KR101037767B1 - The phase prediction device using variation contact resistance of the contact point of circuit braker in live wire state - Google Patents

Abstract

PURPOSE: A phase absent predicting apparatus is provided to prevent the expansion of accidents due to phase absent based on the change of contact resistance in the contact point of a circuit breaker. CONSTITUTION: A circuit breaker switches a current by being in connection with an electric line through a contactor. A test constant voltage generator(200) generates a test constant voltage signal and inputs a test constant voltage signal. A differential amplifier(400) receives the test constant voltage signal before and after the test constant voltage signal passes through a contactor and amplifies the difference of voltages. An A/D converter(600) converts the output signal of the differential amplifier into a digital signal. A microprocessor(700) calculates the current contact resistance value of the contactor.

Description

The phase prediction device using variation contact resistance of the contact point of circuit braker in live wire state}

The present invention relates to a device for predicting an image in advance in a contactor of a circuit breaker through which current of each phase (R, S, T, N) flows, and pre-detecting the image before the image formation accident occurs. More specifically, the present invention relates to a device for preventing an expansion of an accident and protecting a load by predicting and predicting an image loss in advance by detecting a change in contact resistance value of a contactor of a circuit breaker in a live state in which current flows.

If a phase loss occurs in a three-phase power system, unbalanced current flows or single phase power is applied, which can cause enormous damage to the connected load equipment. Therefore, it is necessary to protect the load by detecting the phase condition before the phase loss occurs.

As an example, if a three-phase motor is open when the phase is not started and a single-phase voltage is applied to the motor, a very large large current flows to the motor, which may cause damage in a few minutes. In addition, when a large load is applied to the three-phase motor in operation, when the phase is lost, the torque may be weakened to increase the slip, and a large current may flow and burn out. In other words, if the single phase power is applied while the phase is lost during operation, the motor does not stop the rotation and continues to rotate while increasing the large current, thereby causing a problem of burnout.

In more detail, the main cause of the open phase is the problem of the internal or external wiring, the motor can not rotate or continue to rotate due to the open phase, a large current flows to the rotor of the motor, This increase in current raises the temperature of the windings, destroys the insulation of the coils, damages the contacts of the magnetic contactor and consequently damages the motor.

If the motor is unable to rotate, a large restraint current flows, so it can be protected by overcurrent or restraint. However, if the motor continues to rotate, an imaging protection function is necessary.

In order to solve the above problems, a low voltage switchgear generally includes a phase relay or phase protection circuit, and a load having a large power consumption is generally configured to operate with a three-phase power supply that is more efficient than a single phase power supply. And a breaker is provided at the input of the load device to receive power selectively to protect against abnormalities. That is, the relay and the breaker provided at the input of the load equipment, when abnormality such as short-circuit current, overcurrent, reverse phase or phase loss occur, not only protects the load by quickly shutting off the power supplied to the load, but also causes an accident It also prevents the phenomenon from spreading.

The protection relay and the breaker for the abnormal phenomenon has been implemented by a variety of conventional techniques, in particular, the protection relay for the reverse phase or phase image implemented as an electronic relay rather than a mechanical because it must detect the phase difference between each phase and the potential of each phase in a three-phase power supply It became.

In the prior art, Korean Patent Laid-Open Publication No. 1998-0072117 "Multifunctional Digital Relay" analyzes the voltage waveform of each phase obtained by half-wave rectifying each phase with a microcontroller to detect whether there is a reverse phase or phase loss, and accordingly the relay The output contact is controlled by turning on or off the contact, and the flashing of one light emitting diode is expressed differently, and the control and operation power required for the operation are obtained by a full-wave rectifying circuit composed of diodes.

Further, as a prior art, in Korean Patent Laid-Open Publication No. 10-2007-0035187, "Phase Distribution / Reverse Phase Detection Device", a phase voltage generation microprocessor and a determination microprocessor are formed as an phase / reverse phase determination unit to determine the phase of each phase. Detecting the phase / reverse phase by detecting the signal.

