SU1689896A1 - Device for electromagnetic test of power transformers - Google Patents

Abstract

The invention relates to electrical engineering, in particular to devices for electrodynamic testing of transformers in the short circuit mode. The purpose of the invention is to expand the scope and increase the reliability of the tests. The device contains a three-phase source 1

Description

The invention can be used not only when testing power transformers, but also their full-size models in the network stand conditions and with the help of synchronous shock generators,

The purpose of the invention is to expand the scope and increase the reliability of tests of high-power transformers,

Fig, 1 is a diagram of the proposed device; figure 2 - the same, with single-phase power.

The device contains a three-phase power supply 1, a three-phase safety switch 2, a three-phase test transformer 3, primary 4-6 and secondary 7-9 windings of test transformer 3, high-voltage thyristor valves 10-13, control system 14, voltage transformer 15, test transformer 16 Moreover, the first and second input terminals of the safety switch 2 are connected to the first and second phases in the order of alternating phases of the three-phase power supply 1.

The first and second output terminals of the protective switch 2 are connected to the anode and cathode, respectively, by the first and second pairs of high-voltage thyristor gates 10, 11 and 12, 13 which are connected in parallel with each other.

The terminals of the first pair of high-voltage giristor valves 10 and 11 are connected to the input terminals of the primary windings 4-6 of all three phases of the test transformer 3, the terminals of the second pair of high-voltage-thyristor valves 13 and 12 are connected to the input terminals of the secondary windings 7-9 of all three phases of the test transformer 3, the output terminals of the secondary windings 7-9 of all three phases of the test transformer 3 are connected to the input terminal 17 of the test transformer 16. The input of the system 14 for controlling the high-voltage thyristor valves 10-13 The output of the transformer is 15 volts.

The device works as follows.

A safety switch 2 is turned on, thereby energizing the high-voltage thyristor valves 10–13. After a certain time required for charging

High-voltage thyristor valves (about 1–2 min) from the control system 14 with a pre-selected angle, include high-voltage thyristor valves 10–13, thereby applying voltage to the test transformer 3 and the test transformer that was previously shorted for the experiment

short-circuit, remove control pulses from high-voltage thyristor valves 10-13, blocking them immediately after the first passage of the test current through zero, then turn off the protective switch 2. The transformer 16 under test is considered to have passed the short-circuit test, if during testing Parameters did not go beyond the permissible limits.

When high-voltage thyristor valves 10–13 are turned on, the shock value of current 1 Ud in the windings of the tested transformer 15 can be estimated (without taking into account the active components of the short-circuit resistance

circuits and power supply) by the equation Y (1 + K) Tsf

udХ6 / 3 + Х15 Куд

where K is the transformation ratio of the test transformer 6;

Xe and Xis are the inductive components of the short-circuit impedance of test 6 and test 15 transformers; Kud - shock coefficient; 11f - phase voltage model

secondary windings 10-12 test transformer 6,

The use of the device (Fig. 2) allows for the forced division of current through two parallel thyristor valves 10-13. If one of the valves is not turned on, for example, valve 10, the current through valve 12 is substantially limited by the large resistance of the test transformer, which in this case

- in idle mode. This makes it impossible to emergency mode, which really can occur if one of the valves fails when using their wiring. This is especially important.

when testing powerful high-voltage transformers.

Claims (1)

In addition, the use of the proposed device reduces the influence of voltage fluctuations and the frequency of the power supply (mains). For the device (Fig. 1) y, the relative influence of the change of the supply voltage on the magnitude of the test go is determined by the value of a V7 4-1 | К К2 гДе К The transformation ratio of the test transformer 3. For example, at, 32, i.e. . when the supply voltage decreases by 5% relative to the nominal value, the decrease in the magnitude of the test short circuit current in the transformer under test is 1.32 times less than in the known single-phase testing device. The formula of the invention apparatus for electrodynamic test power transformers in the short circuit mode, comprising a clamp band for connecting the three-phase power supply and a protective circuit breaker, korotkozamykztel three phase test transformer with input and output terminals of windings and subject transformer with input and output terminals of the windings, the secondary winding is shorted , characterized in that, in order to expand the field of application and increase the reliability of tests, it is abzheno voltage transformer with input and output terminals and a control system for short-pri- than the short circuiter is two-phase and each phase of the short circuit consists of a pair of high-voltage anti-junction valves, connected in parallel with input, output and control terminals, the voltage transformer being connected to the power supply source and output terminals to the input of the short circuit control, the first The output of which is connected to the control terminals of the equally connected thyristor valves of both FZZ short circuits, and the second output is connected to the control outputs Dam oppositely turned on tirnstornyh valves, the output terminal of the first and second phase of the protective, connected respectively to rx, oom of the first and second phase of the short stitch; to: tel, r the output terminal of the second phase of the safety switch connected to the z input of the short circuit of the short circuit, the output of the first phase the short circuit is connected to the short-circuited inputs of the primary windings of the test transformer, whose outputs are shorted and grounded, and the output of the second phase of the short circuit is connected to short-circuited secondary inputs bmotok test transformer, the outputs of which are short-circuited and connected to the primary winding of the input transformer of a phase of the test, the inputs of the primary windings of the other two phases of the test transformer is shorted, and the inputs and outputs of the secondary windings of the transformer are grounded ispy- TvsMoro. at WITH - one D four D T Yu  2Јtf sh 3 .Fig.2