Siemens Aktiengesellschaft

Hans-Joachim Freygang

Gabor Kovacs

Reinhold Schmitt

Willi Muller

Manfred Weniger

Panajotis Margaris

Klaus Bollmann

Jurgen Moeller

Disclosed are an inductive voltage transformer having a primary winding connected to a network line and a protective circuit therefor. In order to prevent a large thermal and mechanical stress in such a transformer, the protective circuit comprises a control unit which controls a switching device for connecting a circuit arrangement to a secondary winding of the voltage transformer. The circuit arrangement includes a current generating circuit with a charging capacitor. The protective circuit operates to generate a current causing a counter excitation in the transformer to that caused when the capacitance of the network line is discharged via the primary winding of the transformer. The voltage transformer and the protective circuit are suited particularly for connection to network lines having a large internal capacitance.

Inductive voltage transformer and circuit therefor

In an apparatus comprising a high-voltage measuring capacitor and, in particular, comprising a high-voltage measuring capacitor formed by a high-voltage conductor of a fully insulated, metal-encapsulated high-voltage switch-gear installation and by a surface electrode associated with the former, an auxiliary capacitor is associated with and located adjacent to said high-voltage capacitor. The auxiliary capacitor is part of an evaluation device which generates a signal corresponding to capacitance changes of the auxiliary capacitor resulting from external influences. Following the evaluation device is an indicating device for signaling the occurrence of such capacitance changes and/or a control or regulating device for compensating for capacitance changes of the high-voltage measuring capacitor caused by the same external influences.

Arrangement comprising a high voltage measuring capacitor

A voltage transformer for a fully insulated high-voltage installation containing several conductors includes a plurality of electrodes corresponding to respective ones of the conductors. The electrodes are disposed outside of the arrangement of the conductors in such a manner that each one of the electrodes is disposed directly adjacent a corresponding one of the conductors. Each of the electrodes and the conductor directly adjacent thereto conjointly define a high-voltage capacitor. A plurality of low-voltage capacitors are disposed outside of the region occupied by the electrodes and are connected to corresponding ones of the high-voltage capacitors so as to conjointly define therewith respective capacitive voltage dividers.

Voltage transformer for an insulated high-voltage switching installation

A measuring transformer arrangement with a capacitor bushing and devices for measuring voltage and current associated with the capacitor bushing is suitable for use in a high-voltage installation with metal encapsulation carrying several high-voltage conductors. The capacitor bushing provided for each high-voltage conductor is arranged in a bulkhead partition of the metal encapsulation and carries a current measuring device which includes at the periphery of the bushing at least one current transformer core with a secondary winding system mounted thereon.

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Berlin, Germany

Hans-Joachim Freygang