Creating a new cable or editing an existing cable, brings up the cable edit screen. The cable edit screen is divided into two parts
The edit pages is designed to guide you through the process, with inputting the minimum amount of data. As you go through the form, the selections you make will determine which information is requested (d.c. cables, for example do not require frequency or power factor information). If you get stuck or your calculation is not working, hits are given at the top right (calculation box) on what you need to do.
The calculation box itself is updated after every change and shows current capacity, voltage drop and fault withstand information. The left-hand border is colour coded against some internal checks to indicate if there is a possible issue with the cable. The box overlays the main form and can be hidden (or shown) by clicking the arrow icon.
Note: the application covers all voltages up to and including 33 kV. By changing your cable voltage, the appropriate cables for and options will be presented for you required voltage. The cross-sectional area (CSA) of the cable is selected by the user, however, if a sizing standard is employed, the calculation box will give a suggested size and the user can use this to determine the correct CSA.
The application calculates current capacity to various standards (see the posts sub-topics), positive and zero sequence impedances for the cable by IEC 60909 (see Impedance).
Note: soil resistivity is used in the calculation of zero sequence impedance. If you don't know the actual soil resistivity, leaving it at the default value (100 Ω) is a good option.
Clicking 'Save Changes', saves any changes. You can cancel your editing by clicking the 'Cancel' button.