MV Cable Selection Analysis for 70mm² vs 95mm² For TBM (Tunnel Boring Machine) Power Supply
Note: This is my engineering calculation note for a specific project. The analysis and data shown here are specific to this case study and should not be used as a general calculator.
System Parameters
transformer Rating:3,000 kVA, 22kV/11kV
load:Tunnel TBM Equipment
cable Length:600m
nominal Voltage:11 kV
design Current:157.46 A
Requirements
Cable ampacity must exceed breaker trip setting and TBM load current
Voltage at receiving end must be within ±4%
Cable must withstand short-circuit conditions safely
Key Assumptions
- • Total estimated load: 3,000 kVA (based on transformer size, assuming full load)
- • Air ambient temperature: 40°C
- • Grouping factor: 1 (single cable set with sufficient spacing)
- • Thermal insulation factor: 1 (no thermal insulation)
- • Number of cable sets: 1 (3-core)