DC leakage current measuring device

Abstract

A DC leakage current measuring device according to the present invention is mounted on a pair of conductive wires constituting an electrical circuit and measures DC leakage current. The DC leakage current measuring device comprises: a first core having an annular shape and having a first gap in which a first Hall sensor is placed; a second core spaced apart from the first core, formed in the same annular shape and the same size as the first core, and having a second gap in which a second Hall sensor is placed; a first position-limiting hole for limiting the position at which one of the pair of conductive wires passes through; and a second position-limiting hole for limiting the position at which the other of the pair of conductive wires passes through, wherein each of the conductive wires passes through in a state in which the relative positional relationship with the first gap and the second gap is limited.

Description

DC leakage current measuring device

[0001] The present invention relates to a measuring device for measuring DC leakage current in a DC circuit.

[0002] With the development of industries such as renewable energy and electric vehicles, DC power systems are gradually expanding, increasing the demand for diverse DC current measurement. Common methods for DC current measurement include inserting a shunt resistor with a fixed value between the conductors, which measures current, and combining a gapped core with a Hall effect element.

[0003] Meanwhile, power systems must measure and manage leakage current to ensure stability and prevent accidents such as fire. Since most existing power systems are AC, products that measure AC leakage current are mainstream. However, just as in AC power systems, measuring DC leakage current is essential in DC power systems as well. According to Kirchhoff's Current Law, DC leakage current only appears when the sum of the currents flowing in the wires connected to the load is zero, and only when an alternate path exists.

[0004] The conventional method of measuring DC leakage current, utilizing a gapped core and a Hall-effect element, is relatively simple in structure but presents difficulties in achieving high accuracy. In particular, because DC leakage current values ​​are typically very small, ensuring accuracy is challenging.

[0005] Meanwhile, the method of measuring using a CT (Current Transformer), which is widely used in measuring AC leakage current, cannot be applied to measuring DC leakage current due to the characteristics of DC current.

[0006] The purpose of the present invention is to provide a DC leakage current measuring device capable of improving the measurement precision of leakage current in a DC power system.

[0007] According to one aspect of the present invention, a DC leakage current measuring device is provided for measuring a DC leakage current by being mounted on a pair of conductive lines constituting an electric circuit, the device comprising: a first core having a first gap formed in an annular shape in which a first Hall sensor is mounted; a second core having a second gap formed in an annular shape, the second gap having the same size and shape as the first core, and in which a second Hall sensor is mounted; a first position limiting hole for limiting a position through which one of the pair of conductive lines passes, and a second position limiting hole for limiting a position through which the other of the pair of conductive lines passes, each of the conductive lines being characterized in that each of the conductive lines passes through the first gap and the second gap in a state in which a relative positional relationship with respect to the first gap and the second gap is limited.

[0008] In the above-described DC leakage current measuring device, the central axis of the first core and the central axis of the second core are arranged on a common axis so as to be aligned with each other, and the central axis of the first position limiting hole and the central axis of the second position limiting hole are spaced apart from the common axis by the same distance, but may be on opposite sides with respect to the common axis.

[0009] In the above-described DC leakage current measuring device, when the common axis is viewed as the center of rotation, the first position limiting hole may be at a position rotated 90° from the first gap, the second gap may be at a position rotated 180° from the first gap, and the second position limiting hole may be at a position rotated 270° from the first gap.

[0010] In the above-described DC leakage current measuring device, it may further include a housing that accommodates the first core and the second core; a position limit adapter in which the first position limit hole and the second position limit hole are formed and which is detachably coupled to a through hole formed in the housing;

[0011] In the above-described DC leakage current measuring device, the position-limiting adapter is made of a flexible material and has one or more slits that are connected from the outside to the first position-limiting hole and the second position-limiting hole, so that each of the conductive lines can be inserted by widening the slits.

[0012] In the above-described DC leakage current measuring device, the first position limiting hole and the second position limiting hole are connected to each other, and a single slit can be connected to the first position limiting hole, the second position limiting hole, or a connection point between the first position limiting hole and the second position limiting hole.

