JP2023157359A - Current sensor and watt-hour meter - Google Patents

Abstract

To provide a current sensor which enables currents to be measured highly accurately and at low cost, without being influenced by external magnetic fields and with few current detection sensitivity fluctuations due to positional deviation, and a watt-hour meter.SOLUTION: A current sensor 1 is provided, having a current bar 2 in which the current to be detected flows and a substrate 3 which has at least four or more magnetism detection units 3a-3d, and detecting a current flowing in the current bar 2 on the basis of the magnetism detection results from the magnetism detection units 3a-3d. The current bar 2 has a first conductor bar 2a and a second conductor bar 2b which are arranged in parallel via a folded portion 2c in such a manner that directions of currents flowing in the conductor bars differ from each other. Through-holes 12a, 12b in which the substrate 3 is inserted, are formed in the first and second conductor bars, 2a, 2b, respectively, at positions facing each other. The magnetism detection units 3a-3d are evenly arranged on both respective end sides of the through-holes 12a, 12b centering on the through-holes 12a, 12b of the first and second conductor bars, 2a, 2b.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a current sensor and a watt-hour meter that are low-cost, unaffected by external magnetic fields, and capable of highly accurate current measurement with little variation in current detection sensitivity due to positional deviation.

Conventionally used current sensors include a current transformer (CT), a configuration in which a magnetoelectric conversion element such as a Hall element is placed in the gap of the magnetic collecting core, There are configurations that include a wire-wound coil or an element with a coil pattern formed on a dielectric substrate. Furthermore, there is also a configuration in which the current is detected by directly arranging a Hall element or the like without using a magnetic collecting core. These current sensors are electrically isolated from the circuit through which the primary current flows, which is the object of measurement, so they are superior in that they can accurately measure current without affecting the circuit on the primary current side. . Furthermore, the method of arranging elements formed with coil patterns has excellent linearity and temperature characteristics, and has a feature that the number of parts is small and manufacturing is easy (see Patent Document 1).

In the current sensor described in Patent Document 1, a current bar is passed through the central opening of an annular magnetic collecting core, and a substrate with a coil pattern is placed in the gap of the magnetic collecting core. When a current flows through the current bar, a magnetic flux is generated around the current path that is proportional to the magnitude of the current flowing through the current bar. The generated magnetic flux is collected by a magnetic collecting core. When the current is a periodic current, the generated magnetic flux also changes periodically according to the period. As a result, an induced voltage corresponding to the magnitude and frequency of the current is generated in the detection coil having the coil pattern, and this induced voltage is used as a detection signal for the current flowing through the current bar.

JP2009-210406A

By the way, a current sensor in which two magnetoelectric transducers are arranged in a gap portion of a magnetic collecting core has an effect as a shield against an external magnetic field perpendicular to the substrate, and can perform highly accurate current measurement. Here, when trying to realize a current sensor at low cost, it is desirable to be able to configure it only with a magnetoelectric conversion element without using a magnetic collecting core.

However, when the magnetic flux collecting core is not used, the shielding effect of the magnetic flux collecting core cannot be obtained, so there is a problem that the current measurement accuracy is greatly reduced due to the large influence of the external magnetic field.

In addition, in a current sensor without a magnetic collecting core, the positional relationship between the current bar and the magnetoelectric transducer is likely to change due to misalignment of the board, etc., resulting in fluctuations in current detection sensitivity and reduced current measurement accuracy. There is also the issue of putting it away.

The present invention has been made in view of the above, and is a low-cost current sensor and electric power sensor that can perform highly accurate current measurement without being affected by external magnetic fields and with little variation in current detection sensitivity due to positional deviation. The purpose is to provide a meter.

In order to solve the above-mentioned problems and achieve the objects, a current sensor according to the present invention includes a current bar through which a current to be detected flows and a substrate having at least four or more magnetic detection parts, The current sensor detects the current flowing through the current bar based on the magnetic detection result detected by the detection unit, and the current bar includes a plurality of parallel currents arranged in parallel with each other having different current directions through the folded part. 1 conductor bar and a second conductor bar, through-holes into which the substrate is inserted are formed in opposing positions in the first conductor bar and the second conductor bar, respectively, and the magnetic detection unit includes: The first conductor bar and the second conductor bar are arranged equally on both ends of each through-hole, centering on each through-hole.

Moreover, the current sensor according to the present invention is characterized in that, in the above invention, the magnetic detection section is a patterned coil formed on the substrate.

