KR101358020B1 - Portable device for detecting arc fault signal and electric leakage signal - Google Patents

Abstract

The present invention relates to a portable device for detecting an ARC fault signal and an electric leakage signal. According to one embodiment of the present invention, the portable device for detecting an ARC fault signal and an electric leakage signal includes a sensor part (100); a filter part (200); a signal conversion part (300); a determination part (400); and a display part (500). [Reference numerals] (100) Sensor part; (200) Filter part; (300) Signal conversion part; (400) Determination part; (500) Display part; (600) Operation part; (610) Operation switch; (620) Power switch; (630) Mini USB port

Description

PORTABLE DEVICE FOR DETECTING ARC FAULT SIGNAL AND ELECTRIC LEAKAGE SIGNAL}

The present invention relates to a portable device for diagnosing arc failure and short circuit with an uninterruptible power for preventing an electric fire. More particularly, the present invention relates to wiring for preventing electric fire occurring in a residential house or a fire-vulnerable area and reducing the share of electric fire. The present invention relates to a technique for detecting and diagnosing an arc fault signal from a normal arc by detecting a signal of a broken wire and a portable device using the technique.

In 1976, KS 4613 Earth Leakage Circuit Breaker (ELB) was enacted and the law regulates the installation of earth leakage breaker at the entrance of house to prevent electric shock and electric fire. However, the earth leakage breaker is a device to block the over current and leakage current, but the effect of preventing the electric shock is great, but the electric fire caused by the arc occurring in the normal area cannot be prevented at all. For this reason, the share of domestic electric fires is no longer reduced and remains at the limit.

Advanced countries such as the United States and Canada have mandated the installation of Arc Circuit Breakers (AFCI) in general homes since January 1, 2002, and from 2008 all the circuits except high-risk circuits such as bathrooms and kitchens. An arc circuit breaker is used in the circuit. As a result, the share of electric fires fell from 20% to less than 10%, and the need to expand the installation of arc breakers was recognized. Recently, the installation of arc circuit breakers has been expanded to solar facilities, mobile campers, and prefabricated buildings. In other words, the regulations are being amended so that an electric circuit breaker is in charge of electric fire prevention and an electric circuit breaker is in charge of electric shock accidents.

In order to prevent electrical fires, a diagnostic device that can perform a preliminary check on arcing is essential. Arc, which is the cause of the electric fire, has a characteristic of intermittently lasting for a long time in a place where contact failure occurs, and accordingly, the contact resistance changes over time. In the case of tracks buried in buildings or walls, there is no way to detect the change in contact resistance. In order to solve this problem, the indoor wiring should be checked periodically using a portable arc fault and leakage position detection and diagnosis device. However, the wiring structure is very complicated and diverse in actual houses or buildings, and it is very difficult to verify and verify it even if an arc is generated in the actual underground cavity or the cavity of the building. Therefore, it can be said that it is absolutely necessary to check the conditions when an arc occurs and to check and determine whether it is due to an actual arc or a malfunction.

In case of poor contact or short circuit, it is accompanied by an arc, which causes electric fire. An arc breaker is a device that prevents an electric fire by detecting and blocking an arc signal that causes such an electric fire. However, the general arc circuit breaker can detect an arc failure only when a current of 5 A or more flows through the breaker due to malfunction or the like. Therefore, by overcoming these limitations, by monitoring and detecting arcs generated at currents as low as 0.5A, it is possible to clearly detect low series arcs on the line, and to monitor the instantaneous current, voltage, and fine leakage currents on the line. There is a need for a device that can check the overall quality of the system. For this, it is difficult to be sure of the effect of AFCI in Korea due to environmental differences such as wires, wiring, and grounding used in houses.

For this reason, it is possible to simultaneously diagnose leakage and arc failures occurring in the wiring of residential houses or fire-vulnerable areas, detect the location of leakage and arc failures, and simplify the operation of 'acknowledge signal presence and leakage'. There is a demand for 'a portable device for diagnosing the problem.

