SU1580503A1 - Device for regulation of three-phase voltage - Google Patents

Abstract

The invention relates to electrical engineering, in particular to converter equipment, and can be used to regulate the voltage of power transformers under load. The purpose of the invention is to reduce the consumption of active materials and increase reliability. Essence: the three-phase primary winding of the auxiliary transformer is provided with outputs from the middle point, which are interconnected with two thyristor switches, and each of the input and output terminals of the entire three-phase primary winding of the auxiliary transformer is connected via one of the thyristor switches with the corresponding phase of the three-phase secondary winding network transformer. 2 Il.

Description

by these means to the distribution -prescriptional network. This allows the terminals to connect the power supply to the network and to the five

various urozkoy three-phase voltage, due to what is achieved by

goal 3 p.

The invention relates to electrical engineering, in particular, to converter technology, and days of voltage control of power grasses under load can be used.

The aim of the invention is to reduce the consumption of active materials and the reduction of reliability.

FIG. 1 is a functional diagram of a device for adjusting a three-phase voltage; in fig. 2 - a table of stationary modes of operation of the device and voltage diagrams on the windings of the auxiliary and network transformers; Figure 3 is a block diagram of a device control, protection and alarm system.

A device for controlling three-phase voltage contains a mains transformer 1 with a three-phase secondary 2 and three-phase primary 3 windings, an optional transformer 4 with a three-phase secondary 5 and three-phase primary 6 meters, having a tap from the middle point, thyristor switches 7-18, terminals A , B, C, and a, b, c for connecting a three-phase power supply bar and a three-phase load, respectively.

The control, protection and signaling system of the three-phase voltage control device comprises a power supply unit 19, a measuring unit 20, a signaling unit 21, a protection unit 22, a synchronization unit 23, a trigger unit 24, a counter unit 25, a decoder unit 26, and an amplification and electroplating unit 27 Expanding

The device works as follows.

When the mains is connected to the terminals A. B, C, the voltage from the a, c leads comes through the thyristor switches 7-18 to connect the three-phase mains supply to the three-phase primary winding 6 phases of the auxiliary transformer 4. for connecting a three-phase load from a three-phase secondary winding 2 of a three-phase mains transformer 1. The phase of this voltage depends on which thyristor keys of the device are included in this mode. In this embodiment, the thyristor switches 14 and 15 allow the transformation ratio of the auxiliary transformer 4 to be varied by switching off the center point of the three-phase primary winding 6. {depending on this, the magnitude and phase voltage on the three-phase secondary winding 5 of the auxiliary transformer 4 is geometrically summed (or subtracted) with the supply voltage. This, in turn, leads to a change in the voltage on them at the primary windings of one or several network transformers.

which are connected to the terminals L1, B, C1.

Therefore, the voltage value

conclusions a. B, c for three phase connection

5 loads are determined depending on the possible operation modes of the auxiliary transformer 4. With the chosen number of the thyristor keys, the following five stationary modes are possible: Short circuit mode, when using 15–16 phases of the three-phase primary winding 6 of the auxiliary transformer 4 are short-circuited and the life at the terminals a, b, c is determined by the coefficient of transformation of the mains transformer 1; No-1 mode, when the thyristor switches 15–13, 10, 11, and 12 are turned on at a constant mains voltage, while the phase vectors are

0 voltages of the three-phase primary winding 3 of the mains transformer 1 are reduced by 1/2/3 vectors of the maximum possible voltage of the three-phase secondary winding 5 of the auxiliary transformer

5 4; Release-2 mode, when at constant voltage of the mains supply, the taryst switches 13-14, 10, 11 and 12 are turned on and the phase voltages of the three-phase primary winding 3 of the network transformer 1 are reduced by 1 / V§ of the vector of the maximum possible voltage of the three-phase secondary winding 5 auxiliary transformer 4; Add-1 mode. when at constant voltage

The power supply network 5 includes thyristor switches 17-18, 7, 8, 9 and the phase voltage vectors of the three-phase primary winding 3 of the mains transformer 1 are increased by 1/2 of the maximum possible vcT vector

0 foil three-phase secondary winding 5 auxiliary transformer 4;

Dobzit-2 mode, when at constant power supply voltage, the thyristor switches 13-14, 7, 8, 9 and the three-phase voltage vectors of the three-phase primary winding 3 of the network transformer 1 are increased by 1 / V5 of the vector of the maximum possible voltage of the three-phase secondary overlays 5 auxiliary transformer 4.

Consider the process of regulating the output voltage by transferring the auxiliary transformer 4 from one operating mode to another. Suppose that in the initial state the auxiliary transformer 4 is in the short circuit mode of operation and the thyristor keys 15–15, 17–18 are turned on due to the included output channels in the decoder block 26. All phases of the three-phase primary winding 6 of the auxiliary transformer with 4 thyristor keys are short-circuited, and the auxiliary transformer 4 is in the mode of the current transformer. The voltage at the terminals of the three-phase primary winding 3 of the mains transformer 1 (terminals A1, B1, C1) is equal to the supply voltage (voltage between the terminals A, B, C).

For example, to reduce the voltage at the terminals a, b, c, by one step of regulation, the auxiliary transformer 4 is switched to the Volt-Supplement-1 operation mode. To do this, the Zap command is sent from the measuring body 20 to the trigger block 24 (logic signal 1 ). The trigger block 24, through the counter 25 block and the decoder block 26, at a certain moment in time, strobed with the impulse of the synchronization block 23, turns off the previously disconnected control channel. Thyristor keys 15-18 are disabled, and thyristor keys 10-12 are turned on.

After turning off the thyristor switches 15-16, the three-phase primary winding 6 of the auxiliary transformer 4 is connected in a star circuit. The winding is powered from the output terminals side, and the three-phase secondary winding 5, the voltage of which feeds the three-phase winding 6 of the auxiliary transformer 4, does not coincide with the phases of the latter. The input terminals of the three-phase primary winding 6 of the auxiliary transformer 4 are short-circuited with the thyristor keys 17-18. The vector diagrams of the supply voltage (DAP, Use, UCA) and the phase voltages of the three-phase primary winding 3 of the mains transformer 1 (11-1.UB.-UC) for this mode of operation are shown in FIG. 2. The whole process of voltage change for one stage of regulation takes no more than 0.5 period of supply voltage.

Claims (1)

Invention Formula A device for controlling a three-phase voltage containing a network transformer and an auxiliary transformer, the three-phase primary windings of which are connected to each other via the thyristor switches and to the terminals of the various phases of the three-phase secondary winding of a network transformer, the three-phase primary windings of which are connected to the first three-phase secondary windings of the secondary winding transformer, the second terminals of which are connected to the terminals of the same phases of the mains supply, characterized in that lowering the consumption of active materials and improving the reliability, the three-phase primary winding of the auxiliary transformer is provided with midpoint leads that are connected to each other using two thyristor switches, and each input and output terminals of the entire three-phase primary winding of the auxiliary transformer is connected through one of the thyristor switches the output of the corresponding phase of the three-phase secondary winding of the mains transformer. Figz