KR101180237B1 - The live line electroscope which uses the magnetic field - Google Patents

Abstract

The present invention solves the problem of a live detector using a magnetic field, in particular, a conventional detector having a problem that it is not possible to determine whether the live wire is shielded by electric field shielding, a method for detecting extremely low frequency microwaves generated around a line, The present invention relates to a non-contact portable live wire detector that can be used for both low and high voltages that can detect live wire on all wires without distinguishing the shielded wire.

Description

Live line detector using magnetic field {THE LIVE LINE ELECTROSCOPE WHICH USES THE MAGNETIC FIELD}

The present invention relates to a live line (wire through electricity) detector using a magnetic field, in particular a non-contact portable live line detector that can be used for both low and high pressure irrespective of shielding / unshielding by detecting a magnetic / electric field.

Attention should be paid to the transmission path, which usually runs from several hundreds to tens of thousands of volts, as there is a risk of electric shock in handling. Therefore, in order to test low pressure, a low pressure detector which checks according to the presence and size of a current flowing by contact in a small and contact manner is used. For high pressure, the length can be adjusted in the form of a fishing rod by an electric field. Contactless live wire detectors are used.

However, since transmission lines are buried abundantly not only on the ground but also in the basement, it is impossible to detect whether the shielded transmission lines buried underground are live or not. Therefore, due to the large number of risks, the development of detectors that can determine whether the liveliness is urgently required. In addition, due to the carelessness of the workers during the electric work and the construction of the high voltage underground line, the liveline may be mistaken for a replacement line and the underground line may be shorted during operation. Inconvenience, as well as economic losses will occur. Therefore, some companies pay more attention to safety by designating live alarm of distribution line as essential equipment during electric work.

In general, voltage and live wire detection of high voltage lines should be measured or detected without flowing any current into the line. As a result, the measurement or detection electrode part has to be high insulation resistance, low capacitance, and requires noise resistance.

In addition, since an electric field may become difficult by a flop at the time of a measurement, and a precise measurement may be difficult, the shape dimension of a flop or a detection electrode is made as small as possible. In other words, there are various methods of measuring electric fields and electric potentials, such as a mechanical method of using electrostatic force generated by induced charge or charged charge as a direct driving force, and an electric method of amplifying and measuring an electric signal generated by electric charge. .

As the mechanical measuring method, there is a thin film detector based on the degree of opening of the thin film in response to the induced charge generated in the measuring electrode. This is to calculate the amount of charge, or potential, but since the supporting insulator of the thin film is not a complete insulator, the charge flows out, which makes it difficult to quantitatively measure the potential.

Another method is the Pogels effect, Kerr effect, light emitting device (2000KV class), etc. The use of the Pogels effect is composed of laser, light five, pogels crystal, analyzer, lens, and photodetector. The detection range is about ± 3% accuracy at about 20 kV at low pressure.

However, there is a problem that the equipment using light is expensive equipment and can not be applied to general detectors. Therefore, the principle applied to the current detector is determined by the capacitance C1 and the impedance R of the detection electrode located in the vicinity of the charged object (potential V0) which is the object to be measured. Since R is an extremely high impedance, V0 = terminal voltage V2 when the detector touches the ground. This voltage is transferred to the detector by operating the sound generation and the light emitting LED lamp through the FET or CMOS IC amplifier with high input impedance.

However, the principle of all existing detectors is based on the electric field. Underground cables have semiconducting and order layers around the wires, absorbing the electric field generated by the line voltage and preventing the electric field from dissipating outside the order layers. It is impossible to detect whether the underground cable is live with a detector.

Accordingly, the present invention proposes an apparatus for detecting whether a line is live by detecting a very low frequency micro magnetic field generated by a current flowing in a line.

The present invention is to solve the problem of the existing detector having a problem that can not determine whether the live wire by the electric shield as described above to distinguish the shielded / unshielded wire by a method for detecting very low frequency micro-electromagnetic waves generated around the line. Instead, it aims to develop a detector that can detect liveliness on all wires.

In order to achieve the above object, the present invention detects an AC magnetic field generated around a track by applying a search coil, and detects only a very low frequency component, and detects a micro magnetic field of 10 uT or less.

In addition, for the purpose of the detector, the alarm starts from a certain distance, the closer to the shorter the period of the buzzer sound is produced to ensure the safety of the user.

