JPH0658961A - Inductive decision type electroscope - Google Patents

Abstract

PURPOSE:To allow discrimination between hot line and cold line by providing a rectifier element connected in series between a voltage detector and a live part detecting circuit, and means for directly grounding to the earth, thereby identifying a cold line subjected to electrostatic induction. CONSTITUTION:A diode 10 is connected between an input resistor 2 and a live part detecting circuit 5 for a resistor 3 at detecting part and a voltmeter 4. When a voltage detector 1 in an inductive decision type electroscope is brought into contact with a power line 6, a micro pulsating current caused by the power line voltage with respect to the ground flows in one direction through the input resistor 2, the diode 10, the detecting part resistor 3, and an earth rod 9 if the power line is in live state and a voltage drop appears across the resistor 3. The voltage drop is detected through the voltmeter 4 and a decision is made whether the power line 6 is in hot state or not. If the power line 6 is in hot state, the voltmeter 4 provides an indication stably otherwise zero is indicated. When the power line 7 is hot and the power line 6 is cold, the power line 6 is subjected to electrostatic induction and the potential rises. When the power line 6 is subjected to voltage detection, voltage drop across the detecting part resistor 3 decreases gradually and finally goes to zero. Voltage drop is detected by means of the voltmeter 4 and discrimination is made between cold and hot lines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction discrimination type voltage detector, and more particularly to an induction discrimination type voltage detector capable of distinguishing between a live line and a dead line.

[0002]

2. Description of the Related Art FIG. 7 is an equivalent circuit diagram showing a structure of a conventional voltage detector, in which a worker stands on the ground and holds the voltage detector to detect a power line stretched in the air.

In the figure, 51 is an electron detector, 52 is an input resistance, 53 is a detection unit resistance, and 54 is a voltmeter connected in parallel to the detection unit resistance 53. Reference numeral 55 is the electrostatic capacitance between the body of the worker and the voltage detector, and between the body of the worker and the ground. The capacitance mainly includes the capacitance between the palm of the worker and the grip portion of the voltage detector, and the capacitance between the sole of the worker's foot and the ground.

Reference numeral 56 is a power line to be detected. In this voltage detector, when the power line 56 is in a live state, a small alternating current flows between the power line 56 and the ground through the voltage detector and the body of the worker. Accordingly, the minute voltage drop generated in the detection resistor 53 is detected by the voltmeter 54, and it is detected whether or not the power line 56 is in a live line state, that is, whether or not it is in a charged state.

FIG. 8 is an equivalent circuit diagram showing the configuration of a voltage detector when the power line 57 is adjacent to each other and the power line 57 is the target of power detection.

In FIG. 9, the power line 56 is in a live state and the power line 5 is
7 is a dead line, and is an equivalent circuit diagram when the coupling capacitance Cc between the power line 56 and the power line 57 is taken into consideration when electrostatic induction is generated from the power line 56 to the power line 57.

[0007]

When the power line 57 is detected when the power line 56 and the power line 57 are adjacent to each other as shown in FIG. 9, the power line 57 is not detected.
Subject to electrostatic induction. Assuming that the voltage waveform of the power line 56 is (a) in FIG. 10, the potential V of the power line 57 shown in FIG.
The voltage waveforms of the voltage drop VC of B and the detection unit resistance 53 are as shown in (b) and (c) of FIG. 10, and even though the power line 57, which is a dead line, is detected, A small alternating current flows between the power line 57 and the ground by electrostatic induction through the electroscope and the body of the worker. As a result, there is a problem in that the voltmeter 54 detects a voltage drop that occurs in the detection unit resistor 53 and mistakenly recognizes that the power line 57 is in a live line state.

The present invention has been made by paying attention to such a conventional problem, and a first object of the present invention is to reliably identify a dead line which is subjected to electrostatic induction so that the dead line can be activated. An object of the present invention is to provide an inductive discriminator that can discriminate lines.

A second object of the present invention is to provide an inductive discrimination type voltage detector capable of detecting an accurate voltage between the ground and ground.

A third object of the present invention is to provide an inductive discrimination type voltage detector capable of estimating the magnitude of electrostatic induction received by the dead line.

[0011]

According to another aspect of the present invention, there is provided an induction discrimination type voltage detector in which a detection unit is directly contacted with a charging unit such as a transmission and distribution line, and a charging unit detection circuit is grounded. A voltage detector for detecting the presence / absence of charging is provided with a rectifying element connected in series to the detector and charging section detection circuit, and a grounding means for directly grounding to ground.

The induction discrimination type voltage detector according to the invention of claim 2 is the induction discrimination type voltage detector according to the invention of claim 1 in which a minute current flowing between the detector and the ground or a voltage corresponding to this minute current is generated. Induction that enables to discriminate whether or not the object to be detected is a hot line based on the magnitude of the temporal change, and to estimate the size of line-to-line induction from other hot lines A level identifying means is provided.

