With the rise in prices of electrolytic copper materials, the cost of copper busbars and electrical distribution in engineering has increased. Currently, copper busbars dominate the market.
Is there a product that performs as well as a copper bus but has a lower price? The answer is affirmative.
Aluminum busbars, with their cost-effectiveness and excellent performance, can replace copper busbars.
Currently, the unit price of aluminum busbars is around 50% of the price of copper, making them a viable alternative for reducing costs without compromising performance.
This article mainly introduces the performance of our aluminum busbars to provide a comprehensive understanding to users.
I. Conductivity Analysis of Aluminum Busbars
The conductivity of our copper bars is 99.98%, while market standard copper bars have a conductivity of only 52%~85%. Evidently, the conductivity of our company's copper busbar significantly surpasses that of other brands.
Furthermore, our busbars have a larger cross-sectional area, increasing their safety factor. Given the price and weight of copper busbars, we also offer aluminum busbars, which use aluminum bars with conductivity ≥61%.
Although it is lower than that of copper busbars, it matches the conductivity of some copper busbars on the market, and the cross-sectional area of aluminum busbars has also increased. Therefore, the safety performance of buses will not be compromised by material changes.
II. Current density analysis of aluminum busbars
Comparison of current density between aluminum and copper conductors (Unit: A/mm 2 )
| Electric Current/Materials | 1600A | 1600A~3150A | 3150A~5000A |
| Aluminum | 2~1.5 | 1.6~1.5 | 1.5~1.15 |
| Copper | 2.5~1.78 | 1.78~1.67 | 1.67~1.59 |
Load Current Analysis under Equal Weight Conditions:
The density of aluminum is 2.7 grams per cubic centimeter, while that of copper is 8.9 grams per cubic centimeter.
The density of copper is approximately 3.3 times that of aluminum. Thus, under equal weight, the charging current of aluminum significantly exceeds that of copper.
For example, in a 1600A scenario, aluminum's charging current per unit weight is 2.67 times greater than that of copper. This substantially reduces the weight of the bus, benefiting from lightening the building load and facilitating construction installation.
III. Impedance Analysis
Impedance values for HP-type aluminum or copper conductors used for 50 Hz or 60 Hz three-phase AC power are as follows:
Unit: ×10 -4 Ω/m
| Rated current (A) | 50Hz | 60Hz | |||||
| R（Ω/m） | X（Ω/m） | Z（Ω/m） | R（Ω/m） | X（Ω/m） | X（Ω/m） | ||
| COPPER | 600 | 0.974 | 0.380 | 1,045 | 0.977 | 0.456 | 1,078 |
| 800 | 0.784 | 0.323 | 0.848 | 0.789 | 0.387 | 0.879 | |
| 1000 | 0.530 | 0.235 | 0.580 | 0.536 | 0.282 | 0.606 | |
| 1200 | 0.405 | 0.185 | 0.445 | 0.412 | 0222 | 0.468 | |
| 1350 | 0.331 | 0.152 | 0.364 | 0.338 | 0.183 | 0.384 | |
| 1500 | 0.331 | 0.152 | 0.364 | 0.338 | 0.183 | 0.384 | |
| 1600 | 0.282 | 0.129 | 0.311 | 0.289 | 0.155 | 0.328 | |
| 2000 | 0.235 | .0.107 | 0.259 | 0.241 | 0.128 | 0.273 | |
| 2500 | 0.166 | 0.076 | 0.182 | 0.169 | 0.091 | 0.192 | |
| 3,000 | 0.141 | 0.065 | 0.155 | 0.144 | 0.078 | 0.164 | |
| 3500 | 0.123 | 0.056 | 0.135 | 0.127 | 0.068 | 0.143 | |
| 4000 | 0.110 | 0.051 | 0121 | 0.113 | 0.061 | 0.126 | |
| 4500 | 0.094 | 0.043 | 0.104 | 0.096 | 0.052 | 0.109 | |
| 5,000 | 0.082 | 0.038 | 0.091 | 0.084 | 0.045 | 0.096 | |
| ALUMINUM | 600 | 1,257 | 0.323 | 1,297 | 1,385 | 0.387 | 1,438 |
| 800 | 0.848 | 0.235 | 0.879 | 0.851 | 0.282 | 0.896 | |
| 1000 | 0.641 | 0.185 | 0.667 | 0.645 | 0.222 | 0.682 | |
| 1200 | 0.518 | 0.152 | 0.540 | 0.523 | 0.183 | 0.554 | |
| 1350 | 0.436 | 0.129 | 0.454 | 0.443 | 0.155 | 0.469 | |
| 1500 | 0.378 | 0.113 | 0.394 | 0.386 | 0.135 | 0.409 | |
| 1600 | 0.360 | 0.107 | 0.375 | 0.367 | 0.128 | 0.389 | |
| 2000 | 0.286 | 0.084 | 0.298 | 0.293 | 0.101 | 0.310 | |
| 2500 | 0.218 | 0.065 | 0.228 | 0.221 | 0.078 | 0.235 | |
| 3,000 | 0.180 | 0.054 | 0.188 | 0.184 | 0.064 | 0.195 | |
| 3500 | 0.143 | 0.042 | 0.149 | 0.146 | 0.051 | 0.155 | |
| 4000 | 0.126 | 0.038 | 0.131 | 0.129 | 0.045 | 0.136 | |
| 4500 | 0.120 | 0.036 | 0.125 | 0.122 | 0.043 | 0.130 | |
| 5,000 | 0.095 | 0.028 | 0.099 | 0.098 | 0.034 | 0.103 | |
Taking 1600A as an example, the impedance of copper is: R: 0.282, X: 0.129, Z: 0.311.
