Calculation of touch voltage and ground current can be performed on single phase or three-phase systems. Calculation of Touch Voltage and Ground Current According to the inputs for three-phase system: Line-to-Neutral Volts (Vn), Line 1 Calculated Load (A1), Line 2 Calculated Load (A2), Line 3. Return to Session SHEATH CIRCULATING CURRENT CALCULATIONS AND MEASUREMENTS OF UNDERGROUND POWER CABLES Xiaolin CHEN1, Kai WU2, Yonghong CHENG3, Li YAN4 State Key Lab of Electrical Insulation and Power Equipment (SKLEI), Xi'an Jiaotong University (XJTU).
- Grounding Calculation Example
- Electrical Grounding Calculation
- Grounding Calculation Software Download
- Grounding Calculation Software
In Article ' Grounding Design Calculations – Part One ', I indicated the following:
Grounding System Design Calculations according to type of the building The procedures for performing the Grounding System Design Calculations can differ slightly according to the type of the building as follows:
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First: Domestic, commercial and industrial premises We mean by domestic, commercial and industrial premises, all installations up to 1,000 V ac and 1,500 V dc - between phases, with some minor exceptions. |
And I explained Methods of Grounding Design Calculations of Domestic, commercial and industrial premises in the following Articles:
Grounding Calculation Example
- Grounding Design Calculations – Part One and Grounding Design Calculations – Part Two: Equations Method and solved examples.
- Grounding Design Calculations – Part Three: Nomographs Method
- Grounding Design Calculations – Part Four: Excel Spreadsheets Method
- Grounding Design Calculations – Part Five and Grounding Design Calculations – Part Six: using Tables Method
- Grounding Design Calculations – Part Seven and Grounding Design Calculations – Part Eight: Using Online Earthing Calculators
- Grounding Design Calculations – Part Nine: Software Programs Method
Second: High And Medium Voltage Electricity AC Substations |
I began explaining Grounding Design Calculations for second type of buildings: AC Substations in Article ' Grounding Design Calculations – Part Ten ' where I explained the following:
- Design Procedures for grounding system design as per IEEE 80: Guide for safety in AC substation grounding,
- Step#1: Field Data Collection,
- Step#2: Earthing Grid Conductor Sizing.
Electrical Grounding Calculation
Grounding Design Calculations – Part Twelve: Step#4: Preliminary Design of Grounding System for AC Substations.
Grounding Design Calculations – Part Thirteen: Step#5: Calculation of the Preliminary Grid Resistance, Rg, Of the Grounding System in Uniform Soil.
Grounding Design Calculations – Part Fourteen: Step#6: Determination of Maximum Grid Current, IG.
Grounding Design Calculations – Part Fifteen, I explained the following steps:
- Step#7: Calculation of Maximum Grid Potential Rise and Comparing With the Tolerable Touch Voltage from Step#3
- Step#8: Calculation of Mesh and Step Voltages
Grounding Design Calculations – Part Sixteen, I explained the following steps:
- Step#9: Comparing The Computed Mesh Voltage From Step#8 With The Tolerable Touch Voltage From Step#3
- Step#10: Comparing The Computed Step Voltage From Step#8 With The Tolerable Step Voltage From Step#3
- Step#11: Preliminary Design Modification
- Step#12: Detailed Final Design
You can preview the following Articles for more info:
- Earthing Systems Design steps – Part Three
Excel Spreadsheets for Grounding System Design Calculations of AC Substation |
Today, I will introduce to you, the most powerfulexcel spreadsheet for Grounding System Design Calculations of AC Substation.
Important Use this excel spreadsheet for AC Substation only, and don't use it for Domestic, commercial and industrial premises. (Please review the above definition for domestic, commercial and industrial premises). Another excel spread sheet was provided for Grounding System Design Calculations for Domestic, commercial and industrial premises. Just follow the Link. |
Benefits For Using This Excel Spreadsheet
|
This excels spreadsheet includes (5) nos. worksheets and (9) nos. pages (see below image) as follows:
Worksheet Name | |
1 | 1 |
Design Procedure Block Diagram | |
3 | 5 |
Results Summary Report | |
5 | 1 |
9 |
| Excel Spreadsheets for Grounding System Design Calculations of AC Substation |
First: Table of Contents Worksheet
| Table of Contents Worksheet |
This worksheet lists the other worksheets in an index as shown in below figure, you can go to a specific worksheet by just clicking on its name.
You can send email to me directly by clicking on the phrase 'Designed by: Ali Hassan' for any inquiries or notes.
