KR101864068B1 - Batteryless Apparatus for Protecting Current Transformer Second Terminal Using Delay Circuit - Google Patents

Batteryless Apparatus for Protecting Current Transformer Second Terminal Using Delay Circuit Download PDF

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Publication number
KR101864068B1
KR101864068B1 KR1020170015504A KR20170015504A KR101864068B1 KR 101864068 B1 KR101864068 B1 KR 101864068B1 KR 1020170015504 A KR1020170015504 A KR 1020170015504A KR 20170015504 A KR20170015504 A KR 20170015504A KR 101864068 B1 KR101864068 B1 KR 101864068B1
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KR
South Korea
Prior art keywords
current
capacitor
current transformer
unit
rectifying
Prior art date
Application number
KR1020170015504A
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Korean (ko)
Inventor
김영미
Original Assignee
주식회사 일산이엔지
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Priority to KR1020170015504A priority Critical patent/KR101864068B1/en
Application granted granted Critical
Publication of KR101864068B1 publication Critical patent/KR101864068B1/en

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/18—Status alarms
    • G08B21/182—Level alarms, e.g. alarms responsive to variables exceeding a threshold
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/18—Status alarms
    • G08B21/185—Electrical failure alarms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/29—Terminals; Tapping arrangements for signal inductances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/40—Structural association with built-in electric component, e.g. fuse
    • H01F27/402—Association of measuring or protective means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/40—Structural association with built-in electric component, e.g. fuse
    • H01F2027/408—Association with diode or rectifier

Abstract

The present invention relates to an apparatus for protecting the second terminal of a batteryless current transformer using a delay circuit. More particularly, the present invention relates to an apparatus for protecting the second terminal of a batteryless current transformer using a delay, which is connected to the secondary side of a current transformer for the control of an electric device such as a motor that is operated by power supply, and monitors the change of the driving current of the motor. The apparatus for protecting the second terminal of a batteryless current transformer using a delay circuit according to the present invention can distinguish the generation of a large current due to the generation of a large current due to an inrush current from the generation of the large current due to the generation of a dangerous situation, operate the protection circuit of an electric device and generate an alarm. The apparatus includes a delay circuit part; an opening prevention module; and a 4-20mA current loop transmitter transmission module.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a secondary terminal protection device for a non-power source current transformer using a delay circuit,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a secondary terminal protection device for a non-power source current transformer using a delay circuit, and more particularly, To a secondary terminal protection device of a non-powered current transformer using a delay circuit.

For control of an electrical device such as a motor, a current transformer is installed to measure the current between an electrical device, such as a motor, supplied with power and a power source. A common power supply and a load are connected in series or connected to the primary terminal of the current transformer, and various measuring instruments such as an ammeter, a power meter, a relay, and a recorder are connected to the secondary terminal to monitor the operation current of the electric device.

Unlike conventional electric devices, a current transformer has a constant current source type in which a voltage rises when a circuit is opened.

In the case of a motor installed in a pump used in a special environment such as purified water, there is a case in which the motor suddenly operates due to a sudden fluctuation in the demand quantity, and a configuration is necessary to protect the motor.

An inrush current is generated during a specific initial period when the motor is started. The intensity of the inrush current is about 6 to 30 times the normal rated current. A current that is much larger than the rated current flows continuously for several seconds to several tens of seconds to the vicinity of the synchronous speed of the motor.

Conventional current transformer protection circuit generates an alarm without distinguishing between the case where the secondary side of the current transformer opens or the current flows and the case where the large current flows temporarily on the secondary side of the current transformer due to the rush current when the motor starts, . ≪ / RTI > In addition, since the alarm is generated each time the motor is started, the alertness of the alarm is reduced, so that even when an alarm is generated due to other risk factors, the manager does not take appropriate measures.

In order to solve such a problem, there has been proposed a motor control method using a delay circuit that generates an alarm by distinguishing a case where a starting current is generated at the time of starting the motor and a case where the secondary of the current transformer is actually opened, A current transformer secondary terminal protection device became necessary.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-mentioned problems, and it is an object of the present invention to provide an alarm device that stops an operation of an alarm sending circuit for a certain period of time at the time of starting an electric device and generates an alarm only when a high- And an object of the present invention is to provide a secondary terminal protection device for a non-power source current transformer using a delay circuit.