Moreover, the current sensor according to the present invention is characterized in that, in the above invention, the four or more magnetic detection sections are patterned coils formed on the same plane of the substrate.

Further, in the current sensor according to the present invention, in the above invention, the four or more magnetic detection sections are connected in series so as to mutually strengthen induced voltages generated in each pattern coil when a current flows through the current bar. It is characterized by

Further, in the current sensor according to the present invention, in the above invention, the substrate is parallel to a plane formed by the first conductor bar and the second conductor bar, and the central axis of the substrate is arranged in the through hole. It is characterized by being positioned so as to coincide with the central axis.

Further, the current sensor according to the present invention is characterized in that, in the above invention, a relay is provided in the folded portion.

Further, the watt-hour meter according to the present invention calculates the amount of electric power flowing through the current bar based on the current signal detected by the current sensor described in any one of the above inventions and the voltage signal detected by the voltage sensor. It is characterized by calculating.

Further, in the above-described invention, in the watt-hour meter according to the present invention, when calculating the watt-hours using two or more pairs of current sensors and voltage sensors, the current sensor includes a current sensor using a shunt resistor. It is characterized by being included.

Moreover, the watt-hour meter according to the present invention is characterized in that, in the above-described invention, the current sensor is provided on the power supply side of each single-phase two-wire type wiring to determine the presence or absence of power theft.

Further, the watthour meter according to the present invention is characterized in that, in the above invention, the current sensor provided in the wiring on the reference potential side is a current sensor using a shunt resistor.

According to the present invention, highly accurate current measurement can be performed at low cost, without being affected by external magnetic fields, and with little variation in current detection sensitivity due to positional deviation.

FIG. 1 is a perspective view showing the configuration of a current sensor according to an embodiment of the present invention. FIG. 2 is a plan view of the current sensor shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line AA of the current sensor shown in FIG. FIG. 4 is a diagram showing an example of the configuration of the magnetic detection section. FIG. 5 is an explanatory diagram illustrating the current detection principle according to this embodiment. FIG. 6 is an explanatory diagram illustrating the principle of external magnetic field reduction according to this embodiment. FIG. 7 is an explanatory diagram illustrating fluctuations in current detection sensitivity due to positional deviation between the first conductor bar and the second conductor bar and the substrate. FIG. 8 is a block diagram showing an example of a power meter using the current sensor shown in this embodiment. FIG. 9 is a block diagram showing an example of a power meter using a current sensor in a single-phase three-wire power supply system. FIG. 10 is a block diagram showing an example of a power meter having the configuration shown in FIG. 9 plus a relay. FIG. 11 is a block diagram showing an example of a watt-hour meter using a current sensor corresponding to the current sensor of the embodiment and a current sensor using a shunt resistor in a single-phase, two-wire power supply system. FIG. 12 is a block diagram showing an example of a power meter having the configuration shown in FIG. 11 plus a relay.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

<Overall configuration>
FIG. 1 is a perspective view showing the configuration of a current sensor 1 according to an embodiment of the present invention. Further, FIG. 2 is a plan view of the current sensor 1 shown in FIG. 1. Further, FIG. 3 is a cross-sectional view taken along the line AA of the current sensor 1 shown in FIG. As shown in FIGS. 1 to 3, the current sensor 1 includes a current bar 2 through which a current I to be detected flows, and a substrate 3 having at least four magnetic detection sections 3a to 3d. The current flowing through the current bar 2 is detected based on the magnetic detection results detected by 3a to 3d.

The current bar 2 includes a first conductor bar 2a and a second conductor bar 2b which are arranged in parallel with each other and have different current directions through a folded portion 2c. The folded portion 2c is folded into a U-shape. Note that the shape of the folded portion 2c is arbitrary, and may be U-shaped, for example.

Through holes 12a and 12b into which the substrate 3 is inserted are formed in the first conductor bar 2a and the second conductor bar 2b at opposing positions, respectively. The through holes 12a and 12b are rectangular long holes that are open in the ±X direction and extend in the ±Y direction corresponding to the cross section of the substrate 3.

The substrate 3 forms an XY plane and has a plate shape extending in the ±X direction. The substrate 3 is parallel to the plane formed by the first conductor bar 2a and the second conductor bar 2b, and the central axis of the substrate 3 is positioned to coincide with the central axis of the through holes 12a and 12b. Although the substrate 3 and the inner surfaces of the through holes 12a and 12b are insulated by air, a spacer of an insulating member may be provided also for positioning.