[0013] In the above-described DC leakage current measuring device, it may further include a terminal block mounted so as to be exposed to the outside of the housing and outputting an alarm signal or a fault signal; and a socket mounted so as to be exposed to the outside of the housing and to which a connector of a serial communication cable for transmitting data including a leakage current value is connected.

[0014] In the above-described DC leakage current measuring device, the device may further include: a PCB in which the first Hall sensor is mounted upright on a first plane so that the first Hall sensor is positioned in the first gap, and the second Hall sensor is mounted upright on a second plane opposite the first plane so that the second Hall sensor is positioned in the second gap; a first core bracket mounted on the first plane and fixed by wrapping around the circumference of the first core; and a second core bracket mounted on the second plane and fixed by wrapping around the circumference of the second core.

[0015] In the above-described DC leakage current measuring device, the first core bracket may further include a first fin (Fin) protruding from the first bottom plate portion and inserted into the first gap together with the first Hall sensor, and the second core bracket may further include a second fin (Fin) protruding from the second bottom plate portion and inserted into the second gap together with the second Hall sensor.

[0016] In the above-described DC leakage current measuring device, the device may further include a control unit that calibrates a sensing value from the first Hall sensor using first calibration data and calibrates a sensing value from the second Hall sensor using second calibration data; and a storage unit that stores the first calibration data and the second calibration data.

[0017] The DC leakage current measuring device according to the present invention has an advantage in that the direction and distance between the first conductive line (and the second conductive line) and the first gap (11a) of the first core (11) are constant within a limited range, and the direction and distance between the first conductive line (and the second conductive line) and the second gap (21a) of the second core (21) are constant within a limited range, so that a more improved measurement precision can be secured compared to a conventional case in which a pair of conductive lines penetrating the leakage current measuring device pass through a single large through hole.

[0018] The DC leakage current measuring device according to the present invention has a structure of a first core (11) and a first hall sensor (12) and a second core (21) and a second hall sensor (22), and external noise is eliminated by averaging the two hall sensors, so it has the advantage of securing improved measurement precision compared to the conventional single core single hall sensor method.

[0019] The DC leakage current measuring device according to the present invention has an advantage in that it is possible to respond to conductive wires of different diameters with a single type of main body (1) by having a position-limiting adapter (30) that can be detachably mounted on a through hole (50a) formed in a housing (50) and having various types of position-limiting adapters (30) each having a different diameter of the position-limiting hole, and further has an advantage in that the measurement precision of the DC leakage current can be further improved by mounting an adapter (30) having a position-limiting hole tailored to the diameter of the conductive wire.

[0020] The DC leakage current measuring device according to the present invention has an advantage in that it is made of a flexible material and has a slit (33) that is connected from the outside to the first position limiting hole and the second position limiting hole in a detachable position limiting adapter, thereby allowing a conductive wire (electrical wire) to be moved to the first position limiting hole and the second position limiting hole through the slit (33) and then installed therein. Therefore, there is an advantage in that the outer diameter of the position limiting hole need not be made larger than the outer diameter of the crimp terminal, but can be selected or designed to match the outer diameter of the conductive wire.

[0021] The DC leakage current measuring device according to the present invention has the advantage of being able to obtain high measurement precision of leakage current in a DC power system by having the first position limiting hole (31) rotated 90° from the first gap (11a) when viewed with the axis (common axis) as the center of rotation, the second gap (21a) rotated 180° from the first gap (11a), and the second position limiting hole (32) rotated 270° from the first gap (11a).

[0022] FIG. 1 is a perspective view showing the appearance of a DC leakage current measuring device according to one embodiment of the present invention.

[0023] FIG. 2 is an exploded perspective view showing a position limiting adapter separated from a DC leakage current measuring device according to one embodiment of the present invention.

[0024] FIG. 3 and FIG. 4 are exploded perspective views showing each part of a DC leakage current measuring device according to one embodiment of the present invention.

[0025] FIG. 5 and FIG. 6 are perspective views illustrating a PCB assembly and a first core and a second core separated from a DC leakage current measuring device according to one embodiment of the present invention.

[0026] Figure 7 is a schematic diagram illustrating a simulation overview of a DC leakage current measuring device according to one embodiment of the present invention.

[0027] Figure 8 is a table showing the number of volume elements generated for the core in the simulation.

[0028] Figure 9 is a table showing the simulation results.

