Cable Thermal Analysis

For Underground Cable Raceway Systems

Cable Thermal Analysis

Cable Thermal Analysis

Neher-McGrath & IEC 60287 - Thermal Cable Current Capacity
The Cable Thermal Analysis module helps engineers to design cable raceway systems to operate to their maximum potential while providing a secure and reliable operation.
Cable thermal analysis study in ETAP
The advanced graphical interface allows for design of cable raceway systems to meet the existing and future needs by using precise calculations to determine the required cable sizes, their physical capabilities, and maximum derated capacity / ampacity. In addition, transient temperature analysis computes temperature profiles for cable currents, reducing the risk of damage to cable systems under emergency conditions.

Cable Thermal Analysis Capabilites

  • Printable cable, conduit and raceway layout.
  • Printable dimension indication for conduits and raceways
  • Graphical manipulation of raceways, cables, conduits, etc.
  • Drag & drop cables from one-line diagrams
  • Cables of different sizes in the same raceway
  • Separate phases into different conduits or locations
  • Unsymmetrical positioning of raceways
  • Transient calculations use a dynamic thermal circuit model
  • Option to fix cable size and/or loading
  • Grounded/ungrounded metallic layer
  • Calculate thermal resistance, dielectric losses, conductor loss factor, metallic layer loss factor
  • User-defined cable physical structure
  • Unbalanced load factors
  • Multiple duct banks & direct-buried conduits
  • Place raceways in multiple cross-sections

User-Defined Cable Physical Structure

ETAP cable thermal analysis module can model single core and multiple core cable physical structure in details. Various cable thermal and metallic layer types and corresponding dimensions can be defined individually based on actual cable construction.

  • Insulation
  • Filler
  • Grounded/ungrounded metallic screen
  • Grounded/ungrounded metallic armor
  • Bedding
  • Grounded/ungrounded metallic sheath
  • Jacket
User-Defined Cable Physical Structure

Flexible Operation

  • Multiple raceways
  • Multiple external heat sources
  • Optimization of new cables in existing raceways
  • Cross-sectional analysis
  • Duct banks & direct buried raceways
  • Integrated with cables in one-line diagrams
  • Integrated with load flow results
  • Integrated with cable pulling analysis

Underground raceway study with cables from one-line diagram

Plotting & Reporting

With the advanced web-based plot tools, the cable transient temperature plot can be generated and customized according to engineers’ requirement. 

  • Interactively view and zoom the transient temperature plot to any detail levels
  • Option to combine and compare multiple transient temperature plots from different scenarios
  • Report all physical and calculated data into multiple file formats
PlottingReporting

Interactive User Interface

The enhanced interactive interface helps engineers to design and draw the raceway fast and intuitively. With the snapping guideline, conduits and raceways can be precisely located by dragging without entering the coordinates. Automatic dimension labeling expedites the generation of the raceway layouts without additional editing and annotating.

  • Display multiple cables, conduits, and raceways in the same presentation
  • Option to display raceway dimensions
  • Option to display Edge to Edge and Center to Center distance between conduits.
  • Flag critical & marginal cable temperatures
  • Snapping guideline between Centers, Tops, and Bottoms
Interactive User Interface

The cable capacity / ampacity calculation and cable sizing are based on the NEC accepted Neher-McGrath method and IEC 60287 standard for steady-state temperature calculation. The transient temperature calculation is based on a dynamic thermal circuit model. All of these calculations can handle multi-raceway systems and consider the effect of heat generated by neighboring cables and external heat sources.

Standards / MethodTitle
Neher-McGrathThe Calculation of the Temperature Rise and Load Capability of Cable Systems
IEC 60287-1-1  Ed. 1.2 b:2001Electric cables - Calculation of the current rating - Part 1-1: Current rating equations (100% load factor) and calculation of losses - General
IEC 60287-2-1:2015Electric cables - Calculation of the current rating - Part 2-1: Thermal resistance - Calculation of thermal resistance
IEC 60287-3-1   Ed. 1.1 b:1999Electric cables - Calculation of the current rating - Part 3-1: Sections on operating conditions - Reference operating conditions and selection of cable type
IEC 60287-3-1 Amd.1 Ed. 1.0 b:1999Amendment 1

Videos

How to design, analyze, and optimize Underground Raceway Systems with ETAP

How to design, analyze, and optimize Underground Raceway Systems with ETAP

Learn how to determine optimal cable sizes, physical attributes, and maximum ampacity using ETAP’s Underground Raceway System module, ensuring that cables in duct banks or directly buried are operating within their maximum potential capacity.
In addition, transient temperature analysis computes temperature profiles for cable currents, reducing the risk of damage to cable systems under emergency conditions. All cable steady-state temperature calculations are based on the Neher-McGrath Method and the IEC 60287 Standard.

Cable Thermal Analysis for Underground Raceways

Cable Thermal Analysis for Underground Raceways

Learn how to save design time using the Raceway Rulebook to auto-layout cables within duct banks. Find out how to determine the optimal cable sizes, physical attributes, and maximum derated ampacity using Neher-McGrath method and IEC 287 standard.

Cable Ampacity & Sizing

Cable Ampacity & Sizing

Proper sizing and current derating ensures that cables operate to their maximum potential while providing secure and reliable operation. Learn about design and application requirements to properly size and analyze cable systems based on IEEE and North American cable standards and guidelines: IEEE 399, ICEA P-54-440, NEC NFPA 70

Cable Ampacity, Sizing & Shock Protection - Part II

Cable Ampacity, Sizing & Shock Protection - Part II

Proper sizing and current de-rating ensures that cables operate to their maximum potential while providing secure and reliable operation. This webinar covers cable sizing, current carrying capacity and electrical shock protection based on IEC and British standards.

Cable Thermal Analysis - Part III

Cable Thermal Analysis - Part III

This Cable Thermal Analysis webinar explains how to design cable systems to operate to their maximum potential while providing a secure and reliable operation.

Literature

Underground Raceway Systems

Underground Raceway Systems

Underground Raceway Systems helps engineers to design cable systems to operate to their maximum potential while providing secure and reliable operation.

Cable Magnetic Field Evalution Calculation

Cable Magnetic Field Evalution Calculation

The magnetic field exposure analysis tool uses balanced & unbalanced load-flow currents and angles to determine the location of the worst-case magnetic field exposure due to conductors in underground raceways.

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