In modern electrical systems, the cables of medium voltage (MT) They are essential to guarantee a safe and efficient transmission of energy. The 11KV medium voltage cable is one of the most used in distribution networks, industrial projects, urban infrastructure and renewable energy plants.
This article offers a complete guide on the Cobre and Aluminum 11KV Cable, covering from 25 mm² up to 800 mm², and describing configurations of 1 y 3 drivers, With detailed technical specifications, construction characteristics and installation considerations.
1. What is an 11KV medium voltage cable?
And cable 11kV It is an electric conductor designed to operate nominal tensions of up to 11.000 volts. Is classified within the medium voltage, which generally covers from 1kv to 35kv.
Common applications:
- Urban and rural electric distribution networks
- Food of industrial facilities
- Electrical substations
- Solar and wind parks
- Heavy mining and infrastructure
- Underground and aerial facilities
2. 11KV medium voltage cable structure
The basic design of an 11KV cable includes:
- Conductor: It covers the aluminum, Compact and generally wired (stranded).
- Driver semiconductor screen: Reduces electrical stress in insulation.
- Isolation: Made of XLPE (cross-linked polyethylene) o EPR (ethylene-propylene), resistant up to 90 ° C in continuous operation.
- Semiconductor screen on insulation.
- Metal screen: Threads or copper/aluminum tape for potential control and short -circuit protection.
- inner cover (bedding).
- Armor: Steel wire (SWA) for 3C, or aluminum (AWA) for 1c.
- External cover: Normally PVC, OR of LSZH (halogen free).
3. Applicable regulations
11KV cables must comply with international regulations, such as:
- IEC 60502-2: Energy cables with extruded insulation for 6KV tensions at 30kv.
- BS 6622: British standard for MT cables.
- One-hd 620: European regulations for MT cables.
4. Technical Parameters of the 11KV Cobre Cable
Copper properties:
- High electrical conductivity (~57 MS/m)
- Excellent mechanical resistance
- Greater weight than aluminum
- Better behavior against overloads and short circuits
Copper cable specifications (1C y 3C)
| Section (mm²) | No. of drivers | Approximate diameter (mm) | Approximate weight (kg/km) | Current in air (A) | Underground current (A) | Short -circuit capacity (Ka / 1s) |
|---|---|---|---|---|---|---|
| 25 | 1C | 19 | 700 | 135 | 115 | 3.5 |
| 35 | 1C | 22 | 850 | 165 | 140 | 4.9 |
| 50 | 1C | 24 | 1050 | 200 | 170 | 7.0 |
| 70 | 1C | 27 | 1350 | 250 | 215 | 9.8 |
| 95 | 1C | 30 | 1700 | 300 | 260 | 13.3 |
| 120 | 1C | 33 | 2000 | 350 | 305 | 16.8 |
| 150 | 1C | 36 | 2400 | 400 | 345 | 21.0 |
| 185 | 1C | 39 | 2800 | 455 | 390 | 25.9 |
| 240 | 1C | 44 | 3500 | 530 | 455 | 33.6 |
| 300 | 1C | 48 | 4200 | 615 | 525 | 42.0 |
| 400 | 1C | 52 | 5500 | 725 | 620 | 56.0 |
| 500 | 1C | 58 | 6800 | 840 | 715 | 70.0 |
| 630 | 1C | 63 | 8500 | 975 | 820 | 88.2 |
| 800 | 1C | 70 | 11000 | 1150 | 950 | 112.0 |
To 3 drivers (3C):
- The diameter and weight increase a 1.6x – 1.8X regarding unipolar cable.
- The current capacity decreases between a 10-15% Due to thermal coupling.
5. Technical Parameters of the 11KV aluminum cable
Aluminum properties:
- Less conductivity (~35 MS/m)
- Lightness (ca.. 60% of copper weight)
- Cheaper than copper
- You need more section to match the Copper Current Capacity
Aluminum cable specifications (1C y 3C)
| Section (mm²) | No. of drivers | Approximate diameter (mm) | Approximate weight (kg/km) | Current in air (A) | Underground current (A) | Short -circuit capacity (Ka / 1s) |
|---|---|---|---|---|---|---|
| 25 | 1C | 21 | 420 | 105 | 90 | 2.1 |
| 35 | 1C | 23 | 530 | 130 | 110 | 2.9 |
| 50 | 1C | 26 | 670 | 160 | 135 | 4.2 |
| 70 | 1C | 29 | 900 | 205 | 175 | 5.8 |
| 95 | 1C | 32 | 1150 | 250 | 215 | 7.8 |
| 120 | 1C | 35 | 1400 | 295 | 250 | 9.8 |
| 150 | 1C | 38 | 1700 | 340 | 290 | 12.2 |
| 185 | 1C | 41 | 2050 | 390 | 335 | 15.0 |
| 240 | 1C | 45 | 2550 | 460 | 395 | 19.6 |
| 300 | 1C | 49 | 3200 | 530 | 455 | 24.5 |
| 400 | 1C | 53 | 4100 | 625 | 540 | 32.8 |
| 500 | 1C | 59 | 5100 | 720 | 625 | 41.0 |
| 630 | 1C | 64 | 6400 | 845 | 730 | 51.7 |
| 800 | 1C | 71 | 8100 | 985 | 850 | 65.6 |
To 3 drivers (3C):
- As in copper, The diameter and weight increase proportionally, and the current decreases.
6. Comparative: Copper vs aluminum in 11kv cables
| Feature | Copper | Aluminum |
|---|---|---|
| Conductivity | Superior (~57 MS/m) | Inferior (~35 MS/m) |
| Weight | heavier | lighter (~ 60% copper weight) |
| Cost | Alto | Low |
| Installation | Simpler in short projects | Better for long lines |
| Mechanical Resistance | Alta | Moderate |
| Corrosion Resistance | Alta | It requires special coating |
| Thermal expansion | Baja | Mayor |
7. Installation considerations
By installing 11KV cables it is important to consider:
- Minimum curvature radio: 15x The outer diameter of the cable.
- Operating temperature: -20°C a +90°C (Up to 250 ° C in short circuit).
- Minimum burial depth: Generally 0.6 a 1.0 metros.
- Separation between cables: For adequate thermal dissipation.
8. Conclusion
He 11KV medium voltage cable, either with copper conductor o aluminum, It constitutes a fundamental element in modern electrical infrastructure. The correct selection between copper or aluminum will depend on factors such as the transmission distance, The project budget, Environmental conditions and load requirements.
For projects where performance and durability are priority, he copper It is still the preferred option. For applications where economy and weight are critical factors, he aluminum It is an excellent alternative.
A correct technical specification, along with a professional installation, guarantees a safe and efficient operation of medium voltage electrical systems.