On the substrate 3, magnetic detection units 3a to 3d are arranged at equal intervals Lb in the ±X direction. The magnetic detection parts 3a and 3b are arranged at equal intervals in the ±X direction about the central axis C2a of the through hole 12a of the first conductor bar 2a. Moreover, the magnetic detection parts 3c and 3d are arranged at equal intervals in the ±X direction about the central axis C2b of the through hole 12b of the second conductor bar 2b.

The magnetic detection sections 3a to 3d are patterned coils formed on the substrate 3. The magnetic detection units 3a to 3d are connected in series so that when the current I flows through the current bar 2, the induced voltages generated in each pattern coil are reinforced (added). Note that the induced voltage signals output from the magnetic detection units 3a to 3d are converted into current signals by an arithmetic circuit (not shown) and output. The current sensor 1 also includes this arithmetic circuit, and the arithmetic circuit may be formed on the substrate 3 or provided outside the substrate 3 via a lead wire. In this embodiment, the magnetic detection sections 3a to 3d of the pattern coil have a square spiral shape with side length La, but the shape is not limited to this. For example, the patterned coil may have a circular spiral shape.

Note that the magnetic detection units 3a to 3d may be any sensor that can detect magnetism, and may be a Hall element, for example.

<Example of configuration of magnetic detection unit>
FIG. 4 is a diagram showing a configuration example of the magnetic detection sections 3a to 3d. As shown in FIG. 4, the magnetic detection sections 3a to 3d are formed on the substrate 3. Each magnetic detection section 3a to 3d is a two-layer pattern coil. The magnetic detection unit 3a detects the induced voltage due to the upward (+Z direction) magnetic flux φI generated in the -X direction of the first conductor bar 2a when the current I flows in the +Y direction in the first conductor bar 2a. The magnetic detection unit 3b detects the induced voltage due to the downward (-Z direction) magnetic flux φI generated in the +X direction of the first conductor bar 2a when the current I flows in the +Y direction in the first conductor bar 2a. The magnetic detection unit 3c detects the induced voltage due to the downward (-Z direction) magnetic flux φI generated in the -X direction of the second conductor bar 2b when the current I flows in the -Y direction in the second conductor bar 2b. do. The magnetic detection unit 3d detects the induced voltage due to the upward (+Z direction) magnetic flux φI generated in the +X direction of the second conductor bar 2b when the current I flows in the +Y direction in the second conductor bar 2b. Then, the induced voltages detected by each of the magnetic detection sections 3a to 3d are added and outputted from the output terminals Ta and Tb. Therefore, as described above, the magnetic detection sections 3a to 3d are connected in series.

Specifically, the output terminals Ta and Tb are formed on the back surface of the substrate 3, and the output terminal Ta is connected to the via b1 via a folded line L10 extending to the back surface, and is connected to the magnetic detection section 3a. The magnetic detection section 3a is connected to the clockwise upper layer pattern coil on the front surface side, and is further connected to the clockwise lower layer pattern coil via the via a1. This lower layer pattern coil is connected to the upper layer connection line L12 via the via c1, and is connected to the magnetic detection section 3b.

The magnetic detection section 3b is connected to the counterclockwise upper layer pattern coil on the front surface side, and is further connected to the counterclockwise lower layer pattern coil via the via a2. This lower layer pattern coil is connected to the upper layer connection line L23 via the via c2, and is connected to the magnetic detection section 3c.

The magnetic detection section 3c is connected to the clockwise upper layer pattern coil on the front surface side, and is further connected to the clockwise lower layer pattern coil via the via a3. This lower layer pattern coil is connected to the upper layer connection line L34 via the via c3, and is connected to the magnetic detection section 3d.

The magnetic detection section 3d is connected to the counterclockwise upper layer pattern coil on the front surface side, and is further connected to the counterclockwise lower layer pattern coil via the via a4. This lower layer pattern coil is connected to the output terminal Tb via the lower layer connection line L11.

In FIG. 4, the magnetic detection sections 3a to 3d are formed of two layers of patterned coils, but the patterned coils may have one layer or multiple layers. The larger the number of layers, the larger the detected value of induced voltage can be. Further, although the number of magnetic detection units 3a to 3d is four, the present invention is not limited to this, and the number may be four or more. For example, additional magnetic detection sections may be provided in the ±X directions of each of the magnetic detection sections 3a to 3d, or additional magnetic detection sections may be provided along the first conductor bar 2a and the second conductor bar 2b. The magnetic detection sections are connected in series so as to add the induced voltages.