The impedance of aluminum is: R: 0.360, X: 0.107, Z: 0.375. Unit: (10 -4 Ω/m).
As can be seen, the impedance of aluminum and copper is almost the same. Low impedance can increase transmission distance and improve effective signal delivery.
4. Voltage Drop Analysis
In terms of voltage drop, the voltage drop of copper and aluminum is calculated by the following formula:
Voltage drop calculation △V = √3 I (Rcosφ+Xsinφ)
- △V: Line-to-line voltage drop (V/m)
- I: Charging current (A)
- cosφ: Load power factor
- sinφ: √1- cos2φ
- A: AC resistance under load current (Ω/m)
R=R 95 ×(1+α{55×I/I 0 +20} 2 /1+75α)
- R95: Data in the impedance value table. (10 -4 Ω/m)
- α: Temperature coefficient of resistance Copper: 3.85×10 -3
- Aluminum: 4.00×10 -3
- EU 0 : Nominal Current (A)
- X: Reactance (Ω/m)
For example, when cosφ=0.8:
| Aluminum voltage drop (V/m) | Copper Voltage Drop (V/m) | |
| 1600A | 0.103 | 0.098 |
| 3150A | 0.096 | 0.092 |
| 5000A | 0.086 | 0.080 |
It can be seen that although the difference in voltage drop between aluminum and copper increases slightly with the growth of current, the difference is not very significant and will not affect normal use.
If the bus length is 100 meters, the difference between aluminum and copper for a 3150A bus is 0.4V, which can be practically ignored. Therefore, in terms of voltage drop, the performance of aluminum and copper is basically the same.
V. Analysis of temperature increase
According to the certification of the CCC department, our company's busbar temperature rise complies with the national standard:
1600A Bus:
The national standard stipulates that the temperature rise allowed at the connection is ≤70(K)
The highest temperature rise in our company's aluminum busbar connection is 49.7 (K),
The largest temperature rise at the copper bus connection is 43.1(K).
3150A bus:
The national standard stipulates that the temperature rise allowed at the connection is ≤70(K)
The highest temperature rise in our company's aluminum busbar connection is 52.8 (K),
The largest temperature rise at the copper bus connection is 51.5(K).
5000A bus:
The national standard stipulates that the temperature rise allowed at the connection is ≤70(K)
The highest temperature rise in our company's aluminum busbar connection is 39.4 (K),
The largest temperature rise at the copper busbar connection is 38.2(K).
From the above data, it can be seen that our company's buses not only meet the national standard, but are also far below the national standard.
One point worth noting is that the temperature rise difference between copper and aluminum busbars is only 2~4K.
Therefore, it can be said that our company's aluminum busbars are not inferior to copper busbars in terms of temperature rise, and even better than most copper busbars on the market.
SAW. Analysis of the allowable short-circuit overload current
When a short-circuit fault occurs in the power supply circuit, the short-circuit current in the short-circuit circuit is several to hundreds of times greater than the rated current, often reaching several thousand amps.
The short-circuit current passing through electrical equipment and conductors will inevitably generate a large electromotive force, and the temperature of the equipment may rise sharply, possibly damaging the busbar.