Accordingly, the live line detector using the magnetic field of the present invention includes a detection sensor capable of detecting a small magnetic field, a filtering technique in which the signal measured by the detection sensor is not affected by ambient noise, and an amplifier for amplifying the signal. The magnetic field and the electric field of the amplified signal are displayed on the display unit numerically or the buzzer determines whether or not the live line.

In addition, the detection sensor of the present invention is characterized by increasing the sensitivity by applying a three-axis sensor for the three-dimensional magnetic field analysis.

In addition, the micro-magnetic field of the present invention is characterized in that less than 10uT.

In addition, the signal detected by the three-axis sensor of the present invention is characterized in that the direction of the line can be estimated by displaying the magnitude of the detection magnetic field as an arrow.

In addition, the buzzer sound of the present invention is characterized in that the alarm starts from a certain distance to shorten the cycle as the closer to the live line to ensure the safety of the user.

In addition, the detection sensor of the present invention has a magnetic flux of 60 Hz and applies a core having a magnetic permeability of 20,000 as the MEe ₂ O ₄ ferrite, the magnetic field passing through the shielded wire is 10uT, the number of turns of the winding is 4,000 It features.

The present invention has the effect of preventing the secondary electric shock due to the live wire inspection function of the shielded wire can be inspected the oblique underground cable and the absence of the low-voltage line non-contact live inspection device.

1A and 1B show a conventional live line detector.
2 is a view for explaining the principle of the live wire detector according to the present invention.
3 is a view showing the configuration of the live line detector according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 1a is a view showing a conventional stick-type low-voltage detector can be checked according to the presence and size of the current introduced by the contact and is used for low pressure in that it is small by using the human body grounding method.

Figure 1b is a view showing a non-contact live alarm that can be adjusted in length in the form of a rod using an electric field and used for high voltage.

2 shows the construction principle of the present invention and has a structure in which the sensor module 10 detects the line magnetic field and incorporates a very low frequency filter, and applies two amplification ratios to the small magnetic fields in the amplification units 11 and 11 '. Therefore, it is designed to widen the detection area from low current to large current. In addition, a band pass filter is applied to remove noise inside the circuit and the detection signal.

3 is a view showing the configuration of a live wire detector using a magnetic field according to the present invention.

As shown in the figure, the magnetic field detected by the detection sensor 10 is applied to the lock-in amplifiers 11 and 11 'to form the micro signal detection circuit 12 to establish a countermeasure against noise, and then, to establish the countermeasure against noise, By using the arrows on the display unit 20, the magnitude of the state of the detection magnetic field is displayed to make a structure in which the line direction can be estimated.

In this case, the detection sensor 10 may detect a weak magnetic field of the geomagnetic field as a method of detecting a magnetic field generated by a current, and may detect a magnetic field by applying a three-axis sensor to analyze the three-dimensional magnetic field. Make sure

In the live wire detector of the present invention, since a low-cost sensor has to be developed as a low-cost low-frequency detector, a search coil type applicable to a wide area is applied. The search coil operates only in an alternating magnetic field by winding a copper wire around the core and detects a voltage induced by the alternating magnetic field. However, the search coil has an advantage of detecting both a large magnetic field and a large magnetic field by the number of copper turns. There is also the advantage of being very good.

In general, using a high specific permeability core has the advantage of reducing the number of turns and reducing the distribution capacity. These all contribute greatly to increasing the mounting density. Inductance can be calculated almost accurately by calculating the specific permeability, shape, and number of turns of the core, making it easy to design. On the other hand, depending on the material of the core used, there are disadvantages such as loss of permeability and increase of loss due to high frequency, generation of loss and distortion due to the presence of hysteresis, and self saturation of the core.

Therefore, it is important to select the material size of the core used according to the current flowing in the frequency winding used. In the present invention, since the magnetic flux has a 60 Hz component and the size is very weak, a core having a specific permeability of 20.000 with MFe ₂ O ₄ ferrite was used. Since the magnetic field sensor generates induced electromotive force by the alternating magnetic field, the magnitude V of the AC induced electromotive force detected by the magnetic field sensor can be obtained as follows by the Faraday law.

    V | = ωNSB

Where ω; Each frequency

       N; Turns

       S; Core cross section

       N; Turns

Since the small magnetic field passing through the shielded wire has a value of 10 uT, the number of turns is 4.000 turns.