<Current detection principle>
FIG. 5 is an explanatory diagram illustrating the current detection principle according to this embodiment. In FIG. 5, the upward (+Z direction) magnetic flux φI in which the current I interlinks with the magnetic detection section is defined as a positive value, and the downward (−Z direction) magnetic flux φI is defined as a negative value. Then, +φI interlinks with the magnetic detection parts 3a and 3d, and -φI interlinks with the magnetic detection parts 3b and 3c.

Therefore, the total magnetic flux φ detected by the magnetic detection units 3a to 3d can be expressed by the following equation (1).
Total magnetic flux φ = magnetic flux of magnetic detection section 3a (φI) - magnetic flux of magnetic detection section 3b (-φI)
- Magnetic flux of magnetic detection section 3c (-φI) + Magnetic flux of magnetic detection section 3d (φI)
=4×φI…(1)
Therefore, by connecting the magnetic detection sections 3a to 3d in series so as to take the difference in magnetic flux detected by the left and right pattern coils around the first conductor bar 2a and the second conductor bar 2b, current detection can be made more efficient. can do well.

<Reduction of external magnetic field>
FIG. 6 is an explanatory diagram illustrating the principle of external magnetic field reduction according to this embodiment. As shown in FIG. 6, when external magnetic fields φN4 to φN1 are generated, downward magnetic fluxes are interlinked with each of the magnetic detection sections 3a to 3d. When detecting the current flowing through the current bar 2 in this state, the total magnetic flux φ can be expressed by the following equation (2).
Total magnetic flux φ = magnetic flux of magnetic detection section 3a (φI-φN4)
-Magnetic flux of magnetic detection section 3b (-φI-φN3)
-Magnetic flux of magnetic detection section 3c (-φI-φN2)
+Magnetic flux of magnetic detection section 3d (φI-φN1)
=4×φI-(φN4-φN3-φN2+φN1) …(2)

Here, it is assumed that the external magnetic fields φN4 to φN1 are external magnetic fields having a slope as shown in the following equation (3).
φN4=8×φN
φN3=7×φN
φN2=6×φN
φN1=5×φN…(3)

Then, the total magnetic flux φ can be expressed by the following equation (4).
Total magnetic flux φ=4×φI-(φN4-φN3-φN2+φN1)
=4×φI-(8φN-7φN-6φN+5φN)
=4×φI…(4)
Therefore, in this embodiment, even if the external magnetic field has a slope, the influence of the magnetic flux due to the external magnetic field can be canceled out.

<Changes in current detection sensitivity due to positional deviation>
FIG. 7 is an explanatory diagram illustrating fluctuations in current detection sensitivity due to positional deviation between the first conductor bar 2a, the second conductor bar 2b, and the substrate 3. FIG. 7(a) shows a case where the first conductor bar 2a' and the second conductor bar 2b' are arranged on one side with respect to the substrate 3, and FIG. A case is shown in which the first conductor bar 2a and the second conductor bar 2b are arranged on both sides of the substrate 3.

The strength H of the magnetic field generated by the current I flowing through the first conductor bar 2a and the second conductor bar 2b is expressed as H=I/(2πr), and the strength H of the magnetic field changes depending on the distance r. Therefore, as shown in FIG. 7(a), when the first conductor bar 2a' and the second conductor bar 2b' are arranged on one side of the board 3, the position of the board 3 is shifted by ΔZ in the +Z direction. If the deviation occurs, the distance between each magnetic detection section 3a to 3d and the first conductor bar 2a or the second conductor bar 2b also changes from distance r to distance (ra), so that the current in the magnetic detection sections 3a to 3d changes. This results in a large variation in detection sensitivity.

In contrast, in this embodiment, as shown in FIG. 7B, through holes 12a and 12b are formed in the first conductor bar 2a and the second conductor bar 2b, respectively, The conductor bar 2a and the second conductor bar 2b are arranged vertically (±Z direction). As a result, when the position of the board 3 shifts by ΔZ, the distance from the first conductor bar 2a and the second conductor bar 2b on the upper side (+Z direction) changes from the distance r to the distance (ra). , the distance between the first conductor bar 2a and the second conductor bar 2b on the lower side (-Z direction) varies from distance r to distance (r+a), so the total magnetic field strength H is determined by the variation above and below. Since the two currents work in a direction that cancels each other out, fluctuations in current detection sensitivity can be reduced. Note that by inserting the board 3 into the through holes 12a and 12b, positioning between the first conductor bar 2a, the second conductor bar 2b, and the board 3 becomes easier, and fluctuations in the board 3 can be suppressed. .

