Three-phase balancing device
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.
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.
SUBSTANCE: control method for shunting of power supply units includes the following steps: measurement of the first three-phase output eclectic signal; calculation of the first direct and reverse sequences of the first three-phase output eclectic signal; generating of the preset components for direct and reverse sequences of phases in order to perform automatic compensation for the components of the first direct and reverse sequences thus outputting components of the second direct and reverse sequences; summing-up of the second direct and reverse sequences and output of the second three-phase output eclectic signal in the preset mode.
EFFECT: reducing output voltage ripple.
10 cl, 10 dwg
SUBSTANCE: invention is related to the field of electric engineering and power electronics and can be used for manufacturing of HV three-phase alternating current generating systems for aircraft. The suggested three-phase alternating current generating system with voltage inverter contains a three-phase synchronous generator, a static electric energy transducer based on a three-phase bridge rectifier which inputs are connected to outputs of the synchronous generator, two filter capacitors in the direct current link connected in-series and switched on in parallel to the output terminals of the rectifier and a three-phase bridge voltage inverter which inputs are connected to the rectifier outputs and outputs are connected to inputs of three low-frequency LC filters; a neutral load wire of the generation system is connected to the average point of filter capacitors in the direct current link; an inductance coil is connected by its one output to the neutral load wire of the generation system and by its other output to the neutral wire of the stator three-phase winding of the synchronous generator.
EFFECT: reducing electric losses in elements and improving efficiency ratio of the system as a whole.
SUBSTANCE: voltage stabiliser for a power supply system, which stabilises load of active power, comprises the first AC-DC and DC-AC converter to convert between AC power and DC power; and a nickel-metal-hydride battery located between and connected to a high-voltage cable at the DC side of the first AC-DC and DC-AC converter and a low-voltage cable at the DC side of the first AC-DC and DC-AC converter.
EFFECT: reduced mass and dimension parameters of a device.
10 cl, 17 dwg
SUBSTANCE: balancer is purposed to improve quality of current and voltage balancing in three-phase networks with neutral wire due to self-adjustment of power in case of current change in the neutral wire. The device contains additionally two power stages and automatic control circuit operating as current function of the neutral wire.
EFFECT: improving quality of adjustment due to detuning parameters of the suggested device from current unbalance in the network of 0,38 kV present at the moment.
FIELD: electrical engineering.
SUBSTANCE: power supply device (100) for immediate electric heating of a pipeline system contains basically a three-phase transformer (2), a symmetrisation unit (14), a compensation unit (22). The three-phase transformer (2) is adapted for supporting a single-phase load connected between the first phase (6) and the second phase (8) of the transformer (2). The transformer (2) contains at least one first tap switch (10) on the high-voltage side (12) of the transformer (2). The symmetrisation unit (14) contains the first capacitor means (16) connected between the first phase (6) and the third phase (18) of the transformer and an inductor means (20) connected between the second phase (8) and the third phase (18) of the said transformer (2). The compensation unit (22) contains the second capacitor means (24) connected between the first phase (6) and the second phase (8) of the transformer (2). The first tap switch (10), the first capacitor means (16), the second capacitor means (24) and/or the inductor means (20) are adapted for variation under load.
EFFECT: changing the value of capacity and inductivity of the corresponding capacitive and inductive means under load and optimisation under load on a real time basis.
7 cl, 4 dwg
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.
SUBSTANCE: level of a specified higher harmonics in a power flux picked by a non-linear load is reduced by extraction of its energy in the form of an equivalent energy of sequence of unipolar periodically repeating width-modulated current pulses, by means of a fully controlled pulse-width-modulation rectifier of a transistor type, which is used to control a modulating signal proportional to the current of the specified higher harmonics. The extracted energy of the higher harmonics is disposed of, by means of its usage for supply to a DC load and accumulation in the form of a DC energy.
EFFECT: reduction of higher harmonic components levels in a supplying power system and increased efficiency of power usage.
FIELD: electric engineering.
SUBSTANCE: application: in electric engineering. The three-leg transformer in three-phase balancing device is comprised of three coils with the first, nearest to leg, and the utmost leg being connected in series and in accord between each other and the total number of windings in coils is equal to the number of windings in the second coil to be opposite connected in zigzag pattern. Free terminals of the first coils are connected to input and output clips, while free terminals of the second coils are integrated in one common zero point to connect phase loads. Semi-conducting a.c. switch is energised between zero terminal of power system and three-phase transformer.
EFFECT: improved reliability and reduced resistance of zero-sequence current.
2 cl, 1 dwg
FIELD: electrical engineering.
SUBSTANCE: according to the method, both reactive power and the active power component of the balanced phase group are used to supply DC load. Upon that, initially, the reactive power component is extracted from n-phases of the power grid, and then the active power component is extracted from at least one of the grid's phases, the active power component consists of a balanced phase group, via balancing currents. Furthermore, the power from reactive and active currents is extracted by means of a fully controlled solid state PWM rectifier, with phases being individually controlled via corresponding modulating signal. This power is extracted in the form of equivalent power of unidirectional repeating width-modulated current pulse sequence.
EFFECT: increase of power usage efficiency by reducing its non-productive losses.
SUBSTANCE: power required for supply of DC load is extracted with the help of a fully controllable n-phase WPM-rectifier of transistor type by means of balancing currents, at least from one phase, making a group of balanced phases, - so that the current that remained in each phase of the specified group picked by a non-balanced load, has a module value equal to either the one that has been previously determined or equal to the value of the current module in the reference phase, which has been previously selected from n-supplying phases of unbalanced system of power supply according to the condition of the maximum value of the current module.