[0029] Fig. 1 is a perspective view illustrating the appearance of a DC leakage current measuring device according to an embodiment of the present invention. Fig. 2 is an exploded perspective view illustrating a position limiting adapter separated from a DC leakage current measuring device according to an embodiment of the present invention. Figs. 3 and 4 are exploded perspective views illustrating each component of a DC leakage current measuring device according to an embodiment of the present invention. Figs. 5 and 6 are perspective views illustrating a PCB assembly and a first core and a second core separated from a DC leakage current measuring device according to an embodiment of the present invention.

[0030] Hereinafter, a DC leakage current measuring device according to one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6.

[0031] A DC leakage current measuring device according to one embodiment of the present invention is a measuring device that is mounted on a pair of conductive wires constituting a DC electric circuit and measures a DC leakage current, wherein the pair of conductive wires may supply DC power to a load, and if there is no leakage current, the pair of conductive wires may form a closed circuit, and if there is no leakage current, the current flowing in one of the pair of conductive wires and the current flowing in the other are in opposite directions and have the same current magnitude.

[0032] The first position limiting hole (31) is a through hole through which one of a pair of conductive lines (hereinafter also referred to as the “first conductive line”) passes, but limits the position through which it passes, and the second position limiting hole (32) is a through hole through which the other of a pair of conductive lines (hereinafter also referred to as the “second conductive line”) passes, but limits the position through which the other of the pair of conductive lines passes. The inner diameters of the first position limiting hole (31) and the second position limiting hole (32) may be the same as or slightly larger than the outer diameters of the conductive lines through which they pass.

[0033] The central axis (x1) of the first position limiting hole (31) and the central axis (x2) of the second position limiting hole (32) are parallel to the central axis (y) of the through hole (50a) formed in the housing (50) of the main body (1), but are spaced apart from the central axis (y) of the through hole by the same distance in opposite directions.

[0034] The first position limiting hole (31) and the second position limiting hole (32) may be independently and completely spaced apart. In addition, as illustrated, the first position limiting hole (31) and the second position limiting hole (32) may be connected (communicated) with each other, but at least the first conductive line is limited in its position by the first position limiting hole (31), and the second conductive line is limited in its position by the second position limiting hole (32). Accordingly, each of the conductive lines is characterized in that it penetrates in a state in which its relative positional relationship with the first gap (11a) of the first core (11) and the second gap (21a) of the second core (21), which will be described later, is limited. Therefore, the direction and distance between the first conductive line (and the second conductive line) and the first gap (11a) of the first core (11) are constant within a limited range, and the direction and distance between the first conductive line (and the second conductive line) and the second gap (21a) of the second core (21) are constant within a limited range. Compared to the conventional case where a pair of conductive lines penetrating a leakage current measuring device pass through a single large through hole, there is an advantage in that improved measurement precision can be secured.

[0035] The housing (50) is composed of cases (51, 52, 53) that accommodate the first core (11), the second core (21), and the PCB assembly (A; see FIG. 5), as described below, to accommodate and protect the components that constitute the DC leakage current measuring device and form the exterior of the DC leakage current measuring device.

[0036] The position limit adapter (30) has a length corresponding to the length of the through hole (50a) formed in the housing (50), and is detachably coupled to the through hole (50a) formed in the housing (50) by an installer or user. The position limit adapter (30) is formed with a first position limit hole (31) and a second position limit hole (32) that penetrate from the front to the rear.

[0037] A plurality of types of position limit adapters (30) can be mounted and detached from the same main body (1), but the inner diameters of the first position limit hole (31) and the second position limit hole (32) are different, so that the plurality of types of position limit adapters (30) are provided.

[0038] According to the present invention, the position limiting adapter (30) is detachably mounted on the through hole (50a) formed in the housing (50), and since various types of position limiting adapters (30) having different diameters of the position limiting holes are provided, there is an advantage in that it is possible to respond to conductive wires of different diameters with a single type of main body (1), and further, there is an advantage in that the measurement precision of DC leakage current can be further improved by mounting an adapter (30) having a position limiting hole tailored to the diameter of the conductive wire.

