A conductor is one of the most important assets in the power system network. A conductor is that physical medium used to convey electrical power to consumer’s unit. The proper choice of a conductor is therefore crucial to ensure an excellent transmission of the power generated.
An ideal conductor has the following properties:
- Good electrical conductivity.
- Lower weight/unit volume.
- It should have low specific gravity in order to limit the weight per unit volume.
- High tensile strength to withstand mechanical stress and reduce both wind and ice loading.
- It is affordable so that it can be used in long-distance transmission and distribution without compromising other important properties.
Considering these properties we can easily see that it will be difficult for any particular conductor to provide such requirements. As a result, some options are sacrificed in favour to others. It all depends on the cost, the application as well as electrical and mechanical properties.
For 36KV transmission and above, overhead conductors are used in overhead power lines. Overhead power lines are structures used to transmit electrical energy across large distances. This post talk about the type of conductors used in overhead transmission and distribution lines:
- AAC : All Aluminium Conductor
- AAAC : All Aluminium Alloy Conductor
- ACSR : Aluminium Conductor, Steel Reinforced
- ACAR : Aluminium Conductor, Alloy Reinforced.
However it’s important to see why aluminium cables are preferred than copper.
Copper was most popular for overhead transmission in earlier days. However, Aluminium is comparatively cheaper than copper , it’s about half of weight than this one and it possess a larger diameter for the same amount of current . This makes it more attractive to engineers and designers.
Copper is still widely used at lower voltages and for grounding.
Aluminium on the other hand, has some disadvantages over copper which are:
- Lesser conductivity (about 60% of copper).
- Lesser tensile strength: this is why alluminium can be used with other materials or its alloys.
- Its durability is far less than that of the copper.
- Lesser specific gravity.
The relevant standards applied in conductors used for overhead transmission lines are listed in the following table:
|IEC 61089||Round wire concentric lay overhead electrical stranded conductors||Supersedes IEC 207 (AAC), 208 (AAAC), 209 (ACSR) and 210 (AACSR)|
|EN 50182||Conductor for overhead lines: round wire concentric lay stranded conductor||Supersedes IEC 61089 for European use. BSEN 50182 identical|
|EN 50183||Conductor for overhead lines: aluminium–magnesium–silicon alloy wires|
|BS 183||Specification for general purpose galvanized steel wire strand||For earth wire|
|BS 7884||Specification for copper and copper–cadmium conductors for overhead systems|
- AAC : All Aluminium Conductor:
Also known as ASC( Aluminium stranded conductor) , this conductor it’s a pure aluminium( close to 99.5% minimum aluminium content). Despite having the highest conductivity weight ratio of all the overhead conductors and be less expensive, AAC is mostly used in congested urban areas(where maximum current transfer are required) and distribution lines. This is due the fact that AAC is not as strong as the other conductors.
It is crucial to purchase AAC at a good price. There are many suppliers out there and KV International business & consulting will connect you with the best. The company provides high quality cables from china at an affordable price and with respect to the standards applied to that industry.
These are some cable dimensions:
|Code Word||Size – AWG or MCM||Nominal Cross Sectional Area||Nominal Weight kg/km|
2. AAAC : All Aluminium Alloy Conductor:
This type of conductor is similar in appearance and construction to AAC except the alloy. AAAC conductors have properties (super corrosion resistance for example) that make them a proper choice for installations where corrosion problems are predictable.
Useful characteristics of AAAC conductors:
- Good electrical conductivity: about 52.5% IACS (International Annealed Copper Standard). They are made from aluminium alloy 6201
- High mechanical strength.
- Lower electrical losses.
- Better tensile strength than AAC which is useful for longer spans.
These are some cable dimensions examples:
|Code Word||Size – KCM||Nominal Cross Sectional Area||Nominal Weight kg/km|
You can order your AAAC conductors from here:
3. ACSR : Aluminium Conductor, Steel Reinforced
Historically, ACSR conductors have been widely used due to their mechanical strength as well as the cost and widespread. They become popular in the improvement of aluminium conductors. Indeed it was quite difficult to use them in situations where strength was required. Therefore, the idea to bring steel in order to expand the properties of that conductor was an excellent one. ACSR brings the best of two important materials: The conductivity of Aluminium and the strength of Steel. They are available in a wide range of steel: 6% – 40% approximatively. These conductors are widely used in most transmission and distribution constructions today compared to other conductors.
These are some important advantages of ACSR conductors:
- They have long life span.
- High tensile strength, brought by steel. Which means that they can be installed in areas where wind loading prevails.
- Good flexibility compared to their counterparts.
The following table lists some ACSR cable dimensions:
|Code Word||Size – AWG – MCM||Nominal Cross Sectional Area||Nominal Weight kg/km|
If you want to reach on the most professional ASCR conductor do not hesitate to contact us.
4. ACAR : Aluminium Conductor, Alloy Reinforced.
This conductor is not yet used in most transmission or distribution lines. However due to they electrical and mechanical properties which are equivalent or better than ACSR conductors, they may be used in overhead lines.
ACAR conductors are expensive and cannot be installed in areas that are prone to corrosion.
The construction of a reliable and strong electrical power line depends on many factors like electrical and mechanical designs. The Electrical design involves features like the power used in a specific installation, inductance or capacitance of cables, or the structure and the type of poles. On the other hand, mechanical designs require stress and design analysis.
It is important as a designer or engineer to select proper conductors. Though there are tons of good cable suppliers available in the market, It’s still crucial to find those who do not only understand and know which conductors are suited to your projects, but are available .
Reach kv international business & consulting today.
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