SlideShare a Scribd company logo
©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Ground Grid Systems
Slide 2©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Need for Grounding Grids
• Currents flow into the grounding grid from:
– Lightning Arrester Operations
– Switching Surge Flashover of Insulators
– Line-Ground Fault from Connected Bus
– Line-Ground Fault from Connected Line
Slide 3©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Objectives
• Human and animal safety
• Carry and dissipate current into earth under
normal and fault conditions
• Grounding for lightning impulses and surges
• Low resistance to ground for protective
relays
Slide 4©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Construction
Slide 5©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Common Definitions
• Earth Current
• Ground Fault Current
• Ground Potential Rise
• Step Voltage
• Touch Voltage
Slide 6©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Step 1 – Soil Analysis
• Done at a number of places in the substation
• Several layers with different resistivity
• Lateral surface changes are more gradual
than vertical changes
• Wenner Four-Pin Method
Slide 7©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Wenner Four-Pin Method
2222
4
2
1
4
ba
a
ba
a
aR
a
Slide 8©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Step 2 – Grid Area
• Area should be as large as possible
• Increasing area is more effective than
adding additional conductor to reduce grid
resistance
• Outer conductor should be placed on the
boundary of substation
• Fence should be placed a minimum of 3 feet
inside
• Square, rectangular, triangular, T-shaped, or
L-shaped grids
Slide 9©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Step 3 – Ground Fault
Currents
• L-G fault on substation bus or transmission
line
• Interested in maximum amount of fault
current expected to flow into the ground grid
• Determine maximum symmetrical rms fault
current
Slide 10©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Ground Fault Current
Slide 11©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Ground Fault Current
Slide 12©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Ground Fault Current
Slide 13©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Ground Fault Current
Slide 14©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Symmetrical Grid Current
• Io = Symmetrical rms value of Zero
Sequence fault current in amperes
• Transmission Systems – Model Maximum Io
for L-G fault for present and ultimate
configuration
• Distribution Systems – Model future fault
current with suitable growth factor (1.1)
)3(* ofg ISI
Slide 15©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Decrement Factor
• Accounts for the asymmetrical fault current
• AC component does not decay with time but
remains at its initial value
• Calculated from time duration of fault and X
over R ratio
• Transmission Systems – Use fastest
clearing relay + breaker time
• Distribution and Industrial Systems – Use
worst case backup clearing time
Slide 16©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Typical Shock Situations
Slide 17©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Design Procedure Summary
• Use network of bare conductors buried in the
earth
• Encompass all area within the substation
fence and extend at least 3 feet outside
• Perform soil resistivity test
• Surface material at least 4 inches
• Determine fault current using short circuit
• Determine maximum clearing time
Slide 18©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Design Procedure Summary
• Size conductors
• Conductor should be buried a minimum of
18 inches to 59.1 inches
• Vertical ground rods should be at least 8 ft.
long
• Determine if touch and step voltages are
below tolerable limits
• Few iterations may be required to determine
correct grid design
Slide 19©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Ground Rod Length
• Three schools of thought
– Length of 10ft is adequate
– Length of 40ft is required to reach water table
– Longest possible rod depth should be used
Slide 20©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
IEEE Methods
• Empirical method; limited applications
• Handles 2 layers plus protective surface
material (1 layer for touch potential)
• Rectangular and triangular shapes only, with
vertical and horizontal conductors
• One ground grid only
• Rods; but arrangements are not flexible
• Calculates required parameters
Slide 21©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Finite Element Method
• Handles 2 layers plus a protective surface
material
• Any shape
• Multiple interconnected ground grids
• Rod location modeled in detail
• Calculates required parameters at all points
• Graphic potential profile
Slide 22©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Typical IEEE Grid
Slide 23©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
IEEE Grid Description
• 40 ft. X 40 ft. square grid with 8 conductors
along X-axis and 8 conductors along Y-axis
• Depth = 1.5 ft., 4/0 copper-clad steel wire
• 1 rod in each grid corner, diameter = 0.5 in.,
length = 8 ft. same material as conductor
Slide 24©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
FEM Grid Example
Slide 25©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Step Potential Profile
Slide 26©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Touch Potential Profile
Slide 27©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems
Absolute Potential Profile

