WO2011030796A1

WO2011030796A1 - Electromagnetic field sensor, and receiver

Info

Publication number: WO2011030796A1
Application number: PCT/JP2010/065429
Authority: WO
Inventors: 浩範宮川; 克吉田中; 慎吾井手; 弘昭蒲原
Original assignee: 大電株式会社; 九州電力株式会社
Priority date: 2009-09-14
Filing date: 2010-09-08
Publication date: 2011-03-17
Also published as: CN102498407B; KR20120080167A; KR101744206B1; JP2011059070A; CN102498407A; JP5723089B2; HK1167896A1

Abstract

Disclosed is an electromagnetic field sensor, by which discriminating operation can be simplified, and a cable can be discriminated rapidly and correctly. The clamp-type sensor (30) is provided with: a substantially annular electrode (31), which is composed of a nonmagnetic material having conductivity, and which surrounds a part of a cable in the circumferential direction in a state where the cable is clamped; a magnetic core (33), which is composed of a magnetic material, and is disposed on the outer side of a ring (31a) of the electrode (31) with an insulator (32) therebetween; a winding wire (34), which is wound around the magnetic core (33); and an output section (35), which is led out by means of a lead wire (35a) from the electrode (31), and led out from both the ends of the winding wire (34) by means of a lead wire (35b). An inductive current generated in the winding wire (34) due to electromagnetic induction is outputted from the output section (35), and a voltage generated in the electrode (31) due to electrostatic induction is outputted from the output section (35).

Description

Electromagnetic field sensor and receiver

The present invention relates to an electromagnetic field sensor and a receiver used in a cable search apparatus that can identify a desired cable from a plurality of cables and check a cable laying route.

In the bundled construction method for the construction work of the subscriber optical fiber network, multiple fiber optic cables are laid in one spiral hanger. For this reason, in the interrupting work for newly installing a closure, it takes time to discriminate the optical fiber cable to be worked in the section where the optical fiber cable is multi-striped, and the discriminating work of the optical fiber cable becomes inefficient. ing. Further, since there is a possibility of communication failure due to an error in the attachment of the closure or an erroneous disconnection of the optical fiber cable, it is important to quickly and accurately discriminate the optical fiber cable.

On the other hand, the conventional cable detection device has a single oscillator that can oscillate both the current signal and the voltage signal to a transmitter for transmitting a current signal or a voltage signal to the cable to be specified. Provide a circuit. Accordingly, a receiver that receives and processes a signal representing a magnetic field or electric field generated around the cable to be specified is configured by a single signal processing circuit (see, for example, Patent Document 1).

JP 2005-114561 A

However, in the conventional cable detection device, the electromagnetic induction type detector and the electrostatic induction type detector are separated from each other, and the operator uses the electromagnetic induction type and electrostatic type based on the notification result from the transmitter. Knowing which type of cable detection should be performed, inductive type, one of the electromagnetic induction type detector and electrostatic induction type detector must be connected to the receiver There is a problem that the discrimination work is complicated.
The present invention has been made in order to solve the above-described problems, and provides an electromagnetic field sensor and a receiver that can simplify the discrimination work.

In the electromagnetic field sensor according to the present invention, a substantially non-circular electrode made of a nonmagnetic material having conductivity and surrounding a part of the cable in a circumferential direction while the cable is axially passed, and a magnetic material having conductivity A magnetic core disposed outside the ring of the electrode via an insulator, a winding around which the magnetic core is wound, and an output portion that is drawn from the electrode and drawn from both ends of the winding An induction current generated in the winding by electromagnetic induction based on a current flowing in a cable is output from the output unit, and a voltage generated in the electrode by electrostatic induction based on a voltage applied to the cable is output from the output unit. It is characterized by outputting.

In the disclosed electromagnetic field sensor, the discrimination work can be simplified, and the cable can be discriminated quickly and accurately.

