SU995197A1 - Gate-type single-phase bridge converter protection device - Google Patents

Description

(54) DEVICE FOR PROTECTION OF SINGLE-PHASE BRIDGE VENT. CONVERTER

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The invention relates to electrical engineering and can be applied in protection devices for bridge valve converters.

A device for protecting a valve, a transducer; containing fuses connected in series with the valves, and a special additional converter connected in parallel to the main 1.

The disadvantage of this device is low reliability due to low speed.

The closest to the proposed technical essence and the achieved effect is a device for protection of a single-phase bridge-valve converter, the first, second, third and fourth arms of which consist of several valves connected in parallel, containing fuses according to the number of valves designed for V1Uyu with the corresponding valves in each arm of the converter, the first, second, third and fourth thyristors designed to connect in parallel the corresponding m transformer shoulders, the first and second transformers, each having first and second primary and secondary circuits, a third transformer with first and second secondary windings and a primary winding,

5 intended to be connected with an end to one load terminal, the first, second, third and fourth threshold elements connected by cathodes to the control electrodes of the respective thyristors,

The Q anode of the first threshold element is connected to the Beginning of the secondary winding of the first transformer, the end of which is connected to the end of the first secondary winding of the third transformer, the beginning connected to the cathode of the first thyristor and the beginning

15 of the first primary winding of the first transformer, the end of which is connected to the end of the first primary winding of the second transformer, the beginning of the second thyristor connected to the anode, the anode of the second threshold element 2 is connected to the end of the secondary winding of the second transformer, the beginning of which is connected to the beginning of the second secondary winding of the third transformer connected end to the cathode of the second thyristor 2.

A disadvantage of the known device is low reliability due to the large number of transformers and complexity.

The purpose of the invention is to increase reliability.

The goal is achieved by the fact that in the device the first and second transformers are equipped with additional windings, and the third transformer is equipped with two additional secondary windings, with the Start of one additional secondary winding of the third transformer connected to the cathode of the fourth thyristor , the beginning of the fourth threshold element connected to the anode, the end of another additional secondary winding of the third transformer connected to the cathode of the third thyristor, and its beginning is connected to the beginning of an additional secondary winding of the first transformer, the end of which is connected to the anode of the third threshold element, the beginnings of the second primary windings of the first and second transformers are connected together and intended to be connected to another load terminal, the beginning of the primary winding of the third transformer connected to the ends of the first primary windings of the first and second transformers, the ends of the second primary windings of the first and second transformers are connected They are connected respectively to the cathode of the third and the anode of the fourth thyristors.

The drawing shows a diagram of the proposed device.

A device for protection of a single-phase bridge valve transformer connected by an input to a power source 1, consisting of, first 2, second 3, third 4 and fourth 5 arms, each of which represents several valves connected in parallel, contains fuses 6-9 the number of valves connected in series to the corresponding valves in each arm of the converter; the first 10, second 11, third 12 and fourth 13 thyristors are connected in parallel to the corresponding arms of 2, 3, 4 and 5 converters, first 14, second 15, third 16 and the fourth 17 threshold elements connected by cathodes to the control electrodes of the corresponding thyristors 10, 11, 12 and 13. In addition, the device contains the first transformer with the first and second primary 18 and 19, one main 20 and one additional 21 secondary windings, the second transformer with the first and second primary windings 22 and 23, one main 24 and one additional 25 secondary windings, the third transformer with one primary 26, with the first and second main

secondary 27 and 28 and two additional 29 and 30 secondary windings.

The anode of the first threshold element is connected to the Beginning of the main secondary winding 20 of the first transformer, the end of which is connected to the end of the first main secondary winding 27 of the third transformer, the beginning connected to the cathode of the first thyristor 10 and the beginning of the first primary winding 18 of the first transformer.

The end of the first primary winding of the first transformer is connected to the end of the first primary winding 22 of the second transformer and to the beginning of the primary winding 26 of the third transformer, the end

through which the load 31 is connected to the beginnings of the second primary windings 19 and 23 of the first and second transformers.

The beginning of the first primary winding 22 of the second transformer is connected to

the anode of the second thyristor II, the cathode of which is connected to the end of the second main secondary winding 28 of the third transformer, beginning connected to the beginning of the first secondary winding 24 of the second transformer, the end of which is connected to

5 the anode of the second threshold element 15.

The end of the second primary winding 19 of the first transformer is connected to the cathode of the third thyristor 12 and to the end of the first additional secondary winding 29 of the third transformer, the beginning of which is connected to the beginning of the additional secondary winding 21 of the first transformer f) a, the end of the third threshold element 16 connected to the anode.

The end of the second primary winding 23

5 of the second transformer is connected to the anode of the fourth thyristor 13, the cathode of which is connected to the beginning of the second additional 30 secondary winding of the third transformer, the end of which is connected to the end of the additional secondary winding 25

 the second transformer, the beginning connected to the anode of the fourth threshold element 17.

The security device operates as follows.

In Normal mode, the current of the power supply source I flows alternately through the shoulders 2, 5 and 4, 3 and through the load 31 in the diagonal of the converter. In each case, this current is reversal of the first, second and third transformers. The first second, third and fourth thyristors 10–13 are locked at the same time.

When one of the valves fails in any converter arm, for example in arm 2, the next commutation on shoulders 4 and 3 is broken. As a result, through the shoulders 2 and 3 a through-circuit short-circuit current passes. As a result, a signal will be generated that enables the thyristor 11. When the valves are turned off

the second arm 3, the second thyristor 11 will fill the on state and take all the current itself. This current will flow until “until the safety of the b of the first arm 2, connected in series with the failed valve of the first arm, does not work.

After the operation of the fuse 6 during the next switching, the second thyristor 11 is inhibited and the converter will again operate in the nominal mode.

In the same way, at the exit from the valve in any arm of the converter, the corresponding thyristor will be unlocked and one of the fuses will operate, after which the converter will again operate in nominal mode.

The inclusion of thyristors 10–13 occurs only in the case of the occurrence of a through short-circuit of the converter. This is due to the induction in the windings of the EMF transformers of such directions that only in the case of the end-to-end connection of the shoulders of one phase of the converter to the control electrode of the thyristors 10-13 does the control signal come.

The application of the invention makes it possible to increase the reliability of protection of a single-phase bridge valve converter by simplifying the protection device and increasing its speed.

Claims (2)

1. USSR author's certificate number 177516, cl. H 02 M 7/10 1963. 2. USSR author's certificate No. 738040, cl. H 02 H 7/10, H 02 M 1/18, 0 1980