SU862310A1 - Device for provide subscribers with alternating current - Google Patents

Description

(54) DEVICE FOR ELECTRICAL SUPPLY OF CONSUMERS

AC VOLTAGE

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The invention relates to a device for supplying consumers with alternating current and can be used, in particular, for the development of high-power consumers with high-power synchronous motors, for example, in power supply systems of enrichment plants.

Circuits of substations with transformers with split windings are known in their circuit for limiting short-circuit currents and facilitating the growth of switching equipment. included current-limiting reactors

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However, such a solution is characterized by a high cost in standard {: mode. 20

It is also known a device for power supply of consumers with alternating current in which, in order to facilitate the operation of switching equipment and increase the permissible short-circuit capacitance between the power transformer and the conductor from which synchronous electric motors are powered, the following is installed: a jordic juncher 1.2J ,. )about

This device is used in networks of 6/10 kV enterprises with a motor load connected to the main conductors.

Transformers with a secondary voltage of 6 kV with a capacity of 63.80 IBA were used in power supply systems for especially large industrial facilities at the present time. The secondary winding of said transformers is made split. Each of the split windings is connected to conductors from which electric motors are powered.

The use of such a solution forces the use of two thyristor ones. short circuits, which are installed between the transformer winding and each of the conductors.

Due to the fact that the high-voltage thyristor short-circuitors are made in the form of a significant number of series-connected thyristors, this technical solution leads to an unjustified increase in the installed power of the short gang.

Claims (2)

The purpose of the invention is to reduce the installed power of the thyristors. The delivered target is achieved in the device for supplying consumers with alternating current, containing a step-down transformer with two split secondary windings, to which individual conductors with consumers are connected, two thyristor switches, each of which is connected to its current line and connected to a mode sensor of this conductor, and the grounded current-limiting resistor due to the fact that between the combined second ends of two thyristor jacks and a resistor is turned on A thyristor switch connected to the sensor of the modes of both current leads, each of the switch switches being designed in such a way that the installed power of each of them is less than nominal, and the total installed power of the thyristor switches from each conductor to the resistor is equal to the nominal for the network voltage class. The drawing shows a diagram of the device in a single-phase implementation. The device contains a downstream transformer 1 with two split windings connected to conductors 2 and 3.. Connected to the pipeline are consumers 4, 5 and b and thyristor switches 7 and 8, to the combined ends of which are connected a thyristor switch 9 grounded through a resistor 10. The control of the thyristor switches is carried out from mode sensors 11 and 12 installed on conductors 2 and 3. The device operates as follows. In normal transformer 1 is turned on, electric receivers 4-6 are supplied with power from conductors 2, 3, and the thyristor short circuit switch is disconnected. If an emergency mode occurs, for example, if there is a short circuit at point K1 (damage to electrical condition 5), the sensor 12 is triggered. , connected to the current line 3 of the thyristor switches 8, 9, and thus limiting the strength of the current coming to the place of damage. The electrical receiver 6 is disconnected. After switching off the damage by the switch of the electric receiver 5, the thyristor switches 8 and 9 are switched off. In case of a short circuit at point K2, the device operates in a similar way - sensor 11 mode parameters switches on thyristor switches 7 and 9. The degree of current limiting is determined by the size of resistor 10. In high-voltage thyristor devices, as a rule, sequentially connected bipolar thyristor groups are used. Taking into account that the split windings of the transformer 1 are magnetically connected, the difference in voltages of the phases of the same name of conductors 2 and 3 is small. In the three-beam circuit of the thyristor switches, this allows one to select the bipolar groups of the thyristor switches 7 and 8 for an insignificant part of the phase voltage, and the common part to choose the main part of the voltage. This allows to significantly reduce the number of valve elements. Thus, due to the use of the device, the number of valve elements in the thyristor switches is significantly reduced compared with the use of the full thyristor switches on each section of the conductors. In addition, the presence of thyristor switches 7 and 8 allows you to simultaneously turn on and thereby realize parallel operation of conductors 2 and 3. This allows you to reduce the reactive mains of the network during the start-up period of a powerful electric motor, by parallelly turning on the split windings of the transformer 1. Formula for inventions AC power supply to consumers, containing a step-down transformer with two split secondary windings to which individual conductors are connected. and perspiration The capacitors, two thyristor switches, each of which are connected at one end to its own conductor and connected to the current mode sensor, and a grounded current-limiting resistor, which, in order to reduce the installed thyristor power, between the combined second ends two thyristor switches and a resistor, the third thyristor switch connected with the sensors of the mode of both thyristor switches is turned on, and the switches are designed so that the installed power of each of them is m nshe nominal, and the total installed capacity of thyristor switches of each current lead to the resistor is equal to the nominal network voltage corresponding class. Sources of information taken into account in the examination, 1.Lisovsky G.S. and Kheifits M.E. Main circuits and electrical equipment of substations 35-750 kV. M., Energie, p. 352, fig. 9-19. 2. USSR author's certificate 655019, cl. H 02 J 3/00, 1979 (about the totype).