(A) is a block diagram showing a schematic configuration on the transmission side of the cable search device, (b) is a block diagram showing a schematic configuration on the reception side of the cable search device. FIG. 2A is an outline view showing a schematic configuration of the clamp-type electromagnetic field sensor shown in FIG. 1, and FIG. 2B is a partial cross-sectional view showing a cross section inside the core cover of the clamp-type electromagnetic field sensor shown in FIG. It is. (A) is a fragmentary sectional view which shows the open state of the clamp type electromagnetic field sensor shown in FIG.2 (b), (b) is another Example of the clamp type electromagnetic field sensor shown in FIG.2 (b). It is a fragmentary sectional view shown. (A) is a fragmentary sectional view showing another example of the clamp type electromagnetic field sensor shown in FIG. 2 (b), and (b) is still another example of the clamp type electromagnetic field sensor shown in FIG. 2 (b). It is a fragmentary sectional view showing an example. (A) is a circuit diagram for the evaluation test of a clamp type electromagnetic field sensor, and (b) is a table showing the results of characteristic evaluation of the clamp type electromagnetic field sensor. It is a layout for a simulated field test by a cable search device. It is a table | surface which shows the verification result of the discrimination | determination performance of a clamp type electromagnetic field sensor with an electrode width of 16 mm. It is a table | surface which shows the verification result of the discrimination | determination performance of a clamp type electromagnetic field sensor with an electrode width of 32 mm. It is a table | surface which shows the verification result of the discrimination | determination performance of the clamp type electromagnetic field sensor of electrode width 35mm. It is a table | surface which shows the verification result of the discrimination | determination performance of a clamp type electromagnetic field sensor with an electrode width of 40 mm. It is a table | surface which shows the verification result of the discrimination | determination performance of the clamp type electromagnetic field sensor of electrode width 50mm.

(First embodiment of the present invention)
The optical fiber cable is discriminated by transmitting an electrical signal from a transmitter 10 to a steel wire used as a support wire or tension member of the optical fiber cable via a current transformer (CT) 20. Identification is performed by detecting the signal at the receiver 40 via the clamped electromagnetic field sensor 30 (receiving sensor) according to the present invention. The transmitter 10 and the receiver 40 include, for example, a product name “PTR600 power tracer” manufactured by TASCO.

The transmitter 10 can be connected to various cables (0 to 600 V, alternating current (AC) / direct current (DC)), and is a discrimination target cable (hereinafter referred to as a discrimination target cable). The method of applying a discrimination signal that generates a very weak induced current or voltage according to the situation is adopted.

In FIG. 1A, the transmitter 10 combines on / off with a frequency of 33.3 kHz as a basic signal and on / off with a period of 1 msec (frequency 1 kHz) and on / off with a period of 400 msec (frequency 2.5 Hz). A transmitter 11 for transmitting the received signal, an amplifier 12 for amplifying the signal input from the transmitter 11, and a coupling capacitor 13 for passing an AC signal among the signals input from the amplifier 12 and blocking the DC signal. ing.

In addition, in the signal transmitted from the transmitter 11, the signals of frequency 33.3 kHz and 1 kHz are signals that function as discrimination signals, and the signal of frequency 2.5 Hz is a signal that functions as a buzzer sounding and a lamp blinking. .

Further, as a discrimination signal, a signal having a frequency of 1 kHz is superimposed on a basic signal having a frequency of 33.3 kHz, applied to the discrimination target cable from the transmitter 10, and detected by the receiver 40, thereby being laid around the discrimination target cable. This reduces the influence of external noise generated by other cables that are installed and devices installed in the vicinity, thereby improving the reliability in determining the determination target cable.

The transmission CT 20 has 20 turns (10 turns on each side) wound around a split type philite core having an inner diameter of 27 mm. Note that the number of turns of the winding wound around the philite core is not limited to 20 turns, but as shown in Table 1 below, 20 turns excellent in both voltage application and current conduction characteristics are shown in Table 1. It is preferable to make it. In addition, the CT 20 for transmission according to the present embodiment has a winding core wound around a philite core having an inner diameter of 27 mm, and therefore targets a cable with an outer diameter of 25 mm. In this case, the outer diameter is not limited to the identification target cable.