EFFECT: increased efficiency of power usage by reduction of non-efficient losses in power flow caused by unbalance of phase currents.
FIELD: electrical and power engineering.
SUBSTANCE: proposed method intended for measuring current and voltage unbalance level and organizing on-line impact on them in three-phase power systems characterized in low quality of their power characteristics includes measurement of unbalance level with respect to reverse and zero sequence of both line and phase voltages and currents at frequency of each harmonic component. Frequency at which unbalance in analyzed characteristics occurs is found. Results obtained are used to generate control signal by correcting devices.
EFFECT: facilitated procedure.
1 cl, 5 dwg
FIELD: power engineering.
SUBSTANCE: method allows to fully utilize power of traction transformer due to loading its free phase by rectifiers and inverters, one of which is lead by leading phase of contact network, and second one of late phase, which allows to transfer electric energy to contact network, to exclude idling mode, to provide for lower asymmetry on reverse series in power grid 220 (110) kV, and also decreases level of higher harmonics.
EFFECT: higher efficiency, lowered values of quality coefficients of electric energy - asymmetry coefficient of reverse series and values of higher harmonics.
FIELD: electrical engineering.
SUBSTANCE: proposed method intended to enhance power quality characteristics for users subject to negative influence of higher harmonic components includes generation of circuit current higher harmonic components which are in phase opposition to higher harmonics of supply mains using electrical energy of independent power supply.
EFFECT: enhanced electrical energy quality characteristics for power consumers.
1 cl, 3 dwg
FIELD: electrical engineering.
SUBSTANCE: proposed method used to enhance quality characteristics of electrical energy supplied to users susceptible to impact of negative factors of electrical-energy higher harmonic components includes generation of higher harmonic components of current in network which are acting in phase opposition relative to higher harmonics of supply mains.
EFFECT: enhanced quality characteristics of electrical energy supplied to users.
1 cl, 3 dwg
FIELD: electric engineering, possible use in power circuits of various equipment.
SUBSTANCE: three-phased balancing device contains input and output clamps of powering networks. To output clamps, three-phased transformer is connected, primary windings of which are oppositely coupled in a zigzag. In accordance to the invention, between input and output clamps of powering network, first three-phased automatic switch is coupled, having an independent release. Serially with primary windings of three-phased transformer, second three-phased automatic switch is coupled. As zero contact for connection of phase loads, zero contact of primary windings of three-phased transformer, coupled oppositely in a zigzag, is used. Control block is connected serially to independent release, coupled between output clamp of one of the phases and zero contact of powering network, and ensures supply of voltage to independent release and activation of first automatic switch on disabling of second automatic switch.
EFFECT: increased reliability when powered from three-conductor or four-conductor powering network.
FIELD: electric engineering, possible use for powering various equipment.
SUBSTANCE: the balancing three-phased to one-phased transformer of alternating voltage contains input and output contacts, to which a transformer is connected which has primary windings in all three phases and two secondary windings in phases A and C. Primary windings are connected in a "zigzag". Windings of phases A and B, B and C, and also C and A are connected respectively. Secondary windings in phases A and C are coupled oppositely and are connected to output contacts.
EFFECT: reduction of stabilized power and asymmetry of primary currents and voltages.
FIELD: power production.
SUBSTANCE: when non-sinusoidal shape of supply voltage is decreased, electric power is distributed between electronic devices distorting the shape of supply voltage and electronic devices improving the shape of supply voltage during the semi-wave of supply voltage. Device is connected in parallel with consumers introducing distortions of voltage shape. Main voltage is supplied to the device input. Device includes serial connection of phase-shifting chain, control pulse shaper, dc power supply and power switcher, which connects consumers improving the shape of supply voltage to the mains at a certain period of time.
EFFECT: improvement of supply voltage shape and simplification of device design.
2 cl, 4 dwg
SUBSTANCE: invention concerns current power transmission equipment, particularly high-voltage power transmission. Device includes reactive shunts connected by reactive switches to line, with additional special reactive shunts connected to the line in star network pattern with unearthed neutral conductor.
EFFECT: enhanced shunt compensation of power transmission line in low load mode, stability and reliability in elimination of single-phase short circuits at single-phase reclosing.
FIELD: electrical engineering.
SUBSTANCE: invention relates to electrical engineering and may be used for hardware designing to improve quality and reduce voltage and electric power losses, when such power is transmitted in three-phase four-wire electric networks due to reduction of anharmonicity and asymmetry. Protection device generates 150 Hz frequency current from phase currents. This current is immediately introduced to harmonics 3 current of neutral working wire in opposite phase.
EFFECT: compensating highest current harmonics flowing along neutral conductor.
2 cl, 2 dwg
FIELD: electrical engineering.
SUBSTANCE: invention relates to electrical engineering, and can be used for phase-to-phase distribution of current in magnetically unstable three-phase signals, for example for neutralisation of zero-sequence harmful effects on current feed circuit in three-phase AC-to-DC and DC-to-AC voltage transformers. Proposed device comprises the transformer with its two phase windings connected, each by one output terminal, to zero input terminal, while their other output terminal is connected to appropriate phase input terminal. The transformer comprises two magnetic cores with phase windings connected in series and furnished with central tap. The said windings have their central and extreme free terminals connected to zero and common phase input terminals, respectively. Note here that central output terminal divides the number of turns in each phase windings into unequal parts, smaller ones being connected to opposing phase input terminals.
EFFECT: possibility to use two single-phase transformers with various-shape magnetic cores instead of three-phase transformer.