However, a device that detects such an open phase, for example, the breaker voltage in the case that the voltage of the phase is less than 20-30% of the rated voltage (60-70% unbalance), the deviation of the phase signal occurs above the reference value, etc. It is a device to operate, and ultimately relates to a device for protecting the load in the state of already forming an image.

In other words, the conventional phase detection device detects an imbalance or a phase signal of voltage or current in a state where the phase is already formed and the phase is generated while the load is connected and the current is applied to the operating load, thereby preventing damage to the load. As the method for the present invention, there is a need for an apparatus for predicting the image formation in advance before the image formation proceeds.

In order to solve the above problems, it is an object of the present invention to provide an imaging predictor configured to predict and recognize an image in advance through a change in contact resistance of a contactor of a circuit breaker before the image progresses in a live state.

It is also an object of the present invention to provide a phase predicting device for detecting a phase before a phase loss occurs when the breaker is shipped without detecting the initial phase loss state even though the life expectancy of the contactor is incomplete. It is done.

In order to achieve the above object, the present invention provides a device for detecting the phase of the wire line of each phase in the live state, the circuit breaker is connected through the wire line and the contactor to open and close the current; A test constant voltage generator configured to generate a test constant voltage signal and input the test constant voltage signal to pass through the contactor; A differential amplifier receiving a test constant voltage signal before and after passing through the contactor, amplifying the difference in voltage magnitude and outputting the signal as a signal; An A / D converter for converting a signal output through the differential amplifier into a digital signal; And a microprocessor configured to calculate the current contact resistance of the contactor by receiving and analyzing the digital signal converted through the A / D converter. Provide an imaging prediction device.

The phase predicting device compares the magnitude of the AC voltage applied through the wire line with the magnitude of the test constant voltage signal input from the test constant voltage generator to determine the phase angle of the AC voltage having a magnitude greater than the magnitude of the AC voltage. And a phase discriminator for periodically generating and outputting a constant voltage pulse signal by configuring the test constant voltage signal to be output only for a specific time within the determined phase angle range.

The phase discriminator may further include a memory in which a program for controlling the predetermined time is set at a phase angle of 6 degrees when the AC voltage of the wire line is 40V.

The imaging predictor may further include a memory unit configured to store comparison data in which a deviation is set based on an initial contact resistance value of the contactor detected when the circuit breaker is shipped.

The microprocessor may further include an alarm unit configured to generate an emergency signal for notifying an imaging prediction when the calculated contact resistance is greater than or equal to the deviation, and including an LED lamp driven by a voltage applied through the emergency signal. Can be.

And a filter for removing noise components from the test constant voltage signal before passing through the contactor and after passing through the contactor, respectively.

According to the present invention, the following effects can be obtained by the image forming prediction apparatus using the change of the contact resistance of the circuit breaker contact.

First, through the imaging prediction device of the present invention, before the imaging progresses in the live state, the test constant voltage is applied to the contactor of the circuit breaker to predict and recognize the imaging through the change of contact resistance of the contactor, thereby expanding the accident by the imaging. Can be prevented and the load protected.

Secondly, the imaging predictor of the present invention applies a test constant voltage to the contactor by applying a small change in resistance of the contact resistance of the breaker contactor to amplify the voltage difference across the detected contactor through a differential amplifier, and digitally convert the amplified signal. By calculating the contact resistance value of the contactor by the microprocessor, the effect can be predicted in advance.

Third, the breaker shipped without detecting the initial phase open state can be detected in advance the contact resistance value of the contact calculated by the present invention, even if the life expectancy of the contactor does not meet the expected value at the time of shipment of the breaker. By detecting the effect of the breaker is effective in preventing the damage caused.

Fourth, through the phase discriminator configured in the present invention, the test constant voltage is output to the wire line as a constant voltage pulse signal that can be detected by the microprocessor, thereby reducing the burden on the contactor and at the same time increasing the accuracy of detecting and analyzing the constant voltage pulse signal. It can be effective.

