Release Log

Release 2024 September

Support for Cables in Metal Pipes

Grøft has included the feature to calculate the effects of cables in metal pipes. It calculates the induction and heating of metallic pipes.

Release 2024 August

Fix Display of Insulation Loss

For multi core cables, insulation loss was calculated correctly, but displayed incorrectly in the results. This has no impact on the simulation itself, but after this fix, the insulation and total losses presented in the results might decrease somewhat for trenches that include multi core HV cables.

Improvements to Touch screens

Some usability improvements have been made for devices that use touch input rather than mouse - such as phones and tablets.

Release 2024 June 2

Support for Ampacity Calculation

Ampacity calculations are now supported as an alternative to fixed current simulations. This feature allows you to quickly find cable circuit currents that result in a specified target temperature.

You can select one or multiple cable circuits, but should be aware that the exact specified temperature must be reached for all cable circuits. This is often what you want, but sometimes it’s impossible to achieve - e.g. because one of the cables may always exceed the target temperature when another one satisfies the target temperature. Thus, for more complicated cases, goal seeking is an iterative process where you might need to enter a fixed current for some cable circuit and then rerun for the remaining cable circuits.

Cables in Water Filled Pipes

Cable pipes (ducts) can now be configured with water as fill material. They will then be assigned a thermal resistivity based on IEC 60287-2-1, which is a decent approximation, and will work sufficiently well in most cases. The IEC formula assumes that the cable is centered in the pipe, but moving the cable to the bottom of the pipe has limited impact on the result since conduction is the primary means of heat transfer.

Individual Baselines

When modelling separate trenches on a sloped terrain, the lowest point on any trench was previously used to determine a single baseline. Cover thickness for each trench was then relative to this baseline - resulting in too much actual cover for trenches on elevated ground. This has now been changed so that an individual baseline is calculated for each isolated trench.

Extensions to the Excel-file for Simulation Details

The Excel-file for simulation details has been extended with more data. This includes thermal resistivities and detailed information about cable layers and pipes.

Release 2024 June

Improved result images

Result images are now rendered dynamically while you view them, which results in a few significant improvements:

• You can pan and zoom in and out.
• You can hover the mouse pointer at a location and see the exact temperature at that spot.
• You can select objects in the image, and see their results highlighted in the tables below - and vice versa.
• You can show or hide optional visualization layers or result sets.
• Image resolution is higher.
• Text in an image is no longer hard coded to the language that the simulation was run in.

Export Result Images

Result images can now be downloaded as SVG or PNG files, in the same manner as the geometry image.

Enhancements for the Geometry Image

You must now click the geometry image in order to activate mouse wheel zooming. This swill prevent unintentional zooming while scrolling the page.

X- and Y-axes can now optionally be show.

The informational boxes & control buttons on the right hand side of the geometry image can now be collapsed.

Live Temperature Display During Simulations

When running a simulation, the progress dialog will now show the live temperature. This slightly improves progress feedback, and also provides an early indication about simulations that will reach too high temperatures and can be aborted.

Support for Multiple Languages in Reports

You can now select language when downloading a report. This is most useful if you work on a project in your local language but want to send the report to a third party that does not speak your language.

Minor Adjustment to Cable Capacitance Formula, now Compliant with IEC Standards

The expression for capacitance of cables in Grøft Design® did not consider the thickness of conductor screen. It has been now changed to comply the approach introduced by IEC 60287 standard. It leads, however, to slight increase of dielectric losses of insulation. With reference to Technical Brochure 880 by CIGRE, for reference 33 kV cable land cable (CASE 4) the total heat loss in cable increases by 0.03%. For reference 400kV LPOF Cable (CASE 5) the total heat loss in cable increases by 0.56 %. Dielectric losses are voltage dependent and according to IEC 60287 should be taken into account for nominal system voltage equal to and above 220 kV (for XLPE insulated cables).

Modified Thermal Resistivity for PVC Pipes, now Compliant with IEC Standards

The thermal resistivity for PVC in pipes was previously 8 mK/W, and has been changed to 6 mK/W, as recommended by IEC. Typically, this will only have a minor impact on the result. But in some cases, it might affect the results with as much as one degree Celsius.

