RU33275U1 - Surge Protector with Surge and Surge Protection - Google Patents

Abstract

An AC voltage stabilizer with surge protection and interference, comprising: first and second input terminals for connecting to an unstabilized voltage source; stabilized voltage output terminals for load connection; an output for grounding; input voltage control means; a control transformer having several windings; electromagnetic relays for regulating the output voltage, the contacts of which are connected to the switched terminals of the transformer windings; means for switching the power circuits of the windings of these output voltage regulation relays; a microprocessor control device for switching the power circuits of the windings of said output voltage control relays, which contains input terminals connected to means for controlling the input voltage, and output terminals connected to inputs of said means of switching power circuits of the windings of said output voltage control relays, characterized in that the input terminals of the stabilizer is connected to a varistor voltage limiter; two identical protection nodes are introduced, formed by series-connected varistors and arresters, and the first conclusions of each of these protection nodes are connected to the ground connection, and the second conclusions of each of these protection nodes are connected to the first and second input terminals of the stabilizer; in addition, an interference suppression filter is introduced, made in the form of a high-pass filter containing inductors and capacitors with a cutoff frequency higher than the frequency of the stabilized alternating voltage, and add�

Description

This technical solution relates to the field of electrical engineering and is intended to stabilize an alternating voltage, mainly with discrete regulation of the output voltage by switching the terminals of the transformer windings by mechanical contacts of electromagnetic relays. A scope - stabilizers of alternating voltage of a network of alternating current 220 V, 50-60 Hz.

When the alternating voltage of the electric network at the input of the stabilizer deviates from the nominal voltage in the stabilizer, control signals of electromagnetic relays are generated, the contacts of which switch the terminals of the transformer windings in order to obtain the required voltage at the output.

Known devices for discrete control of AC voltage by switching the terminals of the transformer windings with thyristors. In particular, a variable voltage regulator of discrete action, which contains a transformer with a partitioned winding, the sections of which are connected in series with each other and with the input terminals through direct and shunt semiconductor switches with their control device that provides switching of the terminals at the moments when the voltage of the network passes through zero level 1.

The disadvantage of this device is the low reliability under conditions of overvoltage in the network, the risk of failure of the thyristors.

Other stabilizers 2, 3 have the same disadvantages.

contacts of electromagnetic relays 4, 5. The disadvantages of such devices are the risk of failure during overvoltage of electronic circuits, welding of relay contacts. This is due to the fact that they are made without the use of special circuitry solutions for their protection at large values of the amplitude of the mains voltage.

The closest analogue is an AC voltage stabilizer 6.

In the transformer-key regulatory body, the keys of which are made in the form of mechanical contacts of the relay, the moments of the passage of current through zero are determined and the results are used to control electromagnetic relays.

The disadvantage of such a device, which is closest to the proposed one, is the passage of electrical noise in the power supply to the output of the stabilizer, and the danger of the stabilizer failing during overvoltages arising from lightning discharges and other abnormal phenomena on power lines or substations.

The task to which this technical solution is directed is to eliminate the indicated drawbacks, to protect the stabilizer itself and the load connected to it from overvoltage and interference.

The technical result achieved in this case is to increase the reliability of the stabilizer and the equipment connected to it by preventing malfunctions and failure during operation.

For this, the following solutions are applied.

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unstabilized voltage source;

stabilized voltage output terminals for load connection;

an output for grounding;

input voltage control means;

a control transformer having several windings;

electromagnetic relay for regulating the output voltage, the contacts of which

connected to the switched terminals of the transformer windings;

means for switching the power circuits of the windings of these output control relays

voltage;

microprocessor control device for switching power supply circuits

windings of said output voltage regulation relay, which contains

input terminals connected to input voltage control means, and

output pins connected to the inputs of said circuit switching means

power windings of said output voltage regulation relay.

The signs distinguishing this stabilizer from the closest known to it 6 according to the utility model of the Russian Federation No. 8847 (prototype), are icing.

