Current sensor spaced apart from power line

Abstract

The present invention provides a current sensor spaced apart from a power line, the current sensor being configured to measure a current of a power transmission conductor provided in a power line for transmitting power. The current sensor comprises: a substrate including multiple conductor layers; and a sensor unit including a sensing coil in which multiple upper patterns and lower patterns respectively formed on a pair of conductor layers selected from among the multiple conductor layers are formed in a coil shape, the sensing coil being magnetically coupled to a magnetic flux by a current of the power line to output an induced sensing signal, wherein the sensor unit is disposed on one side of the power line so that a central axis of the sensing coil intersects a current direction of the power line, and the lower pattern of the sensing coil is disposed to be spaced apart from a surface of the power transmission conductor by a predetermined distance or more.

Description

Power line separation type current sensor

[0001] The present invention relates to a power line-separated current sensor, and more specifically, to a power line-separated current sensor that is spaced apart from the surface of a power line or power transmission conductor to be suitable for measuring large currents.

[0002] A current sensor is a sensor that detects the current flowing through a conductor to be measured (e.g., a power transmission conductor of a power line, a busbar, etc.). Among detection methods, magnetic field detection methods that utilize the magnetic field around a conductor through which current flows can be broadly divided into sensors using a Current Transformer (CT) and sensors using a Hall Element.

[0003] Since CT devices utilize the principle of a transformer, they are generally applied to the measurement of AC currents that change over time. When current flows through a wire, a magnetic field is formed around it. In a donut-shaped CT through which the wire passes, when AC current flows through the wire, an induced current flows in the CT's coil due to the magnetic field surrounding the wire.

[0004] A Hall element is a device that utilizes the Hall effect, in which an electromotive force is generated in a direction perpendicular to the current and the magnetic field when a magnetic field is applied perpendicular to the current. Sensors utilizing this Hall effect are called Hall sensors, and a detection signal is generated by a change in the magnetic field of a magnetic object.

[0005] However, current detection methods using CTs have a structure in which a coil is wound around a magnetic core, and there is a problem in that it is difficult to measure large short-circuit currents, ground fault currents, and overcurrents because when the magnetizing force increases beyond a certain size, the magnetic flux density does not increase further and the magnetic core becomes magnetically saturated.

[0006] Furthermore, since Hall elements require a magnetic core, they face limitations in miniaturization as well as magnetic saturation issues. Additionally, because they are sensitive to magnetic signals, they are vulnerable to noise; unless noise is completely shielded, induced magnetism generated during the active state of neighboring busbars can be introduced as noise, leading to increased measurement errors.

[0007] In addition, since most magnetic field detection type current sensors have power lines penetrating the interior of the core, they cannot be mounted by simply attaching them to existing power lines, and they have the disadvantage of requiring a large mounting area.

[0008] Therefore, the present invention has been devised to solve the problems of the prior art, and its purpose is to provide a power line-separated current sensor suitable for measuring large currents, having a structure that is spaced apart from the surface of a power line or power transmission conductor.

[0009] In addition, the purpose is to provide a power line-separated current sensor that can be easily installed or removed by being spaced apart from one side of the power line and positioned in an open manner.

[0010] In addition, the purpose is to provide a power line-separated current sensor that minimizes the influence of noise caused by the electric field from the power line and can miniaturize the size of the sensor itself.

[0011] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0012] To achieve the above objective, the power line separation type current sensor according to the present invention is a current sensor configured to measure the current of a power transmission conductor provided in a power line that transmits power, and comprises a substrate having a plurality of conductive layers, and a sensor unit including a sensing coil having a plurality of upper patterns and lower patterns formed in a coil shape on a pair of conductive layers selected from the plurality of conductive layers, and outputting a sensing signal induced by magnetic coupling with the magnetic flux of the current of the power line, wherein the sensor unit is disposed on one side of the power line such that the central axis of the sensing coil intersects the direction of the current of the power line, and the lower pattern of the sensing coil is disposed such that it is separated from the surface of the power transmission conductor by a separation distance of at least a predetermined distance.

[0013] The sensing coil comprises: a plurality of upper patterns formed parallel to each other at a first pattern interval in the upper layer of the pair of conductive layers; a plurality of lower patterns formed parallel to each other at a second pattern interval in the lower layer of the pair of conductive layers; and a plurality of vertical conductors formed inside the substrate corresponding to each end of the plurality of upper patterns and lower patterns, and electrically connecting the upper patterns and lower patterns to form a coil, and the sensing signal can be induced at both ends of the sensing coil by magnetic induction with the magnetic flux caused by the current flowing through the power transmission conductor.

