Cable Systems Analysis
Electrical cable sizing is one of the most critical aspects in the design and operation of electrical power systems. Improperly sized cables can cause overheating, excessive voltage drops, improper protection tripping, loss of energy efficiency, and even catastrophic failures due to insulation degradation. On the other hand, oversizing leads to unnecessarily high acquisition and installation costs.
The manual calculation approach has limitations when applied to complex industrial and power systems, in which multiple factors (load, grouping, temperature, voltage drop, short circuit) need to be evaluated simultaneously. With electrical systems analysis software, the cable analysis and sizing process becomes faster, more accurate, and integrated with the actual behavior of the electrical system, bringing numerous advantages:
Automatic sizing according to international standards:
The software directly applies methodologies from international standards (IEC, IEEE, NEC, NBR) for cable sizing, considering thermal, dielectric, and voltage drop criteria. This ensures that the results comply with regulatory and normative requirements.
Integration with load and power flow studies:
The software uses power flow results to determine actual operating currents in the cables, eliminating simplified estimates. This allows sizing to be based on actual loading conditions, increasing the accuracy of the analysis.
Voltage drop analysis:
The software automatically calculates the voltage drop across each section of the system, verifying that it meets the limits defined by standards or design specifications. This is essential to ensure the proper operation of sensitive loads, such as motors and automation systems.
Current carrying capacity (ampacity):
The software evaluates cable ampacity taking into account factors such as:
- Environmental temperature;
- Installation type (ducts, trays, underground, outdoors);
- Cable grouping factor;
- Ventilation conditions.
This detailed analysis ensures that the cables do not exceed their maximum allowable temperature, preventing premature aging and insulation failures.
Short-circuit withstand verification:
In addition to the nominal current, the software checks whether the cables can withstand the thermal and dynamic stresses resulting from electrical faults during the protections’ operation. This ensures that the conductors can withstand mechanical and thermal stress until the fault is cleared.
Optimized economic and technical selection:
The software allows you to simulate various cable options (sections, materials, installation methods) and compare costs, losses, and performance. This results in a technically sound and economically viable choice, avoiding both under and oversizing.
Easy graphical visualization and automatic reporting:
The results are displayed directly on the single-line diagram, highlighting cables with overload, excessive voltage drop, or insufficient short-circuit resistance. Furthermore, detailed reports with tables and graphs are automatically generated, streamlining project documentation.
Simulation of operating scenarios:
The software makes it possible to evaluate the performance of cables under different conditions:
- Normal and emergency operation;
- Starting of large motors;
- Change in cargo dispatch;
- Reconfiguration of panels or lines.
Thus, the engineer ensures that the sizing meets not only the nominal regime, but also critical transient conditions.
Integration with other electrical system studies:
Cable sizing is directly related to other studies:
- Power flow (actual currents in the cables);
- Short circuit (thermal and mechanical withstand);
- Protection and selectivity (settings depend on coordination with cables and conductors withstand curves);
Integrating these studies into the software ensures consistent and reliable analyses.
Error reduction and time savings:
The manual sizing process requires repetitive calculations and constant consultation of normative tables. The software automates all these steps, reducing study execution time and virtually eliminating calculation or interpretation errors.