1 is a state diagram showing a change in contact resistance of a contactor of a circuit breaker installed in each phase wire line of the power system.
2 is a block diagram of an image forming prediction apparatus using a constant voltage pulse signal according to the present invention.
3 is an explanatory diagram of an operation principle of a phase discriminator for generating a constant voltage pulse signal according to the present invention.
Figure 4a is an explanatory view showing the reason why the difference in the pulse size of the constant voltage pulse signal across the breaker contact according to the present invention, Figure 4b is an amplified signal of the difference in the pulse size of the constant voltage pulse signal across the contact according to the present invention It is explanatory drawing which shows the.

Hereinafter, an image predicting apparatus using a change in contact resistance of a circuit breaker contact in a live state will be described in detail with reference to the accompanying drawings.

In the case of the embodiment of the present invention, the contactor of the circuit breaker has been described as an embodiment, but it will be apparent to those skilled in the art that the technical idea of the present invention is not limited thereto and may be applied to a general open / close switch having an application for opening and closing electricity.

1 is a state diagram showing a change in contact resistance of a contactor of a circuit breaker installed in each phase wire line of the power system. Referring to the figure, it can be seen that the contact resistance of the contactor increases according to the appearance or deterioration of the contactor.

The contactor, which is the contact point of the circuit breaker, causes arcing or poor shape before imaging, and in particular, in case of poor contact, the contact resistance value increases as shown above.

Therefore, if the contactor of the breaker which is the contact of live wire line is old and the contact resistance is high, there is a high possibility that an image formation may occur. Therefore, by analyzing the appearance of the contactor or measuring the contact resistance, the symptom of the contact may be formed. It can be predicted.

However, since the magnitude of the contact resistance is in the order of tens to hundreds of microns, it is not easy to detect the contact resistance, and more difficult is that it is more difficult to detect the contact resistance in the live wire line.

Accordingly, the present invention is characterized in that the test constant voltage is generated in the live power line to detect the change in the contact resistance of the breaker contactor in advance to predict the open phase.

2 is a block diagram of an image forming prediction apparatus using a test constant voltage signal according to the present invention. Referring to the bar, the breaker is mounted on each wire line in the live state while the contact is connected through the contact line (CB, 100) of the wire line and the breaker to open and close the current.

The test constant voltage generator 200 illustrated to detect the contact resistance of the contactor 100 of the breaker generates a test constant voltage signal passing through the contactor 100 of the breaker.

The test constant voltage signal generated by the test constant voltage generator 200 and applied to the wire line is extracted before and after passing through the contactor 100 and input to the differential amplifier 400, and thus, a difference in voltage magnitude, that is, peak to peak. The signal amplified by the voltage difference is output.

Here, the filter 300 may be further configured to remove various noise components in the wire line or the breaker contact line from the extracted test constant voltage signal.

The filter 300 may be configured to bypass the high frequency signal and the low frequency signal, and to pass only the test constant voltage component.

The signal output through the differential amplifier 400 is buffered through the buffer 500 and input to the A / D converter 600, and is converted into a digital signal through the A / D converter 600 to be converted into a microprocessor 700. ) Is entered.

The microprocessor 700 receives the digital signal converted by the A / D converter 700 to analyze the current contact resistance value of the contactor 100.

That is, the present invention applies a test constant voltage to the contactor by applying a small change in the resistance of the contact resistance of the breaker contactor to amplify the voltage difference across the detected contactors through the differential amplifier, and digitally convert the amplified signal to contact the contactor through the microprocessor. It is characterized by the fact that it is configured to predict the image formation of the contactor or the wire line in advance by calculating the contact resistance value of.

In general, since the contact resistance of the contactor 100 of the circuit breaker is in the range of several tens to hundreds of micro Ω, it is necessary to flow a current to the contactor 100 or more in order to increase the accuracy of detection and analysis. However, in this case, the load on the contactor is burdened with 100W ~ 1KW.

To this end, the test constant voltage generator 200 according to the present invention converts the output type of the test constant voltage generated by the test constant voltage generator 200 from the phase discriminator 1000 into pulses so as to reduce the load on the contactor 100. It was configured to be applied along the line.

