US 5,432,438 AGranted

Combined current and voltage transformer for a metal-enclosed gas-insulated high-voltage switching station

AssigneeAsea Brown Boverti Ltd.

InventorsRudolf Baumgartner, Ken Y. Haffner, Andrzej Kaczowski

Life of this patent

Estimating the term…

Loading patent…

Abstract

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.

Claims10

Dependent claims

A combined current and voltage transformer for metal-enclosed, gas-insulated high-voltage switchgear comprising:

a tubular metal enclosure at ground potential and filled with an insulating gas;
a current sensor enclosed and supported by said enclosure and containing a shielded Rogowski coil, which after installation in the metal enclosure concentrically surrounds a high-voltage conductor of the switchgear;
a voltage sensor enclosed and supported by said enclosure and containing a hollow cylindrical test electrode which after installation in the metal enclosure concentrically surrounds the high-voltage conductor of the switchgear and which is part of a capacitive voltage divider containing:
a high-voltage capacitor formed by the high-voltage conductor and the test electrode;
a low-voltage capacitor formed by the test electrode and the metal enclosure as well as the shield of the Rogowski coil;
and
an ohmic resistor having a first end electrically connected to the test electrode and having a second end electrically connected to the metal enclosure and the shield of the Rogowski coil for forming signals at the output of the voltage sensor which are proportional to the temporal variation in the high voltage of the high voltage conductor;
and
a signal processing device connected to the current sensor and to the voltage sensor and having at least one integration device on which the output signals of the current sensor and of the voltage sensor act

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/904,863Filed 26 Jun 1992
Priority: DE 41 21 654.729 Jun 1991
Granted: 11 Jul 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H01F 38/36
Combined voltage and current transformers: constructions
G01R 15/142
Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks: arrangements for simultaneous measurements of…
G01R 15/18
Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks: using inductive devices, e.g. transformers
G01R 15/181
Using inductive devices, e.g. transformers: using coils without a magnetic core, e.g. Rogowski coils