RU2459337C1 - Three-phase filter balancing device - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: three-phase filter balancing device comprises input and output terminals, to which a transformer is connected, having two groups of primary windings connected as serially and oppositely into a "zigzag". A neutral of the first group of primary windings is connected to a zero wire of a supply network and non-linear phase loads. A neutral of the second group of primary windings is an artificial neutral for linear phase loads.

EFFECT: reduced losses of power and its higher quality by separation of zero sequence currents passage paths for these loads.

1 dwg

Description

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

Known electrical three-phase network with zero phase, containing connected to the phase wires of the network of converters of a three-phase voltage system without a neutral wire into a three-phase system with an artificial zero phase. The disadvantage and complexity is the large installed capacity (1).

Known three-phase AC voltage stabilizer containing a three-phase balancing transformer (2).

The disadvantage is complexity.

Closest to the proposed is a three-phase balancing device containing input terminals for connecting the mains and output terminals to which a three-phase transformer is connected, the primary windings of which are connected in a "zigzag" or "star", but having a primary connection of the three-phase transformer in a "star" "Secondary windings connected in a" triangle "(3). The disadvantage is additional losses when working on a mixed load of a linear and non-linear nature and the presence of mutual influence of the loads on each other.

The purpose of the invention is the reduction of electric energy losses, improving the quality of electric energy and reliability.

This goal is achieved by the fact that in the known device containing input terminals for connecting the supply network and output terminals to which a three-phase balancing transformer is connected, having primary windings connected in opposite series in the “zigzag”, the paths of the zero-sequence currents for non-linear loads are separated , which are sources of higher harmonics and linear loads that do not create higher harmonics, by introducing a second group of primary windings included in the opposite direction in the “zigzag”, in parallel the first group of primary windings.

The attached drawing shows a diagram of the device. The device comprises a balancing transformer 1 having a first group of primary windings 2, 3 included in the zigzag, and a second group of primary windings 4, 5 included in the zigzag. The free leads of the primary windings 2, 3 and 4, 5 are connected to the output terminals of phases A2, B2, C2, respectively. Between the input and output terminals, a three-phase circuit breaker 6 is connected.

The device operates as follows.

When voltage is applied to a three-phase balancing device with a zero output for connecting phase loads of a nonlinear nature, which are the source of the third and multiple higher harmonics, for example, a load of the “computer” type or “modern lighting systems”, the primary output of the counter-included in the “zigzag” serves windings 2, 3 of a three-phase transformer 1, connected to the neutral wire of the supply network, and the zero output for connecting loads that are not a source of higher harmonics (electric motors, incandescent lamps etc.) serves as the zero output included in the "zigzag" primary windings 4, 5. With this inclusion of the primary windings 2, 3 and 4, 5, the three-phase transformer 1 has a high resistance for currents of forward and reverse sequence and low resistance for currents of zero sequence, those. provides zero-point stability and phase-balancing for single-phase loads, which are the source of higher harmonics and non-load.

This embodiment of a three-phase balancing device ensures the creation of a stable zero point in a three-phase network with a zero wire, eliminating phase voltage distortions with asymmetry of the load currents up to 100% of the nominal, and also significantly reduces the resistance of the zero sequence, providing phase voltage balancing of the source power network with a zero wire and providing loss reduction and improving the quality of electric energy.

Technical and economic efficiency when using the device is achieved by dividing the paths of zero sequence currents for non-linear loads (power consumers) that are sources of higher harmonics and for linear loads that are not, excluding the influence of the third and multiple higher harmonics of non-linear loads on linear loads while reducing the number switching elements (circuit breakers), and also provides reliable operation of the balancing device in emergency mode x operation in case of interruption of one phase, thanks to the neutral conductor connection mains zero terminal (neutral) of the primary windings 2 and 3 of the balancing device and to create its own zero point.

Information sources

1. USSR patent 1304121, M. Cl. H2O 3/36, 1987.

1. A.S. USSR No. 1310787, M. Cl. G05F 1/30, 1985.

2. Patent Russia 2314620, M. Cl. H2J 3/26, 2003.

Claims (1)

A three-phase filter-balancing device containing input terminals for connecting the mains and output terminals for connecting the load, a three-phase circuit breaker is connected between the input and output terminals, the output terminals of which are connected to a three-phase balancing transformer, the primary windings of which are included in the "zigzag", with a zero output to connect the phase loads, the zero output of the primary windings included in the opposite zigzag is used, characterized in that, in order to reduce the losses of electric energy and improving the quality of electric energy by separating the paths of zero sequence currents for power receivers that create higher harmonics “non-linear loads” and power receivers that do not create higher harmonics, the three-phase transformer is equipped with another set of primary windings, included in the opposite direction in the “zigzag” parallel to the first primary windings, and the zero output of these windings is connected to the zero output of the supply network and the zero output of phase non-linear loads, and the zero output of the first upy primary windings connected to the zero output of linear phase loads that do not create higher harmonics.