In other words, the test constant voltage signal generated by the test constant voltage generator 200 through the phase discriminator 1000 is configured to be converted into a constant voltage pulse signal having a predetermined period and output.

For example, when the test constant voltage signal generated by the test constant voltage generator 200 through the phase discriminator 1000 is converted into a constant voltage pulse signal of 1A at 1/1000 cycles and flowed to the contactor 100, the load of the contactor While reducing the load to 1W class has the effect of increasing the accuracy of the analysis by the microprocessor (700).

In addition, when the test constant voltage signal generated by the test constant voltage generator 200 is directly applied through the wire line without passing through the phase discriminator 1000, the test constant voltage signal is covered by the AC voltage signal on the wire line and tested by the microprocessor 700. There is a problem that the detection and analysis of the constant voltage signal becomes difficult. This will be described later with reference to FIG. 3.

In addition, the memory unit 800 is configured to provide information to the analysis and operation of the microprocessor 700, the memory unit 800, the initial contact resistance of the contactor 100 detected at the time of shipment of the circuit breaker The comparison data in which the deviation is set based on the reference value is stored, and the microprocessor 700 is configured to generate an emergency signal for notifying the imaging phase when the calculated contact resistance is greater than or equal to the deviation set in the memory unit 800. do.

In the present invention, the alarm unit 900 or the communication unit 1000 is configured to include an LED lamp driven by a voltage applied through the emergency signal oscillated by the microprocessor 700.

3 is an explanatory diagram of an operation principle of a phase discriminator for generating a constant voltage pulse signal according to the present invention.

Referring to FIG. 5, if the DC voltage of the test constant voltage signal generated by the test constant voltage generator 200 is applied to the wire line to which the AC voltage is applied, the test constant voltage signal is hidden by the AC voltage signal on the wire line and is microscopic. There is a problem in that detection and analysis of the test constant voltage signal by the processor 700 becomes difficult. In other words, the test constant voltage signal, which is the DC voltage, may be detected by the microprocessor only in a state larger than the AC voltage signal.

In order to solve the above problem, the phase discriminator 1100 compares the magnitude of the AC voltage applied through the wire line with the magnitude of the test constant voltage signal input from the test constant voltage generator 200 to increase the magnitude of the test constant voltage. The phase angle of the AC voltage larger than the magnitude of the AC voltage is determined.

In other words, the phase discriminator 1100 is configured to output only when the magnitude of the test constant voltage signal input from the test constant voltage generator 200 is greater than the magnitude of the AC voltage flowing through the wire line. The pulse signal is generated to act to output.

More specifically, the phase discriminator 1100 determines the phase angle of the AC voltage in which the magnitude of the test constant voltage is greater than the magnitude of the AC voltage, and the test constant voltage signal is generated only for a specific time Δt within the determined phase angle range. As a result, a constant voltage pulse signal is periodically generated and output.

However, if the magnitude of the AC voltage applied to the wire line is very large, it has a steep slope, and the specific time Δt becomes very short, and the width of the constant voltage pulse signal generated through the phase discriminator 1000 is It becomes so small that detection and analysis of the constant voltage pulse signal by the microprocessor 700 can be difficult.

Therefore, as a result of the experiment of the present invention, a specific time Δt corresponding to a phase angle of about 6 degrees at the low voltage of the AC voltage of 40 V is determined to be ideally suitable for detection and analysis. When the voltage of the AC voltage is 40V, the phase angle for generating the constant voltage pulse signal may be configured to include a memory (not shown) that is set within the range of 6 degrees.

In other words, the phase discriminator further includes a memory (not shown) in which a program for controlling the predetermined time is set at a phase angle of 6 degrees when the AC voltage of the wire line is 40V. Can be configured.

As a result, even if the constant voltage pulse signal outputted through the phase discriminator 1100 is applied to the wire line, the case is not covered by the AC voltage signal, thereby reducing the load burden of the contactor, and at the same time by the microprocessor 700. There is an effect of increasing the accuracy of the detection and analysis of the constant voltage pulse signal.

