Abb Research Ltd.

Friedrich Koenig

Kaveh Niayesh

Jens Tepper

Martin Lakner

Andreas Dahlquist

Stephan Schoft

An electrical resistor has an electrically conductive stack, which includes a plurality of metal first layers and second layers. The stack allows to produce a highly anisotropic resistor, in which the resistance in the direction perpendicular to the layers is much higher than in the plane of the layers. The anisotropy allows the current flowing through the stack to be made homogenous, e.g., to be distributed over the entire stack surface, even if the current is input into the stack in an inhomogenous manner.

Layered electrically conductive material

A process and a device are disclosed for current limiting and/or circuit breaking and a switchgear assembly with such a device. As claimed in the invention a liquid metal is moved by a dielectric fluid drive with a control between a first current path for the rated current (I), a second current path for current limiting (I) and optionally a third current path for current interruption (i=0), the working fluid acting mechanically with a definable drive pressure (p, p) directly on one surface of the liquid metal. Embodiments are, among others, the following: insulating gas or insulating liquid as the drive fluid; pressure drive with pressure vessels and valves or a piezodrive for the working fluid; and design criteria for the liquid metal arrangement, drive pressure (p, p) and piezodrive. Advantages are, among others, the following: reversible current limiting and current interruption, also suited for high voltages and current, fast reaction times, low wear and maintenance-friendly.

Process and device for current switching with a fluid-driven liquid metal current switch

A method and an apparatus are disclosed for current limiting, as is a switchgear assembly having an apparatus such as this. Liquid metal is passed along a resistance element for the current limiting path, in order to achieve current limiting without any arcs for network-dependent short-circuit currents. Exemplary embodiments relate, inter alia, to: an electrical resistance, which rises non-linearly in the movement direction of the liquid metal for a soft current limiting characteristic, a resistance element in the form of a dielectric matrix having channels for the liquid metal, and a combined current limiter circuit breaker. Advantages are, inter alia, reversible current limiting and possibly current disconnection without arcs, also suitable for high voltages and currents, fast reaction times, low wear, and maintenance-friendliness.

Method and apparatus for current limiting by means of a liquid metal current limiter

The present invention relates to a high-voltage insulation system which is suitable for low temperatures and which, in addition to a cooling liquid ( ) comprises a solid material insulator ( ) based on a cellulose fabric ( ). The solid material insulator ( ) is preferably used in the form of pressboards and is impregnated with a polymer resin ( ). It has a high partial discharge inception field of 77 K and, in addition, its thermal coefficient of expansion is optimally matched to that of ceramic high-temperature superconductors. The pressboards can be formed in the dry stage, in particular to produce coil formers, and are joined together alternately with cotton fabrics to form laminates of any desired thickness.

Growing community of inventors

Oberbözberg, Switzerland

Friedrich Koenig