The clamp type electromagnetic field sensor 30 is configured to be clampable with respect to the discrimination target cable, and detects a magnetic field generated based on a current flowing through the discrimination target cable and / or an electric field generated based on a voltage applied to the discrimination target cable. It is a detector.

2 and 3A, the clamp type electromagnetic field sensor 30 is insulated from a substantially annular electrode 31 that surrounds a part of the discrimination target cable in the circumferential direction in a state where the discrimination target cable is clamped and axially passed. A magnetic core 33 disposed outside the ring 31 a of the electrode 31 through the body 32, a winding 34 around which the magnetic core 33 is wound, and a lead wire 35 a from the electrode 31, and from both ends of the winding 34. An output unit 35 drawn out by the lead wire 35 b and a housing 36 that houses the magnetic core 33 are provided.

The electrode 31 is made of a nonmagnetic material having conductivity, and in the present embodiment, is formed symmetrically by bending a substantially rectangular copper plate, and is arranged in a semicircular shape so as to be opposed to each other. It has a butting end surface 31b that protrudes outside the ring 31a and contacts and separates when opening and closing, and has a facing surface 31c that bends in a direction opposite to the butting end surface 31b. The electrode 31 generates a voltage by electrostatic induction based on the voltage applied to the discrimination target cable, and outputs the voltage to the output unit 35 via the lead wire 35a.

The reason why the electrode 31 is made of a nonmagnetic material is to induce a magnetic field in the magnetic core 33 without shielding the magnetic field generated based on the current flowing in the discrimination target cable by the electrode 31.

Further, the electrode 31 has the facing surface 31c, so that the facing surface 31c is brought into contact with a wall surface or the like, and an electric field generated based on a voltage applied to a discrimination target cable laid in the wall or the like can be detected. It is possible to confirm the laying route of the discrimination target cable.

If the clamp-type electromagnetic field sensor 30 does not have a search function for the laying route of the discrimination target cable, the electrode 31 does not need to have the facing surface 31c, and the electrode 31 is, for example, as shown in FIG. As shown, the shape having the ring 31a and the butt end surface 31b, or the shape having only the ring 31a as shown in FIG.

The magnetic core 33 is made of a magnetic material having conductivity. In the present embodiment, a magnetic shield sheet (magnetic film) obtained by laminating a PET (polyethylene terephthalate) film, which is an insulating layer 32a, on a thin film-like metal layer 33a. Are used, and each magnetic film is arranged along the outer side of the ring 31a of the electrode 31 and the butt end face 31b.

Also, since the detection sensitivity of the magnetic core 33 is affected by the air gap in the magnetic circuit, it is important to keep the butt state of the magnetic core 33 in a good state. For this reason, by arranging the magnetic core 33 outside the butted end surface 31b of the electrode 31, it is possible to ensure the opposing area of the left and right magnetic films on the butted end surface 31b of the electrode 31. The characteristics can be stabilized.

Note that the magnetic core 33 according to the present embodiment uses a magnetic film, but a split-type philite core may be used. When a conductive core is used, an insulator is provided between the magnetic core 33 and the electrode 31 in order to insulate the magnetic core 33 and the electrode 31 as shown in FIG. 32 must be interposed.

The winding 34 forms a coil wound around the left and right magnetic cores 33 in the same direction (inner winding in FIG. 2), and the left and right coils are connected in series. Further, in the winding 34, a voltage is induced in the magnetic core 33 by electromagnetic induction based on the current flowing in the determination target cable, and an induced current is generated according to a change in the magnetic field induced in the magnetic core 33, and the winding 34 is connected via the lead wire 35b. The induced current is output to the output unit 35.

The output unit 35 is connected to the receiver 40, outputs an induced current generated in the winding 34 by electromagnetic induction to the receiver 40, and outputs a voltage generated in the electrode 31 by electrostatic induction to the receiver 40.

