General Electric Company

Satoru Ihara

Stanley A Miske, Jr

Wendell Neugebauer

A passive filter device for a capacitor in series with a substantially inductive transmission line of an electric transmission system is disclosed. The passive filter device comprises a double-loop RCL filter in parallel with the series capacitor. At power frequency, the filter device allows the power frequency current to pass through the series capacitor with minimum power losses. At sub-synchronous resonance frequencies, the passive filter device provides bypassing of the series capacitor with maximum selectivity of the RCL filter.

Sub-synchronous resonance filters for series capacitors

Apparatus and method to separate the harmonic problems in the load side circuit of an electrical power distribution system from the source side circuit of a source transformer in a reliable and economical manner. The electrical power distribution system includes at least a source of AC electrical power, a load, and the connection from the source to the load including a source transformer, electrical conductors, wires, or cables. A part of the load is the non-linear load which injects harmonics. A harmonic blocking filter, comprised of an existing source transformer and a series combination of an auxiliary transformer and a capacitor, is connected in parallel with the source transformer. The MVA rating of the auxiliary transformer is chosen to be equal or smaller than the MVA rating of the source transformer, and the leakage impedance of the auxiliary transformer is chosen to be equal or larger than the impedance of the source transformer.

Harmonic blocking at source transformer

This circuit breaker comprises a plurality of vacuum interrupters electrically connected in series. The voltage distribution across the interrupters is controlled by a plurality of capacitive circuits respectively connected across the interrupters. Each of these capacitive circuits comprises: (a) the series combination of a relatively large main capacitor and a resistor connected across its associated interrupter, and (b) means comprising a relatively small auxiliary capacitor for producing a high frequency oscillatory current through said associated interrupter upon spark-over of the interrupter, which oscillatory current produces a natural current zero through said associated interrupter and clearance by said associated interrupter at said natural current zero well before said associated main capacitor has had time to fully discharge through said associated sparked-over interrupter.

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Burnt Hills, NY, United States of America

Satoru Ihara