SU1647470A1 - Device for testing heavy-duty transformers under short-circuit conditions - Google Patents

Abstract

The invention relates to electrical measuring technology and can be used in testing high voltage power transformers in the short circuit mode. The aim of the invention — to increase the reliability of the test results by reducing the turn-on phase of the transformer under test and simplifying the device — was achieved by introducing the reactor 6 and the pulse voltage generator 7 into the device containing the power supply 1, the safety switch 2, the test transformer 3 and the contactor 5 the inputs of charge 8 and start-up 9 and the corresponding connections, 1 Il.

Description

The invention relates to electrical testing equipment and can be used when 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 switch on the tested transformer 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 test transformer. 4, the arc gap 5, the reactor 6, the pulse voltage generator (GIN) 7 with charge inputs 8 and start 9, and the power source 1 through the switch 2 is connected to the output of the primary winding of the test transformer 3, both terminals of the secondary winding of which are connected to the corresponding terminals of the primary windings of the tested transformer 4, the first output of the secondary winding of which is connected through the arc gap 5 to the first output of the reactor by the first output of the GIN 7, the second output of which is connected to a common bus and second outputs of the reactor 6 and the secondary winding 4 of the transformer under test.

The device is used if the power of the power source 1 is sufficiently large (i.e., the internal impedance of the source is many times lower than the impedance of the short-circuited tested transformer 4), when the transformer with an open secondary winding is first connected to the power source 1, and closes after the end of the non-stationary process the secondary winding of the transformer under test 4. Pre-magnetization of the test transformer 4 is not required.

The device operates as follows.

GIN 7 is charged from a low-power source through input 8. The protective switch 2 is turned on, thereby supplying voltage to the test transformer 3 and the primary winding of the transformer under test 4. By supplying a start pulse to the input 9 of the GIN 7 start, the contact gap of the arc gap 5 is punched at the required time, thereby closing the secondary winding of the test transformer 4 to the reactor 6. i.e. ensure that the short circuit test current flows in the transformer under test 4. After the time set for the short circuit test, the protective switch 2 is turned off.

The time of giving the command to the input 9 start GIN 7 is determined by a pre-selected angle of inclusion depending on the required value of the aperiodic component in the short circuit current. The reactor 6 serves to ensure that the voltage pulse generated by the GIN 7 is applied to the arc gap 5. To reduce the effect on the short-circuit current, the reactor 6 can be made with nonlinear inductance, for example, on ferrites, which enters after the beginning of the short-circuit current. The inductance of the reactor 6 drops to units of microgenry, which is orders of magnitude lower than the inductance of the secondary circuit of the tested transformer 4.

The use of GIN 7 in conjunction with the arc gap 5 can significantly improve the accuracy of the phase switch on of the transformer 4 under test and. Thereby increase the reliability of the test results while simplifying the device.

Claims (1)

Claim Device for testing power transformers in short circuit mode. comprising a power source, a protective switch, a test transformer, a contactor, and terminals for connecting a test transformer, the terminals of the primary winding of the test transformer through a protective switch being connected to the terminals of the power source, characterized in 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 nonlinear inductance reactor are introduced to it, and the contactor is made in the form of an arc gap a, and the conclusions of the primary winding of the test transformer are connected respectively to the first and second terminals for connecting the primary winding of the tested transformer, the first terminal for connecting the secondary winding of which is connected via a contactor. With the first output of the pulse voltage generator and the first output of the non-linear inductance reactor, the second output of which connected to a common bus, the second output of the pulse voltage generator and the second terminal for connecting the secondary winding of the tested trans rmatora.