Hydro-quebec

Leonard Bolduc

Gregoire Pare

Gerald Roberge

The electrical dampening circuit for dampening resonance of a power signal in a power distribution network, comprises a capacitor C, an inductance L connected in parallel to capacitor C, and a resistance R connected in series with capacitor C and inductance L, values of capacitor C and inductance L being calculated so that (2.pi.f).sup.2 LC=1, where f is frequency of the power signal. The value of R is calculated so that 3.sqroot.L/C &lt;R&lt;(2/3) .sqroot.L/C whereby dampening of resonance is obtained.

Electrical dampening circuit for dampening resonance of a power signal

The transformer comprises a three-limbed magnetic core having two outer limbs each defining a central air gap. Two windings, an alternating current one and a direct current one, are wound around each outer limb. Primary and secondary windings are disposed on the center limb, the primary one being supplied with alternating current from a source, and the secondary one supplying with alternating current an external load. The two alternating current windings are connected in series and supplied with alternating current by the source, possibly through an additional winding wound around the center limb, while the two direct current windings are connected in series and supplied by the current in the alternating current windings rectified through a diode bridge. The current in the two direct current windings induces a magnetic flux in a closed circuit defined by the outer limbs. The alternating currents in the primary winding and in the two alternating current windings are coupled to first and second alternating current magnetic fluxes assisting each other in the center limb and respectively flowing in two closed magnetic circuits defined, on the one hand, by the center limb and one outer limb, and, on the other hand, by the center limb and the other outer limb. The transformer supplies the external load with electric energy from the source while regulating the source and supply voltages.

Self-regulated transformer-inductor with air gaps

An electric power apparatus, namely a variable inductor comprising a magnetic core provided with a center limb and two outer limbs all having first and second ends. The first ends are interconnected through a first common point of the magnetic core, and the second ends through a second common point of this core. Two primary windings disposed respectively around the two outer limbs are connected in series and supplied with an alternating current, while two control windings also connected in series are respectively superposed to the two primary windings. The alternating current of the primary windings is rectified through a diode bridge for supplying with direct current the control windings. The direction of the different windings along with their interconnections are selected so that the alternating and direct currents induce in one of the two outer limbs alternating and direct current magnetic fluxes which assist each other or which are in opposition and in the other of these two limbs alternating and direct current magnetic fluxes which are in opposition or which assist each other, respectively, depending on the positive or negative value of the alternating current. Each outer limb comprises an air gap traversed by the resultant magnetic flux induced in this limb, and preferably disposed in the center of the corresponding primary and control windings.

Self-controlled variable inductor with air gaps

Variable ratio transformer constructed around a control transformer comprising: two closed magnetic circuits each constructed around a ferromagnetic core. An alternating current magnetic field circulates in the first core and a direct current magnetic field circulates in the second core. The two circuits are located so as to define at least two common magnetic spaces in which the fields are superposed orthogonally. Around the first core is wound a primary winding, a secondary winding and, for a specific application in a three-phase circuit, a tertiary winding. A conventional transformer can be associated with the control transformer to reduce the load supported by the control transformer. The variable ratio transformer according to the invention can be used as a static balance compensator.

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Ste-Julie, Canada

Leonard Bolduc