Hereinafter, the operation principle of the image forming prediction apparatus using the change of the contact resistance of the circuit breaker contact in the live state will be described with reference to the accompanying drawings.

Figure 4a is an explanatory view showing the reason why the difference in the pulse size of the constant voltage pulse signal across the breaker contact according to the present invention, Figure 4b is an amplified signal of the difference in the pulse size of the constant voltage pulse signal across the contact according to the present invention It is explanatory drawing which shows the.

When the constant voltage pulse signal generated by the phase discriminator 1100 is supplied to both ends of the contactor 100 which is a contact point of the breaker, the constant voltage pulse signal lost by the contact resistance of the contactor of the breaker flows.

Referring to FIG. 4A, the principle of changing the magnitude of the constant voltage pulse signal generated by the phase discriminator 1000 according to the contact resistance of the contactor is briefly illustrated.

Each pulse signal at both ends of the contactor 100 extracted from the wire line passes through the filter 300 and is purified to a high quality signal, and then amplified and outputs a difference in pulse sizes from the differential amplifier 400, and outputs an output signal. Is converted into a digital value through the A / D converter 600 and input to the microprocessor 700 to calculate a resistance value, and compares it with the resistance value of the contactor at the time of shipment, which is initial information stored in the memory unit 800. The risk of the current resistance value is judged to be higher than the deviation is determined that the likelihood of missing image is provided to the user through the notification unit.

Although the detailed description of the present invention has been described with reference to the drawings, it is obvious to those skilled in the art that various modifications may be made without departing from the scope of the present invention. something to do.

100: contactor 200: test constant voltage generator
300: filter 400: differential amplifier
500: Buffer 600: A / D Converter
700: microprocessor 800: memory
900: alarm unit 1000: communication unit
1100: phase discriminator

Claims (6)

An apparatus for sensing an open phase of each phase wire line in a live state, the apparatus comprising: a circuit breaker connected to the wire line through a contactor to open and close a current;
A test constant voltage generator configured to generate a test constant voltage signal and input the test constant voltage signal to pass through the contactor;
A differential amplifier receiving a test constant voltage signal before and after passing through the contactor, amplifying the difference in voltage magnitude and outputting the signal as a signal;
An A / D converter for converting a signal output through the differential amplifier into a digital signal; And
Image forming using a change in the contact resistance of the breaker contact in a live state, characterized in that it comprises a; microprocessor for receiving and analyzing the digital signal converted by the A / D converter to calculate the current contact resistance of the contactor Predictor. The method of claim 1,
The phase is determined by comparing the magnitude of the AC voltage applied through the wire line and the magnitude of the test constant voltage signal input from the test constant voltage generator to determine the phase angle of the AC voltage in which the magnitude of the test constant voltage is greater than the magnitude of the AC voltage. And a phase discriminator for periodically generating and outputting a constant voltage pulse signal by configuring the test constant voltage signal to be output only for a specific time within each range. Used imaging prediction device. The method of claim 2,
The phase discriminator further includes a memory having a built-in program for controlling the predetermined time to be set at a phase angle of 6 degrees when the AC voltage of the wire line is 40V. Phase change prediction device using the change of contact resistance of breaker contact point. The method of claim 1,
And a memory unit configured to store the comparison data of which the deviation is set based on the initial contact resistance value of the contactor detected at the time of shipment of the circuit breaker. The imaging prediction using the change of the contact resistance of the circuit breaker contact in a live state is further included. Device. The method of claim 4, wherein
The microprocessor oscillates an emergency signal informing of an image formation prediction when the calculated contact resistance is greater than or equal to the deviation,
And an alarm unit including an LED lamp driven by a voltage applied through the emergency signal. An imaging predictor using a change in contact resistance of a circuit breaker contact in a live state is further configured. The method of claim 1,
And a filter for removing noise components from the test constant voltage signal after passing through the contactor and after passing through the contactor, respectively.

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