, electrode type and size, nearby utilities, and distance between electrodes.
- Common earthing arrangements include TN, TT, and IT systems. Measurement methods like Wenner and Schlumberger are used to determine soil resistivity which impacts earth impedance.
This document discusses electrical grounding and earthing systems. It begins by introducing grounding and earthing, and distinguishing between ground and neutral conductors. It then describes different types of earthing systems according to the IEC standard, including TN, TT, and IT networks. The document also covers different types of grounding used in radio communications, AC power installations, and lightning protection. It discusses the concept of virtual ground and multipoint grounding. Overall, the document provides an overview of electrical grounding and earthing systems, their uses, and important concepts.
This document discusses the analysis of grounding systems for substations. It analyzes the grounding system design for a 220/132/33 kV substation in India as a case study. The key factors considered in grounding system design are discussed, including fault current magnitude, transient overvoltage protection, and safety. Calculations are shown for sizing conductors, determining grid resistance and step/touch voltages based on soil resistivity and other input parameters. The results found that the designed grounding system met safety requirements, with attainable step and touch voltages below tolerable limits and a grid resistance under 1 ohm. Proper grounding system analysis and design is important for safety during faults.
The document provides an earthing system calculation for the Bazian Steel Factory 132/11kV substation in Kurdistan Region, Iraq. It includes soil resistivity measurements, calculations to determine the minimum earth grid conductor size of 120 mm^2 according to IEEE 80-2000, and modeling using CDEGS software to verify that touch and step voltages would be within safe limits. The modeling found a grounding system resistance of 0.31847 ohms, a maximum ground potential rise of 3518.7V, and maximum touch and step voltages below the limits of 953.8V and 3052.8V respectively. Appendices provide further details on soil measurements, grid layout and potential distributions, verifying the
This document discusses the design methodology and components of extra high voltage transmission lines. It covers:
- The key components of transmission lines including conductors, earth wires, insulators, towers, and hardware.
- The design methodology which involves gathering preliminary data, selecting reliability levels, calculating climatic and other loads, choosing appropriate factors, and designing the components.
- Factors that influence the design such as reliability levels, transmission voltages, tower types, tower structures, heights, widths, clearances, and conductor selection criteria including mechanical and electrical requirements.
The document summarizes key aspects of transmission line design and components. It discusses the methodology for designing transmission lines, including gathering design data, selecting reliability levels, and calculating loads. It also covers the selection and design of various transmission line components such as conductors, insulators, towers, and grounding systems. Design considerations include voltage levels, safety clearances, mechanical requirements, and optimization of costs.
This document provides an overview of high speed board design for signal integrity. It discusses transmission line parameters including capacitance, inductance, resistance, and shunt conductance. It describes how signal propagation causes electric and magnetic fields based on dV/dt and dI/dt. Key signal integrity issues are covered such as impedance mismatching causing reflections, crosstalk from electromagnetic coupling, and rail collapse in power distribution systems. Methods to minimize these issues include controlling transmission line characteristics, maintaining consistent impedance, and using Faraday cages to isolate noise.
MOS Process and Single Stage Amplifiers.pptxPrateek718260
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Performance Analysis of Actual Step and Mesh Voltage of Substation Grounding ...Editor IJCATR
The performance of Earthing grid system is very important to ensure the human and protective devices in safe environment. Actual
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greatly influence on actual step and mesh voltage of substation grounding system. Ground potential rise also mainly depends on the length and
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2. Essentials of Earthing DesignEssentials of Earthing Design
Crossection Area Current Density Dangerous
Potentials
Resistance
The Crossection of Continuous Step potential Horizontal Plane
F
The Crossection of
the conductor to
be sufficient for
carrying GRID
Continuous
surface current
density
Step potential Horizontal Plane
Touch potential Vertical Plane
O
R
carrying GRID
fault current
Instantaneous
Surface current
Mesh Potential Mutual resistance
G
O
Surface current
density
GPR
T
T
Transfer PotentialE
N
safety thru design 2
PASS PASS PASSPASS OK
3. Crossection areaCrossection area
• Equation 37 of IEEE 80 2000
• This formulae is good for above ground
conductorconductor
• Enthalpy of vaporization decreases with
increase in temperature.