[0014] The above separation distance can be set to a larger value as the current of the power transmission conductor to be measured increases.

[0015] The upper pattern of the sensing coil may be configured such that the first pattern spacing of the upper pattern located on the outer side in the direction of the central axis of the sensing coil is larger than the first pattern spacing of the upper pattern located on the inner side.

[0016] The lower pattern of the sensing coil may be configured such that the second pattern spacing of the lower pattern located on the outer side in the direction of the central axis of the sensing coil is smaller than the second pattern spacing of the lower pattern located on the inner side.

[0017] The power line separation type current sensor according to the present invention is such that the lower pattern of the sensing coil and the surface of the power transmission conductor are arranged while maintaining the separation distance.

[0018] The above sensor unit may further include a spacer for fixing the above sensor unit to the power line or the base panel on which the power line is placed.

[0019] The above spacer can be configured to form an empty space between the lower pattern of the sensing coil and the surface of the power transmission conductor.

[0020] The power line separation type current sensor according to the present invention may further include a sensing circuit unit configured to operate with a signal ground and a power voltage as a power source, receive a sensing signal from the sensor unit to detect a current flowing through the power transmission conductor, and output a control signal indicating a detection result of the current or a control command according to the detection result.

[0021] The sensing circuit may include: an amplifier unit that amplifies the sensing signal; a control unit that receives the amplified sensing signal from the amplifier unit and outputs a control signal that indicates the detection result of the current or a control command according to the detection result; and a power supply unit that generates and supplies the power voltage to the amplifier unit and the control unit.

[0022] The power line separation type current sensor according to the present invention may further include a conductive shield portion interposed between the sensor unit and the power line to shield the electric field directed from the power transmission conductor to the sensor unit.

[0023] The above shield part can be grounded to the earth ground.

[0024] The shield portion may be configured to be electrically connected to the signal ground of the sensing circuit portion.

[0025] The shield portion may be configured to be grounded to the earth ground by a first shield wire and electrically connected to the signal ground of the sensing circuit portion by a second shield wire.

[0026] The power line separation type current sensor according to the present invention has a structure that is spaced apart from the surface of a power line or power transmission conductor, and has the effect of being suitable for measuring large short-circuit currents, ground fault currents, or overcurrents.

[0027] In addition, the present invention has the effect of facilitating installation or removal by being spaced apart from one side of the power line and arranged in an open manner.

[0028] In addition, the present invention has the effect of minimizing the influence of noise caused by the electric field from the power line and miniaturizing the size of the sensor itself.

[0029] FIG. 1 is a block diagram showing a power line separation type current sensor according to the present invention.

[0030] Figure 2 is a diagram illustrating a case where a current sensor is affected by an electric field from a power line.

[0031] FIG. 3 is a perspective view illustrating the current sensor of the present invention placed spaced apart from a power line.

[0032] FIG. 4 is a cross-sectional view of the current sensor of the present invention projected in the x-axis direction.

[0033] FIG. 5 is a cross-sectional view of a current sensor according to another embodiment of the present invention.

[0034] Figure 6 is a diagram illustrating a configuration that maintains the spacing of current sensors using spacers.

[0035] FIG. 7 is a block diagram of a current sensor according to the present invention configured by adding a shield part to block the electric field effect of the power line.

[0036] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The following detailed description is merely illustrative and illustrates a preferred embodiment of the present invention.

[0037] The power line separation type current sensor according to the present invention is a current sensor configured to measure the current of a power transmission conductor provided in a power line transmitting power by means of magnetic induction, and is characterized by being manufactured as an open type without a magnetic core and configured to be placed parallel to the power line, unlike conventional CT current sensors that use a closed type magnetic core.

[0038] Through this configuration, the current sensor of the present invention is suitable for measuring large short-circuit currents, ground fault currents, or overcurrents because it does not use a magnetic core, and has the advantage of being easy to install or remove from power lines because it is configured as an open type.

[0039] FIG. 1 is a block diagram showing a power line separation type current sensor according to the present invention.

[0040] Referring to FIG. 1, the power line separation type current sensor according to the present invention may be configured to include a sensor unit (100) comprising a substrate (120) having a plurality of conductive layers, and a sensing coil (110) that outputs a sensing signal (Vsen) induced by magnetic coupling to the magnetic flux of the power line (PL), wherein the sensing coil (110) is a current sensor arranged parallel to a power line (PL) to measure the current of a power transmission conductor (PC) provided in the power line (PL) for transmitting power.