Varistor connected in parallel with stabilizer input

voltage limiter;

two identical protection nodes are introduced, formed by series-connected varistors and arresters, and the first conclusions of each of these protection nodes are connected to the ground connection, and the second conclusions of each of these protection nodes are connected to the first and second input terminals of the stabilizer;

In addition, the following are introduced: an interference suppression filter made in the form of a high-pass filter containing inductors and capacitors with a cutoff frequency higher than the frequency of the stabilized alternating voltage, and an additional electromagnetic overvoltage protection relay with normally open contacts and with means for switching the power supply circuit of this relay; the input circuits of the regulating transformer are electrically connected to the input terminals of the stabilizer through a series-connected noise suppression filter and normally open contacts of the electromagnetic surge protection relay, and in the presence of mains voltage and in the absence of overvoltage, these contacts are closed;

d /////

the findings of at least two noise-suppressing capacitors

said interference suppression filter connected to a terminal for connection

grounding;

and a microprocessor device in addition to the power switching control circuit

windings of the output voltage regulation relay, the contacts of which commute

terminals of the control transformer, further comprises the following

schemes:

hazardous overvoltage detection circuit characterized by

increasing the effective value of the input voltage to the limit

acceptable level;

and circuit management circuit switching power windings protection relay against

overvoltage, providing a closed state of the contacts of this relay and

connecting the input of the control transformer through the mentioned filter to

stabilizer input pins during normal stabilizer operation, and

opening of these contacts for emergency disconnection from the mains

transformer during hazardous overvoltage and subsequent automatic

restoration of the on state of the control transformer after

termination of exposure to hazardous overvoltage.

The drawing shows the electrical circuit of the stabilizer.

1,2- conclusions for connecting the input voltage;

3 - output for grounding;

4, 5 - terminals of the output voltage of the stabilizer for connecting the load;

6- adjusting transformer;

7- winding of the output voltage of the stabilizer;

8-switched adjusting winding;

11- microprocessor-based funds management device

switching power circuits of the windings of all relays;

12- means of input voltage control and formation

normalized signal;

13-current sensor and means for generating a normalized signal;

14-functional node surge protection and interference; 15-varistor;

16, 17-arrester; 18, 19-varistors;

20 - anti-interference filter;

21- varistor;

22 - electromagnetic relay with means for switching winding power circuits.

The AC voltage stabilizer with protection against overvoltage and interference contains 5 pins for connection to external electrical circuits. Conclusions 1,2-input, designed to connect the stabilizer to the mains voltage; pin 3 is for grounding; conclusions 4, 5 - the output voltage of the stabilizer, designed to connect the load.

Regulating transformer 6 is designed for discrete regulation of the output voltage by switching the terminals of the additional winding. The winding 7 is connected to the output terminals 4, 5 of the output voltage of the stabilizer. The adjustment winding 8 is connected to the switching contacts of the electromagnetic relay 9. The switched contacts of the relay 9 are connected to the stabilizer output connected to the output 4, also connected to the output of the winding 7, and

switchable normally open contact of relay 10. Relays 9, 10 also include means for switching the power circuits of their windings, for example, transistor switches, the control inputs of which are connected to the output of a microprocessor device 11 designed to control the means of switching the power circuits of the windings of all relays. Two inputs of device 11 are connected to means for monitoring the input voltage and generating a normalized signal 12, compatible in level with the input of device 11, and are also connected to current sensors and means for generating normalized signal 13. Inputs of means for monitoring voltage and current 12.13 through a protective function from overvoltage and interference 14 are connected to the input of the stabilizer - conclusions 1, 2.

The node surge protection 14 is made as follows. A varistor voltage limiter 15 is connected in parallel with the input terminals 1, 2.

Arrears 16, 17 and varistors 18, 19 form two identical protection nodes from series-connected varistors and arresters, and each of these protection nodes is connected with one output to one of the input terminals 1, 2 of the stabilizer, and the second terminal is connected to terminal 3 for grounding .

The interference suppression filter 20 is made in the form of a high-pass filter containing inductors and capacitors, mainly an LC filter, with a cutoff frequency higher than the frequency of the stabilized alternating voltage, and the terminals of at least two noise suppressing capacitors are connected to terminal 3 for grounding. In addition, at the output of filter 20, a second varistor voltage limiter 21 is connected.