[0013]

In the induction discrimination type voltage detector according to the invention of claim 1, a rectifying element is connected in series to the electron detecting and charging section detecting circuit,
Rectifies the current that flows between the detector and ground. As a result,
When the AC component in the current flowing between the electron detector and the ground is unidirectional, and the object to be detected is a dead line that is subjected to electrostatic induction, the above current decreases with time simultaneously with the detection. In addition, when the object to be detected is a hot wire, the current does not change and maintains a predetermined magnitude. Therefore, the live line and the dead line can be discriminated by paying attention to the current or the voltage corresponding to the current. Further, since the grounding means directly grounds the earth, the resistance to ground is reduced, and the accurate voltage to ground of the live line can be detected.

In the induction discrimination type voltage detector according to the second aspect of the present invention, the magnitude of the temporal change rate of the current flowing between the voltage detector and the ground or the voltage corresponding to this current is the live line to be detected. Further, depending on whether or not the object to be detected is not a hot line, it varies depending on the magnitude of interline induction from another hot line. Therefore, it becomes possible to discriminate whether the test object is a live line or a dead line based on the magnitude of the temporal change rate, and it is possible to estimate the magnitude of line-to-line induction from another live line. Become.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 1 is an equivalent circuit diagram showing an embodiment of the inductive discrimination type voltage detector of the present invention.

In the figure, 1 is an electron detector, 2 is an input resistance,
Reference numeral 3 is a detection unit resistance, and 4 is a voltmeter connected in parallel to the detection unit resistance 3. Reference numeral 6 is a power line to be detected. Reference numeral 7 is another power line arranged in parallel with the power line 6.
Reference numeral 8 is a ground wire, which is led out from a connection point P between the detection unit resistance 3 and the voltmeter 4. A ground rod 9 is connected to the tip of the ground wire 8. The ground rod 9 is inserted into the ground, and the ground resistance is low when grounded by the ground rod.

Reference numeral 10 is a diode, which is connected between the parallel circuit of the detection unit resistance 3 and the voltmeter 4 and the input resistance 2. In this inductive discrimination type voltage detector, when the test line 1 is brought into contact with the power line 6, if the power line 6 is in a live state, the power line is grounded via the input resistor 2, the diode 10, the detection unit resistor 3, and the ground rod 8. A unidirectional minute pulsating current due to the voltage flows. This minute pulsating current causes a voltage drop in the detection unit resistance 3. This voltage drop is detected by the voltmeter 4, and it is discriminated based on the indication of the voltmeter whether or not the power line 6 is in a live line state, that is, whether or not it is in a charged state.

When the power line 6 is in a live state, the voltmeter 4 stably displays a predetermined value. On the other hand, when the power line 6 is a dead line, the voltmeter display is zero. But,
When the power line 7 is in a live state and the power line 6 is a dead line,
The power line 6 is subjected to electrostatic induction by the power line 7, and the potential of the power line 6 is rising. FIG. 2 shows an equivalent circuit diagram when the power line 6 is detected in this state. The voltage waveform of each part is shown in FIG.

FIG. 3A shows the voltage waveform of the power line 7 in a live state, and FIG. 3B shows the power line 6 receiving electrostatic induction.
The voltage waveform in FIG. 3C is the voltage drop in the detection unit resistance 3. When the power line 6 receiving the electrostatic induction is detected, as shown in FIG. 3C, the voltage drop in the detection unit resistance 3 gradually decreases and finally becomes zero. Therefore, it is possible to detect the change in the voltage drop in the detection unit resistance 3 by the voltmeter 4, and to identify whether or not the power line to be detected is a live line based on the pattern of this change.

FIG. 4 is a block diagram showing the configuration of another embodiment of the inductive discrimination type voltage detector of the present invention.

In the figure, 21 is an input resistor, 22 is a diode, and 23 is a detector resistance. Reference numeral 24 denotes an amplifier, which amplifies and outputs the voltage drop amount in the detection unit resistance 23. Reference numeral 25 denotes an integrating circuit, which integrates the output of the amplifier 24 based on a predetermined time constant and outputs it. Reference numeral 26 is a voltage controlled oscillator circuit, whose output signal changes according to the output voltage of the amplifier 24. When the output voltage of the amplifier 24 is zero, the output signal of the voltage controlled oscillator circuit 26 is zero. 27 is a drive circuit for the display unit 28. The display unit 28 is provided with a speaker and emits a sound according to the output signal of the voltage controlled oscillator 26.

The amplifier 24, the integrator circuit 25, the voltage controlled oscillator circuit 26, the drive circuit 27, and the display unit 28 form an induction level identification means 29.

Next, the operation will be described. When the power line 6 is in a hot line state, the detection unit resistor 23 detects and outputs the half-wave rectified voltage waveform shown in (b) of FIG. This output is integrated in the integrator 25 and converted into the DC voltage shown in FIG. Since the magnitude of this DC voltage has a substantially constant value, a corresponding signal is output from the voltage controlled oscillator circuit 26. Therefore, a constant sound is emitted from the speaker of the display unit 28.