Meanwhile, Korean Patent No. 10-0996627 relates to a high pressure / low voltage switchgear system to which an arc sensor is applied, and interlocks with a protection relay in a switchgear that processes high voltage or low voltage power and detects an arc in the shortest time to detect a breaker signal. A technique has been disclosed to protect power equipment from arc accidents by sending a trip signal to shorten the interruption time.

However, there is a problem in that it is impossible to simultaneously diagnose an electric leak and an arc failure occurring at various positions of the wiring, and operation is limited to a switchboard, and it is inconvenient to accumulate and analyze arc signal information according to a change of time.

An object of the present invention is to detect the location of arc failure and leakage current through the algorithm for distinguishing the harmful arc signal among the arc signal, to diagnose the occurrence of the occurrence of the fault and to allow the user to know the risk of arc failure, it can be prevented by the existing earth leakage breaker. The aim is to develop a portable device used to prevent electrical fires from missing arcs.

Portable device for diagnosing the presence or short circuit of the arc fault signal of the present invention for achieving the technical problem, the sensor unit 100 for detecting a signal contained in the load current flowing through the wire connected to the wire; A filter unit 200 for filtering to obtain only an arc fault signal from the detected signal; A signal converter 300 for converting an impulse waveform output from the filter unit 200 into a square wave pulse; Determination unit 400 for distinguishing and determining the harmful arc and the normal arc from the signal input from the signal conversion unit 300; A display unit 500 outputting the result determined by the determination unit to the LCD window 510; And an operation unit 600 providing an interface between the user and the device, wherein the filter unit 200 blocks and attenuates the DC component and the low frequency component to detect an arc fault signal among the signals transmitted from the sensor unit 100. A DC blocking circuit module 210; A first high pass filter circuit module 220 for filtering a signal in a low frequency region among the signals through the DC blocking circuit module 210; A finite gain amplifier circuit module 230 receiving a signal through the first high pass filter circuit module 220 to amplify the gain finitely and acting as a buffer; A second active RC trade pass filter module 240 for receiving a signal through the finite gain amplifier circuit module 230 to narrow the transition band and increase the filter order; A first low pass filter circuit module 250 for filtering signals in the high frequency region among the signals through the second active RC trade pass filter module 240; And a second active RC low pass filter circuit module 260 that receives the signal through the first low pass filter circuit module 250 to narrow the transition band and increase the filter order.

According to the present invention as described above, it is possible to distinguish and process the harmful arc signal and the normal arc signal, and to analyze arc failure, leakage, voltage and current through an integrated algorithm that can integrally control the sensor part, the judgment part, and the display part. As a result, the risk of arc failure is expressed as a percentage so that the user can conveniently know the degree of arc failure, thereby preventing the electric fire caused by the arc that cannot be prevented by an earth leakage breaker.

1 is a block diagram showing the configuration of a portable device for diagnosing the presence or absence of an arc fault signal according to the present invention.
Figure 2 is an appearance of a portable device for diagnosing the presence or absence of an arc fault signal according to the present invention.
Figure 3 is a characteristic of the input current output voltage of the clamp CT of the sensor unit (60Hz, 1kΩ).
Figure 4 is a frequency characteristic curve (1mA, 1kΩ) of the clamp CT of the sensor unit according to the present invention.
5 is an arc fault detection filter circuit diagram of a filter unit according to the present invention;
Figure 6 is a waveform of measuring the steady state and arc failure state of the mercury lamp according to the present invention and the voltage signal detected by the input current, arc voltage and clamp CT.
7 is a waveform of measuring the output of the filter unit in the normal state and the arc failure state of the mercury lamp according to the present invention and the voltage signal detected by the input current, the arc voltage and the clamp CT.
8 is a pulse width control circuit diagram of a signal conversion unit according to the present invention.
9 is a waveform and input current of the square wave pulse measured in the normal state and the arc failure state of the mercury lamp according to the present invention, the arc voltage, the filter output signal and the pulse width conversion circuit output signal.
10 is a circuit diagram illustrating a leakage current detection unit in accordance with the present invention.
11 is a point A and leakage-A input waveform in the leakage current detection circuit diagram of the determination unit according to the present invention.
12 is a point A and leakage-B input waveform in the leakage current detection circuit diagram of the determination unit according to the present invention.
13 is a circuit diagram of a load current detection unit of the determination unit according to the present invention.

