SU1288818A1 - Device for controlling power of three-phase capacitor bank - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used for stepwise power control of a three-phase capacitor bank. In order to increase reliability and speed, the switching device for controlling the power of a three-phase capacitor battery by switching from a star to a triangle, containing switches for switching the capacitor battery by a star and a triangle, a control unit 6 and three discharge resistances 13-15, additionally introduced three opto-switch switches 7,8,9,10,11,12 and a contactless discharge control circuit (L o-E ND 00 oo QO 00

Description

ny chains. This scheme includes an OR-NOT 16 element, AND 17.18 elements, a single-vibration 19, a trigger 20, a delay element 21, and an electronic switch 22. The presence of optoelectronic switches and a contactless control circuit providing inverse synchronization

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one

The invention relates to electrical equipment and can be used for stepwise power control of a three-phase capacitor battery. five

The purpose of the invention is to increase the scaling and speed.

The drawing shows a schematic diagram of the proposed switching device for adjusting the sensitivity of a three-phase capacitor bank.

The device contains a switch 1 including capacitors 2-4 of a condensing battery with a triangle and a switch.5 including capacitors of a 2-4 capacitor battery with a star, made on triacs. The control unit 6, depending on the control parameter X, gives commands to turn on or off switches 1 and 5. Parallel to the capacitors 2-4, through the thyristor switches made -. on anti-parallel connected thyristor optocouplers 7-12, discharge resistances 13-15 are turned on. The inputs of the element OR NOT 16 are connected to the corresponding outputs of logic control unit 6 and one inputs of elements AND 17 and 18. Other inputs of elements AND 17 and 18 are connected to the input of the one-vibrator 19, and the outputs of elements And 17 and 18 are connected to the inputs | switches 1 and 5 35 include a capacitor bank.

The emitters of the optocouplers 7-12 are connected in series and connected via a delay element 20 to the output of the dongle 21, whose input is connected to the trigger output 22 and the one-shot 19 input. The one-shot 19 output is connected to the Setpoint input

thirty

A star and triangle connection of discharge depots made with switches increases the reliability of the device, since it allows the previously discharged capacitors to switch to star and triangle circuits. 1 il.

five

. five

0

trigger 22, the output of which Reset is connected to the output of the element OR NOT 16.

The device works as follows.

Depending on the value of the monitored parameter X, a signal appears at one of the outputs of control unit 6. Suppose that the control signal (Log.1) is wired on the top (according to the circuit) output of the control unit, then Log.O is kept at the output of the OR-NOT element 16, which keeps trigger 22 in the initial state from Log.1 at the output which is fed to the corresponding inputs of the elements And 17 and 18, allowing the control signal to turn on the switch 1. The triacs of the switch 1 are turned on, the capacitors 2-4 are connected to the network in a delta circuit.

In the case when the controlled parameter 1 has changed so much that switching of the capacitor battery from the triangle circuit to a star or vice versa is necessary, Log.O. appears briefly on both outputs of the logic control unit 6. Then the output of the OR-NOT 16 element appears Log 1, which (via a differential circuit) is fed to the input of Trigger Setpoint 22 and translates it into another stable state. On the trigger trigger 22, a Log.O. appears, which prohibits the passage of control signals through the AND elements 17 and 18 to the switches 1 and 5 (disconnecting the capacitor battery from the mains), turns on an electronic switch 21 with a low delay. are emitters of thyristor optocouplers. Small

the time delay is created by the delay element 20 and is necessary for reliably locking the respective sy- sistors of the switches before turning on the thyristor optocouplers 7-12, which 5 connect the discharge resistances to the capacitors of the 2-D capacitor bank. At the same time, the signal from the output of the trigger 22 triggers the one-shot 19, which generates a pulse O (negative polarity), at the Reset input of the trigger 22, at the end of which the trigger returns to its initial state with Log, 1 at the output. The duration of the one-shot pulse is not less than the time required for the full discharge of the capacitor battery and the suppression of the thyristor optocouplers 7-12. The signal Log. G at the output of the trigger is applied to the corresponding inputs of the elements And 17 and 18, allowing the passage of the control signal from the logic unit to enable one of the switches 1 and 5.

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time of discharge capacitors. For this, the magnitude of the discharge resistance is chosen based on the permissible shock current of the optothyristors.

Other types of semiconductor switches can also be used as switches in bit circuits.

Claims (1)

Invention Formula A device for adjusting the power of a three-phase capacitor battery by switching from star to delta, containing a star switch for the capacitor battery and a triangle for switching the capacitor battery, a control unit with inputs for connecting to an adjustable-parameter sensor and three discharge resistances that differ from , in order to maintain reliability and fastThe presence of optothyristor circuit breakers, three thyristors were inserted into it30 Leu and contactless control circuit, providing inverse-synchronized with star and triangle switches, connection of discharge circuits, increases the reliability of the device, since it allows pre-discharged capacitors to switch to star and triangle circuits. As a result, current and voltage spikes during capacitor switching decrease, their service life decreases. Especially important is the full discharge of capacitors when switching from a triangle to a star, because otherwise the voltage on the capacitor due to residual voltage may be 1 (1 + 1 / V3) times the nominal, which is unacceptable. In addition, the presence of optothyristor switches in bit circuits and control circuits increases the speed of the device by reducing the length of 35 Editor S. Patrushev Compiled by O. Nakazna Tehred M. Khodanich Correction. But ha Order 7818/53 Circulation 641 Subscription VNISHI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk, Hia6., 4/5 Production and printing company, Uzhgorod, st. Project, 4 time of discharge capacitors. For this, the magnitude of the discharge resistances is chosen based on the permissible shock current of the optothyristors. Other types of semiconductor switches can also be used as switches in bit circuits. Invention Formula A device for adjusting the power of a three-phase capacitor battery by switching from star to delta, containing a star switch for the capacitor battery and a triangle for switching the capacitor battery, a control unit with inputs for connecting to an adjustable-parameter sensor and three discharge resistances that differ from , in order to ensure reliability and quickly two switches, an OR-NOT element, a one-shot, a trigger, a delay element, an electronic switch, the output of which is connected to series-connected emitters of the thyristor optocoupler new, and the input is connected through the delay element with the trigger output and the one-shot input, the output of which is connected to the reset reset trigger, the input of which is connected to the output of the OR-NOT element, the inputs of which are connected Ina with the corresponding outputs of the control unit and one input of the elements AND, the other inputs of which are connected to the input of the one-shot, and. the outputs are connected to the inputs of the respective switching switches of the capacitor battery.