The sensor module 10 is a circuit which is applied to suppress the signal to be measured from being affected by ambient noise as described above, and applies a small magnetic field in the amplifiers 11 and 11 'to apply two amplification ratios to low current. It consists of a structure which widens a detection area from to a large current, and is a response signal obtained by adding an external AC signal source to a measured object when a detection signal is periodic. For example, measuring impedance and converting it into impedance is affected by back electromotive force or ambient noise.At this time, AC current flows from the signal source and the voltage drop of AC component synchronized with the signal source is measured by the lock-in amplifier. Unaffected impedance measurements are possible.

The phase detection detector is an AC-DC converter, which is the most important part of the device. In order to use the lock-in amplifiers 11 and 11 ', the frequency of the signal desired by the user must be accurately input from the original signal including the noise signal. The reference signal is designed not to receive a signal from the oscillator connected to the measurement signal because the frequency is exactly the same when the reference signal is input from the oscillator connected to the measurement signal.

Next, the signal input through the lock-in amplifier was input and converted into a digital signal through the ADC. The digital signal was obtained as the average effective value of the signal which was input ten times, and the detection range was selected to be 10uT, 100uT, 1mT. If a value larger than the selected range is input, the system is configured to output 1 on the screen, and the main board adopts the Arm series CPU, and also has 8k bytes of internal memory and the processing speed is 16 MIPS, and 32 input / output ports. The built-in 512k bytes of EEOROM allow data to be stored even in a non-powered state. The oscillation frequency of MCU is 8 [MHz] oscillator so that it can be supplied from outside, and C-language is used for palmware.

The lock-in amplifier circuit is a circuit which is applied to suppress the signal from being affected by ambient noise. The lock-in amplifier circuit is a signal obtained by applying an external AC signal source to a measurement object when the detection signal is periodic. For example, measuring impedance and converting it into impedance is affected by back electromotive force or ambient noise.At this time, AC current flows from the signal source and the voltage drop of the AC component synchronized with the signal source is measured by a lock-in amplifier. Unaffected impedance measurements are possible. This system is also a circuit for detecting that the magnetic field of the low voltage AC signal decreases and appears as a fine signal.

The phase detection detector is an AC-DC converter and the most important part of the device. To use the lock-in amplifier, the user must input the frequency of the desired signal from the original signal containing the noise signal. The reference signal is designed not to receive a signal from the oscillator connected to the measurement signal because the frequency is exactly the same when the reference signal is input from the oscillator connected to the measurement signal.

In addition, in the main system 13, the signal input through the amplifiers 11 and 11 ′ is sampled so that the detection magnetic field is displayed on the display 20 by the arrow and the numerical value and the current direction are displayed according to the magnitude of the external magnetic field. It automatically selects an amplifier and controls it so that it has an appropriate amplification degree.

Next, the display unit 20 indicates the magnetic field and the electric field of the three-axis measurement signal strength numerically, and indicates whether or not the live line is judged on the buzzer and the display unit 20, so that the display unit 20 can also be used as an electromagnetic wave detection device.

The present invention can be used in a live line detector for detecting live lines using a micro magnetic field detection sensor during electrical work and high-voltage underground line construction.

Claims (6)

In live detector using magnetic field,
Three-axis sensor for three-dimensional magnetic field analysis that can detect a small magnetic field by applying two amplification ratios,
It is provided with a filtering technology that is not affected by ambient noise from the three-axis sensor and an amplifier that automatically adjusts the ratio of the amplified signal according to the signal strength,
The live line detector using the magnetic field of the amplified signal to display the state of the detection magnetic field on the display unit with an arrow or to determine whether the live wire buzzer sound. delete The method of claim 1,
The minute magnetic field is a live line detector using a magnetic field, characterized in that less than 10uT. The method of claim 1,
The signal detected by the three-axis sensor is a live line detector using a magnetic field, characterized in that the direction of the line can be estimated by displaying the magnitude of the detected magnetic field as an arrow. The method of claim 1,
The buzzer sound is a live line detector using a magnetic field, characterized in that to start the alarm from a certain distance to shorten the cycle as the closer to the live line to ensure the safety of the user. The method of claim 1,
The three-axis sensor has a magnetic flux of 60 Hz component and applies a core having a specific permeability of 20,000 as MEe ₂ O ₄ ferrite, the magnetic field passing through the shielded wire is 10uT, the number of turns is 4,000 magnetic field, characterized in that Live line detector.

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