Enabled Horizontal and Vertical Adjustments for Aerial Objects

The limitation of not allowing positional adjustments of objects in air has been lifted. This means that you can e.g. center a cable in an air filled pipe, or place a cable in an air filled cable trough on a “pretended shelf”.

Updated Help text for Thermal Resistivity with Relevant Example Values

The guidance text for thermal resistance has been extended and improved with guiding values from CIGRE, IEC and research/measurements done by SINTEF Energy Research and Norwegian University of Life Sciences.

Extended Cable Results

Simulation results now include maximum surface temperature for all cables. For multi core cables with a dedicated screen per core, the screen current results are now shown per core.

Excel Export with Detailed Simulation Results

An Excel file can now be downloaded from the results page. This file includes the magnetic field data from the previous Excel file, plus detailed results for cables, pipes etc.

Larger “hotspot” for Hovering, Clicking and Dragging Small Objects

Selecting or dragging objects like sensors and ground wires in the geometry image can be difficult due to their small size. This has been improved by allowing a larger “hotspot” area around them.

Release 2024 February

Cable Circuits

Cable groups and multi core cables used to implicitly define a circuit, and Multiple Cables per Phase was a separate concept. This release introduces cable circuits as streamlined and configurable entities. Benefits include:

• Identical handling for all circuits (Single and Multi Cables per Phase).
• Flexibility in how cables are mapped to circuits.
• Improved clarity and separation between cable and cable circuit configuration and results.

Revised tabs

The tabs on the configuration page have been redefined for improved clarity and usefulness.

Release 2023 December

Change the System Frequency

With the new update you can change the system frequency from the dropdown in on the trench segment overview page.

Different frequencies within the same trench section is not supported.

Custom Objects

With custom object you can quickly define your own object that is in the trench. Please note that metallic materials are not supported for now.

Choose among different geometries or create your own.

Release 2023 November

Simulate Drying Out of Masses

Grøft Design® now includes an advanced capability to simulate the drying out of masses. This feature allows for a comprehensive understanding of how masses within the trench interact and dry out over time, offering a more accurate representation of real-world conditions.

The dry out functionality is a step function that depends on the temperature for the trench zones. With that you spesify how the thermal resistivity of the masses changes with changing temperature.

The figure below is an example of how you can set the termal resistivity to 1mK/W up to 60°C in the conductor zone. Above 60°C these masses start to dry out so you would increase the termal resistivity to 2mK/W.

Notice the highlighted temperature line for the dry out zone at 60°C. It is only applicable for the trench zones with defined dry out zones.

Report Updates and Output Layout Enhancements

We’ve improved and updated the reporting functionality within Grøft Design®. Enhancements to the report layouts provide a clearer presentation of data, making it easier to interpret and analyze results.

Reports for Selected Trench Sections

With the new update, you can now generate reports specifically for selected trench sections. This feature offers a more customized approach, enabling you to focus on specific sections of interest and extract comprehensive reports accordingly.

Export Geometry image as SVG or PNG

The export image function is more flexible. In addition to SVG-format you can now export the trench section image as PNG. Select if the image should be sized automatically or manuelly override the height, and toggle project information in the image.

Release 2023 September

Document the Cable

In the Cable Designer you can add documentation for your cables. With this release you can also add links to online documentation.

This is particularly usefull if you have documentation that you need to restrict access to by linking to your own content management system.

Verify the Cable

When designing a cable its important to verify the design. Under the verification tab in the Cable Designer you can create simulations that verifies the cable temperature for a given current.

Create trench for verification

Set a target temperature for the trench

View the temperature report

Component Language Improvements

When you create new componets you might want to share those componets with other users. If the user have a different language you can now translate the component directly in the Component Designer.

All components have a standard languange. In addition they can have an optional translation.

The standard language of the component is decided by the component owner. REN should probably default to English, and always add translation to Norwegian and other supported languages.

If you publish a component with translation, users will view the translation if it is in their language. If not it will fall back to default. Grøft Design® will look at the active language, not at the other languages the user might have.

Release 2019 Desember

Grøft Design® is released to the Norwegian market 🎉