The housing 36 is formed of resin, has a substantially arc shape that accommodates the pair of magnetic cores 3 and is opposed to the core cover 36a as a pair, and the electrode 31 fixed to the inner surface of the core cover 36a. And a pair of levers 36b for contacting and separating the butt end surfaces 31b from each other.

In the receiver 40, only the signal transmitted from the transmitter 10 is automatically identified by the internal microprocessor, so that the workability and certainty for determining the cable are greatly improved. Note that the determination of the cable by the receiver 40 is performed when a closed circuit through the conductive portion of the determination target cable is configured, since a voltage is hardly applied to the determination target cable and a current flows. The target cable can be discriminated from the magnitude of the magnetic field generated on the basis thereof. On the other hand, when a closed circuit through the conductive portion of the discrimination target cable is not configured, since a current hardly flows through the discrimination target cable and a voltage is applied, the magnitude of the electric field generated based on this voltage is determined. The target cable can be identified.

1B, the receiver 40 includes an electromagnetic field detection unit 41, an adder 42, a signal amplification / sensitivity adjustment unit 43, a filter 44, a signal level detection unit 45, and a notification unit 46. ing.

The electromagnetic field detector 41 detects an electric field (voltage) and / or magnetic field (induced current) from the voltage and / or induced current input from the clamp type electromagnetic field sensor 30, and converts the detected induced current into a voltage. And output to the adder 42. In the detection of the magnetic field (inductive current), the evaluation test described below was performed when the resonance circuit was configured and when the resonance circuit was not configured. Therefore, it is preferable that the electromagnetic field detection unit 41 incorporates a resonance circuit in the detection of the magnetic field (induced current).

The adder 42 adds the voltage based on electrostatic induction and the voltage obtained by converting the induced current, which are input from the electromagnetic field detection unit 41, and outputs the result to the signal amplification / sensitivity adjustment unit 43.

The signal amplification / sensitivity adjustment unit 43 sets the amplification factor to 50 times when the reception intensity is strong (hereinafter referred to as strong reception) with respect to the voltage input from the adder 42, and the reception intensity is low (hereinafter, referred to as “high reception”). In the case of weak reception), the amplification factor is set to 2.5 times and output to the filter 44. Note that the signal amplification / sensitivity adjustment unit 43 according to the present embodiment has been able to optimize the compatibility with the clamp type electromagnetic field sensor 30 connected to the receiver 40 in the examination of the specifications of the clamp type electromagnetic field sensor 30 described later. Although the amplification factor is set, the amplification factor is not limited to this.

The filter 44 is a band-pass filter (BPF) that passes only a predetermined frequency among the signals input from the signal amplification / sensitivity adjustment unit 43, and the signal having a predetermined frequency that has been passed through is a signal. Output to the level detector 45.

The signal level detection unit 45 detects the level of the signal input from the filter 44 based on a predetermined threshold value, and outputs the detected signal level to the notification unit 46.

The notification unit 46 notifies the worker by sounding a buzzer and / or lighting of a lamp according to the level of the signal input from the signal level detection unit 45.
Here, the specification of the clamp type electromagnetic field sensor 30 is examined.

First, for the optimum number of turns of the winding 34 in the clamp type electromagnetic field sensor 30, the evaluation test circuit shown in FIG. 5A is used to detect an electric field when the resistance value of the closed circuit is large (10 kΩ or more). FIG. 5B shows the result of adjustment in combination with the receiver 40 for detecting the magnetic field when the resistance value of the closed circuit is small (10 kΩ or less). Here, the width in the length direction (direction perpendicular to the circumferential direction) of the electrode 31 and the magnetic film (the metal layer 33a and the insulating layer 32a) in the clamp type electromagnetic field sensor 30 is set to 16 mm.

As shown in FIG. 5B, when the number of turns of the winding 34 is 30 turns and 40 turns, a good result is obtained in the discrimination performance in the magnetic field detection. Therefore, the clamp-type electromagnetic field sensor according to this embodiment is obtained. At 30, 40 turns were selected as the number of turns of the winding 34. The winding 34 according to the present embodiment is wound around the magnetic film including the metal layer 33a (magnetic core 33) with 40 turns (20 turns to the left and right), but the number of turns is limited. Instead, it is preferable to adjust the number of turns according to the sensitivity of magnetic field detection required for the clamp type electromagnetic field sensor 30.