Second: Design Procedure Block Diagram Worksheet
You can send email to me directly by clicking on the phrase 'Designed by: Ali Hassan' for any inquiries or notes.
Second: Design Procedure Block Diagram Worksheet
| Design Procedure Block Diagram Worksheet |
- Rectangular shapes: for data entering and data calculation,
- Diamond shape: for logical comparison between different values.
Note: The diamond shapes based on their logical answer 'yes or no' will change the calculations sequence i.e. you may continue to next step or you may move forward or backward to other steps. |
Third: Grounding System Calculations Worksheet
This worksheet includes general data that must be known in the starting of Grounding System Design Calculations of AC Substations, which are included in step#1 as follows:
- Soil Resistivity, ρ
- Gravel Resistivity, ρs
- Symmetrical Short Circuit Current, Ig
- Duration of Earth Fault Current, ts
- Maximum Allowable Conductor Temperature
- Design Ambient Temperature
- Thickness of Crushed Gravel, hs
- Depth of Earth Grid, h
- Reference depth of the Grid, ho
| STEP#1: GENERAL DESIGN DATA |
Important: The data input cells are the yellow color ones |
Important
|
Also, this worksheet helps you to calculate the following:
- Step#2: The size of the grid conductor in Kcmil, mm2 and its diameter
- Step#3: Tolerable touch voltage and step voltages (Etouch and Estep)
- Step#5: Grid resistance calculation, Rg
- Step#6: Maximum Grid Current calculation, IG
- Step#7: Ground Potential Rise GPR
- Step#8: Calculation for Actual Derived Step & Mesh Voltage (Es and Em)
For step#2 You need to select the grid conductor material type from the drop-down menu existing in this step, the choices are:
Based on your selection, the Material Constants will change according to Table-1 Material Constants included in Used Tables Worksheet and extracted from standard IEEE 80-2000, page 42. |
Note: The default of this excel sheet for Tolerable touch voltage and step voltages in Step#3 was made for 70 Kg persons, if there is a need to calculate for 50 Kg persons, just send email to me as a modification request.
|
Important: The data Results cells are the Pink color ones |
For Step#4: Initial Design Assumptions This step depends on the experience of the designer to provide good initial design parameters that suit the case under design, for more information about this step and how to assume its data, please review our Article ' Grounding Design Calculations – Part Twelve '.
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| Step#5: Grid resistance calculation |
| Step#6: Maximum Grid Current calculation |
In addition to the above, this worksheet helps you to logically compare between the different designs parameters as follows:
- In Step#7: comparing the computed GPR with the Tolerable Touch Voltage from Step#3,
- In Step#9: Comparing the Computed Mesh Voltage from Step#8 with the Tolerable Touch Voltage from Step#3,
- In Step#10: Comparing the Computed Step Voltage from Step#8 with the Tolerable Step Voltage from Step#3.
Important: The results of the logical comparison for the above (3) steps are included in the yellow cells between brackets.
|
- Earthing Systems Design steps – Part Three
Excel Spreadsheets for Grounding System Design Calculations of AC Substation |
Today, I will introduce to you, the most powerfulexcel spreadsheet for Grounding System Design Calculations of AC Substation.
Important Use this excel spreadsheet for AC Substation only, and don't use it for Domestic, commercial and industrial premises. (Please review the above definition for domestic, commercial and industrial premises). Another excel spread sheet was provided for Grounding System Design Calculations for Domestic, commercial and industrial premises. Just follow the Link. |
Benefits For Using This Excel Spreadsheet
|
This excels spreadsheet includes (5) nos. worksheets and (9) nos. pages (see below image) as follows:
Worksheet Name | |
1 | 1 |
Design Procedure Block Diagram | |
3 | 5 |
Results Summary Report | |
5 | 1 |
9 |
| Excel Spreadsheets for Grounding System Design Calculations of AC Substation |
First: Table of Contents Worksheet
| Table of Contents Worksheet |
This worksheet lists the other worksheets in an index as shown in below figure, you can go to a specific worksheet by just clicking on its name.
You can send email to me directly by clicking on the phrase 'Designed by: Ali Hassan' for any inquiries or notes.
Second: Design Procedure Block Diagram Worksheet
You can send email to me directly by clicking on the phrase 'Designed by: Ali Hassan' for any inquiries or notes.
Second: Design Procedure Block Diagram Worksheet
| Design Procedure Block Diagram Worksheet |
- Rectangular shapes: for data entering and data calculation,
- Diamond shape: for logical comparison between different values.