In order to accomplish the above object, there is provided an apparatus for protecting a secondary side terminal of a non-powered current transformer using a delay circuit according to the present invention comprises a first rectifying part connected to a secondary side of a current transformer for rectifying and smoothing a voltage of a secondary side of the current transformer, A constant current regulator for passing only a current equal to or lower than a reference current value to a voltage output from the rectifying part; a first capacitor for charging the current outputted from the constant current regulator; and a second capacitor connected in parallel to the first capacitor, An alarm unit connected to the first capacitor and the discharge resistor unit for generating an alarm to inform a primary current of the current transformer when the first capacitor is fully charged, And a second capacitor connected between the first capacitor and the alarm unit to supply current to the alarm unit when the first capacitor is being charged. And an operation unit for supplying an electric current to the alarm unit to operate the alarm unit when charging of the first capacitor is completed. A second rectifying section for rectifying and smoothing the voltage output from the transforming section, and a rectifying section for rectifying and smoothing the voltage output from the transforming section when the voltage output from the second rectifying section exceeds a predetermined reference voltage And an opening prevention module having a short circuit portion in which the semiconductor switching element is switched to form a closed circuit.

The secondary protection device of the secondary protection circuit of the non-power source current transformer using the delay circuit of the present invention is effective in providing an alarm by distinguishing the generation of the temporary high current due to the inrush current of the electric device and the actual failure situation in which the secondary side of the transformer is opened.

FIG. 1 is a circuit diagram showing a secondary terminal protection device for a non-power source current transformer using a delay circuit according to an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a delay circuit portion of a secondary protection device for a non-power source current transformer using the delay circuit shown in FIG.
3 is a circuit diagram showing the opening prevention module shown in Fig.
4 is a circuit diagram of the 4-20 mA current loop signal transmission module shown in FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a secondary terminal protection device for a non-power source current transformer using a delay circuit according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing a secondary terminal protection device for a non-power source current transformer using a delay circuit according to an embodiment of the present invention.

1, the non-powered current transformer secondary terminal protection apparatus using the delay circuit of the present embodiment includes a delay circuit unit 200, a 4-20 mA current loop signal transmission module and an opening prevention module 100 .

The delay circuit unit 200 includes a first rectification unit 210, a current regulator 220, a first capacitor 230, a discharge resistor unit 240, an alarm unit 250, an operation unit 260 .

The first rectification part 210 is connected to the secondary side of the current transformer to rectify and smooth the voltage of the secondary side of the current transformer. The first rectifier 210 rectifies and smoothens the voltage of the secondary side of the current transformer using the first bridge rectifier 211 and the third capacitor 212.

A constant current regulator 220 is connected to the output side of the first rectification part 210. The constant current regulator 220 serves to pass only a current equal to or lower than a reference current value to the current output from the first rectifier 210. In the present embodiment, the constant current regulator 220 serves to pass only a current of 4.8 mA or less and shut off a current of 4.8 mA or more. A heating resistor R17 is disposed between the first rectifying part 210 and the constant current regulator 220 and connected in parallel to the first rectifying part 210. [ A current of 4.8 mA or more which is cut off by the constant current regulator 220 flows into the heat generating resistor R17 and is consumed as heat. When an inrush current is generated in a load such as a motor and a large current flows in the primary side of the current transformer, the magnetic flux due to the large current increases and a large organic electromotive force is generated in the secondary side of the current transformer. A large current is induced in the secondary side of the current transformer due to the offset magnetic flux generated at this time. Only a predetermined specific value (4.8 mA in this embodiment) of the large current flows through the constant current regulator 220 to the rear end of the circuit.

A large current is also generated in the secondary side of the current transformer, and such current flows through the constant current regulator 220 to the output side.

A first capacitor 230 is connected to the output side of the constant current regulator 220 and a discharge resistor unit 240 is connected to the first capacitor 230 in parallel. The current passing through the constant current regulator 220 is charged to the first capacitor 230. The charge is charged in the first capacitor 230 by the potential difference generated by the discharge resistor unit 240.

