SU1317555A1 - Device for protection of high-voltage electronic unit - Google Patents

Abstract

The invention relates to electrical engineering and can be used for protection against overcurrent of high-power electrovacuum devices powered from a low-voltage network through a step-up transformer and rectifier from a filter; and. The aim of the invention is to increase the speed of a device for protecting a high-voltage electrovacuum device. The goal is achieved by introducing three thyristor switches into the protection device, consisting of pairs of anti-parallel connected thyristors 10–15, a width of resistors 16-21, an auxiliary rectifier 22 and an intermediate relay 23.1. Increased speed is achieved due to the fact that the response time of the intermediate relay 23.1 does not enter at the time of the protection operation. 1 il. 5.1 276 FB. K.1 Kof. on the inclusion of i (L cond sd sp

Description

The invention relates to electrical engineering and can be used for protection against overcurrent of high-power electrovacuum devices supplied from a low-voltage network through a step-up transformer and a rectifier with a filter.

The purpose of the invention is to increase the speed of a device for protecting a high-voltage electrovacuum device.

The drawing shows a diagram of a high voltage rectifier for powering an electrovacuum device with a device for its protection.

Electrovacuum device 1 is powered from a low-voltage network through a step-up transformer 2 and rectifier 3 with filter 4 and is connected to the network through an electromagnetic switching device 5.1 with contacts 5.2-5.4.

The current relay and the high-potential isolation node are made at the same time in the form of a reed switch, the excitation winding 6 of which is separated from the reed switches 7 and 8 by high-voltage insulation 9.

Between the primary winding of the transformer 2 and contacts 5.2-5.4 of the electromagnetic disconnecting device 5.1 on the low voltage side, the thyristor switches are included, consisting of pairs of opposite-connected thyristors 10–15 in each phase.

The device is also equipped with two groups of resistors connected in a star, one of which (16-18) is connected to three phases in front of the thyristor key, and the other (19-21) to the third phase in front of the thyristor key and to two phases behind the thyristor key.

Between the zero points of both groups is connected via rectifier 22 intermediate relay 23.1 with open contacts 23.2-23.5. The opening contacts 23.2-23.4 of the intermediate relay 23.1 are connected to each other by current-limiting, resistors 24-26 and thyristor control electrodes 10-15. In series with these contacts, the disconnecting contacts of reed switches 7 and 8 are included in the control circuit of the thyristors of the two phases.

The device works as follows.

In the normal mode, the current of the electrovacuum device 1 is not sufficient to trigger the reed switches 7 and 8. The thyristor control circuits 10-15 are closed, the thyristors are open, and the voltage at the input of the rectifier 22 is zero. Relay 23.1 is de-energized.

When an emergency partial breakdown occurs in the electrovacuum device 1, the winding 6 current increases, which causes the reed switches 7 and 8. The control circuits of the thyristors 12-15 open, and when the current first passes through zero, the thyristors 12-15 lock up, de-energizing the primary winding of the transformer 2.

After thyristors 12–15 are locked between the zero points of the stars formed by resistors 16–18 and 19–21, a voltage arises that triggers intermediate relay 23.1, contacts 23.2–23.4 of which further break the control thyristors of the keys, preventing the power from being turned on again discharging filter elements and closing the contacts of reed switches 7 and 8.

The closing contact 23.5 of the relay 23.1 gives the command to turn off the electromagnetic switching device 51 to completely (galvanically) disconnect the device from the power supply.

An increase in the speed of the protection device is achieved by the fact that the response time of the intermediate relay 23.1 does not enter during the operation of the protection.

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Claims (1)

The invention of the Device for the protection of high-voltage electrovacuum device connected to the three-phase supply network through a series-connected electromagnetic disconnecting device that increases 5 a three-phase transformer, a rectifier and a filter containing a current relay connected in series to the high-voltage circuit and a high-potential isolation node, characterized in that, in order to improve speed, three thyristor switches are inserted into it to be connected between the output terminals of the electromagnetic disconnecting device and the corresponding conclusions of the primary winding of the step-up transformer and made in the form of Pairs anti-parallel  switched on thyristors with a current limiting resistor, six resistors, an auxiliary rectifier and an intermediate relay, and the terminals of the thyristor switches intended for connection to the output of the electromagnetic switching device through the first, second and third resistors, respectively the output of the first thyristor switch through the fourth resistor - with its second 5 an input terminal connected via the fifth and sixth resistors to the terminals of the first and second thyristor switches for connection to the transformer windings; the output of the auxiliary rectifier is connected to the winding of the intermediate relay, the breakers of which are connected between the control electrodes of the thyristors of the thyristor switches in series with current-limiting resistors, while the current relay and the node of the high potential isolation are made in the form of a reed switch, and the disconnecting contacts of the reed switches include s current limiting resistor in series with the first and second thyristor switches.