Hydro-quebec

Raymond Berthiaume

Marcel Dery

Rene Blais

A system for and a method of extracting energy from a capacitive source, for example the energy induced in an insulated section of the overhead wire of an AC transmission line. The energy is extracted from the overhead wire by tapping the primary winding of a voltage step-down transformer which develops at its secondary an AC voltage the value of which is regulated through shunt switching. The shunt switching regulation as such is achieved by power thyristors the firing of which is selectively controlled in accordance with the phase and the amplitude of the output voltage. A comparator is used to compare the output voltage value with that of a signal delivered by an internal ramp generator. Moreover, the firing instant of the thyristors is governed by the output signal of the comparator and also in function of the information on the polarity of the output voltage cycles. Such shunt switching regulation allows the extraction from the overhead wire a maximum of power per kilometer of insulated wire and ensures a high stability of the output voltage despite substantial variations in the load connected to the secondary of the step-down transformer. The instant extracting system allows inter alia an economic and steady supply of power to microwave repeater stations which usually run along energy transmission lines and remote from central supply sources.

Energy extraction system from a capacitive source with shunt switching

A system for energizing incandescent lamps of beacons by means of the capacitive energy extracted from an insulated section of the overhead wire of power transmission lines to which the wire is capacitively coupled. The supply system comprises a device for transforming the AC energy from the overhead wire into an AC current which feeds at least one of the incandescent lamps and a regulation circuit mounted in shunt with the transforming device so as to control the current flow through those lamps. Current regulation is carried out by means of switching circuit having a switching time governed by a control circuit. In addition, the control circuit includes an integrator circuit which actually controls the switching time of the switching circuit and a comparator circuit which ensures the forming of symmetrical waveforms at the input of that switching circuit.

Feeding system for incandescent lamps by overhead wires of transmission

The present invention relates to a system for energizing flash-tubes of beacons by means of the capacitive energy extracted from an insulated section of the overhead wire of power transmission lines. The supply system comprises a circuit for transforming the AC capacitive energy from the overhead wire into DC voltage, the latter feeding at least one flash-tube and a regulation circuit shunted across the transforming circuit for controlling a DC voltage threshold value supplying the tubes. Such regulation is achieved by detecting the predetermined DC voltage threshold value across the lamp terminals and by switching to the earth any capacitive energy extracted from the overhead wire exceeding that threshold value. Moreover, a circuit delivers a pulse at predetermined time intervals to control the firing of each flash-tube when the latter is subjected to a DC voltage corresponding to the predetermined threshold value and regulated by shunt switching.

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Ste-Julie, Canada

Raymond Berthiaume