An operation unit 260 is connected to the first capacitor 230 and an alarm unit 250 is connected to the output side of the operation unit 260. The operation unit 260 includes a transistor as shown in FIG. During the charging of the first capacitor 230, the collector of the operating part 260 and the emitter are electrically connected to each other and the current flows out to the ground through the emitter of the operating part 260. Since the Zener impedance of the Zener diode D1 connected to the operation part 260 is larger than the impedance between the collector and the emitter of the operation part 260, a current flows to the Zener diode D1 during the charging of the first capacitor 230 A current flows to the ground through the emitter of the operation unit 260. [ When the charging of the first capacitor 230 is completed, the resistance of the discharging resistor 240 is very large, so that the current does not flow to the base of the operating part 260. Therefore, the current can not flow through the emitter, The current flows through the Zener diodes D1 and D2.

In the present embodiment, the light emitting diode is connected to the output side of the operation unit 260 as the alarm unit 250. When a large current is generated in the current transformer over a period of time to buffer the first capacitor 230, a current flows to the alarm unit 250 to emit an alarm light. As the alarm unit 250, a speaker or other configuration may be used in addition to the light emitting diode.

If the inrush current does not continue for a predetermined time or more, the first capacitor 230 is not buffered and the operation unit 260 blocks the current to the alarm unit 250. The current that charges the first capacitor 230 is consumed in the discharge resistor unit 240. [ When the inrush current is continuously supplied to the current transformer for a predetermined time or longer and the first capacitor 230 is fully charged, the operation unit 260 supplies the current to the alarm unit 250 to operate the alarm unit 250.

When a large current flows for a short time in a state where the motor is not in a dangerous state, such as when the motor is started, the delay circuit unit 200 controls the operation of the alarm unit 250 by a predetermined time delay Thereby preventing unnecessary alarms of the alarm unit 250 from occurring.

The operation part 260 of the delay circuit part 200 operates the alarm part 250 so that the current of the primary side of the transformer primary side To notify that a problem has occurred.

Since the delay circuit unit 200 uses the current of the current transformer, a separate power source is unnecessary, so that it can be implemented with a relatively simple and simple configuration. The delay circuit unit 200 can easily maintain maintenance and effectively prevent the risk of the motor or the pump connected to the primary side of the current transformer There are advantages to be able to.

The delay circuit unit 200 of the present embodiment is provided with a current limiting element such as the constant current regulator 220 at the front end of the circuit unit to prevent the delay circuit unit 200 from being damaged by a large current while stably preventing the risk of inrush current or large current There is an advantage to be able to monitor.

Referring to FIGS. 1 and 4, a 4-20 mA current loop signal transmission module 300 is connected to the secondary side of the current transformer. The 4-20 mA current loop signal transmission module 300 is configured with a circuit for monitoring the current on the secondary side of the current transformer. The 4-20 mA current loop signal transmission module 300 includes a current-voltage conversion circuit and an amplification circuit.

The 4-20 mA current loop signal transmission module 300 has an advantage that it can easily transmit the signal of the current of the secondary side of the current transformer while minimizing the influence of noise even at a long distance. Using the 4-20 mA current loop signal transmission module 300, the controller of the motor or the pump can easily monitor the operation state of the motor or the pump and the occurrence of a dangerous situation even at a distance of 100 meters or more.

The user does not have to connect to the monitor device when the function is not needed. The power of the circuit is supplied from the monitor unit.

Referring to FIG. 3, the opening prevention module 100 includes a transformer 110, a short-circuit switch 120, a second rectifier 130, and a short-circuit 140.

When the ammeter connected to the secondary terminal of the current transformer is broken or the connected line is broken or is being inspected or repaired, the opening prevention module (100) prevents the secondary terminal of the current transformer In order to stably short-circuit.

The transformer 110 is for transforming the voltage applied to the transformer 110 when the secondary terminal of the transformer is opened. The voltage transformed by the transformer 110 is applied to the power supply of each component to form a closed circuit.

The short-circuiting switch 120 is used to check the ammeter or the like or completely erase the latching current of the semiconductor switching element.

The second rectifier 130 is for rectifying the AC voltage applied through the transformer 110 to be converted into DC.