Specific features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, terms and words used in the present specification and claims are to be interpreted in accordance with the technical idea of the present invention based on the principle that the inventor can properly define the concept of the term in order to explain his invention in the best way. It should be interpreted in terms of meaning and concept. It is to be noted that the detailed description of known functions and constructions related to the present invention is omitted when it is determined that the gist of the present invention may be unnecessarily blurred.

As shown in FIG. 1, a portable device for diagnosing whether an arc fault signal is present and a short circuit according to the present invention includes: a sensor unit 100 connected to a wired wire and detecting a signal included in a load current flowing through the wire; A filter unit 200 for filtering to obtain only an arc fault signal from the detected signal; A signal converter 300 for converting an impulse waveform output from the filter unit 200 into a square wave pulse; Determination unit 400 for distinguishing and determining the harmful arc and the normal arc from the signal input from the signal conversion unit 300; A display unit 500 outputting the result determined by the determination unit to the LCD window 510; And an operation unit 600 that provides an interface between the user and the device, and the operation unit 600 includes an operation switch 610, a power switch 620, and a mini USB port 630. Specifically, the appearance of the external appearance is as shown in FIG. 2.

Hereinafter, the detailed configuration of the portable device for diagnosing the presence or absence of an arc fault signal according to the present invention is as follows.

Specifically, the sensor unit 100 detects all signals included in the load current as a part of the portable device for diagnosing the presence of an arc fault signal and a short circuit. In the present invention, a clamp CT that is easy to carry as a sensor is selected, and the clamp CT has characteristics such as quick response to measure high frequency arc, ease of use as a clamp type, and general use that can be used in many places. The core material is ferrite and its size is 55 X 45mm, which is easy to measure arc failure and leakage current and ensures reliability in consideration of the thickness of wires used in home and industrial distribution panels. Clamp CT does not need to be connected to the instrument body and wires, and has the advantages of being convenient, durable and portable. In general, clamp CT is used to measure current, leakage current, etc. as a power device, but in the present invention, a special design is applied to accurately detect an arc fault signal. The developed clamp CT was able to maintain linearity at low current so as to accurately detect low current arc fault signal as shown in FIG. In other words, accuracy is maintained even in 500mA low current arc fault signal, and it is possible to measure up to 150A current range of large current. In general, 80% of nickel (Ni) is used as a core of a leakage ammeter used as a power device, and 45% of nickel (Ni) or silicon steel (Fesi) is used as a shielding shield. However, the core and shield of the clamp CT used in the present invention used a nickel (Ni) 80% material. Since the arc fault signal contains high frequency components, a core having excellent high frequency characteristics should be used. In general, the ferrite core is excellent in high frequency characteristics compared to the core core or nickel core. However, durability is weak and the change of the output characteristic with temperature occurs largely. Therefore, in the present invention, the nickel 80% core was used to improve the ferrite core properties and was developed to have excellent high frequency characteristics as shown in FIG.

In addition, the filter unit 200 is a filter circuit that detects the arc failure signal through a filter designed from among the current detected using the clamp CT as shown in FIG. 5 to determine the characteristics of the arc failure signal. The filter circuit consists of a highpass filter and a lowpass filter, and the final output has a bandpass filter characteristic.

