SU1251225A1 - Device for limiting switching surges in thyristor converter with artificial commutation - Google Patents

Abstract

The invention relates to electrical engineering and is used in secondary power sources. The purpose of the invention is to increase reliability to limit switching overvoltages. The device contains a transformer (Tr) 1, a return Tr 2, the secondary voltage of which exceeds the secondary voltage Tr 1. The introduction of a blocking Tr 12, diodes 6-9 and resistors 10, 11 automatically connects the secondary winding Tr 2 to the secondary winding Tr 1 when any overvoltage occurs in the secondary circuit of Tr 1. This is due to unlocking the thyristors by overvoltage themselves through a simple and reliable blocking unit. I il. with e (L

Description

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The invention relates to electrical engineering and can be used in converting plants with artificial switching to limit switching overvoltages.

 The purpose of the invention is to increase the reliability of the device to limit switching overvoltages.

The drawing is a schematic diagram of the device.

The device contains a converter transformer 1, a returnable transformer 2 with a secondary voltage, surpassing the voltage of the secondary winding of the converter power transformer 1, anti-parallel connected thyristors 3 and 4, a node 5 of blocking the control circuits of counter-parallel-connected thyristors containing diodes 6- 9 resistors 10 and 11, a blocking transformer 12 with two secondary windings 13 and 1A.

The device works as follows

In the half-period of the supply voltage, When the voltage on the right side of the secondary winding of the converter transformer 1 is positive, the voltage of the winding 14 includes a diode 9, through which the current determined by the voltage of the winding 14 and the resistance value of the resistor 11 starts to flow. the half-period of the voltage of the winding 13 turns off the diode 7 and the control electrode circuit of the thyristor 3 is open, which excludes the possibility of its inclusion under the action of the difference of the voltage of the secondary windings of the converter transformer 1 and the transformer 2 return to normal operation.

If, in the considered half-period, a switching voltage exceeding the permissible voltage arises in the secondary winding of the converter transformer 1, a current through the switched diode 9 will flow through the control electrode of the thyristor 4 under the influence of this overvoltage. The thyristor 4 switches on and connects the secondary voltage to the secondary winding transformer 1 the secondary winding of the return transformer 2, providing a flow of energy, caused the resulting overvoltage, from the converter

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transformer 1 to the mains through a return transformer 2. After overvoltage is reduced, thyristor 4 is turned off under the action of the difference in voltage between the secondary windings of transformers 2 and 1.

Processes similarly occur when switching overvoltages occur in the next half-period, but

connecting the secondary winding of the return transformer 2 to the secondary winding of the converter transformer 1 produces a thyristor 3.

The proposed device for limiting switching overvoltages in converter plants with artificial switching in comparison with the known ones possesses more high voltage. Low reliability, as it automatically connects the secondary winding of the return transformer 2 to the secondary winding of the converter transformer 1 when any overvoltage occurs in the secondary winding circuit of the converter transformer I due to unlocking the thyristors by overvoltage itself through a simple and reliable blocking unit.

Claims (1)

Invention Formula A device for limiting switching overvoltages in a thyristor converter with artificial switching, including a converter transformer, a return transformer, the primary winding of which is intended to be connected in parallel with the primary winding of a converter transformer, and the secondary winding is intended to be connected to the secondary winding of the converter transformer through a first and The second anti-parallel thyristors, characterized in that, in order to increase over zhnosti, introduced three-winding transformer locking the first and second resistors, the first and second diode pair, the primary .obmotka blokirukschego transformer connected to the primary winding of the transformer return, and each pair of diodes connected in series between the anode and the control electrode of the corresponding thyristor che312512254 cut the corresponding resistor and the secondary connected to the cathodes to the corresponding winding of the blocking transfer diode pair.