[0039] The position limit adapter (30) is made of a flexible material, which may be rubber or silicone, and may be composed of two parts. The first part (30a) of the position limit adapter (30) may be forcefully fitted into a through hole (50a) at the front of the housing (50), and the second part (30b) of the position limit adapter (30) may be forcefully fitted into a through hole (50b) at the rear of the housing (50).

[0040] The first part (30a) of the position-limiting adapter (30) is provided with a first front hole (31a) corresponding to half of the first position-limiting hole (31) and a second front hole (32a) corresponding to half of the second position-limiting hole (32), and the second part (30b) of the position-limiting adapter (30) is provided with a first rear hole (31b) corresponding to half of the first position-limiting hole (31) and a second rear hole (32b) corresponding to half of the second position-limiting hole (32).

[0041] The through hole (50a) is roughly cylindrical in shape, and has a hole plane portion (50b) that is a plane extending in the longitudinal direction at the bottom by cutting off a portion of the cylinder. The first part (30a) of the position-limiting adapter (30) has a first adapter plane portion (34a) that is cut flat from the bottom so as to align with the hole plane portion (50b), and the second part (30b) of the position-limiting adapter (30) has a second adapter plane portion (34b) that is cut flat from the bottom so as to align with the hole plane portion (50b). By using the hole plane portion (50b), the first adapter plane portion (34a), and the second adapter plane portion (34b), the first position limiting hole (31) and the second position limiting hole (32) are always at the same specified angle when the position limiting adapter (30) is mounted in the through hole (50a) of the housing.

[0042] The position limit adapter (30) is provided with a slit (33) that is connected from the outside to the first position limit hole and the second position limit hole, so that each conductive wire can be inserted by spreading the slit of the position limit adapter (30) made of a flexible material. In the drawing, the first position limit hole and the second position limit hole are interconnected, so that the first position limit hole and the second position limit hole are connected from the outside by a single slit (33: 33a, 33b) that is connected to the connection point between the first position limit hole and the second position limit hole. In addition, the single slit may be connected to the first position limit hole or the second position limit hole.

[0043] Meanwhile, in the case where the first position limiting hole and the second position limiting hole are not connected to each other but are configured separately, two slits that are connected to each of the first position limiting hole and the second position limiting hole may be provided.

[0044] Typically, a Y-type or O-type crimp terminal is attached to the end of an electric wire, but the outer diameter encompassing the circumference of such a crimp terminal is much larger than the outer diameter of the electric wire. In order to insert the end of the electric wire with the crimp terminal attached into a position-limiting hole like the present invention and pass the electric wire through, the inner diameter of the position-limiting hole must be larger than the outer diameter of the crimp terminal, and therefore, there is a disadvantage in that the inner diameter of the position-limiting hole becomes much larger than the thickness of the electric wire to be passed through.

[0045] However, the present invention has an advantage in that a slit (33) is provided in a flexible material and a detachable position-limiting adapter that communicates with a first position-limiting hole and a second position-limiting hole from the outside, thereby allowing a conductive wire (electrical wire) to be moved to and settled in the first position-limiting hole and the second position-limiting hole through the slit (33). Therefore, there is an advantage in that the outer diameter of the position-limiting hole need not be made larger than the outer diameter of the crimp terminal, but can be selected or designed to match the outer diameter of the conductive wire.

[0046] A main body (1) of a DC leakage current measuring device according to one embodiment of the present invention comprises a housing (50:51,52,53), a PCB assembly (A:40,12,22,13,23,41,42), a first core (11) and a first pad (14) formed in the front of the PCB assembly (A), a second core (21) and a second pad (24) formed in the rear of the PCB assembly (A), and a mounting plug (61).

[0047] The housing (50:51, 52, 53) is composed of a main case (51), a front case (52) covering the front of the main case (51), and a top case (53) covering the upper part of the main case (51). A mounting plug (61) is inserted into a fixing groove of the main case (51), and a DC leakage current measuring device can be mounted on a fixed object using a piece or bolt, etc., by utilizing the provided through-hole.

[0048] The PCB assembly (A:40,12,22,13,23,41,42) is composed of a PCB (40), a first Hall sensor (12), a first core bracket (13), a second Hall sensor (22), a second core bracket (23), a terminal block (42), and a socket (41).