Next, a facility simulating the field shown in FIG. 6 was constructed, and the results of verifying the cable discrimination performance by the cable search device including the transmitter 10, the transmission CT 20, the clamp type electromagnetic field sensor 30, and the receiver 40 were verified. Is shown in FIG. Here, the width in the length direction of the electrode 31 and the magnetic film in the clamp type electromagnetic field sensor 30 is set to 16 mm.

In the simulated field, the distance between one table and another table is about 20 m, and the number of optical fiber cores is suspended by an arm at a height of about 1.5 m from the ground. , A substantially U-shaped route for returning a combination of 12-fiber and 12-fiber optical fiber cables from one table to another table via another table was created. Of these substantially U-shaped routes, a verification test was conducted on two routes of three lines of 200 cores, 100 cores and 12 cores and three lines of 12 cores, 12 cores and 12 cores.

Also, the length of the used optical fiber cable is 68 m for a 200-core optical fiber cable, 145 m for a 100-fiber optical fiber cable, and 46 m for a 12-core optical fiber cable. In addition, about the extra length of an optical fiber cable, the test is carried out by grasping at the terminal part.

Further, the resistance value of the grounding point and the resistance value of the support wire in each of the 200-fiber, 100-fiber and 12-core optical fiber cables are as shown in the following Table 2.

Furthermore, in the verification test, as the simulated pillar pattern without the wraparound of the discrimination signal, when the discrimination target cable and the two other cables are not connected and both ends of the discrimination target cable are not grounded (simulation equipment) When the pillar pattern 1) is not connected to the discrimination target cable and two other cables and one end of the discrimination target cable is grounded (simulated pillar pattern 2), the discrimination target cable and two The case where the other cable is not connected and both ends of the discrimination target cable are grounded (simulated column pattern 3) was verified for each route.

Also, in the verification test, the discrimination target cable and one other cable are connected at one end as a simulated pillar pattern in which the discrimination signal wraps around and does not constitute a closed circuit, and one end of the discrimination target cable is grounded If the identification target cable and one other cable are connected at one end and both ends of the determination target cable are grounded (simulated pillar pattern 5) Were verified for each route.

Also, in the verification test, there is a wraparound of the discrimination signal, and the discrimination target cable and one other cable are connected at both ends as a simulated pillar pattern that constitutes a closed circuit, and one end of the discrimination target cable is When grounded (simulated pillar pattern 6), when the discrimination target cable and one other cable are connected at both ends, and both ends of the discrimination target cable are grounded (simulated pillar pattern 7) ) And the case where the discrimination target cable and two other cables are connected at both ends and both ends of the discrimination target cable are grounded (simulated pillar pattern 8) were verified for each route.

In this verification test, as shown in FIG. 7, the result that the performance of detecting the electric field (cable discrimination performance when the closed circuit is not configured) is inferior. Therefore, in order to improve the electric field detection performance, the width in the length direction of the electrode 1 is changed in the range of 30 mm to 40 mm. It was confirmed that the operation was good.

In FIG. 7, double circles (◎) indicate a case where five LED (light-emitting diode) lamps that are the notification unit 46 of the receiver 40 are lit, and the reaction is very good. The evaluation result that is possible is shown. In addition, a circle (◯) indicates an evaluation result that 3 to 5 LED lamps that are the notification unit 46 of the receiver 40 can be turned on or the level can be determined, and the response is good, and the determination is possible. Show. A triangle (Δ) indicates an evaluation result in which the LED lamp as the notification unit 46 of the receiver 40 is lit and the response is low, and the determination is possible based on the number of lit LED lamps. In addition, a cross (x) mark indicates an evaluation result that 0 to 3 LED lamps that are the notification unit 46 of the receiver 40 are lit and cannot be distinguished.