• For a large grid the fault current getsFor a large grid the fault current gets
multiple parallel paths hence Tm
doesn’t pose a problem.
• If the Tm is allowed to rise beyond a y
limit in smaller grids or pits the water
molecules beyond a point water
instantaneously vaporizes and escapes
from the soil surrounding theC d
Heat of Heat of from the soil surrounding the
conductor.
• Tm also applies to surface layer coating
or cover.
Compound
At 1000C
vaporization
(kJ mol‐1)
vaporization
(kJ kg−1)
Water 40.65 2257 or cover.
safety thru design 3
4. Evaluation of CrossectionEvaluation of Crossection
M h i l El t i lMechanical Electrical
Tm 1510 99
T 20 20Ta 20 20
TCAP 3.28 3.28
tc 1 0.3c
αr 0.0016 0.0016
ρr 15.9 15.9
I 25 25
K0 605 605
A 199 41 349 54A 199.41 349.54
safety thru design 4
6. Long term Surface Current DensityLong term Surface Current Density
Th l t f t tl t th• The long term surface currents are seen mostly at the
following points
– Neutral pitsp
– Harmonic filters
– PT’s and CT’s etc…
• The surface area of few electrodes are as follows• The surface area of few electrodes are as follows
– 600X600 mm plate =0.72 m2 Capacity= 28.8 A
– 1000X1000 mm plate = 2.0 m2 Capacity= 80.0 Ap p y
– 40mm 3m length pipe=0.37m2 Capacity= 14.5 A
• If the unbalance current in a large system is 68A, the 2Nos.
Of 600X600mm plate will be insufficient Heat will beOf 600X600mm plate will be insufficient. Heat will be
generated in the neutral pit and it will deteriorate. We may
need larger plate size, or the 3rd plate.
safety thru design 6
7. Short Term Surface Current DensityShort Term Surface Current Density
I h id f ll• In case the grid parameters are as follows:
– 15m X 12m grid, with 3m spacing
147 t 30 d i d d t– 147mt 30mm rod is used as conductor
– The surface area of the conductor thus is 13.85m2
If the soil resistivity is 100 Ωm and clearing time is 0 3sec– If the soil resistivity is 100 Ωm and clearing time is 0.3sec
the max IG the grid can handle is only 1387A/m2.
– Hence the maximum possible fault current the grid can p g
handle in 13.85m2 is 19KA.
• If the fault current IG is more than 19 KA then the grid
will fail, as the temperature around the conductor will
rise and steam the water.
safety thru design 7
8. Symbol unit Value
Fault Current IG KA 23000 Input
Diameter of electrode d m 0.04 Input
Length of Electrode
Soil ls m 37 Input
l 1 IWater lw m 1 Input
Resistivity
Soil ρs Ωm 360 Input
Water ρ Ωm 2 InputWater ρw Ωm 2 Input
Resistance
Soil Rs Ω 12.25394 Equation 55 IEEE 80 2000
Water R Ω 1 368891 Equation 55 IEEE 80 2000Water Rw Ω 1.368891 Equation 55 IEEE 80 2000
Combined Rc Ω 1.231338
Permissible Current Density
Soil σ A/m2 730.9304 Clause 15.2 BS7340σs A/m 730.9304 Clause 15.2 BS7340
Water σw A/m2 9806.46 Clause 15.2 BS7341
Area
Soil As m2 4.6472 πdlss s
Water Aw m2 0.1256 πdlw
Current Division Resistance Capacity Design
Soil 2311.1568 3396.779785 1
Water 20688.843 1231.691433 17
safety thru design 8
9. Polar Curve for Single PointPolar Curve for Single Point
safety thru design 9
10. Polar curve
•Resistivity taken in min 8
directions
•Angular distance between
readings 450
C ti l I t l t th•Cautiously Interpolate the
readings to 7.50
•Join the Points to form a
polar curvepolar curve
•Calculate the area of the
polar curve
•Draw equivalent Circular q
area