[0049] The terminal block (42) is mounted on the PCB (40) so that it is exposed to the outside of the housing (50) and a digital signal line can be connected thereto. Through this, an alarm signal or a fault signal, which is a digital signal output by a control unit such as an MPU mounted on the PCB, is output to the outside. The alarm signal or fault signal is a signal output when a leakage current exceeds a set value.

[0050] The socket (41) is mounted on the PCB (40) so as to be exposed to the outside of the housing (50), and a connector of a serial communication cable is connected to it, and is used to transmit data including a leakage current value calculated and output by a control unit such as an MPU mounted on the PCB (40).

[0051] On the PCB (40), a first Hall sensor (12) is mounted upright on a first plane facing forward so as to be positioned in the first gap (11a) of the first core (11), and a second Hall sensor (22) is mounted upright on a second plane opposite to the first plane so as to be positioned in the second gap (21a) of the second core (21). The first Hall sensor (12) and the second Hall sensor (22) are mounted on each of the two planes of the PCB (40), are sensors that utilize the Hall effect, and are positioned in each gap. The two cores are independently spaced apart from each other, and the Hall sensors (12, 22) are positioned at the exact center of each gap (11a, 21a).

[0052] The first core bracket (13) is mounted on a first plane facing forward on the PCB (40) and is configured to include a first bottom plate portion (13a) in the shape of an annular disk corresponding to the size of the first core (11) and a first side plate portion (13b) in the shape of a cylindrical dam standing upright on the edge of the first bottom plate portion (13a) so as to wrap around and fix the bottom and side surfaces of the first core (11).

[0053] The second core bracket (23) is mounted on a second plane facing rearward on the PCB (40) and is configured to include a second bottom plate portion (23a) in the shape of an annular disk corresponding to the size of the second core (11) to wrap around and fix the bottom and side surfaces of the second core (21) and a second side plate portion (23b) in the shape of a cylindrical dam that stands upright on the edge of the second bottom plate portion (23a).

[0054] The first core bracket (13) has a first fin (13c) that protrudes from the first bottom plate (13a) and is inserted into the first gap (11a) together with the first Hall sensor (12), and the second core bracket (23) has a second fin (23c) that protrudes from the second bottom plate (23a) and is inserted into the second gap (21a) together with the second Hall sensor (22). The fin has a thickness that is the same as or slightly smaller than the gaps (11a, 21a) and a width corresponding to the width of the gaps (11a, 21a). The fin may have a fin shape and may have gaps through which the leads of the Hall sensors can pass. The fin is inserted into the gap to help align the gap of the core (11, 21) precisely with the Hall sensor and prevent the Hall sensor from tilting due to movement or rotation of the core, thereby helping to maintain precise alignment of the gap and the Hall sensor.

[0055] The first pad (14) is inserted between the front case (52) and the first core (11) to press the first core into the storage space of the first core bracket (13), and the second pad (24) is inserted between the main case (51) and the second core (21) to press the second core into the storage space of the second core bracket (23).

[0056] The first core (11) is configured at the front of the PCB (40) and is seated in a storage space formed by the first bottom plate (13a) and the first side plate (13b) of the first core bracket (13), and the second core (21) is configured at the rear of the PCB (40) and is seated in a storage space formed by the second bottom plate (23a) and the second side plate (23b) of the second core bracket (23). The first core and the second core are arranged on both sides with the PCB (40) as the center.

[0057] The first core (11) has a square cross-section and an overall circular shape, and is configured with a first gap (11a) in the middle where the first Hall sensor (12) is mounted. The second core (21) is spaced apart from the first core (11), has a square cross-section and an overall circular shape, and is configured with a second gap (21a) where the second Hall sensor (22) is mounted, and is configured with an annular shape having the same size and shape as the first core (21). The cores (11, 21) are, for example, ferrite cores.

[0058] The central axis (z1) of the first annular core (the central axis of the ring) and the central axis (z2) of the second annular core (the central axis of the ring) are arranged to coincide with each other, and the two central axes are arranged on a common axis, that is, a common axis (z). The arrangement of the central axes on the common axis (z) is also the same for the core bracket, the pad, the through hole of the PCB, and the through hole of the main case. Meanwhile, in the position limiting adapter (30), the central axis (x1) of the first position limiting hole (31) and the central axis (x2) of the second position limiting hole (32) are characterized in that they are parallel to the common axis (z) and spaced apart by the same distance, but on opposite sides with respect to the common axis (z).