More Related Content

What's hot

Generator Protection Relay Setting Calculations
Generator Protection Relay Setting CalculationsGenerator Protection Relay Setting Calculations
Generator Protection Relay Setting Calculations
Power System Operation
 
Reactors
ReactorsReactors
Reactors
Molla Morshad
 
ABB - TRANSFORMERS-PROTECTION-COURSE (2001)
ABB - TRANSFORMERS-PROTECTION-COURSE (2001)ABB - TRANSFORMERS-PROTECTION-COURSE (2001)
ABB - TRANSFORMERS-PROTECTION-COURSE (2001)
J. FR
 
ETAP - Power system modeling
ETAP - Power system modelingETAP - Power system modeling
ETAP - Power system modeling
Himmelstern
 
ETAP - Coordination and protecion 2
ETAP -  Coordination and protecion 2ETAP -  Coordination and protecion 2
ETAP - Coordination and protecion 2
Himmelstern
 
Introduction to mv switchgear
Introduction to mv switchgearIntroduction to mv switchgear
Introduction to mv switchgear
Modal Holong Education
 
ETAP - Ugs Underground Raceway Systems
ETAP - Ugs Underground Raceway SystemsETAP - Ugs Underground Raceway Systems
ETAP - Ugs Underground Raceway Systems
Himmelstern
 
ETAP - Load flow and panel rev2014-1
ETAP - Load flow and panel   rev2014-1ETAP - Load flow and panel   rev2014-1
ETAP - Load flow and panel rev2014-1
Himmelstern
 
1.substation layouts
1.substation  layouts1.substation  layouts
1.substation layouts
ayyadurai SHANMUGAM
 
Tan delta test for power transformers
Tan delta test for power transformersTan delta test for power transformers
Tan delta test for power transformers
jibinjoy1988
 
Practical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineersPractical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineers
SARAVANAN A
 
ETAP - csd - Control System Diagram
ETAP - csd - Control System DiagramETAP - csd - Control System Diagram
ETAP - csd - Control System Diagram
Himmelstern
 
Sag in overhead transmission line, sag calculation & string chart
Sag in overhead transmission line, sag   calculation & string chartSag in overhead transmission line, sag   calculation & string chart
Sag in overhead transmission line, sag calculation & string chart
vishalgohel12195
 
Voltage Drop Calculation.pdf
Voltage Drop Calculation.pdfVoltage Drop Calculation.pdf
Voltage Drop Calculation.pdf
MesiasJohnFederico
 
Principles of Cable Sizing
Principles of Cable SizingPrinciples of Cable Sizing
Principles of Cable Sizing
Leonardo ENERGY
 
Ehv substation
Ehv substationEhv substation
Ehv substation
Demsew Mitiku
 
ETAP - Short circuit ansi standard
ETAP - Short circuit ansi standardETAP - Short circuit ansi standard
ETAP - Short circuit ansi standard
Himmelstern
 
Power System Analysis unit - I
Power System Analysis unit - IPower System Analysis unit - I
Power System Analysis unit - I
arunatshare
 
ETAP - Transient stability 2
ETAP - Transient stability 2ETAP - Transient stability 2
ETAP - Transient stability 2
Himmelstern
 
Maintenance of Substation Equipment | Operation And Maintenance Of Substation
Maintenance of Substation Equipment | Operation And Maintenance Of SubstationMaintenance of Substation Equipment | Operation And Maintenance Of Substation
Maintenance of Substation Equipment | Operation And Maintenance Of Substation
System Protection
 

What's hot (20)

Generator Protection Relay Setting Calculations
Generator Protection Relay Setting CalculationsGenerator Protection Relay Setting Calculations
Generator Protection Relay Setting Calculations
 
Reactors
ReactorsReactors
Reactors
 
ABB - TRANSFORMERS-PROTECTION-COURSE (2001)
ABB - TRANSFORMERS-PROTECTION-COURSE (2001)ABB - TRANSFORMERS-PROTECTION-COURSE (2001)
ABB - TRANSFORMERS-PROTECTION-COURSE (2001)
 
