REACTIVE POWER ELECTRONIC ADJUSTMENT OF REACTORS

Abstract: A reactor (1) with electronic adjustment of reactive power, comprising at least one main winding (2) and an adjustment winding (3). The particularity of the reactor, according to the present invention, consists of the fact that it furthermore comprises a voltage regulator circuit (4), which is connected to the main winding and to the terminals of the adjustment winding (100, 101) and is suitable to generate an alternating adjustment voltage, which is meant to be added to and/or subtracted from a sinusoidal voltage generated by the main winding.

Description: REACTIVE POWER ELECTRONIC ADJUSTMENT OF REACTORS DESCRIPTION The present invention relates to a reactor of the parallel or series type, with electronic adjustment of reactive power. It is known that reactors arranged in a parallel configuration, having a fixed number of turns, are used to compensate the capacitive power of high-voltage lines. Likewise, reactors which again have a fixed number of turns are arranged in series in order to limit short-circuit currents in high- voltage lines. These two kinds of use of reactors, however, have the drawback that they are not flexible enough as regards the variability of the conditions of electric power lines. The variability of power electric lines, in fact, makes it necessary to be able to vary the reactance introduced in the line by the reactor. The aim of the present invention is to provide a reactor of the parallel or series type, with electronic adjustment of the reactive power. Within the scope of this aim, an object of the present invention is to provide a reactor of the parallel or series type, with reactive power adjustment, which is capable of continuously adjusting its own reactance within set limits. Another object of the present invention is to provide a reactor of the parallel or series type, with electronic adjustment of the reactive power, in which said reactance adjustment can occur both so as to increase the reactance and so as to decrease it. Another object of the present invention is to provide a reactor of the parallel or series type with reactive power adjustment, which is highly reliable, relatively easy to provide and at competitive costs. Thus, the present invention provides a reactor with electronic adjustment of reactive power, comprising at least one main winding and an adjustment winding. The reactor, according to the present invention is characterized in that it comprises a voltage regulator circuit, said voltage regulator circuit being connected to said main winding and to the terminals of said adjustment winding and being suitable to generate an alternating adjustment voltage, which is meant to be added to and/or subtracted from a sinusoidal voltage generated by said main winding. Further characteristics and advantages of the invention will become apparent from the description of preferred embodiments of the reactor according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a circuit diagram of a first embodiment of the reactor according to the present invention; and Figure 2 is a circuit diagram of a second embodiment of the reactor according to the present invention. With reference to the above cited figures, the reactor, generally designated by the reference numeral 1 , comprises a primary winding 2, an adjustment winding 3, and a voltage regulator circuit 4, which are connected as follows. One terminal of the primary winding 2 is connected to the power supply line, while the opposite terminal is connected to the terminals of the adjustment winding 3, after interposing a pair of regulators 5 and 6 which are connected to the terminals of the adjustment winding 3. The voltage regulator circuit 4 comprises, in addition to the regulators 5 and 6, another pair of regulators 7 and 8. The regulators 7 and 8 are respectively connected between a first terminal 100 of the adjustment winding 3 and the ground and a second terminal 101 of the adjustment winding 3 and the ground. The adjustment voltage generated by the adjustment winding 3 can be added to, and subtracted from, the main voltage induced in the primary winding 2. By dividing the adjustment winding 3 into steps, the number of positions, with perfectly sinusoidal waveforms in the adjustment range, is increased. By acting on the power-on side of the regulators it is possible to shift from one sinusoidal voltage step to the next continuously, accepting a very small voltage rounding with a negligible harmonic content. The advantage of electronic adjustment therefore consists in adjusting the voltage continuously with limited noise (small step) or discontinuously without noise, according to the requirements of the user. In practice, the voltage generated by the adjustment winding 3 is added to, or subtracted from, the sinusoidal alternating voltage generated by the primary winding 1. Figure 1 illustrates the first embodiment, in which there is only a primary winding 1. Figure 2 instead illustrates the case in which there is also a secondary winding 10, which is connected to the voltage regulator circuit 4 and in particular in series to the regulator 8. In practice, it has been found that the reactor with electronic adjustment according to the invention fully achieves the intended aim, since the adjustment winding allows to vary the reactance that the reactor can introduce in a line, by acting specifically on the sinusoidal voltage generated by the adjustment winding, which can be added to, and subtracted from, the sinusoidal base voltage generated by the primary winding of the reactor. The reactor thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with other technically equivalent elements.

Claims: CLAIMS 1. A reactor with electronic adjustment of reactive power, comprising at least one main winding and an adjustment winding, characterized in that it furthermore comprises a voltage regulator circuit, said voltage regulator circuit being connected to said main winding and to the terminals of said adjustment winding and being suitable to generate an alternating adjustment voltage, which is meant to be added to and/or subtracted from a sinusoidal voltage generated by said main winding. 2. The reactor according to claim 1, characterized in that said voltage regulator circuit comprises a first pair of regulators, which are connected to the terminals of said adjustment winding and a common node of which is connected to a terminal of said primary winding, and an additional pair of regulators, which are respectively connected between one end of said adjustment winding and the ground and the other end of said adjustment winding and the ground. 3. The reactor according to claim 2, characterized in that it comprises an additional winding which is series-connected to said voltage regulator circuit. 4. The reactor according to claim 3, characterized in that said additional winding is connected to the regulator of said regulator circuit that is connected between one terminal of said adjustment winding and the ground.

Inventors: IEMMI DORINO, LANCIANO GIOVANNI, LANZAVECCHIA LORENZO, TESTIN GIOVANNI, IEMMI, DORINO, LANCIANO, GIOVANNI, LANZAVECCHIA, LORENZO, TESTIN, GIOVANNI
Applicants: ABB RICERCA SPA, IEMMI DORINO, LANCIANO GIOVANNI, LANZAVECCHIA LORENZO, TESTIN GIOVANNI, ABB RICERCA S.P.A., IEMMI, DORINO, LANCIANO, GIOVANNI, LANZAVECCHIA, LORENZO, TESTIN, GIOVANNI
Application year: 2000
Main classification: G05F1
IPC codes: G05F1