In the filter unit 200, the DC blocking circuit module 210 corresponding to the region (a) of FIG. 5 blocks the DC component and the low frequency component to detect an arc fault signal among the signals transmitted from the sensor unit 100. And attenuate and limit the signal to a certain magnitude using a zener diode. The first high pass filter circuit module 220 corresponding to the region (b) of FIG. 5 filters the signal in the low frequency region among the signals through the DC blocking circuit module 210. The finite gain amplifier circuit module 230 corresponding to the region (c) of FIG. 5 receives a signal through the first order high pass filter circuit module 220 and amplifies the gain finitely and serves as a buffer. The secondary active RC high pass filter module 240 corresponding to region (d) of FIG. 5 receives a signal through the finite gain amplifier circuit module 230 to narrow the transition band and increase the filter order. The primary low pass filter circuit module 250 corresponding to the region (e) of FIG. 5 filters the signal of the high frequency region among the signals through the second active RC trade pass filter module 240. The secondary active RC low pass filter circuit module 260 corresponding to region (f) of FIG. 5 receives a signal through the primary low pass filter circuit module 250 to narrow the transition band and increase the filter order.

6 shows a signal measured from the clamp CT, which is the sensor unit 100, a waveform measuring the steady state and the arc failure state of the mercury lamp, and is a voltage signal detected by the input current, the arc voltage, and the clamp CT. When the arc failure occurs, it can be seen that the phenomenon that the sensed signal is distorted.

Figure 7 shows the output signal passing through the filter unit 200 of the present invention in order to detect the arc fault signal, the waveform of measuring the filter output in the normal state and the arc fault state of the mercury lamp and the input current, arc voltage, Filter output signal. In the normal state as shown in FIG. 7A, the filter output signal is not generated. When arc failure occurs as shown in FIG. 7B, an impulse caused by the arc failure signal is output to the output signal passing through the filter unit 200. It can be seen that the waveform of the shape is generated.

The signal converter 300 converts the impulse waveform output from the filter unit 200 into a square wave pulse. 8 is a circuit diagram of the signal converter 300. It occurs at the frequency fed back to the amplifier's input with the largest amplitude. For very low frequencies fed back into the series R-C circuit, C is an open circuit and the voltage going into the amplifier (Vin) has a very small value. Vin increases gradually with the frequency of the feedback signal, and when the parallel capacitor C becomes a short circuit, Vin has a peak value, which occurs only at frequencies where Vout is in phase shift with Vin. The square wave pulse width is adjusted by the hysteresis circuit and the RC time constant to be input to the microprocessor (MCU) of the determination unit 400.

9 shows that the arc fault impulse signal is converted into a square wave pulse signal by the signal converter 300. 9 is a square wave pulse waveform measured in a steady state and an arc failure state of a mercury lamp, and is an input current, arc voltage, filter output signal, and pulse width conversion circuit output signal. It can be seen that the filter output signal does not occur in the normal state as shown in FIG. 9 (a) and that the output of the pulse width conversion circuit does not appear. When arc failure occurs as shown in FIG. A signal is generated and a square wave pulse is generated in the pulse width conversion circuit.

The determination unit 400 distinguishes and determines a noxious arc from a normal arc among the signals input from the signal conversion unit 300. At this time, the presence of the arc fault signal and the determination algorithm is performed by the microprocessor, but the present invention is not limited thereto. The microprocessor is a microcomputer with an 8bit 20MHz frequency and an Analog to Digital Converter (ADC) inside. It has a memory function inside to store the magnitude of the arc fault signal in the event of an arc failure. An important part of the arc signal detection judgment is the repetitive characteristic. One-time arc signal inputs are classified as transient operating characteristics of instantaneous switch arcs or loads, and can be classified as hazardous arcs and normal arcs by repeated arc signal generation. The determination unit determines whether the arc is blocked by using this repetitive characteristic.