ETAP - Power system modeling
ETAP - Power system modelingETAP - Power system modeling
ETAP - Power system modeling
 
ETAP - Coordination and protecion 2
ETAP -  Coordination and protecion 2ETAP -  Coordination and protecion 2
ETAP - Coordination and protecion 2
 
Introduction to mv switchgear
Introduction to mv switchgearIntroduction to mv switchgear
Introduction to mv switchgear
 
ETAP - Ugs Underground Raceway Systems
ETAP - Ugs Underground Raceway SystemsETAP - Ugs Underground Raceway Systems
ETAP - Ugs Underground Raceway Systems
 
ETAP - Load flow and panel rev2014-1
ETAP - Load flow and panel   rev2014-1ETAP - Load flow and panel   rev2014-1
ETAP - Load flow and panel rev2014-1
 
1.substation layouts
1.substation  layouts1.substation  layouts
1.substation layouts
 
Tan delta test for power transformers
Tan delta test for power transformersTan delta test for power transformers
Tan delta test for power transformers
 
Practical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineersPractical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineers
 
ETAP - csd - Control System Diagram
ETAP - csd - Control System DiagramETAP - csd - Control System Diagram
ETAP - csd - Control System Diagram
 
Sag in overhead transmission line, sag calculation & string chart
Sag in overhead transmission line, sag   calculation & string chartSag in overhead transmission line, sag   calculation & string chart
Sag in overhead transmission line, sag calculation & string chart
 
Voltage Drop Calculation.pdf
Voltage Drop Calculation.pdfVoltage Drop Calculation.pdf
Voltage Drop Calculation.pdf
 
Principles of Cable Sizing
Principles of Cable SizingPrinciples of Cable Sizing
Principles of Cable Sizing
 
Ehv substation
Ehv substationEhv substation
Ehv substation
 
ETAP - Short circuit ansi standard
ETAP - Short circuit ansi standardETAP - Short circuit ansi standard
ETAP - Short circuit ansi standard
 
Power System Analysis unit - I
Power System Analysis unit - IPower System Analysis unit - I
Power System Analysis unit - I
 
ETAP - Transient stability 2
ETAP - Transient stability 2ETAP - Transient stability 2
ETAP - Transient stability 2
 
Maintenance of Substation Equipment | Operation And Maintenance Of Substation
Maintenance of Substation Equipment | Operation And Maintenance Of SubstationMaintenance of Substation Equipment | Operation And Maintenance Of Substation
Maintenance of Substation Equipment | Operation And Maintenance Of Substation
 

Similar to ETAP - Ground grid systems

ETAP - device coordination
ETAP - device coordinationETAP - device coordination
ETAP - device coordination
Himmelstern
 
Shortcircuit-IEC.pdf
Shortcircuit-IEC.pdfShortcircuit-IEC.pdf
Shortcircuit-IEC.pdf
Wilfredo870952
 
Cabos_5.1.pdf
Cabos_5.1.pdfCabos_5.1.pdf
Cabos_5.1.pdf
RafikCherni
 
ETAP - Arc flash introduction
ETAP - Arc flash introductionETAP - Arc flash introduction
ETAP - Arc flash introduction
Himmelstern
 
Electrical Substations and Switchyard Design
Electrical Substations and Switchyard DesignElectrical Substations and Switchyard Design
Electrical Substations and Switchyard Design
Living Online
 
ETAP - Ac networks
ETAP - Ac networksETAP - Ac networks
ETAP - Ac networks
Himmelstern
 
equipments like CT,PT SUBSTATION PPT.ppt
equipments like CT,PT SUBSTATION PPT.pptequipments like CT,PT SUBSTATION PPT.ppt
equipments like CT,PT SUBSTATION PPT.ppt
srinjayjha
 
EMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATION
EMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATIONEMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATION
EMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATION
Piero Belforte
 
final presentation edit.pptx
final presentation edit.pptxfinal presentation edit.pptx
final presentation edit.pptx
ssuser0ee912
 