The interference suppression filter 20 is connected by an input to the input terminals 1, 2 of the stabilizer. An additional electromagnetic relay 22 with means for switching the power supply circuits of the winding for overvoltage protection has normally open contacts, and the output terminals of the contacts of this relay 22 are connected to the input circuits of the control transformer 6, and the input terminals of the switching contacts of this relay are connected to the output of the filter 20.

The stabilizer works as follows.

When the voltage supplied to the input 1, 2 of the stabilizer, not exceeding the permissible, the contacts of the relay 22 are closed. The input voltage is supplied to the control transformer 6 and the control elements 9-13.

The regulation of the output voltage is carried out by switching the terminals of the winding 8 by the contacts of the relay 9 after closing the switching contact with the normally open contact in the relay 10, and, if necessary, the output voltage is increased or decreased at the output of the stabilizer - terminals 4, 5.

At a rated voltage of the network, the winding 8 of the transformer 6 is not involved, the relays 9, 10 are de-energized.

When the mains voltage deviates from the nominal voltage by analog signals from the input voltage control means 12 and the current control means 13, the microprocessor device 11 generates a control signal for switching the power supply circuits of the relay windings 9, 10. Analog-to-digital converters of the microprocessor control device 11 convert signals proportional to the current and digitally energized. In the myth-processing device 11, the effective values of current and voltage are determined programmatically, the result

is compared with the value of the corresponding setting, and control signals of electromagnetic relays are generated.

Next, the corresponding relays with means for switching the power circuits of their windings switch the necessary conclusions of the transformer windings. As a result, the voltage at the output terminals 4, 5 connected to the winding 7 of the transformer 6, discretely changes to the required value, within the margin of error. By the switching contacts of the relay 9, the winding 8 is connected to the winding 6 in phase or out of phase, creating a voltage lower or higher relative to the input.

When the nominal voltage of the network is restored, the process is repeated and completed by reverse contact switching.

In the initial state, at rated voltage, through normally closed contacts of the relay 9, 10, voltage 4, 5 is output from input 1, 2 without using winding 8.

When the input voltage is increased by the microprocessor device 11, the output voltage is regulated by closing the switching contact with the normally open contact in relay 10, and through the normally closed contacts of relay 9, winding 8 is connected to winding 7. In this case, current flows through windings 7, 8 connected to In this case, according to the scheme of the step-down autotransformer, through the current sensor in the means of generating the normalized signal 13, the relay contacts 22 are closed, the filter 20, the relay contacts 10 are connected to the input 1, 2 and There is a decrease in voltage at the output of the stabilizer 4, 5 to an acceptable level.

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When the input voltage is reduced by the microprocessor device 11, the output voltage is regulated by closing the switching contact with the normally open contact in the relay 10, and by switching the switching contacts with the normally open contacts to the relay 9, through these contacts of the relay 9, the winding 8 is connected to the winding 7 in the opposite polarity. In this case, the current flows through the windings 7, 8, connected in this case according to the step-down autotransformer circuit, and through the current sensor and means 13 for generating a normalized signal proportional to the current, closed relay contacts 22, filter 20, relay contacts 10 with input 1, 2. In this case, the voltage at the output of the stabilizer - terminals 4,5- rises to the required level. The signals of the current sensor and the means for generating a normalized signal 13 are processed by a microprocessor device 11, which controls the electromagnetic relays in such a way that the switching of the contacts by the contacts of these relays occurs at the instant of transition of the alternating current almost through zero, without arcing and burning of the contacts.

The number of switched control steps, regulating windings of the transformer and, accordingly, relays, switching outputs of the transformer windings, as well as the necessary means for switching the power circuits of the windings of these relays, can be any. Additional transformer windings can be either insulated or interconnected, forming an autotransformer with taps.

With significant overvoltages between the ground terminal 3 and terminals 1, 2, the arresters 16, 17 and the varistors 18, 19 are triggered.

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With significant overvoltages directly between the terminals 1, 2, the varistors 15, 21 are triggered.