[0041] In addition, the current sensor of the present invention may further include a sensing circuit unit (200) configured to operate with a signal ground (SGND) and a power voltage (VCC) as a power source, receive a self-induced sensing signal (Vsen) from a sensor unit (100) to detect the current flowing through a power transmission conductor (PC), and output a control signal (VCON) that indicates the current detection result or a control command according to the detection result.

[0042] The power line (PL) may be composed solely of a power transmission conductor (PC), or may further include a wire sheath covering the power transmission conductor (PC) with an insulator. Here, the power transmission conductor (PC) may be a conventional circular wire or a busbar configured in a flat bar shape, and may also be a configuration including a conductor capable of conducting current.

[0043] The substrate (120) may be a multilayer printed circuit board (PCB) having two or more conductive layers, but is not limited to a PCB if it is configured such that an insulating layer (dielectric layer) and a conductive layer are stacked to form two or more conductive layers, and may be configured to form a single multilayer substrate or multiple substrates stacked to form a multilayer.

[0044] A sensing coil (110) is formed in a coil shape by a plurality of patterns formed on a conductive layer of a substrate (120) and a vertical conductor (113) connecting them, and is arranged parallel to one side of a power line (PL) such that the central axis of the sensing coil (110) intersects the current direction of the power line (PL), thereby magnetically coupling to the magnetic flux formed around the power line (PL) to induce a sensing signal (Vsen).

[0045] The detailed structure of the sensing coil (110) will be described later.

[0046] The sensing circuit unit (200) may be configured to receive a self-induced sensing signal (Vsen) from the sensor unit (100), detect the current flowing through the power transmission conductor (PC), and output a control signal (VCON) that indicates the detection result or a control command based on the detection result.

[0047] For example, the sensing circuit unit (200) may be configured to include an amplifier unit (210) that receives and amplifies a self-induced sensing signal (Vsen) from a sensor unit (100), a control unit (220) that receives the amplified sensing signal (Vsen) from the amplifier unit (210) and outputs a control signal (VCON) that indicates a current detection result or a control command based on the detection result, and a power supply unit (230) that generates and supplies a power voltage (VCC) to the amplifier unit (210) and the control unit (220).

[0048] The amplifier section (210) can be designed to have an appropriate amplification ratio by considering the sensing signal (Vsen) generated in response to the magnitude of the current to be measured, and a filter function to pass the required frequency or remove noise signals can be further added.

[0049] The control unit (220) can output a control signal (VCON) indicating a detection result of detecting a current value from an amplified sensing signal (Vsen), or output a control signal (VCON) indicating a control command to control a switch to cut off the current flowing through the power line (PL) when the current value exceeds a preset threshold value according to the detection result.

[0050] To this end, the control unit (220) may be configured to include, although not specifically illustrated in the drawing, a comparator for comparing an amplified sensing signal (Vsen) with a threshold value, an MCU for performing digital calculations and processing, and a communication means for transmitting and receiving a control signal (VCON) to the outside.

[0051] The power supply unit (230) is a component that generates and supplies a power supply voltage (VCC) to the amplifier unit (210) and the control unit (220), and generates the power supply voltage (VCC) with the signal ground (SGND) as the reference potential, and the sensing circuit unit (200) including the amplifier unit (210) and the control unit (220) operates by receiving the power supply voltage (VCC) with the signal ground (SGND) as the reference potential.

[0052] The above-described sensing circuit (200) may be configured on the same substrate as the substrate (120) on which the sensing coil (110) is formed, but it is also possible to configure it on a separate substrate.

[0053] The sensor unit (100) of the present invention may be positioned on one side of the power line (PL) such that the central axis of the sensing coil (110) intersects the current direction of the power line (PL), preferably perpendicularly.

[0054] In particular, the sensor unit (100) of the present invention is characterized in that, in order to reduce the influence of the electric field from the power line (PL) and sensitivity at low current, the lower pattern (112) of the sensing coil (110) is arranged to be spaced apart from the surface of the power transmission conductor (PC) by a distance (SD) greater than a predetermined distance. Here, the distance (SD) can be defined as the shortest distance between the power transmission conductor (PC) and the sensing coil (110).

[0055] Furthermore, the sensor unit (100) of the present invention may be configured to be placed on the grounded power line (PL) side in the case of a grounded system in order to minimize the influence of the electric field from the power line (PL).

[0056] Through this configuration, the current sensor of the present invention minimizes the influence of noise caused by the electric field from the power line (PL), thereby reducing the occurrence of errors in current measurement, while having the effect of obtaining valid measurement values ​​without magnetic saturation for the large current to be measured.