•Radius of the circle is the
average soil resistivity
h h d l l•This method is particularly
beneficial when the
resistivity varies significantly
in different directions
safety thru design 10
12. 3D Plot of Soil Resistivity3D Plot of Soil Resistivity
safety thru design 12
13. Equal Earth Conductor SpacingEqual Earth Conductor Spacing
EARTHING LAYOUT EVALUATION Grid1 Grid 2 Grid3 Grid4 Total Values
Real Soil resistivity σs 724.25 724.25 724.25 724.25
Soil resistivity after TEREC+ Application σ 307.81 307.81 307.81 307.81y pp
Soil resistivity of washed 0.025 to 0.050m in gravel σs 5000.00 5000.00 5000.00 5000.00
Length of the earth mat Lx 125.00 175.00 175.00 25.00 200.00
Breadth of the earth mat Ly 75.00 100.00 50.00 150.00 150.00
Assumed spacing for the conductors D 5.50 5.50 5.50 5.50
Area of earth mat AG 9375.00 8125.00 8125.00 4375.00 30000.00
Permissible step voltage Estep 4019.71 4019.71 4019.71 4019.71
E step Es 1341.19 1390.38 1210.15 1168.07
Permissible touch voltage Etouch 1127 96 1127 96 1127 96 1127 96Permissible touch voltage Etouch 1127.96 1127.96 1127.96 1127.96
Emesh Em 1051.41 1116.88 1016.25 1126.61
Total quantity of conductors laid Lc 3602.74 3134.82 3134.82 1723.20 11595.58
Grid Resistance (Schwarz) Rg 1.33 1.39 1.43 1.90 0.37
safety thru design 13
14. Variable Earth conductor SpacingVariable Earth conductor Spacing
EARTHING LAYOUT EVALUATION G id1 G id 2 G id3 G id4 T t l V lEARTHING LAYOUT EVALUATION Grid1 Grid 2 Grid3 Grid4 Total Values
Real Soil resistivity σs 535.00 679.00 744.00 939.00
Soil resistivity after TEREC+ Application σ 227 38 288 58 316 20 399 08Soil resistivity after TEREC+ Application σ 227.38 288.58 316.20 399.08
Soil resistivity of washed 0.025 to
0.050m in gravel
σs 5000.00 5000.00 5000.00 5000.00
Length of the earth mat Lx 125.00 175.00 175.00 25.00 200.00
Breadth of the earth mat Ly 75.00 100.00 50.00 150.00 150.00
A d i f th d t D 6 10 5 70 6 20 5 80 5 95Assumed spacing for the conductors D 6.10 5.70 6.20 5.80 5.95
Area of earth mat AG 9375.00 8125.00 8125.00 4375.00 30000
Permissible step voltage Estep 4001.44 4015.34 4021.61 4040.44
E step Es 1254.24 1319.35 1131.73 1108.32
Permissible touch voltage Etouch 1123.40 1126.87 1128.44 1133.15
Emesh Em 1115 98 1107 60 1091 72 1131 89
safety thru design 14
Emesh Em 1115.98 1107.60 1091.72 1131.89
Total quantity of conductors laid Lc 3267.42 3031.15 2801.25 1640.91 10740.73
Grid Resistance (Schwarz) Rg 0.99 1.31 1.49 2.49 0.35
15. ComparisonComparison
S C G id i bl G idSI.No. Constant Grid Variable Grid
Conductor Length 11595 m 10740 m
Difference in Mesh 110 V 40 VDifference in Mesh
Potential
110 V 40 V
Difference in Step
Potential
222 V 180 V
Potential
Grid Resistance 0.37 0.35
Economics 94 Lcs 82 Lcs
Variable grid may be Techno commercially more Viable compared to an equal spacing grid
safety thru design 15
22. Formulae to Calculate ResistanceFormulae to Calculate Resistance
f l t thi• for plate earthing
R = (ρ/4)* sqrt(π/2A)
• for pipe earthingfor pipe earthing
R = (ρ/2πL)* [ln(8L/d)‐1]
• for strip earthing
R=(ρ/PπL)* [ln(2L2 /(wh))+ Q]
• for grid earthing
R ρ[(1/L )+ (1/sqrt(20A) (1+ (1/1+h) sqrt(20A)R=ρ[(1/LT)+ (1/sqrt(20A) (1+ (1/1+h) sqrt(20A)
Is Material of the grid important for achieving resistance?Is Material of the grid important for achieving resistance?
