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.

 

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