[0057] Figure 2 is a diagram illustrating a case where a current sensor is affected by an electric field from a power line.

[0058] Referring to FIG. 2, when the sensor unit (100) and the power transmission conductor (PC) of the power line (PL) are adjacent, a parasitic capacitance (Cp) is formed between them, and the electric field generated from the power line (PL) can affect the sensing coil (110) through the parasitic capacitance (Cp). As a result, in addition to the signal corresponding to the current value, the sensing signal (Vsen) generated in the sensing coil (110) carries a noise signal from the electric field from the power line (PL), which can be a factor in reducing the accuracy of the measurement value.

[0059] In particular, when the sensing coil (110) is generally placed in close contact with the power transmission conductor (PC) to improve measurement sensitivity so as to measure low current, the parasitic capacitance (Cp) increases inversely proportional to the distance, and the influence of the electric field becomes greater.

[0060] Accordingly, the current sensor of the present invention is characterized in that the lower pattern (112) of the sensing coil (110) is positioned so as to be spaced apart from the surface of the power transmission conductor (PC) by a distance (SD) greater than a predetermined distance, in order to minimize the influence of noise caused by the electric field from the power line (PL) to reduce the occurrence of errors in current measurement, and to obtain valid measurements without magnetic saturation for the large current to be measured.

[0061] At this time, the distance (SD) between the lower pattern (112) of the sensing coil (110) and the surface of the power transmission conductor (PC) can be set larger as the magnitude of the current to be measured increases.

[0062] Generally, as the separation distance (SD) increases, both the parasitic capacitance (Cp) and the magnitude of the magnetic field decrease inversely proportional to the separation distance (SD); however, as the separation distance (SD) increases, the curvature of the path formed by the magnetic field decreases while the flatness increases.

[0063] Therefore, the current sensor of the present invention has the advantage of being able to further reduce the influence of the electric field while maintaining the sensitivity of the current measurement to some extent by placing the sensor unit (100) at a distance (SD) greater than a predetermined distance from the power transmission conductor (PC), based on the observation that when the length of the power line (PL) arranged in a straight line, such as a sensing unit, is much larger than the width of the sensing coil (110), the magnetic flux linkage caused by the magnetic flux and the sensing coil (110) decreases less than the degree to which the parasitic capacitance (Cp) decreases even if the distance (SD) is increased.

[0064] FIG. 3 is a perspective view showing the current sensor of the present invention placed spaced apart from the power line (PL).

[0065] Referring to FIG. 3, the current sensor of the present invention may be configured to include a sensor unit (100) comprising a substrate (120) having a plurality of conductive layers, and a sensing coil (110) in which a plurality of upper patterns (111) and lower patterns (112) formed in a coil shape are formed on a pair of conductive layers selected from the plurality of conductive layers, and which outputs a sensing signal (Vsen) induced by magnetic coupling with the magnetic flux of the current of a power line (PL).

[0066] The sensor unit (100) is characterized by being positioned on one side of the power line (PL) such that the central axis of the sensing coil (110) intersects the current direction of the power line (PL), and the lower pattern (112) of the sensing coil (110) is positioned so as to be spaced apart from the surface of the power transmission conductor (PC) by a distance (SD) greater than or equal to a predetermined distance.

[0067] For example, when applying the xyz space illustrated in FIG. 3, the power transmission conductor (PC) may be arranged along the x-axis direction so that current flows in the x-axis direction, and the sensor unit (100) may be arranged on top of the power transmission conductor (PC) in the z-axis direction. In this case, the sensing coil (110) may be formed such that the central axis of the sensing coil (110) is in the y-axis direction.

[0068] Accordingly, when current flows through the power transmission conductor (PC), a magnetic field is formed parallel to the y-axis, and a sensing signal (Vsen) is induced at both ends (S, E) of the sensing coil (110) by the magnetic flux that links with the sensing coil (110).

[0069] According to FIG. 3, the sensing coil (110) may be configured to include a plurality of upper patterns (111) formed parallel to each other at a first pattern interval in the upper layer of a pair of conductive layers, a plurality of lower patterns (112) formed parallel to each other at a second pattern interval in the lower layer of a pair of conductive layers, and a plurality of vertical conductors (113) formed inside a substrate (120) corresponding to each end of the plurality of upper patterns (111) and lower patterns (112), and electrically connecting the upper patterns (111) and lower patterns (112) to form a coil. Here, a connection pad (114) may be formed at the connection point between the vertical conductor (113) and the upper pattern (111), or between the vertical conductor (113) and the lower pattern (112), so that they may be electrically connected to each other.

