New aluminium alloys for long-lasting electrical connections
With the expansion of renewable energies, increased amounts of electrical energy will need to be transported in the coming years. In particular the large onshore and offshore wind farms in the sparsely populated north, which have an installed capacity of about 44 GW, along with the load centres in the energy-intensive south make it essential to find new ways for transporting power. The current grid structure is reaching the limits of its physical capability. In the ALLEE project, Professor Olaf Kessler and four research partners are researching new aluminium alloys that meet the increased demands.
Aluminium offers several advantages in this regard compared with copper: it is cheaper and lighter, and it also has a higher density-related electrical conductivity. This becomes evident when comparing copper and aluminium from the power engineering viewpoint: the base material AL99.5 used for many aluminium alloys requires, for example, 1.7 times the conductor cross-section in comparison with copper. With a cross-section 1.9 times greater than copper, AIMgSi even requires a cross-section almost twice as large in order to transmit the same power. However, the lower density of aluminium means that its weight is only about half as much as copper for the same current-carrying capacity.
A problem with the use of aluminium, however, is its low creep resistance at high temperatures. This means that aluminium conductors subjected to constant mechanical loads will deform plastically over time. If this occurs in a connection, the electrical resistance, power loss and thus the temperature of the material can considerably increase. The connection ages faster as a result and can already fail within the planned service life.
The aim of this research project is to develop creep-resistant aluminium alloys for use in energy technology. Specifically, this means that the material retains its physical properties at high temperatures of around 140 °C and thus enables electrical connections to be made that remain stable in the long term. The developers are focussing here on busbars. These shall be produced in a typical geometry and then investigated in long-term studies as bar stock and when used in screw connections as well as under typical loads.
09/2014 – 08/2017
Fakultät für Maschinenbau und Schiffstechnik
18059 Rostock, Germany