[0059] When viewed from the common axis (z), the first gap (11a) and the second gap (21a) are spaced at an angle of 180°, and the two cores are fixed to the core bracket and the housing so as to maintain a symmetrical position with respect to the common axis.

[0060] In addition, each of the conductive lines (a pair of conductive lines) is penetrated in a state in which the relative positional relationship with the first gap (11a) of the first core (11) and the second gap (21a) of the second core (21) is limited by using two position-limiting holes (using a position-limiting adapter).

[0061] The PCB (40) comprises a control unit that controls and calculates the overall functions of the DC leakage current measuring device, such as an MPU, an ADC for analog-to-digital conversion, and a storage unit that stores various data and necessary software. The storage unit stores first calibration data for the first Hall sensor and second calibration data for the second Hall sensor.

[0062] The analog sensing signals sensed by the first Hall sensor (12) and the second Hall sensor (22) are each converted into digital sensing values ​​using an ADC and input to the control unit. The control unit calibrates the sensing value from the first Hall sensor (12) using the first calibration data, calibrates the sensing value from the second Hall sensor (22) using the second calibration data, and obtains two leakage current values ​​from each sensing value, i.e., a leakage current value derived using the first core and the first Hall sensor and a leakage current value derived using the second core and the second Hall sensor. Then, the control unit averages the two current values ​​to obtain an average leakage current value.

[0063] The control unit periodically transmits the average leakage current value to the upper system through the socket or when requested by the upper system, and when the average leakage current value exceeds a preset value, generates an alarm signal or a fault signal and outputs it to the terminal and reports it to the upper system.

[0064]

[0065] FIG. 7 is a schematic diagram illustrating a simulation overview of a DC leakage current measuring device according to one embodiment of the present invention, FIG. 8 is a table showing the number of volume elements generated for a core in the simulation, and FIG. 9 is a table showing the simulation results.

[0066] Altair's Flux was used, and DC 40 A current entered one conductive wire (conductive wire marked with 'X') and DC 40 A current exited the other conductive wire (conductive wire marked with 'O'). The central axes of the two cores (11, 21) were arranged on the axis (z) with a gap in the front and back, the gaps of the cores were at 0° and 180°, and the two conductive wires were symmetrically positioned around the axis (z). The outer diameter of the core was 85 mm, the inner diameter of the core was 75 mm, the height of the core was 5 mm, the gap of the cores was 1.4 mm, the spacing between the cores was 4 mm, the diameter of the conductive wires was 15 mm, and the separation distance between the centers of the two conductive wires was 50 mm.

[0067] In the simulation, the magnetic flux density obtained from each gap by each Hall sensor was converted into a leakage current value as in the following mathematical equation 1, and the average of the two leakage current values ​​produced from each gap was calculated.

[0068]

[0069] In simulation, even with the same core shape, if the number of meshes is small, the error in the simulation increases, and an error exists because the mesh of the first gap (11a) and the mesh of the second gap (21a) are not exactly symmetrical. As shown in the table in Fig. 8, the number of meshes (number of volume elements) increases from Case 1 to Case 4, and the number of other nodes, lines, and surfaces also increases.

[0070] And looking at the arrangement of the pair of challenge lines, when the axis (z) is viewed as the center of rotation, they are arranged at 45° and 225° in Position 1 (Fig. 7(a)), 90° and 270° in Position 2 (Fig. 7(b)), 135° and 315° in Position 3 (Fig. 7(c)), and 180° and 365° (0°) in Position 4 (Fig. 7(d)).

[0071] Fig. 9 shows the leakage current values ​​(Gap1, Gap2) and average leakage current values ​​(Average) of each gap derived according to the combination of each Case and Position. It can be confirmed that the leakage current values ​​(Gap1, Gap2) and average leakage current values ​​(Average) of each gap are smaller and have desirable results when in Position 2 compared to Position 1, Position 3, and Position 4.