[0070] At this time, the sensing signal (Vsen) can be induced at both ends (S, E) of the sensing coil (110) by magnetic induction with the magnetic flux caused by the current flowing through the power transmission conductor (PC).

[0071] The substrate (120) may be a multilayer substrate having two or more conductive layers, and may be formed by combining one or more substrates.

[0072] Basically, the upper pattern (111) can be formed at a constant first pattern interval, and the lower pattern (112) can be formed at a constant second pattern interval, and the first pattern interval and the second pattern interval can be the same interval.

[0073] The vertical conductor (113) is a component that penetrates the upper and lower surfaces of the substrate (120) to electrically connect the upper pattern (111) and the lower pattern (112), and can be implemented in the form of a via hole or other conductor.

[0074] FIG. 4 is a cross-sectional view of the current sensor of the present invention projected in the x-axis direction.

[0075] Referring to FIG. 4, the sensor unit (100) of the present invention is positioned at a predetermined separation distance (SD) from the surface of the power transmission conductor (PC) of the power line (PL).

[0076] At this time, the power line (PL) may be composed solely of a power transmission conductor (PC), but may be covered with a wire sheath (WC) of a certain thickness as shown in the drawing.

[0077] In order to minimize the parasitic capacitance (Cp) between the power transmission conductor (PC) and the sensing coil (110), it may be necessary to maintain the permittivity between the power transmission conductor (PC) and the sensing coil (110) at a low value.

[0078] For example, the wire sheath (WC) may be formed from a material having low dielectric constant properties, or the power line (PL) may be formed only from the power transmission conductor (PC) so that an air layer known as a low dielectric constant is formed between the power transmission conductor (PC) and the sensing coil (110), or the separation distance (SD) may be set to a value greater than the thickness of the wire sheath (WC), or the wire sheath (WC) between the power transmission conductor (PC) and the sensing coil (110) may be removed. Here, a low dielectric constant may generally refer to a dielectric with a relative dielectric constant of 3 or less.

[0079] As shown in Fig. 4, when current flows in a plane along the power transmission conductor (PC) in the x-axis direction, magnetic flux is formed clockwise around the power transmission conductor (PC).

[0080] When looking at the first to third magnetic fluxes (B1 to B3) shown in FIG. 4 among the magnetic fluxes formed around the power transmission conductor (PC), it can be seen that the first magnetic flux (B1) links with all the coil windings constituting the sensing coil (110), and the electromotive force induced by the first magnetic flux (B1) accounts for a large portion of the sensing signal (Vsen).

[0081] On the other hand, the second magnetic flux (B2) located inside the first magnetic flux (B1) links with most of the coil windings constituting the sensing coil (110) but does not link with the coil windings at point P2 at both ends, so it induces a smaller electromotive force compared to the first magnetic flux (B1), and the third magnetic flux (B3) located outside the first magnetic flux (B1) passes outside the point P1 at both ends of the sensing coil (110), so there are no coil windings constituting the sensing coil (110) that link with the third magnetic flux (B3), so it can be said that it does not contribute to the induction of the sensing signal (Vsen).

[0082] To improve this, the substrate (120) constituting the sensor unit (100) of the present invention may be plate-shaped, having a cross-section bent parallel to the curved magnetic flux, or may have the shape of an arc in the cross-sectional view. In this case, the cross-sectional shape of the substrate (120) may be formed with different curvatures depending on whether the cross-section of the power transmission conductor (PC) is circular or plate-shaped, such as a busbar.

[0083] However, since manufacturing the substrate (120) of the sensor unit (100) in a curved shape with a certain curvature rather than a flat substrate can increase the difficulty of manufacturing and reduce productivity, it is necessary to devise a method to increase the magnetic flux linkage between the magnetic flux and the sensing coil (110) while using a flat substrate for the sensor unit (100).

[0084] FIG. 5 is a cross-sectional view of a current sensor according to another embodiment of the present invention.

[0085] Referring to FIG. 5, in a current sensor according to another embodiment of the present invention, the upper pattern (111) of the sensing coil (110) may be configured such that the first pattern spacing (du) of the upper pattern (111) located on the outer side in the direction of the central axis of the sensing coil (110) is larger than the first pattern spacing (du) of the upper pattern (111) located on the inner side.

[0086] Additionally or alternatively, the lower pattern (112) of the sensing coil (110) may be configured such that the second pattern spacing (dl) of the lower pattern (112) located on the outer side in the direction of the central axis of the sensing coil (110) is smaller than the second pattern spacing (dl) of the lower pattern (112) located on the inner side.