Based on the evaluation results shown in FIG. 7, the cable search device uses the clamp-type electromagnetic field sensor 30 in which the width in the length direction of the electrode 1 is 32 mm and the width in the length direction of the magnetic film is 16 mm. FIG. 8 shows the result of verifying the cable discrimination performance using the simulation field shown in FIG.

In this verification test, as shown in FIG. 8, it was possible to discriminate the cable under all conditions, and it was confirmed that the cable search device has good performance as a cable discriminator.

As described above, when the electrode 1 and the magnetic film in the clamp type electromagnetic field sensor 30 are verified in the simulated field with the width in the length direction being 16 mm, further improvement of the electric field detection performance is required. It was found that the width in the length direction of the electrode 1 is preferably 32 mm or more.

On the other hand, increasing the width in the length direction of the electrode 1 increases the force required to open and close the clamp-type electromagnetic field sensor 30, and increases the amount of protrusion of the electrode 1 with respect to the housing 36. It is assumed that the workability of the clamp work is reduced, or the discrimination target cable cannot be sufficiently clamped and cannot be discriminated.

On the other hand, in consideration of the reliability and practical use of the cable discrimination by the cable search device, the electrode 1 having a width in the length direction of 32 mm, 35 mm, 40 mm, 45 mm and 50 mm in the range of 32 mm to 50 mm. Table 3 shows the result of verifying the characteristics of the electromagnetic field detection by the evaluation test circuit shown in FIG. Note that the receiver 40 used is a resonator circuit that can improve the performance of magnetic field detection.

As shown in Table 3, the characteristics of the clamp-type electromagnetic field sensor 30 are not significantly different when the width in the length direction of the electrode 1 (hereinafter referred to as the electrode width) is 32 mm to 50 mm. The electrode width of 32 mm is better than the electrode width of 35 mm, and the magnetic field detection performance in weak reception can be determined with a smaller current as the loop resistance is larger. Therefore, the performance is better when the electrode width is 40 mm or more.

Therefore, it is considered that 40 mm is appropriate as the electrode width of the clamp-type electromagnetic field sensor 30 in consideration of practical use. Therefore, the electrode widths of 35 mm and 50 mm including the electrode width of 40 mm are verified in the simulation field.

A facility simulating a field different from the field shown in FIG. 6 is constructed, and the verification result when the electrode width is set to 35 mm is shown in FIG. The verification result in this case is shown in FIG. 10, and the verification result when the electrode width is 50 mm is shown in FIG.

In the simulated field, a verification test was conducted on the above-described simulated pillar patterns 1 to 8 in one of the three routes of 12 cores, 12 cores, and 12 cores. The lengths of the 12-core optical fiber cables used are 90 m, 60 m, and 60 m.
Furthermore, the resistance value of the grounding point and the resistance value of the support wire in each of the 12-core optical fiber cables are as shown in Table 4 below.

In this verification test, as shown in FIGS. 9, 10, and 11, when one end of the discrimination target cable is grounded, a slight difference appears in the electric field detection performance, and the electrode widths are 35 mm, 40 mm, and 50 mm in this order. It can be seen that the performance is improved.

Judging from all the conditions, the electrode widths of 35 mm, 40 mm and 50 mm are considered to have no problem in discrimination performance. However, considering the practical aspect and reliability of discrimination performance, the electrode width should be 40 mm. Is considered reasonable.

As described above, in the clamp-type electromagnetic field sensor 30 according to the present embodiment, a magnetic field generated based on a current flowing in the discrimination target cable and a voltage applied to the discrimination target cable in one clamping operation. Thus, there is an effect that the cable discrimination workability can be greatly simplified.

Moreover, in the clamp type electromagnetic field sensor 30 according to the present embodiment, the electrode 31 has the facing surface 31c, thereby detecting the electric field generated based on the voltage applied to the discrimination target cable laid in the wall or the like. Thus, there is an effect that the laying route of the discrimination target cable can be confirmed.

