RU149004U1 - HIGH VOLTAGE ELECTRICAL EQUIPMENT TEST DEVICE - Google Patents

Abstract

A device for testing high-voltage electrical equipment, containing a capacitor bank connected to the first voltage converter, an inductance coil connected to the capacitor bank through a switch, and a booster transformer, the secondary winding of which is connected between the output of the inductor coil and the output terminal of the device, and the primary winding is connected to the output of the second voltage converter controlled by current and voltage at the output of the device with the possibility of generating an additional voltage that compensates for active losses in the device and the tested electrical equipment.

Description

Technical field

The utility model relates to the field of electric power and, in

in particular, to devices for electrodynamic testing by short-circuit currents (KZ) of high-voltage power transformers of high power, reactors, circuit breakers and other high-voltage electrical equipment.

State of the art

Known devices for testing power transformers with power from the network [RU 2041472, RU 2505600] and from autonomous three-phase current generators [SU 1394172, SU 1608595].

Known devices do not allow electrodynamic tests of high-power power transformers (more than 80 MVA), since during such tests the load surges on the power system can reach several thousand MVA.

So, for example, for testing a transformer of type TDTs 250000/220 with a capacity of 250 MVA, 220 kV, meeting the requirements of [GOST 20233-74. Transformers spruce. Short-circuit test methods.] Short-term power of the power system ≈ 15600 MVA is required. At the same time, the problem is not only the generation of the required power by the power system, but also the adaptation of the power system, its generating and other electrical equipment to impulse disturbances arising from a series of such tests.

The use of an oscillatory LC-circuit to obtain a test voltage of the industrial frequency with preliminary energy storage in it does not provide the required stability of the test voltage for a short circuit time specified by GOST (0.2 s) due to damping of oscillations due to active losses in the oscillatory circuit and the test equipment (e.g. transformer).

Utility Model Disclosure

The technical result of the utility model is to increase the stability of the test voltage and reduce the required power of the power source.

The subject of a utility model is a device for testing high-voltage electrical equipment, comprising a capacitor bank connected to the first voltage converter, an inductor connected to the capacitor bank via a switch, and a boost transformer, the secondary winding of which is connected between the output of the inductor and the output terminal of the device, and the primary winding connected to the output of the second voltage Converter, controlled by current and voltage at the output of the device with the possibility of forming an additional voltage that compensates for active losses in the device and the tested electrical equipment

This allows you to get the above technical result.

Brief Description of the Drawings

In FIG. 1 shows a diagram of a device with elements of a test bench.

In FIG. 2 shows the results of computer simulation tests of a powerful transformer for short-circuit resistance, carried out using the proposed device.

Utility Model Implementation

The device contains a capacitor bank (KB) 1, an inductor 2 with taps of various levels of high voltage 110-750 kV, a switch 3, a first voltage converter 4, a boost transformer 5, a second voltage converter 6, an output current and voltage sensor 7 (conventionally shown one combined sensor).

In FIG. 1 also shows the elements of the test bench: a power transformer 8, from the windings of which in a particular case, can be powered by converters 4 and 6, an operator console 9, a key 10 controlled from the console 9, as well as the tested transformer 11. (In addition to the claimed device on the test bench devices for other types of electrical equipment tests using elements 8-10) may be placed.

Converter 4 can be made in the form of two rectifier inverters with a control unit and a smoothing inductor.

Converter 6 can be made according to the voltage inverter circuit with pulse-width (PWM) control and a single-phase output, to which the primary winding of transformer 5 is connected.

The circuit of FIG. 1 works as follows.

In the initial state, the key 10 and the switch 3 are open. The secondary winding of the transformer under test 11 is shorted. The control panel 9 of the test bench on the instructions of the operator (or under the control of the program) generates the commands "Charge KB" - "Excitation circuit" - "Short circuit" - "Blanking circuit".

By the command "Charge KB", the first converter 4 is turned on in the charge mode of the capacitor bank 1 to a predetermined voltage level.

By the command “Excitation of the circuit”, the converter 4 exits the charge mode (the control pulses of the keys of the converter 4 are removed), the switch 3 closes, and an oscillatory circuit with a natural frequency close to the industrial frequency of 50 Hz is formed from the battery 1 and coil 2.

By the command “Short circuit”, a series of opening pulses with a duration of 0.2 s each is supplied to the key 10. The sensor 7 of the output current and voltage gives the Converter 6 signals corresponding to the values of current and voltage at the output of the device.

в соответствии с векторным выражением:The Converter 6, controlled by the current and voltage of the sensor 7 generates a compensation voltage on the secondary winding of the transformer 5

in accordance with the vector expression:

where U ₀ is the nominal value of the test voltage;

U _n is the current value of the test voltage;

- ток на выходе устройства;

- current at the output of the device;

k _u. , k _i - regulation coefficients of the Converter 6 for voltage and current, respectively.

с автоматической адаптацией к характеристикам испытуемого объекта.This control provides stabilization of the output voltage of the device by changing the depth of the positive current feedback

with automatic adaptation to the characteristics of the test object.

суммируется с напряжением

, снимаемым с отвода катушки 2. Сумма

поступает на первичную обмотку испытуемого трансформатора 11, обеспечивая на выходе устройства стабильное испытательное напряжение промышленной частоты в режиме КЗ.Voltage

sums up with voltage

removed from the retraction of the coil 2. Amount

enters the primary winding of the transformer under test 11, providing a stable test voltage of industrial frequency in the short circuit mode at the output of the device.

After 0.2 s, by the command “Quenching the circuit”, the key 10 is opened, and the converter 4 is transferred to the inverter mode to recover the unspent energy of the oscillatory circuit into the network.

In FIG. Figure 2 shows the waveform of computer simulation of a single-phase short-circuit mode of a power transformer of the type ТДЦ 400000/220 kV for two different switching phases of switch 10, at which the shock current of the short circuit (aperiodic component) is 0 and the maximum value. Designations on the waveform:

U _n is the voltage at the transformer under test, (Volt);

I _n - current of the primary winding of the transformer under test, (Ampere);

U _k - voltage on the oscillatory circuit, (Volt).

As can be seen from the waveform, the voltage U _n on the primary winding of the transformer under test during the tests for resistance to short circuit is maintained stable and equal to the nominal value (voltage amplitude value ≈ 200 kV).

Claims (1)

A device for testing high-voltage electrical equipment containing a capacitor bank connected to the first voltage converter, an inductor connected to the capacitor bank through a switch, and a boost transformer, the secondary winding of which is connected between the output of the inductor and the output terminal of the device, and the primary winding is connected to the output of the second a voltage converter controlled by current and voltage at the output of the device with the possibility of forming additional th voltage compensating resistive losses in the device under test and the electrical system.

Images