[0087] As the pattern spacing is adjusted in this way, the second magnetic flux (B2) links with all coil windings, including the coil windings at both ends of the sensing coil (110), thereby increasing the magnetic flux linkage due to the second magnetic flux (B2). Additionally, as the third magnetic flux (B3) links with the coil windings at both ends of the sensing coil (110) with respect to the third magnetic flux (B3) on the outside, the magnetic flux linkage due to the third magnetic flux (B3) also increases. Consequently, a higher sensing signal (Vsen) can be obtained for the same current compared to when the first and second pattern spacings (du, dl) are kept constant regardless of whether the inner or outer coil windings are shown in FIG. 4, thus improving the sensing sensitivity.

[0088] In the above example, the first and second pattern spacing (du, dl) is adjusted only for the outermost coil winding among the sensing coils (110), but this does not exclude the configuration of adjusting the pattern spacing between the upper pattern (111) and the lower pattern (112) located inside.

[0089] However, even in such a case, it is preferable that the first pattern interval (du) satisfies the condition that the inner first pattern interval (du) ≤ the first pattern interval (du) ≤ the outer first pattern interval (du), and the second pattern interval (dl) satisfies the condition that the outer second pattern interval (dl) ≤ the second pattern interval (dl) ≤ the inner second pattern interval (dl).

[0090] Figure 6 is a diagram illustrating a configuration that maintains the spacing of current sensors using spacers.

[0091] Referring to FIG. 6, the power line separation type current sensor according to the present invention may further include a spacer (300) that fixes the sensor unit (100) to a power line (PL) or a base panel (BP) on which the power line (PL) is placed so that the lower pattern (112) of the sensing coil (110) and the surface of the power transmission conductor (PC) can maintain a separation distance (SD).

[0092] At this time, the spacer (300) can be configured such that a low dielectric constant dielectric (e.g., empty space (ES)) is formed between the lower pattern (112) of the sensing coil (110) and the power transmission conductor (PC) so that the parasitic capacitance (Cp) between the sensing coil (110) and the power transmission conductor (PC) is reduced, thereby causing the sensing coil (110) to be less affected by the electric field from the power line (PL).

[0093] As shown in FIG. 6(a), the spacer (300) may be configured to be interposed between a power line (PL) or a power transmission conductor (PC) and a sensor unit (100), preferably being a dielectric with low dielectric constant, and additionally or alternatively, a hollow space (ES) may be formed inside.

[0094] In this way, the spacer (300) interposed between the power line (PL) or power transmission conductor (PC) and the sensor unit (100) may be configured to be directly fixed to the power line (PL) or power transmission conductor (PC) or fixed to the base panel (BP) on which the power line (PL) or power transmission conductor (PC) is placed.

[0095] Additionally, the spacer (300) may be configured to include a plurality of support legs that support the substrate (120) of the sensor unit (100) by maintaining a distance (SD) between the lower pattern (112) of the sensing coil (110) and the surface of the power transmission conductor (PC), as shown in FIG. 6(b).

[0096] By supporting the sensor unit (100) with multiple supports, an empty space (ES) having a low dielectric constant air layer is formed between the sensing coil (110) and the power transmission conductor (PC), which can contribute to reducing the parasitic capacitance (Cp) along with the separation distance (SD).

[0097] The spacer (300) of FIG. 6(b) may be configured to be directly fixed to a power line (PL) or a power transmission conductor (PC) or fixed to a base panel (BP) on which the power line (PL) or a power transmission conductor (PC) is placed, and may further be provided with a height adjustment part (310) that can adjust the distance (SD) according to current measurement specifications or environment.

[0098] FIG. 7 is a block diagram of a current sensor according to the present invention configured by adding a shield part to block the electric field effect of the power line.

[0099] Referring to FIG. 7, the power line separation type current sensor according to the present invention may further include a conductive shield portion (400) interposed between the sensor unit (100) and the power line (PL) to shield the electric field directed from the power transmission conductor (PC) to the sensor unit (100).

[0100] As previously explained, by setting a separation distance (SD) greater than a predetermined distance between the sensing coil (110) and the power line (PL) to reduce the parasitic capacitance (Cp) between the two, the influence of the electric field from the power line (PL) to the sensing coil (110) can be reduced, and a conductive shield portion (400) can be interposed between the sensor unit (100) and the power line (PL) to further block the influence of the electric field.

[0101] At this time, the shield portion (400) is interposed between the sensor unit (100) and the power line (PL), and can be positioned closer to the sensor unit (100).

