SU1647469A1 - Device for testing heavy-duty transformers under short-circuit conditions - Google Patents

Abstract

The invention relates to means of controlling electrical parameters and can be used to test high-voltage power transformers in the short circuit mode. circuit breaker 2, test transformer 3, contactor 5, reactor 6 and pulse voltage generator 7 with charge inputs 8 and run 9 and related communications. 1 silt

Description

The invention relates to means for monitoring electrical parameters in electrical engineering to ms-zhzt to be used for testing power transformers in short circuit mode (short circuit).

The purpose of the invention is to increase the reliability of the test results by increasing the accuracy of the phase of inclusion of the tested treadmill and simplifying the device.

The drawing shows a diagram of the device.

The device contains a power source 1 (mains or shock generator), a protective switch 2, a test transformer 3, a transformer under test 4. an arc gap 5, a reactor 6, a pulse voltage generator (GIN) 7 with charge inputs of 8 m run 9, and the primary winding of the test transformer 3 through a switch 2 is connected to a power source 1, the first output of the secondary winding of the test transformer. 3 through a series-connected arc gap 5 and a reactor 6 connected to the first terminal of the primary winding of the transformer 4 under test, the second terminal of which is connected to a common bus, the second terminal of the secondary winding of the test transformer 3 and the first output of the generator 7, the second output of which is connected to the combined terminals of the arc gap 5 and reactor 6, both terminals of the secondary winding of the transformer 4 under test are combined.

The device is used in cases where the internal impedance of the power source 1 is so significant that an increase in the EMF of the power source 1 is required in order to pass the required short-circuit current through the tested transformer 4.

The device operates as follows.

GIA 7 is charged from a low-power source through input 8. Turn on the protective switch 2, thereby supplying voltage. To test transformer 3, by applying a start pulse to input 9 of start-up of generator 7 at the required time, the contact gap of the arc gap 5 is punched, including thereby the test transformer 4 into the test circuit, and after the time set for the short-circuit test, the protective switch 2 is turned off. The time instant for issuing the command to the input 9 of the start of the generator 7 is determined by the preselected angle Ia according to the required masks ve DC component in a current short-circuit.

The reactor 6 serves to prevent the generator 7 from being shorted to the input capacitance of the transformer 4 under test. Thanks to the reactor 6, the voltage pulse generated by the generator 7 is almost completely applied to the contact gap of the arc gap 5, since the inter-electrode capacitance of the latter is many times smaller than the input capacitance of the secondary winding test transformer 3. To reduce the effect on the short-circuit current, the reactor 6 can be made with non-linear inductance, for example, on ferrites, which enters the saturation after the beginning of the flow of short circuit current. The inductance of reactor 6 drops to microgenry units, which is by orders of magnitude lower than the short-circuit inductance of the transformer under test 4.

When the voltage of the generator 7 in the shock, significantly exceeding the static discharge voltage of the arc gap 5, the own burden of operation does not exceed several microseconds. This allows you to carry out the turn-on phase of the tested transformer 4 on the short circuit with accuracy not achievable when using a different type of contactor. The gap of the arc gap 5 can be both adjustable and unregulated. In the latter case, it should be such that its static discharge voltage exceeds, with the required margin, the highest voltage of the secondary winding of the test transformer 3 or the source of the test voltage in the general case, if several transformers connected to different circuits are used as the latter. Accordingly, the generator 7 must be designed for the required voltage, ensuring a guaranteed breakdown of the arc gap 5.

Instead of the arc gap 5, a high voltage circuit breaker (BBH) can be used that does not have a stable intrinsic turn-on time. In this case, the command to turn on the BBH is given somewhat ahead of the moment of supplying the start pulse to the starting spark gap of the generator 7. In such a circuit, the short-circuit current can be switched off using the BBH.

Using the invention provides an economic effect by reducing the cost of testing equipment, as well as increasing the reliability of test results.

Claims (1)

Claim A device for testing power transformers in short circuit mode, containing a power source, a protective switch, a test transformer, a contactor and terminals for connecting the test transformer, the terminals of the primary winding of the test transformer through the protective switch being connected to the terminals of the power source, the first terminal of the secondary winding of the test transformer is connected with the first output of the contactor, the terminals for connecting the secondary winding of the test transformer 15 are connected to It is expected that, in order to increase the reliability of the test results and simplify the device, a pulse voltage generator with charge and start inputs and a reactor with 5 nonlinear inductance are introduced into it, and the contactor is made in the form of an arc gap, the second terminal of the contactor is connected to the first output of the pulse voltage generator and through a reactor with nonlinear 10 inductance to the first terminal for connecting the primary winding of the transformer under test, the second terminal of the same purpose is connected and a common bus, the second output pulse voltage generator and the second terminal of the test transformer's secondary winding.