Fire Safety (Common Design Issues) .pptx
Fire Safety (Common Design Issues) .pptxFire Safety (Common Design Issues) .pptx
Fire Safety (Common Design Issues) .pptx
Rafat30
 
AODesign&Protection_2015_noNDA
AODesign&Protection_2015_noNDAAODesign&Protection_2015_noNDA
AODesign&Protection_2015_noNDA
Kevin Duke
 
tutorial-Deterministic-Ethernet-stp.ppt
tutorial-Deterministic-Ethernet-stp.ppttutorial-Deterministic-Ethernet-stp.ppt
tutorial-Deterministic-Ethernet-stp.ppt
ssuser3855be
 
H08 Principles of Power Systems Design
H08 Principles of Power Systems Design H08 Principles of Power Systems Design
H08 Principles of Power Systems Design
phase3-120A
 
Offshore platform powered with new electrical motor drive system_presentation...
Offshore platform powered with new electrical motor drive system_presentation...Offshore platform powered with new electrical motor drive system_presentation...
Offshore platform powered with new electrical motor drive system_presentation...
dariolandriel02
 
Ml101610106
Ml101610106Ml101610106
arc-flash-analysis-done-right.pdf
arc-flash-analysis-done-right.pdfarc-flash-analysis-done-right.pdf
arc-flash-analysis-done-right.pdf
ssusera5c9a31
 
ETAP - Arc flash analysis etap
ETAP - Arc flash analysis etapETAP - Arc flash analysis etap
ETAP - Arc flash analysis etap
Himmelstern
 
ETAP - Arc flash analysis done Right
ETAP - Arc flash analysis done RightETAP - Arc flash analysis done Right
ETAP - Arc flash analysis done Right
Himmelstern
 
ETAP - ocp - Optimal Capacitor Placement
ETAP -  ocp - Optimal Capacitor PlacementETAP -  ocp - Optimal Capacitor Placement
ETAP - ocp - Optimal Capacitor Placement
Himmelstern
 
EIT_Presentation
EIT_PresentationEIT_Presentation
EIT_Presentation
Ernst Lourens de Villiers
 

Similar to ETAP - Ground grid systems (20)

ETAP - device coordination
ETAP - device coordinationETAP - device coordination
ETAP - device coordination
 
Shortcircuit-IEC.pdf
Shortcircuit-IEC.pdfShortcircuit-IEC.pdf
Shortcircuit-IEC.pdf
 
Cabos_5.1.pdf
Cabos_5.1.pdfCabos_5.1.pdf
Cabos_5.1.pdf
 
ETAP - Arc flash introduction
ETAP - Arc flash introductionETAP - Arc flash introduction
ETAP - Arc flash introduction
 
Electrical Substations and Switchyard Design
Electrical Substations and Switchyard DesignElectrical Substations and Switchyard Design
Electrical Substations and Switchyard Design
 
ETAP - Ac networks
ETAP - Ac networksETAP - Ac networks
ETAP - Ac networks
 
equipments like CT,PT SUBSTATION PPT.ppt
equipments like CT,PT SUBSTATION PPT.pptequipments like CT,PT SUBSTATION PPT.ppt
equipments like CT,PT SUBSTATION PPT.ppt
 
EMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATION
EMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATIONEMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATION
EMCLO PROJECT: EMC DESIGN METHODOLOGY FOR LAYOUT OPTIMIZATION
 
final presentation edit.pptx
final presentation edit.pptxfinal presentation edit.pptx
final presentation edit.pptx
 
Fire Safety (Common Design Issues) .pptx
Fire Safety (Common Design Issues) .pptxFire Safety (Common Design Issues) .pptx
Fire Safety (Common Design Issues) .pptx
 
AODesign&Protection_2015_noNDA
AODesign&Protection_2015_noNDAAODesign&Protection_2015_noNDA
AODesign&Protection_2015_noNDA
 
tutorial-Deterministic-Ethernet-stp.ppt
tutorial-Deterministic-Ethernet-stp.ppttutorial-Deterministic-Ethernet-stp.ppt
tutorial-Deterministic-Ethernet-stp.ppt
 
H08 Principles of Power Systems Design
H08 Principles of Power Systems Design H08 Principles of Power Systems Design
H08 Principles of Power Systems Design
 
Offshore platform powered with new electrical motor drive system_presentation...
Offshore platform powered with new electrical motor drive system_presentation...Offshore platform powered with new electrical motor drive system_presentation...
Offshore platform powered with new electrical motor drive system_presentation...
 
