SU1737380A1 - Device for testing converter induction apparatus for electromagnetic stability - Google Patents

Abstract

Usage: in test equipment for testing induction apparatus. The essence of the invention: the device contains a power source 12, a switching device 13 connected to an object of control - an induction device comprising a transformer 1 and a reactor 2. 2 Il. (L C vj ico i4 from 00 o

Description

The invention relates to electrical engineering, in particular to devices for testing an induction apparatus consisting of a converter transformer and an equalizing reactor, and which is an integral part of the converter.

Six-phase converters according to the rectifying scheme of two reverse stars with a balancing reactor are becoming more and more widely used in various areas of electrical engineering.

For these converters, induction devices are used, consisting of a converter transformer with a three-phase primary winding and a secondary winding, connected according to the scheme two reverse stars, and a reactor.

In emergency mode, the converter during a short circuit (short-circuit) at its output through the windings of the transformer and the branches of the surge reactor, currents flow, the electromagnetic effect of which is dangerous for the induction apparatus.

Therefore, at the factory of the induction apparatus it is subjected to tests for electrodynamic resistance.

The requirements and methods of conducting single-phase and three-phase tests for electrodynamic resistance of induction apparatuses are known, which include a device containing a power source, a switching device connected between the power source and the induction apparatus, and the three-core magnetic field transformer itself, the secondary winding which is connected according to the scheme two reverse stars,

If it is necessary to test an induction apparatus consisting of a transformer and an equalizing reactor in accordance with the indicated method, a separate transformer, a separate reactor must be tested. At the same time, the reactor has to pass the largest shock current short-circuit, which is determined from the experience of the transformer test. But the law of change in the amplitude of the current in the reactor is different from the actual. In addition, a separate test of the durability of the reactor requires several test runs to obtain the voltage that must be supplied to the reactor in order to provide the specified value of the shock current.

Closest to the invention is a device for testing the electrodynamic resistance of an induction apparatus, consisting of a converter transformer with a three-core magnetic circuit, a three-phase primary

a winding and a secondary winding, connected according to the scheme two reverse stars, and a surge reactor connected between the zero points of the stars, i.e. an induction apparatus, in which the first terminals of the forward and reverse stars of the secondary winding of the transformer are connected to the first and second terminals of the compensation reactor, respectively.

The device contains the induction unit itself, a power source, a unit, to which the second secondary leads of the induction unit are connected, and a switching unit, connected between the rectifier unit and the midpoint of the equalization reactor.

Different rectifying installations are also required to test the durability of different current and voltage inductive devices. This complicates and increases the cost of the test setup, especially in the conditions of the manufacturer of the induction apparatus.

The purpose of the invention is therefore to simplify and increase the reliability of the device for testing the electrodynamic resistance of an induction apparatus consisting of a converter transformer and a surge reactor and designed for a converter according to the rectifier circuit of two reverse stars with a surge reactor.

This goal is achieved by the fact that in the device under consideration, which contains a power source and a switching device, the first conclusions, respectively, of the forward and reverse stars of the secondary winding of the transformer of the control object are connected to the first and second outputs of the control reactor of the control object. connect the stars of the secondary winding to the second terminals of the other two phases of the reverse star of the transformer's secondary object of the control object and connect to the middle point of the equalizer the reactor of the control object, connect the power source through the switching device to the corresponding terminals of the transformer primary winding of the control object.

FIG. 1 shows a six-phase converter with induction apparatus; in fig. 2 is a device for testing an induction apparatus.

The six-phase transducer according to the charging circuit two reverse stars with a balancing reactor contains a transformer 1 and a balancing reactor 2, forming an induction apparatus - an object of control, the transformer of which feeds the rectifying unit 3.

On the three rods x 4, 5, 6 of the magnetic conductor of the transformer 1, there is a primary three-phase winding 7 and a six-phase secondary winding 8, the aixi and 34x4 phases of which are located on the rod 4, the Luz and Leb phases - on the 5 rod, cszs and C2Z2 phases - rod 6.

