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Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 1 of 14
Secondary Substation Earthing Design Tool - ICP User Guide
Contents
1 Starting the Earthing Design Tool .......................................................................... 2
2 Quick Guide ............................................................................................................. 3
3 Earthing Design Tool Overview .............................................................................. 3
4 Source Substation Data (Box 1-2) .......................................................................... 5
5 Protection Settings (Box 3) ..................................................................................... 5
6 Cable and Overhead Line Data (Box 4) .................................................................. 6
7 Project Details (Box 5) ............................................................................................ 8
8 Calculations Explained (Boxes 6-10) ................................................................... 10
9 Notes (Box 5) ......................................................................................................... 11
10 Console .................................................................................................................. 11
11 Forms ..................................................................................................................... 11
12 Save Study ............................................................................................................. 12
13 Open Existing Study ............................................................................................. 12
14 Clear Values ........................................................................................................... 13
15 Useful Documentation .......................................................................................... 13
16 Help and Support................................................................................................... 13
Appendix A – Warning and Error Messages ................................................................... 14
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 2 of 14
1 Starting the Earthing Design Tool
Start the tool using the Substation Earthing Design Tool icon.
The earthing design tool will start and connect to the back-end database as shown below.
If the earthing design tool cannot connect to the SQL server that holds the tool data the message below is displayed with the option to close the tool. The tool will not work without a connection to the SQL server. Refer to section 17.
An overview of the main interface and functionality is shown overleaf. The sections that follow describe each step of the earthing design and the functionality and in more detail.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 3 of 14
2 Quick Guide
To carry out a quick earthing study with the minimal amount of data entry:
1. Select network and source substation.
2. Extract cable and overhead line records from the available geographical or modelling system.
3. Enter cables and overhead lines.
4. Enter project details.
5. Use the Calculate Rb button to estimate the earth resistance for a safe site and COLD site.
6. Enter value in HV Earth Resistance field.
7. Save study.
8. Produce data form.
3 Earthing Design Tool Overview
See next page.
Secondary Substation Earthing Design Tool - ICP User Guide Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 4 of 14
(1) Select the network and source substation
(11) Print data form
(12) Buttons to clear study, open study, save study and open user guide
(2) Source substation earthing details auto-populated
(5) Enter project details and substation location
(8) Fault level, ground return current and EPR results
(4) Enter cable and overhead line details
(10) User message console displays progress and warning messages
(3) Source substation default protection settings auto-populated
(7) Add notes
(6) Use Calculate Rb button to estimate resistance for COLD site
(9) COLD/HOT site results
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 5 of 14
4 Source Substation (Box 1-2)
In Box 1 select the Network, Source Substation and Feeder from the drop-down lists.
Note: If there is an auto-transformer between the source and the secondary substation the drop-down can be used to select the correct voltage conversion e.g. 11kV to 6.6kV.
The source substation Earth Fault Level, Neutral Earthing, Earth Resistance and EPR should be automatically populated in Box 2 when the substation is selected.
Note: If the Earth Resistance is not available in the tool’s dataset, a default value of 0.1Ω is used. If the EPR value is blank and the secondary substation is supplied via cable and is the first on the circuit or within 500 metre of the source substation request the value from UK Power Networks, otherwise leave blank.
5 Protection Settings (Box 3)
The protection settings are automatically populated with the default values when the Source Substation is selected in Box 1.
Actual settings from the source or upstream protection may be entered to calculate a more realistic Fault Clearance Time if required.
The Settings drop-down list allows the default settings to be re-selected if required.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 6 of 14
6 Cable and Overhead Line Data (Box 4)
6.1 Overview
Cable and overhead line data can be entered manually or imported from other systems. The tool allows a 100 sections of cable and line to be entered and edited via Box 4.
6.2 Add Cable/Line
To enter the cable/line data click the Add button to display the form below. Select the Circuit Type, Cable/Line Type and enter the Length in km. Click the Add button to transfer the data to the Calculator form.
This process can be repeated as required by changing the selections to enter further cables and lines to populate the list as shown below. Click the Close button when finished.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 7 of 14
6.3 Edit Cable/Line
To edit a cable or line select it from the list and double-click to display the Edit box as shown below. Amend the details as required and click the Update button to save the changes.
6.4 Delete Cable/Line
The selected cable(s) and line(s) can be removed using the Delete button. CTRL and SHIFT can be used with the mouse to select multiple items. Alternatively the Delete All button can be used to remove all cables and lines.