10 is a circuit for determining a leakage state caused by arc failure and detecting a leakage current. The national standard for leakage current is to shut off within 0.03 seconds if a leakage occurs more than 30mA. The leakage current detection circuit can be basically divided into four parts.When leakage current, which is the basic principle of ZCT, occurs, the magnetic flux changes due to the imbalance of current flowing in the line in ZCT. It is a circuit to detect. The first part accepts the signal detected by the ZCT. The second part is the part that converts the input signal into the signal level that can be input from the MCU because the MCU is used in the detection circuit. The third part is to determine whether the input signal is a current that flows more than 30mA which is the standard of leakage current. And the fourth is the part that analyzes the signal in the MCU. When a leakage current occurs, waveforms as shown in FIGS. 11 and 12 appear at point A, and appear as square waves as shown in FIGS. 11 and 12 at point B and C. FIG. Therefore, it is possible to know the magnitude of the leakage current according to the magnitude of the square wave pulse width.

13 is a circuit for detecting a load current. In the case of load current detection, this part monitors the current generated when an arc occurs. The characteristic of the breaking time of the arc failure time test is set to be 1 second at low current and 0.1 second at high current because the higher the current is, the more likely it is to develop into a fire. In the arc fault detection circuit, the current is measured when an arc is generated and a change in the current is detected. The load current detection circuit is divided into three parts. First, select the CT measurement range as the parallel resistance part. Second, the RC-low pass filter part is used to remove the noise component measured by the sensor. Third, the parallel capacitor part is used to remove the harmonics and transmits the input signal to the MCU.

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It will be appreciated by those skilled in the art that numerous changes and modifications may be made without departing from the invention. And all such modifications and changes as fall within the scope of the present invention are therefore to be regarded as being within the scope of the present invention.

100: sensor unit 200: filter unit
210: DC blocking circuit module 220: primary high pass filter circuit module
230: finite gain amplifier circuit module 240: secondary active RC trade pass filter module
250: 1st lowpass filter circuit module
260: 2nd active RC lowpass filter circuit module
300: signal conversion unit 400: determination unit
500: display unit 600: operation unit
610: operation switch 620: power switch
630: mini USB port

Claims (3)

In a portable device for diagnosing the presence of an arc fault signal and a short circuit,
A sensor unit 100 connected to the wires for wiring to detect a signal included in a load current flowing through the wires;
A filter unit for filtering to obtain only an arc fault signal from the detected signal;
A signal converter 300 for converting an impulse waveform output from the filter unit 200 into a square wave pulse;
A determination unit 400 for distinguishing and determining a noxious arc from a normal arc among the signals input from the signal conversion unit 300;
A display unit 500 outputting the result determined by the determination unit to the LCD window 510; And
Including an operation unit 600 for providing an interface between the user and the device,
The filter unit 200,
A DC blocking circuit module 210 for blocking and attenuating the DC component and the low frequency component in order to detect an arc fault signal among the signals transmitted from the sensor unit 100;
A first high pass filter circuit module 220 for filtering a signal in a low frequency region among the signals through the DC blocking circuit module 210;
A finite gain amplifier circuit module 230 that receives a signal through the first high pass filter circuit module 220 and amplifies a gain and serves as a buffer;
A second active RC trade pass filter module 240 for receiving a signal through the finite gain amplifier circuit module 230 to narrow the transition band and increase the filter order;
A first low pass filter circuit module 250 for filtering a signal of a high frequency region among the signals through the second active RC trade pass filter module 240; And
The presence or absence of an arc fault signal, characterized in that it comprises a second active RC low-pass filter circuit module 260 for receiving the signal through the first low-pass filter circuit module 250 to narrow the transition band and increase the filter order Portable device to diagnose whether. The method of claim 1,
The sensor unit (100)
Clamp CT has the convenience to use as a quick response and clamp type to measure high frequency arc,
The material of the clamp CT core is ferrite,
The size of the clamp CT is a portable device for diagnosing the presence and leakage of arc fault signal, characterized in that the arc fault and leakage current measurement is easy to measure 55 x 45 mm. delete

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