Asea Brown Boveri Inc.

Asea Brown Boverti Ltd.

Rudolf Baumgartner

Ken Yves Haffner

Heinz Hageli

Andrzej Kaczowski

Andrezej Kaczkowski

A combined current and voltage transformer for a metal-enclosed, gas-insulated high-voltage switching station. It has a current and voltage sensor (10) and a signal processing device connected following the current and voltage sensor (10). A coil (14) wound in the shape of a torus serves as current sensor, and a hollow cylindrical test electrode (15) serves as voltage sensor. After installation of the current and voltage sensor (10) in the metal enclosure (4), the coil (14) and test electrode (15) concentrically surround a conductor (5) of the switching station. This combined current and voltage transformer is cost effective in production, has small dimensions, and a high measurement accuracy. This is achieved when the current and voltage sensors are constructed such that signals corresponding to the temporal variation in the current to be determined and in the voltage to be determined are present at their outputs, and the signal processing device has at least one integration device on which the output signals of the current and voltage sensors (10) act.

Combined current and voltage transformer for a metal-enclosed

The current and voltage transformer (10, 11) is intended for a metal-encapsulated, gas-insulated high-voltage installation. It has an annular supporting body (13) which can be fixed inside the metal encapsulation (7) and is used for holding a current sensor and a voltage sensor. The current sensor, held on the supporting body (13), is constructed as a toroidally wound coil (14) and the voltage sensor, held on the supporting body (13), is constructed as a hollow-cylindrical measurement electrode (15). After fitment in the installation, the coil (14) and measurement electrode (15) concentrically surround a current conductor (5) of the installation. This current and voltage transformer is intended to have small dimensions and is intended to be capable of fitment without problems at any point in the installation. This is achieved in that the coil (14) is wound in the manner of a Rogowski coil on an annular core (29) of non-ferromagnetic material, of essentially rectangular cross-section when cut in the axial direction, having a small radial dimension in comparison with the radius of the core ( 29) and with its axial extent, and is arranged in a hollow-cylindrical space (19) in the supporting body (13), which space is shielded against electric fields and whose boundary wall providing the electrical shielding is connected, after fitment, to the potential of the metal encapsulation (7).

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Gebenstorf, Switzerland

Rudolf Baumgartner