Introduction
33KV medium voltage cables are fundamental in modern electrical distribution, especially in industrial applications, urban infrastructure and renewable energy projects. These cables are designed to operate nominal tensions up to 33KV and must comply with international regulations such as IEC 60502-2 and the Bs 6622.
What is a medium voltage cable 33kv?
And medium voltage cable 33kV It is an electric conductor designed to transport electricity in the range of 1kv to 35kv, being the 33KV one of the most common tensions in industrial applications, Urban electric distribution networks and infrastructure projects.
This type of cable is usually used for the connection between substations, feeding large industrial facilities and connection of wind farms or solar with the electricity grid. Its construction must meet strict security requirements, Mechanical insulation and resistance.
General structure of the 33KV cable
A typical 33KV cable consists of the following layers:
Conductor: It covers the aluminum, generally wiring for greater flexibility.
Internal semiconductor screen: Minimizes electrical stress in insulation.
Isolation: XLPE (cross-linked polyethylene), resistant up to 90 ° C in continuous operation.
External semiconductor screen: Ensures a uniform distribution of the electric field.
Metal screen: Copper threads or tapes for potential control and short -circuit protection.
inner cover: Provides a separation layer between the metal screen and the armor.
Armor: Steel threads (SWA) For tripolar or aluminum cables (AWA) For unipolar cables.
External cover: PVC, OR of LSZH, according to environmental conditions and security requirements.
33KV cable types: Copper vs. Aluminum, Unipolar vs. Tripolar
Los medium voltage cable 33kv are available with drivers of copper o aluminum, as well as in versions unipolares (A single driver) o tripolares (Three integrated conductors).
Copper: Best conductivity, more compact, greater weight and cost.
Aluminum: cheaper and light, but with greater diameter for the same capacity.
Advantages of 33KV cable with XLPE or EPR insulation
Medium voltage cables at 33KV are usually isolated with XLPE (cross-linked polyethylene) o EPR (Ethylene rubber propylene):
XLPE: Excellent thermal resistance (90–130°C), lower weight, Simple installation.
EPR: High flexibility, Ideal for areas with pronounced curves.
Both types are suitable for air facilities, directly buried or in ducts.
Technical specifications of copper cables
Copper properties
High electrical conductivity (~57 MS/m).
Excellent mechanical resistance.
Greater weight and cost compared to aluminum.
Technical data for copper unipolar cables (33kV)
Next, Specifications for medium voltage cable 33KV copper unipolar with XLPE insulation are presented:
Section (mm²) Approximate outer diameter (mm) Approximate weight (kg/km) Nominal current in air (A) Nominal current on land (A) 25 29 1000 140 120 35 30 1100 170 145 50 31 1250 200 170 70 33 1500 250 210 95 34 1800 300 250 120 35 2150 350 290 150 37 2400 400 330 185 38 2800 460 380 240 42 3400 540 440 300 43 4000 620 500 400 44 4950 720 580 500 46 6050 820 660 630 50 8150 950 760 800 53 9600 1100 880
Medium voltage cable 33kv:Technical data for copper tripolar cables (33kV)
Section (mm²) Approximate outer diameter (mm) Approximate weight (kg/km) 25 38 2320 35 41 2730 50 44 3220 70 48 4000 95 52 4910 120 55 5840 150 59 6830 185 63 7910 240 68 9390 300 73 10900 400 79 12900 500 85 15100 630 92 17800 800 99 20800
Technical Specifications of Aluminum Cables
Aluminum properties
Lower electrical conductivity (~35 MS/m).
Lighter and more economical than copper.
It requires greater section to match Copper's current capacity.
Medium voltage cable 33kv:Technical data for unipolar aluminum cables (33kV)
Section (mm²) Approximate outer diameter (mm) Approximate weight (kg/km) Nominal current in air (A) Nominal current on land (A) 25 29 900 120 100 35 30 1050 150 130 50 31 1150 180 160 70 33 1350 230 200 95 34 1650 280 240 120 35 1900 330 280 150 37 2150 380 320 185 38 2500 440 370 240 42 3100 520 430 300 43 3800 600 500 400 44 4750 700 580 500 46 5800 800 660 630 50 8050 930 760 800 53 9450 1070 880
Medium voltage cable 33kv:Technical data for aluminum tripolar cables (33 kV)
Section (mm²) Approximate outer diameter (mm) Approximate weight (kg/km) 25 37.9 1870 35 41.5 2100 50 44.3 2370 70 47.9 2770 95 51.6 3210 120 55.4 3690 150 59.2 4210 185 63.0 4780 240 68.0 5610 300 73.0 6480 400 79.0 7600 500 85.0 8800 630 92.0 10100 800 99.0 11600
Comparison between copper and aluminum
Feature Copper Aluminum electrical conductivity Alta (~57 MS/m) Moderate (~35 MS/m) Weight Mayor Smaller (ca.. 60% of copper) Cost Higher Cheaper Mechanical strength Superior Inferior Flexibility Smaller Mayor It requires greater section No Yeah Typical applications Substations, industry Air distribution networks
Installation considerations
Maximum operating temperature: 90 °C.
Maximum short circuit temperature: 250 °C.