Ml101610106
Ml101610106Ml101610106
Ml101610106
 
arc-flash-analysis-done-right.pdf
arc-flash-analysis-done-right.pdfarc-flash-analysis-done-right.pdf
arc-flash-analysis-done-right.pdf
 
ETAP - Arc flash analysis etap
ETAP - Arc flash analysis etapETAP - Arc flash analysis etap
ETAP - Arc flash analysis etap
 
ETAP - Arc flash analysis done Right
ETAP - Arc flash analysis done RightETAP - Arc flash analysis done Right
ETAP - Arc flash analysis done Right
 
ETAP - ocp - Optimal Capacitor Placement
ETAP -  ocp - Optimal Capacitor PlacementETAP -  ocp - Optimal Capacitor Placement
ETAP - ocp - Optimal Capacitor Placement
 
EIT_Presentation
EIT_PresentationEIT_Presentation
EIT_Presentation
 

Recently uploaded

Swimming pool mechanical components design.pptx
Swimming pool  mechanical components design.pptxSwimming pool  mechanical components design.pptx
Swimming pool mechanical components design.pptx
yokeleetan1
 
Series of visio cisco devices Cisco_Icons.ppt
Series of visio cisco devices Cisco_Icons.pptSeries of visio cisco devices Cisco_Icons.ppt
Series of visio cisco devices Cisco_Icons.ppt
PauloRodrigues104553
 
Exception Handling notes in java exception
Exception Handling notes in java exceptionException Handling notes in java exception
Exception Handling notes in java exception
Ratnakar Mikkili
 
Embedded machine learning-based road conditions and driving behavior monitoring
Embedded machine learning-based road conditions and driving behavior monitoringEmbedded machine learning-based road conditions and driving behavior monitoring
Embedded machine learning-based road conditions and driving behavior monitoring
IJECEIAES
 
CSM Cloud Service Management Presentarion
CSM Cloud Service Management PresentarionCSM Cloud Service Management Presentarion
CSM Cloud Service Management Presentarion
rpskprasana
 
14 Template Contractual Notice - EOT Application
14 Template Contractual Notice - EOT Application14 Template Contractual Notice - EOT Application
14 Template Contractual Notice - EOT Application
SyedAbiiAzazi1
 
basic-wireline-operations-course-mahmoud-f-radwan.pdf
basic-wireline-operations-course-mahmoud-f-radwan.pdfbasic-wireline-operations-course-mahmoud-f-radwan.pdf
basic-wireline-operations-course-mahmoud-f-radwan.pdf
NidhalKahouli2
 
A review on techniques and modelling methodologies used for checking electrom...
A review on techniques and modelling methodologies used for checking electrom...A review on techniques and modelling methodologies used for checking electrom...
A review on techniques and modelling methodologies used for checking electrom...
nooriasukmaningtyas
 
Understanding Inductive Bias in Machine Learning
Understanding Inductive Bias in Machine LearningUnderstanding Inductive Bias in Machine Learning
Understanding Inductive Bias in Machine Learning
SUTEJAS
 
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSA SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
IJNSA Journal
 
Advanced control scheme of doubly fed induction generator for wind turbine us...
Advanced control scheme of doubly fed induction generator for wind turbine us...Advanced control scheme of doubly fed induction generator for wind turbine us...
Advanced control scheme of doubly fed induction generator for wind turbine us...
IJECEIAES
 
Iron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdf
Iron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdfIron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdf
Iron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdf
RadiNasr
 
sieving analysis and results interpretation
sieving analysis and results interpretationsieving analysis and results interpretation
sieving analysis and results interpretation
ssuser36d3051
 
Harnessing WebAssembly for Real-time Stateless Streaming Pipelines
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesHarnessing WebAssembly for Real-time Stateless Streaming Pipelines
Harnessing WebAssembly for Real-time Stateless Streaming Pipelines
Christina Lin
 