If the current value of the input voltage of the acceptable level is exceeded for a long time, the microprocessor device 11 turns off the power of the winding of the overvoltage protection relay 22, the contacts of which open and the regulating transformer is disconnected from the network. After the termination of the hazardous overvoltage exposure, the microprocessor device 11 again turns on the power of the winding of the overvoltage protection relay 22, the contacts of which close and connect the regulation transformer to the network, automatically restoring the on state of the regulation transformer.

Electrical interference is attenuated by an interference suppression filter 20, which attenuates interference at frequencies above the cutoff frequency of the filter.

The microprocessor device 11 may have an autonomous power supply or energy storage means, providing it with power when the contacts of the relay 22 are open.

The technical result achieved is to increase the reliability of the AC voltage stabilizer by reducing the likelihood of failures during overvoltages due to the following reasons: lightning discharges, voltage surges on power lines or substations, electric vehicles and other reasons; and also reduces the effect of short-term and long-term electrical interference on the operation of the stabilizer and the load connected to it. st to

This technical solution can be used in AC voltage jams for communication equipment, hardened equipment, for domestic and industrial installations. Sources of information. 1. Gelman M.V., Lokhov S.P. Thyristor AC voltage regulators, p. 97, fig. 39. 2. Patent of the Russian Federation No. 2119229, IPC6 Н02М 5/12, G05F 1/253. A method of regulating voltage under load and a device for its implementation. 3. RF patent No. 2133977, IPC6 G05F 1/20. The method of switching branches of the transformer winding and a device for its implementation. 4.Useful model No. 18810, MPK7 Н02М 2/22, 5/12. Device for stepwise regulation of alternating voltage. 5. RF patent No. 2188496, IPC7 Н02М 5/12, G05F 1/30. Device for stepwise regulation of alternating voltage. 6.Useful model No. 8847, MPK6 Н02М, 5/22. AC voltage stabilizer.

Claims (1)

An AC voltage stabilizer with surge protection and interference, comprising: first and second input terminals for connecting to an unstabilized voltage source; stabilized voltage output terminals for load connection; an output for grounding; input voltage control means; a control transformer having several windings; electromagnetic relays for regulating the output voltage, the contacts of which are connected to the switched terminals of the transformer windings; means for switching the power circuits of the windings of these output voltage regulation relays; a microprocessor control device for switching the power circuits of the windings of said output voltage control relays, which contains input terminals connected to means for controlling the input voltage, and output terminals connected to inputs of said means of switching power circuits of the windings of said output voltage control relays, characterized in that the input terminals of the stabilizer is connected to a varistor voltage limiter; two identical protection nodes are introduced, formed by series-connected varistors and arresters, and the first conclusions of each of these protection nodes are connected to the ground connection, and the second conclusions of each of these protection nodes are connected to the first and second input terminals of the stabilizer; in addition, an interference suppression filter is introduced, made in the form of a high-pass filter containing inductors and capacitors with a cutoff frequency higher than the frequency of the stabilized alternating voltage, and an additional electromagnetic overvoltage protection relay with normally open contacts and with means for switching the power supply circuit of this relay; the input circuits of the regulating transformer are electrically connected to the input terminals of the stabilizer through a series-connected noise suppression filter and normally open contacts of the electromagnetic surge protection relay; wherein the terminals of at least two noise suppressing capacitors of said noise suppression filter are connected to a terminal for connecting ground; and the microprocessor device, in addition to the power switching circuit of the windings of the output voltage regulation relay, the contacts of which switch the terminals of the regulating transformer, additionally contains the following schemes: a circuit for detecting the occurrence of dangerous overvoltage, characterized by an increase in the effective value of the input voltage to the maximum permissible level; and a control circuit for the power supply circuits of the windings of the overvoltage protection relay, providing a closed state of the contacts of this relay and connecting the input of the regulating transformer through the mentioned filter to the input terminals of the stabilizer during normal operation of the stabilizer, and opening these contacts for emergency disconnection of the regulating transformer from the network during dangerous overvoltage and subsequent automatic restoration of the on state of the regulating transformer after termination exposure to hazardous overvoltage.