As a result, in this embodiment, fluctuations in current detection sensitivity due to positional misalignment between the first conductor bar 2a and second conductor bar 2b of the current bar 2 and the magnetic detection sections 3a to 3d are prevented from being affected by an external magnetic field. A highly accurate current sensor can be provided. Moreover, since no magnetism collecting core is used, the cost is low.

<Power meter>
FIG. 8 is a block diagram showing an example of a power meter 200 using the current sensor 1 shown in this embodiment. This power meter 200 measures the three-phase power amount between the three-phase, three-wire power supply SP and the load LD, and calculates it by a two-wattmeter method.

As shown in FIG. 8, the power meter 200 includes current sensors 103a and 103b, voltage sensors 201a and 201b, a power amount calculation section 202, and an output section 203, which correspond to the current sensor 1 shown in the embodiment. The current sensor 103a detects the R-phase line current IR using the S-phase as a reference potential. The current sensor 103b detects the T-phase line current IT using the S-phase as a reference potential. Further, the voltage sensor 201a detects the R-phase line voltage VRS using the S-phase as a reference potential. The voltage sensor 201b detects the T-phase line voltage VTS using the S-phase as a reference potential.

The power amount calculation unit 202 calculates the R-phase power obtained from the line current IR, the line voltage VRS, and the power factor, and the T-phase power obtained from the line current IT, the line voltage VTS, and the power factor. The three-phase power is calculated by the two-wattmeter method of adding the power. The output unit 203 displays or outputs the calculated power amount to the outside.

FIG. 9 is a block diagram showing an example of a power meter 300 using current sensors 103a and 103b corresponding to the current sensor 1 in a single-phase three-wire power supply system. Although the power supply system shown in FIG. 8 was a three-phase three-wire system, the power supply system shown in FIG. 9 is a single-phase three-wire system from the power supply SP2 to the load LD2. In the single-phase three-wire system, one line current I1 is detected by the current sensor 103a, and one line voltage V1 is detected by the voltage sensor 201a, using the neutral wire N shown in FIG. 9 as a reference potential. Further, the other line current I2 is detected by the current sensor 103b, and the other line voltage V2 is detected by the voltage sensor 201b. The power amount calculation unit 302 calculates each power amount of one side and the other side, and also calculates the total power amount of one side and the other side.

FIG. 10 is a block diagram showing an example of a power meter having the configuration shown in FIG. 9 plus a relay. As shown in FIG. 10, this watt-hour meter 400 is different from the watt-hour meter 300 of FIG. 9 in that relays R1 and R2 for turning on and off the current bar line are provided at positions corresponding to the folded portions of the current bar. The relays R1 and R2 switch in response to external control signals. Switching of relays R1 and R2 facilitates maintenance, and when relays R1 and R2 are turned off, it is possible to calculate noise signals and dark current caused by external magnetic fields of current sensors 103a and 103b, and current sensor 103a , 103b can be obtained.

FIG. 11 is a block diagram showing an example of a watt-hour meter 500 using a current sensor 103a corresponding to the current sensor 1 of the embodiment and a current sensor 511 using a shunt resistor in a single-phase two-wire power supply system. It is. The power supply system shown in FIG. 11 is a single-phase two-wire system from power supply SP3 to load LD3. The current sensor 511 provides a shunt resistor in the current bar 510 on the reference potential side, measures the potential difference between both ends of the shunt resistor, and calculates the current value by dividing this potential difference by the resistance value of the shunt resistor. Note that in FIG. 11, a current sensor 511 including a shunt resistor is shown. The correlated voltage is obtained from the difference between the potential V11 detected by the voltage sensor 201a and the potential V12 detected by the voltage sensor 201b. In FIG. 11, two current sensors 103a and 511 are arranged in a single phase, but the current sensor 511 is provided on the reference potential side, the current sensor 103a is used as the main current sensor, and the current sensor 511 is used as a sub current sensor. There is. Further, the current sensor 511 and the current sensor 103a are each arranged on the power supply SP3 side.