The windings aixi, L3 and cszs are connected according to the forward star scheme, windings 34x4, Leue and C2Z2 - according to the reverse star scheme, the first conclusions of the forward star (xi, knots, zs) are interconnected and connected to the first terminal 9 of reactor 2, and the first leads of the return star (x4, ye, 22) are interconnected and connected to the second pin 10 of reactor 2.

The second terminals ai, b3, cs and 34, be and C2 are connected to the valves of the rectifying installation 3. The output of the converter is closed to the load 11.

In emergency mode, the converter (short-circuit at its output) currents of short-circuit currents will flow through the windings of the induction apparatus, the electrodynamic action of which should not cause a failure in operation.

For testing the electrodynamic resistance of an induction apparatus comprising a transformer 1 and a reactor 2, a device is proposed (Fig. 2), including the induction apparatus 1 and 2 itself, a sinusoidal voltage source 12, and a switching apparatus 13.

In order to carry out tests in order to obtain electrodynamic forces identical to those that occur in real transducers, the following connection scheme of the transformer windings and reactor legs must be implemented.

The terminals A, B, C of the primary winding, connected, for example, in a delta circuit, are connected to the terminals of the switching device 13, the second terminals of which are connected to the source 12.

The switching device can be either three-phase or single-phase.

When using a three-phase apparatus, the scheme of its connection in the device corresponds to flg. 2. When using a single-pole apparatus (single-phase test), it is switched on between one of the primary terminals, for example A, and the corresponding output of the power source. The other end of the winding B is connected directly to the power source, and the output C is not connected to the power source, i.e. open

The first terminals xi, knots, zs of the direct star of the secondary winding are connected to the first terminal 9 of the reactor, and the first conclusions X4yez2 of the reverse star are connected to the second terminal 10 of the reactor. For example, the ai terminal of the aixi phase, located on the magnetically conductive rod 4, is combined with the be and C2 of the Leue and C2Z2 phases located on the rods x 5 and 6, and is connected to the midpoint of the reactor 2.

The device works as follows.

The switching device 13 includes a power source in the circuit. The connection must be made at the time when the voltage passes through a zero value at the phase AX (for the circuit under consideration, when the terminals ai. Be and C2 are combined), which corresponds to the greatest shock current.

The predetermined switching on moment of the switching device is carried out by means of a known automatic control device, which is included in the switch control circuit.

After switching on the switch 13, currents will flow through the primary winding 7, the secondary winding 8 and the compensation reactor 2. According to the law of the total current on the rods x 4, 5, 6 magnetic cores ms.s. primary and secondary windings are practically balanced, i.e.

iai X1 .iye be .iz2 C2

   ; icz --pNT1cht1cht

where KT - transformation ratio;

iax, iby, ic.z - currents in the primary winding;

ixiai, iye be. z2c2 secondary currents.

Because

 Ubb + x2 b2 1x1 ai,

then, as shown in FIG. 2, the equalizer reactor magnetic circuit is also balanced and the currents in its branches x are equal to each other. With the opposite direction The equalizer reactor branches form a small stream of dispersion in it. This means that after switching on the switching device, the transformer operates in almost three-phase short-circuit mode.

The percussion and steady-state currents in the phases of the direct star ash and the primary winding AH, as well as in the surge reactor of the proposed device (FIG. 2) are equal to the corresponding currents in the converter (FIG. 1), since the reactances are the same. Equal currents cause equal electromagnetic forces, i.e. reliability of tests is provided.

Claims (1)

Invention Formula Electrodynamic resistance testing devices for an induction unit of a converter consisting of a transformer and a surge reactor, containing a power source, a switching device, and the first terminals of the control object’s transformer secondary winding and reverse, respectively, are connected to the first and second ends of the plant's balancing reactor 0 control, characterized in that. In order to simplify the device and increase reliability, the second output of one phase of the direct star of the secondary winding is connected to the second terminals of the other two phases of the reverse star of the secondary winding of the transformer of the control object and connected to the middle point of the equalization reactor of the control object, the power supply is connected through the switching device with the corresponding the findings of the primary winding of the transformer object control.