Therefore, the bus must be capable of withstanding the short-circuit current required by the national standard.
After the CCC type test, the short-term endurance test results of our company's aluminum busbars are shown in the following table:
Short Circuit Test Performance Comparison Table for Copper and Aluminum Busbars
| Materials/test current | copper bus | Aluminum Busbar |
| 30KA | Parent Line: During a test with a current of 30KA and an energization time of 1ms, the aluminum bus did not suffer any damage or deformation by mechanical parts or insulators.
Functional Unit: During testing with a current of 35KA and an energization time of 1ms, the plug contacts showed no signs of fusion welding and there was no damage to mechanical or insulating parts. Neutral Bus: With a current of 18KA and an energization time of 1ms, the aluminum bus did not suffer damage or deformation from mechanical parts or insulators. This is in full compliance with national standards. |
Parent line: With a test current of 30KA and an electrification time of 1ms, the aluminum bus did not suffer damage or deformation of the mechanical or insulating parts.
Functional Unit: With a test current of 35KA and an electrification time of 1ms, the plug contacts showed no signs of fusion welding and there was no damage to the mechanical and insulating parts. Neutral Line: In the 18KA, with an electrification time of 1 ms, the aluminum bus did not suffer damage or deformation in any mechanical or insulating part. This is in full compliance with national standard regulations. |
| 65KA | Parental Line: During the test with a current of 65KA and a duration of 1ms, the aluminum bus did not suffer any damage or deformation to any mechanical or insulating component.
Functional Unit: During the test with a current of 35KA and a duration of 1ms, the plug contact did not show any welding phenomenon and there was no damage to any mechanical or insulating components. Neutral Line: With 39KA and a duration of 1ms, the aluminum bus did not suffer any damage or deformation to any mechanical or insulating component. It fully complies with national standard regulations. |
Mother Line: The test current was 65KA and the energization time was 1ms. The aluminum busbar has not been damaged or deformed by any mechanical or insulating parts.
Functional Unit: The test current was 35KA and the energization time was 1ms. The plug contacts did not show any welding phenomenon, and no mechanical or insulating parts were damaged. Neutral Line: 39KA, energization time was 1ms. The aluminum busbar has not been damaged or deformed by any mechanical or insulating parts. Fully complies with the provisions of national standards. |
| 80KA | Main bus: The test current is 80KA, the energization time is 1ms, the aluminum bus is not damaged and there is no deformation of any mechanical parts and insulating parts.
Functional Unit: The test current is 35KA, the energizing time is 1ms, the plug contact has no welding phenomenon, and there is no damage to any mechanical and insulating components. Neutral bus: 48KA, energization time is 1ms, the aluminum bus is not damaged and does not show deformation of any mechanical components and insulating parts. It fully complies with national standard regulations. |
Main bus: Test current 80KA, electrification time is 1ms, the aluminum bus has not been damaged or deformed by any mechanical parts and insulating parts.
Functional Unit: Test current 35KA, electrification time 1ms, there was no welding phenomenon at the plug contact, and no mechanical or insulation parts were damaged. Neutral bus: 48KA, 1ms electrification time, the aluminum bus has not been damaged or deformed by any mechanical parts and insulating parts. It fully complies with the regulations of national standards. |
Our product fully complies with the national standard GB7251.2-2006. In this sense, copper and aluminum busbars share the same performance. Notably, our buses were subjected to testing in Japan, where the test current was 240KA.
Consequently, the performance of our buses not only meets national standards, but also exceeds them. Therefore, if a short circuit occurs during use, our buses can withstand even more rigorous tests.
VII. Practical applications
As is widely known, aluminum, due to its inherent properties, is easily corroded when used as a metal, especially in humid air. Harmful gases dissolve in water to form electrolytes, and when aluminum comes into contact with other metals, a primary cellular reaction occurs due to differences in standard electrode potentials between the metals.
The presence of impurities in aluminum can lead to microcellular reactions. The critical humidity of aluminum is 65%, and the higher the relative humidity that exceeds this critical level, the faster the aluminum will corrode.
The aluminum surface will form an oxide film, which will generate heat during electrification, causing an excessive increase in temperature on the contact surface, which may even result in an explosion.
However, our busbar contacts are treated with a special tinning process that effectively resolves the adverse performance of aluminum as a conductor, allowing it to be widely reused in the area of power transmission.
