SU1411876A1 - Device for monitoring phase failures in three-phase network - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase the reliability of operation while simplifying its operating conditions. When the device is connected to a controlled three-phase voltage source, diodes 7-9 are alternately unlocked. Through the diode 10, the charge current of the capacitor 1 1 begins to flow. The LED of the transistor optron 13 emits a luminous flux that opens its transistor. Each transistor of the optocoupler 13 shunts the LED of the thyristor optocoupler 14, i.e. The optocoupler transistor 13 is in an open state until the voltage of one or several phases disappears or decreases to a level at which the optocoupler 13 LED does not work. which gives a light pulse, which opens the thyristor and on and off of the signaling and power supply circuit of the protected network 1 sludge. § SL

Description

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The invention relates to electrical engineering and can be used in three-phase voltage control systems of low-voltage power sources.

The purpose of the invention is to increase the reliability of the device while simplifying its operating conditions.

The drawing shows a schematic diagram of the proposed device.

A device for monitoring a three-phase network breakage contains the first, second and third star-connected resistive voltage dividers, formed by resistors 1-6, the inputs of which have terminals for connecting to the phases of the monitored network a three-phase half-wave rectifier consisting of diodes 7- 9, the common connection point of the cathodes of which I is connected to the anode of the diode 10. The point I of the connection of the cathode of diode 10 with the positive terminal of the capacitor 11 through the first resistor 12 is connected to the I combined transistor j transistor collector ornogo I photocoupler 13 and the anode of the LED of optocoupler 14 tiristo molecular weight.

The positive output of a three-phase half-wave rectifier through the second resistor 15 is also connected to the anode of the LED of the transistor optocoupler 13. In this case, the emitter of the photo-transistor and the cathode of the LED of the transistor optocoupler 13, the negative terminal of the capacitor 11 and the cathode of the LED of the thyristor optocoupler 14 are connected to the neutral point of the resistor dividers and grounded. Thyristor Opt.rona 1A BKJno4eH to the alarm circuit or to the power supply circuit of the protected network

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The device works as follows.

After connecting the device to a controlled three-phase voltage source, diodes 7-9 connected respectively to the outputs of the voltage dividers of phases A, B, C are unlocked alternately, once during the mains voltage period. Through the diode 10, the charge current of the capacitor 11 begins to flow. The LED of the transistor optocoupler 13 emits a luminous flux, which opens its transistor in each positive half-cycle of phases A, B, C and open

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This transistor of the optocoupler 13 shunts the LED of the thyristor optocoupler 14.

Thus, the transistor of the optocoupler 13 is in the open state until the voltage of one or several phases disappears or decreases to a level at which the LED of the optocoupler 13 does not work. In the latter case, the discharge current of the capacitor 11 flows through the first resistor, 12 and the LED thyristor optocoupler 14, which emits a light pulse, which opens its thyristor and includes an alarm circuit or a power supply circuit of the protected network.

The introduction of resistive voltage dividers ensures the operation of the proposed device at a lower voltage, which contributes to an increase in the reliability of its operation. Introduction of a transistor optocoupler and the implementation of a three-phase rectifier with one-half period:; eliminates the need to configure the proposed device, which simplifies the conditions of its operation.

Formula of the invention

A device for monitoring three-phase network failure, containing a first resistive voltage divider, a three-phase output, to the plus output of which a diode anode, capacitor, first and second resistors and a thyristor optocoupler are connected, the photo thyristor of which is connected to an alarm circuit, characterized in that in order to increase the reliability of operation while simplifying its operating conditions, the second and third resistors voltage dividers and the transistor optocoupler, photothyrist collector, are additionally introduced into it The orifice of which is connected to the anode of the LED of the thyristor opto and through the first resistor is connected to the connection point of the cathode of the diode and the positive terminal of the capacitor, the anode of the LED of the transistor optocoupler through the second resistor is connected to the positive terminal of the aforementioned three-phase rectifier, out- full-wave and connected by inputs to the outputs of the first, second and third star-connected resistive dividers, the inputs of which have terminals for connection to the phases of the controlled network, with

31411876

This photoresistor emitter and cathode of the LED of the thyristor opto-LED of the transistor optocoupler are not connected to the neutral point

negative capacitor and resistive dividers and grounded

Claims (1)

A device for monitoring the phase of a three-phase network, comprising a first resistive voltage divider, a three-phase rectifier, to the positive terminal of which a diode anode _ν capacitor is connected, the first and second resistors and a thyristor optocoupler, the photo-thyristor of which is included in the signaling circuit, characterized in that, in order to increase reliability of operation while simplifying the conditions of its operation, it additionally introduced the second and third resistive voltage dividers and a transistor optocoupler, a collector of a photo thyristor connected to the anode of the LED of the thyristor breakage of the optocoupler and through the first resistor connected to the junction point of the cathode of the diode and the positive output of the capacitor, the anode of the LED of the transistor optocoupler through the second resistor is connected to the positive terminal of the three-phase rectifier, made half-wave and connected to the outputs of the first, second and the third resistive dividers connected to the star, the inputs of which have terminals for connecting to the phases of the controlled network, while the emitter of the photoresistor and to The LED of the transistor optocoupler LED, the negative terminal of the capacitor, and the LED cathode of the thyristor optocoupler are connected to the neutral point of the resistive dividers and are grounded.