No. If corrosion factor is taken care of
safety thru design 22
23. Relook at Alternating CurrentRelook at Alternating Current
C i f• Current is not movement of
charge or holes.
• In Alternating Current theIn Alternating Current, the
charge actually does not
travel at all. It only vibrates
i i i iin its mean position.
• Across a Cross section area,
the vibration begins withthe vibration begins with
one charge and increases to
the maximum number of
h i if icharges signifying
amplitude of the sinusoidal
AC waveform.
safety thru design 23
24. Relook at Alternating TensionRelook at Alternating Tension
• The extent of movement
of the charge from the
iti i d tmean position is due to a
prevailing Tension (similar
to force) exerted duringto force) exerted during
positive or negative cycle.
• More tension creates• More tension creates
greater displacement of
the particle from thethe particle from the
Crossection surface.
safety thru design 24
25. Relook at Alternating EnergyRelook at Alternating Energy
• It is the ENERGY that is• It is the ENERGY that is
transferred thru vibrating charges
across a Crossection to the next
adjoining Crossection. j g
• Current is the movement of the
disturbance and not the charge.
The Energy transferred is
lproportional to
• the number charges vibrating,
• the displacement of the charges
f h i i dfrom the mean position and
• the number of vibrations per
second
Thi i f d h• This energy is transferred thru
series and parallel circuits to
obtain desired results
safety thru design 25
26. EarthEarth
E th i h ith• Earth is a huge mass with
enormous amount of
charges.
• Energy is applied to earth,
spreads, the displacement
of charge from the mean g
position progressively
reduces.
• Finally the displacement orFinally the displacement or
tension becomes
infinitesimal. In normal
condition charges in EARTHcondition charges in EARTH
appear stable with hardly
any tension.
safety thru design 26
33. Tackling Different FrequenciesTackling Different Frequencies
f d d• Dissipation of energy depends on
Earth loop impedance.
• High frequency signals encounter g q y g
high inductive impedance if the
loop length is long. Hence the
Ground path needs to be as shortGround path needs to be as short
as physically possible.
• As ground is a dielectric, it is also
d h l l d fgood to have a plate electrode for
higher displacement current.
• Higher frequencies do not enter g q
deep earth, hence it is imperative
to have more number of shallow
earthearth
• Use Earth Bond
safety thru design 33
34. Revisit your Earth GridRevisit your Earth Grid
D h th E th id d d b t• Do you have the Earth grid drg. and subsequent
record of changes conducted in your premises
• Is Earth pit reading in the grid different at• Is Earth pit reading in the grid different at
different places
• Has the Source increased• Has the Source increased
• Has number of feeders or distributors changed
A U b l d H i b i ti f• Are Unbalances and Harmonics been existing for
a long time.
• Is off schedule maintenance a regular feature• Is off schedule maintenance a regular feature
• GET YOUR SELF AUDITED
safety thru design 34
35. Who can be an AuditorWho can be an Auditor
• H i K l d f• Having Knowledge of
– IEEE 80 2000 for substation
– IEEE 665 1995 for Generating Station
– IEEE 142 1991 for Industrial establishment
f h– IEEE 81 1993 for Earthing Measurements
– IEEE 1100 for powering and grounding electronic equipments.