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
IJECEIAES
 
New techniques for characterising damage in rock slopes.pdf
New techniques for characterising damage in rock slopes.pdfNew techniques for characterising damage in rock slopes.pdf
New techniques for characterising damage in rock slopes.pdf
wisnuprabawa3
 
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdfBPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
MIGUELANGEL966976
 
哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样
哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样
哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样
insn4465
 
132/33KV substation case study Presentation
132/33KV substation case study Presentation132/33KV substation case study Presentation
132/33KV substation case study Presentation
kandramariana6
 
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
University of Maribor
 

Recently uploaded (20)

Swimming pool mechanical components design.pptx
Swimming pool  mechanical components design.pptxSwimming pool  mechanical components design.pptx
Swimming pool mechanical components design.pptx
 
Series of visio cisco devices Cisco_Icons.ppt
Series of visio cisco devices Cisco_Icons.pptSeries of visio cisco devices Cisco_Icons.ppt
Series of visio cisco devices Cisco_Icons.ppt
 
Exception Handling notes in java exception
Exception Handling notes in java exceptionException Handling notes in java exception
Exception Handling notes in java exception
 
Embedded machine learning-based road conditions and driving behavior monitoring
Embedded machine learning-based road conditions and driving behavior monitoringEmbedded machine learning-based road conditions and driving behavior monitoring
Embedded machine learning-based road conditions and driving behavior monitoring
 
CSM Cloud Service Management Presentarion
CSM Cloud Service Management PresentarionCSM Cloud Service Management Presentarion
CSM Cloud Service Management Presentarion
 
14 Template Contractual Notice - EOT Application
14 Template Contractual Notice - EOT Application14 Template Contractual Notice - EOT Application
14 Template Contractual Notice - EOT Application
 
basic-wireline-operations-course-mahmoud-f-radwan.pdf
basic-wireline-operations-course-mahmoud-f-radwan.pdfbasic-wireline-operations-course-mahmoud-f-radwan.pdf
basic-wireline-operations-course-mahmoud-f-radwan.pdf
 
A review on techniques and modelling methodologies used for checking electrom...
A review on techniques and modelling methodologies used for checking electrom...A review on techniques and modelling methodologies used for checking electrom...
A review on techniques and modelling methodologies used for checking electrom...
 
Understanding Inductive Bias in Machine Learning
Understanding Inductive Bias in Machine LearningUnderstanding Inductive Bias in Machine Learning
Understanding Inductive Bias in Machine Learning
 
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSA SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
 
Advanced control scheme of doubly fed induction generator for wind turbine us...
Advanced control scheme of doubly fed induction generator for wind turbine us...Advanced control scheme of doubly fed induction generator for wind turbine us...
Advanced control scheme of doubly fed induction generator for wind turbine us...
 
Iron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdf
Iron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdfIron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdf
Iron and Steel Technology Roadmap - Towards more sustainable steelmaking.pdf
 
sieving analysis and results interpretation
sieving analysis and results interpretationsieving analysis and results interpretation
sieving analysis and results interpretation
 
Harnessing WebAssembly for Real-time Stateless Streaming Pipelines
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesHarnessing WebAssembly for Real-time Stateless Streaming Pipelines
Harnessing WebAssembly for Real-time Stateless Streaming Pipelines
 
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
 
New techniques for characterising damage in rock slopes.pdf
New techniques for characterising damage in rock slopes.pdfNew techniques for characterising damage in rock slopes.pdf
New techniques for characterising damage in rock slopes.pdf
 
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdfBPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
BPV-GUI-01-Guide-for-ASME-Review-Teams-(General)-10-10-2023.pdf
 
哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样
哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样
哪里办理(csu毕业证书)查尔斯特大学毕业证硕士学历原版一模一样
 
132/33KV substation case study Presentation
132/33KV substation case study Presentation132/33KV substation case study Presentation
132/33KV substation case study Presentation
 
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...
 