Note: The diamond shapes based on their logical answer 'yes or no' will change the calculations sequence i.e. you may continue to next step or you may move forward or backward to other steps. |
Third: Grounding System Calculations Worksheet
This worksheet includes general data that must be known in the starting of Grounding System Design Calculations of AC Substations, which are included in step#1 as follows:
- Soil Resistivity, ρ
- Gravel Resistivity, ρs
- Symmetrical Short Circuit Current, Ig
- Duration of Earth Fault Current, ts
- Maximum Allowable Conductor Temperature
- Design Ambient Temperature
- Thickness of Crushed Gravel, hs
- Depth of Earth Grid, h
- Reference depth of the Grid, ho
| STEP#1: GENERAL DESIGN DATA |
Important: The data input cells are the yellow color ones |
Important
|
Also, this worksheet helps you to calculate the following:
- Step#2: The size of the grid conductor in Kcmil, mm2 and its diameter
- Step#3: Tolerable touch voltage and step voltages (Etouch and Estep)
- Step#5: Grid resistance calculation, Rg
- Step#6: Maximum Grid Current calculation, IG
- Step#7: Ground Potential Rise GPR
- Step#8: Calculation for Actual Derived Step & Mesh Voltage (Es and Em)
For step#2 You need to select the grid conductor material type from the drop-down menu existing in this step, the choices are:
Based on your selection, the Material Constants will change according to Table-1 Material Constants included in Used Tables Worksheet and extracted from standard IEEE 80-2000, page 42. |
Note: The default of this excel sheet for Tolerable touch voltage and step voltages in Step#3 was made for 70 Kg persons, if there is a need to calculate for 50 Kg persons, just send email to me as a modification request.
|
Important: The data Results cells are the Pink color ones |
For Step#4: Initial Design Assumptions This step depends on the experience of the designer to provide good initial design parameters that suit the case under design, for more information about this step and how to assume its data, please review our Article ' Grounding Design Calculations – Part Twelve '.
|
| Step#5: Grid resistance calculation |
| Step#6: Maximum Grid Current calculation |
In addition to the above, this worksheet helps you to logically compare between the different designs parameters as follows:
- In Step#7: comparing the computed GPR with the Tolerable Touch Voltage from Step#3,
- In Step#9: Comparing the Computed Mesh Voltage from Step#8 with the Tolerable Touch Voltage from Step#3,
- In Step#10: Comparing the Computed Step Voltage from Step#8 with the Tolerable Step Voltage from Step#3.
Important: The results of the logical comparison for the above (3) steps are included in the yellow cells between brackets.
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Grounding Calculation Software Download
| Step#8: Calculation for Actual Derived Step and Mesh Voltage |
Fourth: Results Summary Report Worksheet
| Results Summary Report Worksheet |
This worksheet gives results summary under three sections as follows:
Section#1: Earth Grid Conductor, it gives:
- Type of Conductor,
- Size of Conductor,
- Length of Conductor,
- Depth of Conductor.
Section#2: Ground Rods, it gives:
- Total Length of Ground Rods,
- Length of Individual Ground Rods,
- No. of Ground Rods.
Section#3: Human Safety, it gives:
- The permissible (Tolerable) values of the touch and step voltages,
- The designed value of the touch and step voltages,
- The result of logical comparison between the Computed Mesh Voltage from Step#8 with the Tolerable Touch Voltage from Step#3,
- The result of logical comparison between the Computed Step Voltage from Step#8 with the Tolerable Step Voltage from Step#3.
Fifth: Used Tables Worksheet
| Used Tables Worksheet |
This worksheet includes the used table in calculations which is Table-1 for grid conductor Material Constants. This table is extracted from standard IEEE 80-2000, page 42.
The Material Constants provided by Table-1 are as follows:
- Material conductivity (%)
- αr factor at 20 °C (1/°C)
- Ko at 0 °C (0 °C)
- Fusing temperature Tm (°C)
- ρr 20 °C (μΩ·cm)
- TCAP thermal capacity [J/(cm3·°C)]
And the grid conductor materials will be as indicated in above Grounding System Calculations worksheet.
To download your copy of Excel Spreadsheet For Grounding System Design Calculations Of AC Substation, please click on the link. non-registered members in Electrical-Knowhow website will not be able to open and use this excel spreadsheet. To register as a member of Electrical-Knowhow website, do the following:
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In the next Article, I will explain Lightning Design Calculations. Please, keep following.
Grounding Calculation Software
Back To Course EE-5: Grounding System Design Calculations |