The short-circuit unit 140 receives the power rectified by the second rectification unit 130, and when the voltage of the power source is greater than a predetermined reference voltage, the short-circuit unit 140 uses a semiconductor switching element (SSR: Solid State Relay or SCR) Thereby forming a closed circuit for closing the open state of the secondary terminal.

When a voltage higher than the reference voltage is applied to the semiconductor switching element SSR of the short circuit portion 140, the zener diodes D11, D12, D13 and D14 operate and the switching element Traic or SCR is turned on by the trigger circuit on to form a closed circuit.

When the circuit is restored and a current less than the latching current flows in the semiconductor switching element (SSR or SCR), the circuit is automatically opened.

That is, when a voltage exceeding the reference voltage is applied to the short circuit portion 140, it is determined that the secondary terminal of the current transformer is in the open state, and the short circuit portion 140 prevents the open state from being maintained by forming the closed circuit.

3 is a circuit diagram of an opening prevention module 100 of a secondary terminal protection device for a non-power source current transformer using a delay circuit according to the present embodiment.

The transformer 110 is connected in parallel with an ammeter for measuring the current of the power supply line. The transformer 110 transforms the voltage on the secondary side of the transformer. The output of the transforming unit 110 is transmitted to the short-circuiting switch 120.

The shorting switch 120 does not form a closed circuit in a state that it is normally off. The shorting switch 120 is manually turned ON only when the opening prevention module 100 is tested to form a closed circuit.

The output voltage transformed by the transformer 110 is transmitted to the second rectifier 130.

The second rectifier 130 includes a second bridge diode 131 and a second capacitor 132. The current rectified in the first bridge diode 131 is smoothed in the second capacitor 132. [

The direct current rectified by the second rectification part 130 is transmitted to the short circuit part 140.

The multi-stage switch SW1 is connected to zener diodes D11, D12, D13 and D14 having different breakdown resistance characteristics. The voltage strength of the short circuit portion 140 can be determined using the multi-stage water position SW1 and the plural zener diodes D11, D12, D13, and D14. The voltage across the zener diodes D11, D12, D13 and D14 is applied to the gate of the thyristor 144. [ When the voltage applied to the thyristor 144 exceeds the reference voltage of the thyristor 144, the anode and the cathode of the thyristor 144 are electrically connected to each other and a current flows.

The turned on thyristor 144 keeps its state continuously and maintains the state until the power source is not applied, so that the closed circuit is continuously formed while the secondary open state is maintained. When a signal is applied to the gate of the thyristor 144 once, it maintains the energized state until it is reduced to the holding current of the reverse current or the Zener diode in the main circuit. The diode 145 is provided to prevent the current applied to the thyristor 144 from flowing in the anode direction from the cathode of the thyristor 144. [

The open-circuit prevention module 100 constructed as described above includes the short-circuiting switch 120 and the short-circuiting unit 140, and thus operates when a large current flows through the secondary side of the current transformer or when the secondary terminal of the current transformer is opened. However, in the non-powered current transformer secondary terminal protection device using the delay circuit of the present embodiment, the open module does not generate an alarm by itself because it does not have a separate alarm part. Even when a load such as a motor connected to the primary side of the current transformer is activated and a large current flows as a starting current, the short circuit portion 140 of the opening prevention module 100 operates to close the open state, but does not generate an alarm every time. .

The delay circuit unit 200 plays a role of generating an alarm when a high voltage is generated in the secondary side of the current transformer. As described above, the delay circuit unit 200 does not operate during the time when the first capacitor 230 is fully charged even if a large current flows due to the inrush current generated by a load such as a motor. The delay circuit unit 200 operates the alarm unit 250 to generate an alarm only when a large current flows through the secondary side of the current transformer for a predetermined period of time.

As described above, the function of closing the open state when a large current flows in the transformer secondary side and the function of generating an alarm only when a large current flows in the secondary side of the transformer over a certain period of time are referred to as the opening prevention module 100 and the delay circuit portion 200 It is possible to prevent the occurrence of unnecessary alarms while at the same time causing an alarm to occur only when the administrator must know the actual danger.

According to the configuration of the present invention as described above, it is possible to improve the effectiveness of alarm generation on the secondary side of the current transformer and to provide a wake-up call for the alarm occurrence by the manager, thereby more effectively preventing the occurrence of the safety accident.