6.5 Move/Combine Cable/Line
The Combine button can be used to combine cables and lines of the same type into one – see before and after example below. The lengths, total sections and total length are adjusted accordingly.
The Move Up and Move Down buttons can be used to rearrange the individual items within the list.
6.6 Import Cable/Line
Reserved for future use.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 8 of 14
6.7 Cable/Line Advanced Edit
The Edit button can be used to display a greater number of cables/lines and allows any ‘unknown’ cables/lines to be filtered. The other functionality (add, edit, delete, combine, move and import) described previously is also available. Click Close to finish and update the Calculator form.
7 Project Details (Box 5)
Enter the name of the project/secondary substation, project number, your name and the location of the substation as shown.
The location should be a grid reference, postcode etc.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 9 of 14
8 Earth Resistance Rb (Box 5)
Once the source substation, protection settings and cable/line data have been entered use the Calculate Rb button calculate the value of earth resistance for a COLD site with combined HV/LV earths.
The console window is updated to show the calculation progress and once complete the value is displayed as shown in the example below.
Enter value into the HV Earth Resistance box as shown below. The results are calculated and shown in Box 6. See Section 9 for further details of the calculations and results.
The HV Earth Resistance box can be used to explore the results from any value of earth resistance.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 10 of 14
9 Calculations Explained (Boxes 6-10)
9.1 EPR Calculation (Box 6)
Box 6 shows the calculated EPR (Igr x Rb) value for the secondary substation.
9.2 Transfer Voltage (Box 6)
If the substation is the first on the feeder (use First Substation on Feeder) or within 500 metres of the source substation and entirely supplied by cable the transfer voltage (i.e. the voltage rise conveyed from the source substation to the new substation via the cable sheath, for faults occurring at the source substation) is also calculated.
9.3 ITU Classification (Box 8)
Box 8 shows whether the site is HOT or COLD and whether the HV/LV earthing can be combined. If the classification is due to the transfer voltage this is also indicated.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 11 of 14
10 Notes (Box 5)
The notes section in Box 5 can be used to provide a narrative of the design, any project specific notes or other comments.
11 Console
The console window in the middle of the screen provides feedback on the status of the study together with any warning or error messages.
12 Forms
The Data Form button can be used to produce a pdf data form as shown below.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 12 of 14
13 Save Study
The Save button is used to save a copy of the study as an xml file.
14 Open Existing Study
The Open button can be used to reload the data from a previously saved study (xml) including the older studies created using the Excel version of the tool (xlsx).
A warning is given if any missing data, old data or data differences are detected.
Any missing or invalid data will be highlighted with a red box and it will be necessary to re-select the valid values from the drop-down lists before the result are calculated.
Data differences are highlighted in blue text. The latest values (e.g. source fault level, earth resistance etc.) can be used by reselecting the source substation.
Examples of data differences and missing data are shown below.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 13 of 14
15 Clear Values
The Clear button can be used to reset all or parts of the tool. The first two options clear all data entered and the second option resets the form. The final option can be used to remove the red boxes displayed to indicate that data is missing (useful when reloading a project with minimal data e.g. Competition-in-Connections).
16 Useful Documentation
EDS 06-0014 – Secondary Substation Earthing Design
EDS 07-0302 – Secondary Substation Civil Design (contains earthing arrangement drawings)
EDS 06-0015 – Pole-mounted Equipment Earthing Design
EDS 06-0016 – LV Earthing Design
EDS 06-0017 – Customer Installation Earthing Design
ECS 06-0023 – Secondary Distribution Network Earthing Construction
17 Help and Support
All IT system, database or earthing tool issues should be reported to UK Power Networks Competition-in-Connections team.
For further information or help with any aspects of the earthing tool please contact UK Power Networks Competition-in-Connections team.
Secondary Substation Earthing Design Tool - ICP User Guide
Document Number: User Guide
Version: 5.2
Date: 22/02/2018
© UK Power Networks 2018 All rights reserved 14 of 14
Appendix A – Warning and Error Messages
The tool has three types of warning and error message as described below.
Information Message
Displayed to convey information to the user about the current earthing study.
Warning Message
Usually displayed to inform the user of an invalid operation e.g. trying to open an invalid file or the omission of required data.
Error Message
Displayed if a system error occurs. The module where the error occurred and the error description is included in the message. A screenshot of these errors should be sent to your system administrator (see Section 17).
