4. High Currents and Contact Technology

Electrical power systems and transport systems are subject to profound changes all around the world. This is accompanied by higher requirements for the components of stationary or mobile equipment of electrical power engineering. Especially a compact design, a higher current load under normal operating conditions, and in the case of a fault, disparate environmental conditions and the demand for higher availability, reliability, and safety are great challenges for designers, manufacturers, constructors, and operators.

This chapter gives an overview of current-conducting arrangements (conducting systems) whose load is cause by electric current and ambient conditions, the resulting thermal and mechanical stress, and the long-term and reliably necessary strength of the conducting components.

Fundamentals on the thermal behavior of equipment and analytical approaches to the calculation of temperatures at relevant spots are presented that have proven themselves over decades in practice. If necessary, they can be supplemented by numerical methods, which will not be explicitly discussed here. Regarding the mechanical-dynamical behavior of current-conducting arrangements exposed to short-circuit currents or thermal elongation due to current load, methods for determining the strain and the necessary strength are presented with regard to the material properties in the elastic range and the plastic range. Stationary electrical contacts and connections have been the subject of scientific research at TU Dresden for more than four decades and will be discussed here in an overview in terms of design, operating, and long-term behavior.

All results presented in this chapter are, to a great extent, results of scientific research at TU Dresden and have been taken from the course material presented to the students.