– IEEE 575 for sheath bonding and induced voltages
– BS 7340 1998 Code of practice for Earthing
IEC 62305 P t 1 t P t 4– IEC 62305 Part 1 to Part 4
– NFPA 70 and NFPA 780
– API RP 2003 for statics and lightning protection
– And many more ref. texts
H i R i it i t t h k it l t i t• Having Requisite equipments to check vital parameters using stray
current filters.
• Has the desired National and International Experience to Audit
Refineries– Refineries
– Power Stations etc.
• Should be a Solution providerp
safety thru design 35
37. Rejuvenation of live gridRejuvenation of live grid
• Measure the soil resistivity with• Measure the soil resistivity with
– Stray current filter
– Variable frequency
High and low current injection probe– High and low current injection probe
• Make polar graph for accurate soil resistivity
• Design the earth grid as per IEEE 80 2000 as if it was for the new grid
Th f f iti th it b l 1 7% f th f• The surface area of exiting earth pit may be only 1‐7% of the surface area
of the entire Earth grid.
• May involve multiple layer/tier of peripheral correction.
U i li d t i d t k li d t ti• Use specialized manpower trained to work on live yard or station
• New trenching can be very tedious. It may cut across existing HV, LV or
control cables
At th d f ti All th th it h ld h l t• At the end of correction, All the earth pits should have almost same
resistance value without any pit correction
safety thru design 37
41. Sigma EarthSigma Earth
•The Energy after leaving the electrode encounters different
k d f l h fl f lkinds of soil where reflection factor comes into play
•Sigma earth ensures that artificial treatment compounds are
laid in a specific geometric pattern to minimize the reflection
•Thru proper calculation, can achieve less than 1 ohm in veryThru proper calculation, can achieve less than 1 ohm in very
hard soil.
•Used for Independent Electronic Earth or reference earth
safety thru design 41
42. Iris earthIris earth
• One earth sensor is put inside an old• One earth sensor is put inside an old
or new pit.
• Various parameters like date,
location, value etc are logged in every
sensor.
• The sensor is programmed to alarm
on few criteria’s.
• There is multiple level of alarm• There is multiple level of alarm.
• A peripheral command center (PCC)
can talk to approximately 100 earth
pits.
• A hand held tester is provided to
check the earth pit conditions
remotely
• The PCC can be locally connected to a• The PCC can be locally connected to a
local Laptop and a remote Server on
LAN or GSM.
safety thru design 42
43. Geomagnetic Storms caused by Solar
Flares or CME
• Earth’s magnetic field being
pushed out of the way by the
nuclear explosion or solar storm
f ffollowed by the field being restored
to its natural place.
•This process can produce geo‐
magnetically induced currents in
long electrical conductors (like
power lines) which can damage or
d l fdestroy power line transformers.
safety thru design 43
44. Nasa warns solar flares 'huge
space storm'cause devastation
• According to VERY rough• According to VERY rough
calculations, that solar flare was
approximately 250,640 km tall,
and 342,050 km wide. ,
• To put that in perspective, the
Earth is about 12,756 km in
diameter. That means it was
b h ll dabout 19.6 Earths tall and 27
Earths wide.
• In a new warning, Nasa said the
super storm nearing 2013 wouldsuper storm nearing 2013 would
hit like “a bolt of lightning” and
could cause catastrophic
consequences for the world’s
• March 1989 (Quebec)
– 480nT/min, Knocked out power
to 6 million people in 92 seconds
• May 1921q
health, emergency services and
national security unless
precautions are taken
– Up to 4,800nT/min
• Sept. 1859 (Carrington event)
– 2,000 to 5,000nT/min
• NOW 2013‐2023
safety thru design 44
NOW 2013 2023
– Expected 5000nT/min
45. What will happen to our GridsWhat will happen to our Grids
• All long transmission lines,
Railway lines, Pipelines will
withstand the impact of GICwithstand the impact of GIC
• Incorporation of
– Neutral
• Resistors
• Capacitors with shunt
switch
– Series Capacitors
safety thru design 45