[0072] And, since Position 2 shows the best result, when the axis (common axis) is considered as the center of rotation, it can be seen that the accuracy of the leakage current measurement is the highest when the first position limiting hole (31) is at a position rotated 90° from the first gap (11a), the second gap (21a) is at a position rotated 180° from the first gap (11a), and the second position limiting hole (32) is at a position rotated 270° from the first gap (11a).

[0073] Since the DC leakage current in the normal state is generally a very small value, it can be affected by an external magnetic field in addition to the current flowing through the conductive wire pair. However, the arrangement of the core and gap described above can exclude the influence of an external magnetic field and obtain very high precision.

[0074] According to the present invention, when the axis (common axis) is viewed as the center of rotation, the first position limiting hole (31) is at a position rotated 90° from the first gap (11a), the second gap (21a) is at a position rotated 180° from the first gap (11a), and the second position limiting hole (32) is at a position rotated 270° from the first gap (11a), thereby providing an advantage of obtaining high measurement precision of leakage current in a DC power system.

Claims

1. In a DC leakage current measuring device that is mounted on a pair of conductive wires constituting an electric circuit and measures DC leakage current, A first core having a first gap formed in an annular shape and in which a first Hall sensor is mounted; A second core having a second gap formed in an annular shape and spaced apart from the first core and having the same size and shape as the first core, and in which a second Hall sensor is mounted; A first position limiting hole for limiting a position through which one of the pair of conductive lines is penetrated, and a second position limiting hole for limiting a position through which the other of the pair of conductive lines is penetrated are respectively configured, so that each of the conductive lines is penetrated in a state in which the relative positional relationship with the first gap and the second gap is limited. DC leakage current measuring device.

2. In claim 1, The central axis of the first core and the central axis of the second core are arranged on a common axis so as to be aligned with each other, The central axis of the first position limiting hole and the central axis of the second position limiting hole are spaced apart from the common axis by the same distance, but are characterized in that they are on opposite sides with respect to the common axis. DC leakage current measuring device.

3. In claim 2, When viewed with the above common axis as the center of rotation, The above first position limiting hole is at a position rotated 90° from the above first gap. The second gap is at a position rotated 180° from the first gap. The second position limiting hole is characterized in that it is at a position rotated 270° from the first gap. DC leakage current measuring device.

4. In claim 1, A housing accommodating the first core and the second core; It is characterized in that it further includes a position limit adapter in which the first position limit hole and the second position limit hole are formed and which is detachably coupled to the through hole formed in the housing. DC leakage current measuring device.

5. In claim 4, The above position-limiting adapter is, By being made of a flexible material and having one or more slits that are connected from the outside to the first position limiting hole and the second position limiting hole, each of the conductive lines can be inserted by opening the slits. DC leakage current measuring device.

6. In claim 5, The above first position limiting hole and the above second position limiting hole are connected to each other, wherein a single slit is connected to the first position limiting hole, to the second position limiting hole, or to a connection point between the first position limiting hole and the second position limiting hole. DC leakage current measuring device.

7. In claim 4, A terminal block mounted to be exposed to the outside of the housing and outputting an alarm signal or a fault signal; and A socket to which a connector of a serial communication cable is connected, the connector being mounted so as to be exposed to the outside of the housing and transmitting data including a leakage current value; DC leakage current measuring device.

8. In claim 1, A PCB in which the first Hall sensor is mounted upright on a first plane so that the first Hall sensor is positioned in the first gap, and the second Hall sensor is mounted upright on a second plane opposite to the first plane so that the second Hall sensor is positioned in the second gap; A first core bracket mounted on the first plane and fixed by wrapping around the circumference of the first core; Further comprising a second core bracket mounted on the second plane and wrapped around and fixed to the circumference of the second core; DC leakage current measuring device.

9. In claim 8, The first core bracket further includes a first fin protruding from the first bottom plate and inserted into the first gap together with the first hall sensor. The second core bracket further includes a second fin protruding from the second bottom plate and inserted into the second gap together with the second hall sensor. DC leakage current measuring device.

10. In claim 1, A control unit that calibrates a sensing value from the first Hall sensor using first calibration data and calibrates a sensing value from the second Hall sensor using second calibration data; Further comprising a storage unit for storing the first calibration data and the second calibration data; DC leakage current measuring device.

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