The compensation device asymmetry of mains voltage
(57) Abstract:Usage: in a three-phase electric systems to reduce the asymmetry of the voltage. Entity: an unloaded induction motor with a wound rotor, a rotor winding which is connected to the network with a reverse phase sequence, connect to the network through the switch. Before connecting the motor, the rotor is accelerated to double podsyhanii speed. 1 Il. The invention relates to a device for reducing the asymmetry of the voltage in three-phase networks.Known way to eliminate voltage unbalance in three-phase network, caused by non-uniform load phases, characterized by the application is included in the network three-phase asynchronous machine with slow-phase rotor and the timing and amount consumed by the machine current reverse sequence by rotation of the rotor and the magnitude of the load in the rotor circuit.Known way to eliminate the asymmetry of mains voltages unfit to eliminate the asymmetry arising from the electrical connection single-phase load intermittent nature (for example, spot welding units), because the appearance, the awns) method proposes to eliminate the asymmetry by rotation of the rotor manually or by an actuator and a load control circuit of the rotor, that would require more time than the connection time is short single-phase load.The aim of the present invention is to provide a simple and effective compensator asymmetry of mains voltages, capable of reducing the asymmetry of the voltage to an acceptable level, for example to a level acceptable standard on the quality of electricity whenever the nature of the source of asymmetry.The essence of the invention lies in the fact that the proposed device asymmetry of mains voltages, containing an unloaded induction motor with a wound rotor, the stator winding of which is connected to the mains findings with direct phase rotation, and the rotor winding is connected to an electrical outlet with reversed phase rotation, the stator and rotor are connected to the power switch, when the compensator rotor rotates at double the synchronous speed, the device has a starter for the pickup of the rotor to double synchronous speed of rotation before connecting the compensator to an electrical outlet. During operation of the proposed device compensation voltage are known useful properties of asynchronous motor in dual mode synchronous near to an electrical outlet, and no inductor.Low resistance of the scattering of the windings provides efficient load compensator at an acceptable low values of skewness voltage outlet, in addition, the lowest specific motor losses compared to other types of motors.The invention is illustrated by the drawing which shows a diagram of connection to the mains:
1 - grid with phases A, B and C;
2 - switch;
3 - stator winding with leads 1, 2, 3;
4 - rotor winding with the conclusions of the 11, 21, 31.The compensation device asymmetry of mains voltages is as follows.The rotor of the compensator is accelerated by the starter (not shown) to double podsyhanii speed, turns on switch 2 and the stator winding and the rotor 3 and 4 are connected to an electrical outlet; in the stator and the rotor will occur rotating in different directions of the magnetic field, which engages, and the rotor will rotate at double speed. In the absence of asymmetry in the voltage of the mains current in all three phases of the machine will be of the same order of 10% of nominal. In case of asymmetry of mains voltages,>> U2-3> U3-1on the conclusions of the rotor AND1-3> AND2-3> AND2-1since the stator and the rotor have the same primary magnetic flux from the power up phase with a higher voltage stator 1-2 /phase AB outlet/ will be transformed in phase 21- 11rotor /CA phase mains/; from the same phase of the rotor 11- 31/phase AB/ will be transformed into a phase 3-1 stator /phase CA/ etc. Through a loop current flows reverse order, thus will be the asymmetry compensation voltage in the mains. The compensation device asymmetry of mains voltages, containing induction motor, the stator winding of which is connected to the mains with direct phase sequence, characterized in that the applied induction motor with a wound rotor, the windings of which are connected with reverse alternation of phases of the stator winding and the rotor is connected to the mains through a switch, you have the starter to accelerate the rotor before connecting to the mains to double synchronous speed.
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.