[0102] Additionally, the shield portion (400) may be configured to include a first shield plate (410) interposed between the sensor unit (100) and the power line (PL) to block the electric field influence of the power line (PL) facing the sensor unit (100), and a second shield plate (420) coupled to the first shield plate (410) at a predetermined angle to wrap around both ends of the sensor unit (100) along the length direction of the power line (PL) in order to further block the electric field influence from the remaining part of the power line (PL) in addition to the power line (PL) facing the bottom of the sensor unit (100).

[0103] The parasitic capacitance (Cp) between the sensing coil (110) and the power transmission conductor (PC) shown in FIG. 2 can be considered as an equivalent circuit in which a first parasitic capacitance (not shown in the drawing) between the power transmission conductor (PC) and the shield part (400) and a second parasitic capacitance (not shown in the drawing) between the shield part (400) and the sensing coil (110) are connected in series according to the installation of the shield part (400).

[0104] At this time, in order to block the effect of the electric field from the power transmission conductor (PC) on the sensing coil (110), it is desirable to maintain a constant value at the second parasitic capacitance between the shield part (400) and the sensing coil (110) without fluctuation.

[0105] To this end, the shield section (400) may be configured to be grounded to the earth ground (EGND) through the first shield wire (430), or alternatively or additionally, electrically connected to the signal ground (SGND) of the sensing circuit section (200) using the second shield wire (440).

[0106] When the shield portion (400) is grounded to the earth ground (EGND), the noise current induced in the shield portion (400) due to fluctuations in the electric field is bypassed to the earth along the first shield wire (430), and the earth potential of the shield portion (400) can be stabilized to some extent. However, depending on the magnitude or frequency of the electric field generated from the power line (PL), the grounding state of the first shield wire (430), or the length or impedance of the first shield wire (430), the earth potential of the shield portion (400) may fluctuate, and electric field noise may be carried on the sensing signal (Vsen).

[0107] Additionally, when the shield portion (400) is connected to the signal ground (SGND) of the sensing circuit portion (200), even if noise is induced in the shield portion (400) due to fluctuations in the electric field, the potential of the shield portion (400) can be maintained stably with respect to the signal ground (SGND). However, depending on the magnitude or frequency of the electric field generated from the power line (PL), the length or impedance of the second shield line (440), or the capacitance of the signal ground (SGND) with respect to the ground, the potential of the shield portion (400) with respect to the signal ground (SGND) may fluctuate, and some electric field noise may be carried in the sensing signal (Vsen).

[0108] Accordingly, the shield section (400) is configured to be grounded to the earth ground (EGND) by the first shield wire (430) and simultaneously electrically connected to the signal ground (SGND) of the sensing circuit section (200) by the second shield wire (440), thereby minimizing the generation of noise to the sensing coil (110) by the electric field from the power line (PL).

[0109] At this time, the first and second shield lines (430, 440) need to be configured to minimize the shared path between them, and preferably, the first and second shield lines (430, 440) may be configured so that each is individually drawn out from the shield section (400) without any shared section between them.

[0110] In addition, the current sensor of the present invention may be installed within the enclosure (not shown in the drawing) of a switchboard, control panel, or distribution panel, and in this case, the shield portion (400) may be configured such that the first and second shield wires (430, 440) are electrically connected to the ground (EGND) through the chassis of the enclosure.

[0111] In addition, although not shown in the drawings, the current sensor of the present invention may be installed on the back surface of the base panel (BP) opposite the power line (PL) at a predetermined distance (SD) from the power transmission conductor (PC) when the power line (PL) is mounted or fixed on one side of the conductive base panel (BP). In this case, it is also possible to configure the base panel (BP) to function as a shield (400) by grounding it to the earth ground (EGND) or connecting it to the signal ground (SGND) of the sensing circuit (200).

[0112] Through the above-described configuration, the power line separation type current sensor according to the present invention is structured to be spaced apart from the surface of a power line (PL) or a power transmission conductor (PC), and is suitable for measuring large short-circuit currents, ground fault currents, or overcurrents. By being spaced apart from one side of the power line (PL) and arranged in an open type, it is easy to install or remove, and has the effect of minimizing the influence of noise caused by the electric field from the power line (PL) and miniaturizing the size of the sensor itself.

[0113] Although the present invention has been described and illustrated above based on preferred embodiments to exemplify the principles of the invention, the invention is not limited to the configuration and operation as described and illustrated. The embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalents thereof should be interpreted as being included within the scope of the invention.

