SU851357A1 - Device for regulating three-phase voltage - Google Patents

Description

one

The invention relates to electrical engineering, in particular, to converter technology, and can be used, for example, to regulate and stabilize the voltage of three-phase power sources.

A device for controlling three-phase voltage is known, comprising a transformer, each phase primary or secondary sponge of which is made in the form of sections from Bcwaiei, and controlled valve cus adPZ.

The disadvantages of the known device are significant distortions of the input voltage due to the presence of zero-sequence flows during co-ordination of the taps of the transformer winding sections, as well as the presence of compensating windings.

The purpose of the invention is to simplify the device and reduce distortion of the output voltage when powered from a four-wire network.

The goal is achieved. By the fact that each pair of control key valve keys is connected, respectively, between the ends and the same names of taps of the CS1RD of the first and second windings of the celine phases, the beginnings of the coyrh are connected, respectively, to the input and output terminals of the device.

In this case, all sections of the phase windings have the same number of turns, and their like taps are made at the same distance from the beginning or end of the corresponding section.

FIG. 1 shows a fuctional 10 on the circuit of the device; in fig. 2 temporary diagrams, according to the principle of operation of the device.

The device contains a transformer

1D 1, the first and second sections 2, 3, 4 and 5, 6, 7 of the respective phase nabs of the transformer 1, respectively, controlled valve wrenches 8-10 and 11-13 for switching the ends

The 20 and like taps of each first and second windings of adjacent phases, respectively, are phase and zero input or output pins 14-16 and 17 of the device, respectively.

25

O is the voltage curves on the windings of the phases of transformer 1, respectively;

5 shows voltage curves for a pair of sections 2 and 5, Zib, 4 and 7 connected by keys 8, 9, 0 or 11, 1.2, 30 13, respectively;

b - modulation functions describing the state of valve switches, e.g. 12 and 9, respectively

7- is the voltage curve in the phase of the load connected, for example, between the phase terminal 15 and the zero terminal 17.

The device works as follows.

A load connected to a star is connected to pins 14-16 and 17 if the regulation is carried out on the secondary side, or the phase and zero of the supply network, respectively, if the regulation is performed on the primary side of the transformer 1.

At the same time, controlled valve switches 8-13, which transmit current through the oppositely connected first 2, 3, 4, second 5, 6, 7 sections of the respective phase windings located on different transformer rods, can be performed, for example, in the form of - parallel thyristors, controlled by various schemes with natural and artificial switching,

In phase-phase control mode, the valve wrenches 11-13 are unlocked each at the beginning of the corresponding half-cycle of voltages (Fig. 2a and three other valve wrenches 8-10 with some delay relative to the moment of unlocking the valve wrenches 11-13.

Unlocking the valve wrenches 8-10 results in locking the valve wrenches 11-13 and, accordingly, to a change in the transformation ratio of the transformer 1 and, consequently, to a change in the value of the output voltage c. corresponding to the phase of the load (Fig.2G).

The load voltage can also be adjusted by changing the unlocking angle of the wrench 1113 or 8-10.

As it follows from the functional diagram shown in FIG. 1, in the proposed device with any combination of closed and open

valve wrenches 8–13, the total magnetizing force of the adjustable side of transformer 1 is zero if the number of turns of the sections and their parts located on different rods and connected with the keys is the same, and the sections themselves are switched in opposite.

In this case, the magnetizing forces of the first 2, 3, 4 and second 5, 6, 7 sections of the phase windings are equal in magnitude and opposite in direction.

 Thus, the proposed device, in comparison with the known, allows to reduce the distortion of the output voltage due to the absence of zero-sequence flows,

5 and, consequently, to exclude from the circuit of the device compensating windings.

Claims (2)

1. A device for regulating a three-phase voltage containing a transformer, each phase primary or secondary winding of which is designed as sections with taps and controlled valve switches, characterized in that, in order to simplify and reduce distortions of the output voltage when powered from a four-wire network, each pair of controlled valve switches is connected respectively between the ends and the like branches of each first and second windings of adjacent phases, which are connected 5 respectively with phase and zero input or output pins of the device. 2. Device POP.1, characterized in that all sections 0 phase syncope have the same the number of turns, and their like taps are made at the same distance from. the beginning or end of the corresponding section. Sources of information taken into account in the examination 1. Electricity, 1979, 2, p. 32. ru .xjx ) Chu / sh / r y