On the other hand, the power line 6 to be detected is a dead line, and the power line 7 is arranged in parallel with the power line 6 in the vicinity thereof.
Is a hot line, the detection unit resistor 23 detects and outputs an intermittent voltage waveform in which the peak value gradually attenuates, as shown in FIG. This output is the integrator 2
5 and is converted into a DC voltage whose amplitude value is gradually attenuated as shown in FIG. Therefore, the output signal of the voltage controlled oscillator circuit 26 changes from a high frequency to a low frequency, for example. Therefore, the speaker of the display unit 28 emits a sound that changes from a high sound to a low sound.

A worker operating this induction discrimination type voltage detector can identify whether or not the power line to be detected is a live line by the presence or absence of a sound emitted from the speaker of the display unit 28.

Further, the rate of change when the DC voltage shown in FIG. 5 (e) is attenuated corresponds to the magnitude of the influence of electrostatic induction from the other power line in the live state. That is, when the influence of electrostatic induction is small, the DC voltage shown in (e) of FIG. 5 is rapidly attenuated to zero in a short time, whereas when the influence of electrostatic induction is large. Gradually decays. Therefore, the magnitude of electrostatic induction from other live lines can be estimated by determining the magnitude of the rate of change when the amplitude value of the DC voltage is attenuated.

In the induction discrimination type voltage detector described above, the voltage drop in the detection unit resistance 3 is detected by the voltmeter, and based on this, it is determined whether or not the power line to be detected is a live line. It is possible to estimate the magnitude of the electrostatic induction based on the pattern in which the voltage drop in the detection unit resistance 3 changes, as shown in FIG. It is possible to detect the minute current flowing between the power line and the ground by the ammeter 31 and to identify whether the power line to be detected is a live line or a dead line based on this, and further, the minute current. It may be possible to estimate the magnitude of electrostatic induction according to the changing pattern of.

[0028]

According to the first aspect of the present invention, a rectifying element is connected in series to the tester and the charger detection circuit to rectify the current flowing between the tester and the ground. As a result, when the object to be detected is a dead line that is subjected to electrostatic induction, the above-mentioned current decreases simultaneously with the detection of electric power. On the other hand, when the object of electric power detection is a hot wire, the current does not change and maintains a predetermined magnitude. Therefore, the live line and the dead line can be discriminated by paying attention to the current flowing between the detector and the ground or the voltage corresponding to this current. Further, since the grounding means directly grounds the earth, it is possible to reduce the resistance to earth and to detect the accurate voltage between the live wires and the ground.

According to the second aspect of the present invention, the magnitude of the temporal change in the current flowing between the detector and the ground or the voltage corresponding to this current depends on whether or not the object to be detected is a hot wire. Furthermore, when the object to be detected is not a hot wire, it changes according to the magnitude of line-to-line induction from another hot wire, so the object to be detected is based on the magnitude of the temporal change or the pattern at the time of change. It is possible to distinguish between a live line and a dead line, and it is possible to estimate the magnitude of line-to-line induction from another live line.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram of an embodiment of an induction discrimination type voltage detector according to the present invention.

FIG. 2 is an equivalent circuit diagram when a dead line receiving electrostatic induction is being detected.

FIG. 3 is a voltage waveform diagram of each part of the induction discrimination type voltage detector.

FIG. 4 is a block diagram showing the configuration of another embodiment of the inductive discrimination type voltage detector of the present invention.

FIG. 5 is a voltage waveform diagram of each part of the induction discrimination type voltage detector according to another embodiment.

FIG. 6 is an equivalent circuit diagram of an inductive discrimination type voltage detector using an ammeter.

FIG. 7 is an equivalent circuit diagram showing a configuration of a conventional voltage detector.

FIG. 8 is an equivalent circuit diagram showing a configuration of a voltage detector in which a dead line receiving electrostatic induction is a target of voltage detection.

FIG. 9 is an equivalent circuit diagram when a coupling capacitance between power lines is considered.

FIG. 10 is a voltage waveform diagram of each part in the conventional voltage detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic detection 5 Charging part detection circuit 6, 7 Electric power line 9 Ground rod (grounding means) 10 Diode 29 Inductive level identification means

Claims (2)

[Claims] 1. In a voltage detector for detecting the presence / absence of charging of a charging unit by bringing the detecting unit into contact with a charging unit such as a transmission / distribution line and grounding the charging unit detection circuit, the detection unit and the charging unit detection circuit are connected in series An inductive discrimination type voltage detector including a connected rectifying element and a grounding means for directly grounding to the ground. 2. It is possible to discriminate whether or not an object to be detected is a live line based on a magnitude of a temporal change in a minute current flowing between an electron detector and ground or a voltage corresponding to the minute current. The lead-discrimination-type voltage detector according to claim 1, further comprising lead-level discriminating means capable of estimating the magnitude of inter-line lead from another live line.