[0114]

[0115] [Explanation of the symbol]

[0116] 100: Sensor unit 110: Sensing coil

[0117] 111: Upper pattern 112: Lower pattern

[0118] 113: Vertical conductor 114: Connection pad

[0119] 120: Substrate

[0120] 200: Sensing circuit section 210: Amplifier section

[0121] 220: Control unit 230: Power supply unit

[0122] 300: Spacer 310: Height adjustment part

[0123] 400: Shield section 410, 420: 1st and 2nd shield plates

[0124] 430, 440: 1st and 2nd shield lines

[0125] PL: Power line PC: Power transmission conductor

[0126] WC: Wire insulation

[0127] du: 1st pattern interval dl: 2nd pattern interval

[0128] ES: Empty space BP: Base panel

[0129] SGND: Signal Ground EGND: Earth Ground

[0130] Vsen: Sensing signal VCC: Power supply voltage

[0131] VCON: Control signal Cp: Parasitic capacitance

[0132] SD: Separation distance B1~B3: 1st to 3rd magnetic flux

Claims

1. A current sensor configured to measure the current of a power transmission conductor provided in a power line that transmits power, A sensor unit comprising a substrate having a plurality of conductive layers, and a plurality of upper and lower patterns formed in a coil shape on each of a pair of conductive layers selected from the plurality of conductive layers, and a sensing coil that outputs a sensing signal induced by magnetic coupling to the magnetic flux of the current of the power line. A power line separation type current sensor characterized in that the sensor unit is positioned on one side of the power line such that the central axis of the sensing coil intersects the current direction of the power line, and the lower pattern of the sensing coil is positioned such that it is separated from the surface of the power transmission conductor by a distance greater than a predetermined distance.

2. In Paragraph 1, The above sensing coil is, A plurality of upper patterns formed parallel to each other at a first pattern interval on the upper layer among the above pair of conductive layers; A plurality of lower patterns formed parallel to each other at a second pattern interval on the lower layer among the above pair of conductive layers; and It includes a plurality of vertical conductors formed inside the substrate corresponding to each end of the plurality of upper patterns and lower patterns, and electrically connecting the upper patterns and lower patterns to form a coil. A power line separation type current sensor characterized in that the above sensing signal is induced at both ends of the sensing coil by magnetic induction with the magnetic flux caused by the current flowing in the power transmission conductor.

3. In Paragraph 1, A power line separation type current sensor characterized in that the above separation distance is set to a larger value as the current of the power transmission conductor to be measured increases.

4. In Paragraph 2, A power line spacing type current sensor characterized in that the upper pattern of the sensing coil is formed such that the first pattern spacing of the upper pattern located on the outer side in the direction of the central axis of the sensing coil is larger than the first pattern spacing of the upper pattern located on the inner side.

5. In Paragraph 2, A power line spacing type current sensor characterized in that the lower pattern of the sensing coil is formed such that the second pattern spacing of the lower pattern located outwardly in the direction of the central axis of the sensing coil is smaller than the second pattern spacing of the lower pattern located inwardly.

6. In Paragraph 1, A power line spacing type current sensor characterized by further including a spacer for fixing the sensor unit to the power line or the base panel on which the power line is placed so that the lower pattern of the sensing coil and the surface of the power transmission conductor are arranged while maintaining the spacing distance.

7. In Paragraph 6, A power line spacing type current sensor characterized by the above spacer being configured to form a void space between the lower pattern of the sensing coil and the surface of the power transmission conductor.

8. In Paragraph 1, A power line separation type current sensor characterized by further including a sensing circuit unit configured to operate as a power source with a signal ground and power voltage, receive the sensing signal from the sensor unit to detect the current flowing through the power transmission conductor, and output a control signal indicating the detection result of the current or a control command according to the detection result.

9. In Paragraph 8, The above sensing circuit is, An amplifier section for amplifying the above sensing signal; A control unit that receives the amplified sensing signal from the amplifier unit and outputs a control signal that indicates the detection result of the current or a control command according to the detection result; and A power line separation type current sensor characterized by including a power supply unit that generates and supplies the power voltage to the amplifier unit and the control unit.

10. In Paragraph 8, A power line-separated current sensor characterized by further including a conductive shield portion interposed between the sensor unit and the power line to shield the electric field directed from the power transmission conductor to the sensor unit.

11. In Paragraph 10, The above shield portion is characterized by being grounded to the earth ground, a power line separation type current sensor.

12. In Paragraph 10, A power line-separated current sensor characterized in that the shield portion is electrically connected to the signal ground of the sensing circuit portion.

13. In Paragraph 10, A power line-separated current sensor characterized in that the shield portion is grounded to the earth ground by a first shield wire and electrically connected to the signal ground of the sensing circuit portion by a second shield wire.

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