Three-phase balancing device

FIELD: electricity.

SUBSTANCE: invention relates to electric engineering. The invention claims a three-phase balancing device where a three-phase three-leg transformer contains windings connected in an opposite staggered way. Free leads of the first windings are connected to output terminals and free leads of the second windings are connected into a common zero point to couple phase loads. In each phase there is one or two in-series voltage adding windings coupled through a two- or three-position switch in sequence with load at the side of the supply mains.

EFFECT: provision of the phase voltage balancing.

1 dwg

 

The invention relates to electrical engineering and can be used in power supply circuits of various equipment.

Known three-phase AC voltage stabilizer, containing balancing transformer (1).

The disadvantage is a large installed power transformer

Known three-phase symmetrise device containing the input terminals for connection to the mains supply and output terminals to which are connected three-phase transformer, the primary winding connected in a "zigzag" (2).

The disadvantage is the complexity and large installed capacity balancing transformer.

Closest to the proposed device is a three-phase symmetrise device between input and output terminals which included a three-phase circuit breaker, and to the output or input terminals connected three-phase transformer, the primary windings of which are connected in opposite and connected in a "zigzag" (3).

The lack of significant asymmetry of the phase voltages when the unbalance of the input line voltages.

The purpose of the invention is the provision of balancing phase voltages upon line voltage unbalance

This objective is achieved in that in the known device containing the input terminals Al, B1, C1, N1 for connecting the mains supply and output terminals A2, B2, C2, N2 for the switching of the load and connected to three-phase three transformer, two of the primary winding of which is connected a counter-sequentially in a "zigzag", in each phase of the transformer put one or two connected in series booster winding included, from the mains through a two or three position switch, in series with the load. Thus, the proposed device complies with the criteria of the invention of "novelty."

Comparison of the proposed technical solution is not only the prototype, but also with other technical solutions in this field of technology found in them the features distinguishing the claimed technical solution to the prototype that allows to make a conclusion about the technical solutions according to the criterion of "significant differences".

The drawing shows a diagram of the device. The device includes input terminals for connection to the mains A1, B1, C1, N1 and output terminals for connecting a load A2, B2, C2 and N2, three-phase three balancing transformer 1 having a primary winding 2, 3,which included a counter in a "zigzag" with the windings 3, located on other rods. First free the conclusions of the first windings are connected with output terminals of the phases A2, B2, C2, and free pins of the second windings are connected at one common point 4 and are zero output for connection phase loads N2. In each phase of the transformer introduced two pic is edutella United booster winding 5 and 6, conclusions : in the three-position switch 7 having three positions 8, 9, 10, connected to the corresponding phases A1, B1, C1 mains, and one of the conclusions of the respective position 9, to the output terminals A2, B2, C2, respectively.

The device operates as follows.

When the supply voltage three-phase symmetrise device, a zero output for connection phase loads is zero pin 4 of counter-included in "zigzag" primary windings 2, 3 three-phase three transformer 1. When such inclusion primary windings in three-phase zigzag transformer has a high resistance to direct currents and reverse and low impedance to zero-sequence currents, i.e. provides a stable zero point balancing phase voltages and filtering of harmonic zero-sequence currents. It is known that when such inclusion windings zero-sequence resistance is determined by the parameters short circuit its transformer elements. Under the proposed inclusion of booster coils 5,6 via the three-position switch 7 to the corresponding phases A1, B1, C1, even under unbalanced input line voltages is possible to provide the balancing phase voltages by setting switch 7 different positions the s phase. For example, if a high input line voltage is the voltage between phases A1, B1 and B1C1, and low - line voltage between phases A1C1, the switch 7 phase is set to position 8, and the switches of the phases a and C at position 9 or 10 depending on the current value of the line voltage unbalance. The voltage on the windings 5 and 6 is set in the range from 2.5 to 10% of nominal phase voltage. If low input line voltages are B1C1 and C1A1, and relatively high above line voltage - the voltage A1 B1, the phase switch To be set to 10, and the switches of the phases a and b at position 8 or 9.

The normalization of the phase voltages is provided by setting the switches in such position, in which the asymmetry of these stresses is minimal. If the asymmetry of the input line voltage is negligible, it is possible to apply only one booster winding 5 or 6 and dip switch 7, which will simplify and increase the reliability of the device.

This embodiment of the three-phase balancing device enables operation in both modes of symmetry of the input line voltage and in the presence of a pronounced asymmetry of the line voltage.

Technical and economic efficiency PR is the use of the device is achieved by normalizing the voltage and improve the quality of electric energy, even when there is asymmetry of the input line voltages.

1. "Electrical engineering Handbook", Moscow, publishing house of MPEI, 1998, str, RES.

2. AS the USSR №1324086. MCL. H02M 5/12, 1985.

RF patent №2314620 H02J 3/26, H02H 3/253.

Three-phase balancing device, mainly for three-wire or four-wire mains containing the input terminals for connection to the mains A1, B1, C1, N1 and output terminals A2, B2, C2, N2 for load connection, three-phase three transformer with two primary windings of which are connected in a "zigzag" and included on the output terminals, characterized in that to ensure the balancing phase voltages upon line voltage unbalance introduced in each phase one or two connected in series booster winding connected from the mains through a two - or three-position switch in series with load.



 

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