Meanwhile, as described above, the 4-20 mA current loop signal transmission module 300 is connected to the secondary side of the current transformer so as to monitor the current of the secondary side of the current transformer at a remote distance regardless of the operation of the alarm part 250. The manager can monitor the current flowing in the current transformer through a signal received in real time via the 4-20 mA current loop signal transmission module 300 at a long distance.

100: Opening prevention module 110: Transformer
120: short circuit switch 130: second rectifying part
140: short circuit part 131: second bridge rectifier
D11, D12, D13, D14: Zener diode 132: Second capacitor
144: Thyristor 145: Diode
200: delay circuit part 210: first rectification part
211: first bridge rectifier 212: third capacitor
220: constant current regulator 230: first capacitor
240: discharge resistance section 250: alarm section
260:
300: 4-20mA current loop signal transmission module

Claims (1)

A first rectification part connected to the secondary side of the current transformer for rectifying and smoothing the voltage of the secondary side of the current transformer; a constant current regulator for passing only a current equal to or lower than the reference current value to the voltage output from the first rectification part; A discharging resistor connected in parallel to the first capacitor to consume the charge charged in the first capacitor; and a discharging resistor connected in parallel to the first capacitor and the discharging resistor, An alarm unit for generating an alarm to inform the primary side of the current transformer when the first capacitor is fully charged, and an alarm unit connected between the first capacitor and the alarm unit for supplying current to the alarm unit when the first capacitor is being charged, When charging of the first capacitor is completed, current is supplied to the alarm unit and the alarm unit is activated Comprising a delay circuit section for operation of;
A second rectifying unit for rectifying and smoothing the voltage output from the transforming unit, and a rectifying unit for rectifying and smoothing the voltage output from the transforming unit when the voltage output from the second rectifying unit exceeds a preset reference voltage An opening prevention module having a short circuit portion in which a semiconductor switching element is switched to form a closed circuit; And
A 4-20 mA current loop signal (Current Loop Transmitter) connected to the secondary side of the current transformer and having a current-voltage conversion circuit and an amplification circuit so that the current of the secondary side of the current transformer can be monitored without being affected by external noise even in a long distance Module,
Wherein the second rectifying part of the opening prevention module includes a second bridge rectifier for rectifying the input voltage and a second capacitor for smoothing the voltage output from the second bridge rectifier,
Wherein the short circuit portion includes a plurality of zener diodes connected in parallel to each other with different breakdown voltages, a multi-stage switch selectively connected to one of the plurality of zener diodes, and a current flowing through one of the zener diodes is triggered, And a diode provided to prevent a current from flowing from the cathode of the thyristor to the anode,
Wherein the first capacitor, the second capacitor, the diode and the thyristor are connected in parallel, the anode of the plurality of Zener diodes is connected to the gate of the thyristor, the cathode of the plurality of Zener diodes is connected to the multi- Wherein the second terminal protection device is connected to the diode.
KR1020170015504A 2017-02-03 2017-02-03 Batteryless Apparatus for Protecting Current Transformer Second Terminal Using Delay Circuit KR101864068B1 (en)

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KR1020170015504A KR101864068B1 (en) 2017-02-03 2017-02-03 Batteryless Apparatus for Protecting Current Transformer Second Terminal Using Delay Circuit

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KR1020170015504A KR101864068B1 (en) 2017-02-03 2017-02-03 Batteryless Apparatus for Protecting Current Transformer Second Terminal Using Delay Circuit

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10144540A (en) * 1996-11-07 1998-05-29 Toshiba Corp Secondary open circuit protective equipment of current transformer
KR100860858B1 (en) * 2008-07-09 2008-09-29 와이피피디지텍(주) Apparatus for self-diagnosing break line in secondary-side coil for current transformer for electronic watt hour meter using auxiliary relay

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10144540A (en) * 1996-11-07 1998-05-29 Toshiba Corp Secondary open circuit protective equipment of current transformer
KR100860858B1 (en) * 2008-07-09 2008-09-29 와이피피디지텍(주) Apparatus for self-diagnosing break line in secondary-side coil for current transformer for electronic watt hour meter using auxiliary relay

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