ETAP - Ground grid systems

  • 1. ©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Ground Grid Systems
  • 2. Slide 2©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Need for Grounding Grids • Currents flow into the grounding grid from: – Lightning Arrester Operations – Switching Surge Flashover of Insulators – Line-Ground Fault from Connected Bus – Line-Ground Fault from Connected Line
  • 3. Slide 3©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Objectives • Human and animal safety • Carry and dissipate current into earth under normal and fault conditions • Grounding for lightning impulses and surges • Low resistance to ground for protective relays
  • 4. Slide 4©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Construction
  • 5. Slide 5©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Common Definitions • Earth Current • Ground Fault Current • Ground Potential Rise • Step Voltage • Touch Voltage
  • 6. Slide 6©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Step 1 – Soil Analysis • Done at a number of places in the substation • Several layers with different resistivity • Lateral surface changes are more gradual than vertical changes • Wenner Four-Pin Method
  • 7. Slide 7©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Wenner Four-Pin Method 2222 4 2 1 4 ba a ba a aR a
  • 8. Slide 8©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Step 2 – Grid Area • Area should be as large as possible • Increasing area is more effective than adding additional conductor to reduce grid resistance • Outer conductor should be placed on the boundary of substation • Fence should be placed a minimum of 3 feet inside • Square, rectangular, triangular, T-shaped, or L-shaped grids
  • 9. Slide 9©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Step 3 – Ground Fault Currents • L-G fault on substation bus or transmission line • Interested in maximum amount of fault current expected to flow into the ground grid • Determine maximum symmetrical rms fault current
  • 10. Slide 10©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Ground Fault Current
  • 11. Slide 11©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Ground Fault Current
  • 12. Slide 12©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Ground Fault Current
  • 13. Slide 13©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Ground Fault Current
  • 14. Slide 14©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Symmetrical Grid Current • Io = Symmetrical rms value of Zero Sequence fault current in amperes • Transmission Systems – Model Maximum Io for L-G fault for present and ultimate configuration • Distribution Systems – Model future fault current with suitable growth factor (1.1) )3(* ofg ISI
  • 15. Slide 15©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Decrement Factor • Accounts for the asymmetrical fault current • AC component does not decay with time but remains at its initial value • Calculated from time duration of fault and X over R ratio • Transmission Systems – Use fastest clearing relay + breaker time • Distribution and Industrial Systems – Use worst case backup clearing time
  • 16. Slide 16©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Typical Shock Situations
  • 17. Slide 17©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Design Procedure Summary • Use network of bare conductors buried in the earth • Encompass all area within the substation fence and extend at least 3 feet outside • Perform soil resistivity test • Surface material at least 4 inches • Determine fault current using short circuit • Determine maximum clearing time
  • 18. Slide 18©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Design Procedure Summary • Size conductors • Conductor should be buried a minimum of 18 inches to 59.1 inches • Vertical ground rods should be at least 8 ft. long • Determine if touch and step voltages are below tolerable limits • Few iterations may be required to determine correct grid design
  • 19. Slide 19©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Ground Rod Length • Three schools of thought – Length of 10ft is adequate – Length of 40ft is required to reach water table – Longest possible rod depth should be used
  • 20. Slide 20©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems IEEE Methods • Empirical method; limited applications • Handles 2 layers plus protective surface material (1 layer for touch potential) • Rectangular and triangular shapes only, with vertical and horizontal conductors • One ground grid only • Rods; but arrangements are not flexible • Calculates required parameters
  • 21. Slide 21©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Finite Element Method • Handles 2 layers plus a protective surface material • Any shape • Multiple interconnected ground grids • Rod location modeled in detail • Calculates required parameters at all points • Graphic potential profile
  • 22. Slide 22©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Typical IEEE Grid
  • 23. Slide 23©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems IEEE Grid Description • 40 ft. X 40 ft. square grid with 8 conductors along X-axis and 8 conductors along Y-axis • Depth = 1.5 ft., 4/0 copper-clad steel wire • 1 rod in each grid corner, diameter = 0.5 in., length = 8 ft. same material as conductor
  • 24. Slide 24©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems FEM Grid Example
  • 25. Slide 25©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Step Potential Profile
  • 26. Slide 26©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Touch Potential Profile
  • 27. Slide 27©1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Ground Grid Systems Absolute Potential Profile