Vision Cable Analysis / application
Cable type editor: add your own cables to the cable library
In Vision Cable Analysis you can add an external heat source |
IEC 60287
The IEC 60287 standard describes the calculation of cable losses and thermal resistances for the cable and its environment.
Functionality
Vision Cable Analysis calculates:
- Maximum current rating for multiple circuits of single and three core cables
- Temperatures of all cables for specified currents
- Temperature of the surrounding soil
- Sensitivity analysis
All results are graphically presented on the screen. The result of any change is presented immediately.
Cable types
The starting point for the calculation is always the cable construction. Vision Cable Analysis supports calculation of all commonly used single core and three core cable types of standard isolation materials and construction, like XLPE, PVC, Oil pressure, mass impregnated and pipe-type cables.
For all cable types, properties, specifying type and construction, can be viewed and edited in a graphical Cable Editor. Using this Cable Editor the cable database can easily be modified and extended.
Configuration
The ampacity can be calculated for cables installed in free air and for buried cables. Vision Cable Analysis enables the user to input and manipulate the configuration of all cable circuits graphically.
Calculation
For buried cables, depth and relative positions to each other are important factors. Additionally, heat sources, by specification of either temperature or heat production, are easily applicable.
Vision Cable Analysis calculates the cable current rating for the situations where:
- no drying-out of the soil occurs,
- partial drying-out of the soil occurs (two-zone approximate physical model) and drying-out of the soil is to be avoided.
Dynamic current 1 day interface
Cyclic temperature behaviour during 7 days
Step response 168 hours |
IEC 60853
The IEC 60853 standard describes the methods for calculation of the cyclic cable rating and the emergency cable rating.
The dynamic cable rating calculation is based on the fact that a cable, not conducting 100 % of the maximum continuous current, has not reached its maximum temperature. Thanks to the dynamic properties of cable and soil, the temperatures respond slowly to a step change in current, enabling the operator to overload the cable during a short time in emergency situations.
Vision Cable Analysis calculates:
- Cyclic rating (7 daily 24-hour cycles)
- Emergency rating
- Step response
These calculations show how much more than the continuous current rating the cables can conduct in case of a cyclic varying load. The cyclic rating depends on the shape of the daily load cycle.
These calculations also show how many extra loads can be added to the cable in case of emergencies. The emergency current rating strongly depends on the starting temperature and the emergency duration.