Further, in the clamp type electromagnetic field sensor 30 according to the present embodiment, the magnetic core 33 is disposed outside the butt end surface 31b of the electrode 31 so that the left and right magnetic films on the butt end surface 31b of the electrode 31 face each other. Thus, there is an effect that the area to be secured can be secured and the characteristics of the magnetic core 33 can be stabilized.

In the above description, the electromagnetic field sensor has been described using a clamp-type electromagnetic field sensor configured to be clampable with respect to the determination target cable in order to facilitate the shafting of the determination target cable. For example, a toroidal electromagnetic field sensor may be configured by using a toroidal magnetic core 33.

The electromagnetic field detector 41 of the receiver detects an electric field (voltage) and / or a magnetic field (induced current) from the voltage and / or induced current input from the clamp type electromagnetic field sensor 30, and the detected induced current is converted into a voltage. However, the addition signal may cancel out due to the difference in phase between the electric field detection signal and the magnetic field detection signal, and an erroneous determination may be made. In order to prevent this erroneous determination, the signal level is determined by detecting the electric field (voltage) and / or the signal level is determined by detecting the magnetic field (induced current), and then comprehensively determined. With this circuit configuration, the discrimination performance can be improved. As another means for preventing erroneous determination, the detected electric field (voltage) signal is rectified and then amplified, and / or the detected magnetic field (induced current) signal is rectified and then amplified, and then added. Thus, the discrimination performance can also be improved by adopting a circuit configuration for determining the signal level.

In addition, although the optical fiber cable has been described as an example of the determination target cable, it is not limited to the optical fiber cable, and the clamp type electromagnetic field sensor 30 according to the present embodiment is a metal communication cable, a power cable, or the like. It can be applied to various electric wire / cable discrimination and wiring route exploration.

1 Electrode 3 Magnetic Core 10 Transmitter 11 Transmitter 12 Amplifier 13 Coupling Capacitor 20 Transmitting CT
30 Clamp-type Electromagnetic Field Sensor 31 Electrode 31a Ring

31b End Face

31c Opposing Face 32 Insulator 32a Insulating Layer 33 Magnetic Core 33a Metal Layer 34 Winding 35 Output

35a Lead Wire

35b Lead Wire 36 Housing 36a Core Cover 36b Lever 40 Receiver 41 Electromagnetic Field Detection Unit 42 Adder 43 Signal Amplification / Sensitivity Adjustment Unit 44 Filter 45 Signal Level Detection Unit 46 Notification Unit

Claims

A substantially annular electrode that is made of a nonmagnetic material having electrical conductivity and surrounds a part of the cable in the circumferential direction in a state where the cable is passed through,
A magnetic core made of a magnetic material and disposed outside the ring of electrodes through an insulator;
A winding for winding the magnetic core;
An output portion drawn from the electrode and drawn from both ends of the winding;
Inducting current generated in the winding by electromagnetic induction based on current flowing in the cable is output from the output unit, and voltage generated in the electrode by electrostatic induction based on voltage applied to the cable is output from the output unit. A characteristic electromagnetic field sensor.
The electromagnetic field sensor according to claim 1,
The electrodes have a semi-annular shape and are opposed to each other as a pair. The electrodes have an abutting end surface that protrudes outside the ring and contacts and separates at the time of opening and closing, and are opposed in a direction opposite to the abutting end surface. An electromagnetic field sensor having a surface.
The electromagnetic field sensor according to claim 2,
The electromagnetic field sensor according to claim 1, wherein the magnetic core is disposed along an outer side of a butt end surface of the electrode.
The electromagnetic field sensor according to any one of claims 1 to 3,
The electromagnetic field sensor, wherein the width in the longitudinal direction of the electrode and / or the magnetic core is adjusted so as to satisfy an output level satisfying a request from a receiver connected to the output unit.
In the receiver connected to the electromagnetic field sensor according to any one of claims 1 to 4,
A receiver comprising: an adder that adds a voltage based on electrostatic induction and a voltage based on an induced current input from the output unit.