MV Cable Selection Analysis
70mm² vs 95mm² for TBM Power Supply
Engineering Note: This analysis is specific to a tunnel boring machine (TBM) project. The calculations and data are case-specific and should not be used as a general reference without proper engineering review.
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)