This will explain how to measure the ground clearance of the powerlines in your design under different environmental conditions. By the end of this tutorial you will be able to:
- Measure the clearance between a line and any objects below it
- Set up different ground clearance heights
- model conductor sag under different environmental conditions
Measuring clearance
From within a Neara file, the ground clearance tool can be selected from the left menu bar which when left-click on a conductor will depict the clearance between it and the ground. From the perspective field on the right, you are able to change the environment to see clearances under different conditions, with the cable sagging in accordance with these being depicted as well.
This can be seen and used in both the profile and perspective views of your diagram.
The worst case ground clearance of a span is represented by a magenta line, with the environment and clearance written next to the line as shown below.
It is also possible to measure the clearance between a span and any other object, such as a building or foliage in the same manner as shown above as the tool will automatically measure to the highest point below. If you want to measure the clearance between two spans, use the span clearance tool as shown here.
Ground clearance height
A height clearance can be set for the entire file:
One of the most important aspects of any design is ensuring that conductors do not sag below a certain ground clearance height. If it sags too low either its tension must be increased or its supporting poles moved closer together. Utilising the profile view, this can be easily visualised in our software, with the blue line parallel to the ground representing the clearance level and the dotted/black lines representing the cable span under different environmental conditions. This is shown in the image below:
This line can be adjusted, or new multiple clearance lines added using the 'Clearances' section in the menu. This also allows you to specify clearance rules to specific environments as shown in the image below:
Any new clearance lines added will be shown in the Profile view as another blue line at the specified height.