In addition to the load LD3, the current sensor 511 is arranged to detect, for example, an external load that is grounded for the purpose of power theft. The power amount calculation unit 502 calculates and monitors the amount of power based on the amount of current detected by the current sensor 103a and the current sensor 511, and calculates the amount of power calculated based on the amount of current detected by the current sensor 511. However, if a difference of a certain value or more occurs compared to the amount of electric power calculated based on the amount of current detected by the current sensor 103a, it is determined that the power has been stolen. Note that the power amount calculation unit 502 may determine the presence or absence of power theft by comparing the amount of current detected by the current sensor 511 and the amount of current detected by the current sensor 103a instead of the amount of power.

FIG. 12 is a block diagram showing an example of a power meter having the configuration shown in FIG. 11 plus a relay. As shown in FIG. 12, this watt-hour meter 600 is different from the watt-hour meter 500 in FIG. is provided. This relay R1 switches in response to an external control signal. Switching of relay R1 facilitates maintenance, and when relay R1 is turned off, noise signals and dark current caused by external magnetic fields of current sensor 103a can be calculated, and correction information of current sensor 103a can be obtained. I can do it.

Note that when calculating the amount of power using two or more pairs of current sensors and voltage sensors, it is not necessary for all of the current sensors to use the magnetic detection section described above; for example, a current sensor using a shunt resistor may be used. may be combined. As described above, a current sensor using a shunt resistor calculates a current value by dividing the voltage drop across the shunt resistor by the shunt resistance value.

In addition, although the examples of the three-phase three-wire system, single-phase three-wire system, and single-phase two-wire system are shown above, the current sensor 1 can be applied as appropriate.

It should be noted that each configuration illustrated in the above embodiments is functionally schematic and does not necessarily have to be physically configured as illustrated. In other words, the form of dispersion/integration of each device and component is not limited to the one shown in the diagram, but all or part of it may be functionally or physically dispersed/integrated in arbitrary units depending on various usage conditions. It can be configured as follows.

1,103a, 103b, 511 Current sensor 2,510 Current bar 2a First conductor bar 2b Second conductor bar 2c Folded part 3 Substrate 3a to 3d Magnetic detection part 12a, 12b Through hole 200, 300, 400, 500, 600 Power Quantity meter 201a, 201b Voltage sensor 202, 302, 502 Electric energy calculation section 203 Output section a1 to a4, b1, c1 to c3 Via C2a, C2b Center axis I Current I1, I2, IR, IT Line current L10 Return line L11 , L12, L23, L34 Connection wire La Side length Lb Equal spacing LD, LD2, LD3 Load N Neutral wire r Distance R1, R2 Relay SP, SP2, SP3 Power supply Ta, Tb Output terminal V1, V2, VRS, VTS Line voltage V11, V12 Potential φ Total magnetic flux φI Magnetic flux φN1 to φN4 External magnetic field

Claims (10)

A current comprising a current bar through which a current to be detected flows and a substrate having at least four magnetic detection sections, and detects the current flowing through the current bar based on the magnetic detection result detected by the magnetic detection section. A sensor,
The current bar has a first conductor bar and a second conductor bar arranged in parallel with each other having different current directions through a folded part,
Through holes into which the substrate is inserted are formed in the first conductor bar and the second conductor bar at opposing positions, respectively;
The current sensor is characterized in that the magnetic detection portions are equally arranged at both ends of each through hole of the first conductor bar and the second conductor bar, respectively. The current sensor according to claim 1, wherein the magnetic detection section is a patterned coil formed on the substrate. 3. The current sensor according to claim 2, wherein the four or more magnetic detection sections are patterned coils formed on the same plane of the substrate. 4. The current sensor according to claim 3, wherein the four or more magnetic detection sections are connected in series so that when a current flows through the current bar, induced voltages generated in each pattern coil are reinforced. The substrate is parallel to a plane formed by the first conductor bar and the second conductor bar, and the central axis of the substrate is positioned to coincide with the central axis of the through hole. The current sensor according to claim 4. The current sensor according to claim 1, further comprising a relay provided in the folded portion. The amount of electric power flowing through the current bar is calculated based on the current signal detected by the current sensor and the voltage signal detected by the voltage sensor according to any one of claims 1 to 6. Total. 8. The watt-hour meter according to claim 7, wherein when calculating the electric energy using two or more pairs of current sensors and voltage sensors, the current sensor includes a current sensor using a shunt resistor. . 8. The electricity meter according to claim 7, wherein the current sensor is provided on the power supply side of each single-phase two-wire type wiring to determine whether or not power is stolen. 10. The watt-hour meter according to claim 9, wherein the current sensor provided in the wiring on the reference potential side is a current sensor using a shunt resistor.

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