Apparatus and method for coupling to a multi-core cable

Abstract

Apparatus and methods for coupling to a multi-core steel wire armored cable or a multi-core cable are described. The apparatus may include one or more magnets and one or more magnetic field sensors, and / or may include an array of two or more one or more sensors to enable the accommodation of the twisting of a plurality of conductors or cores. The apparatus is configured such that when the apparatus is coupled to the multi-core steel wire armored cable, a magnetic field corresponding to the one or more magnets is applied to an area of the multi-core steel wire armored cable. The apparatus is configured such that when the apparatus is coupled to the multi-core steel wire armored cable, each magnetic field sensor is oriented to detect a magnetic field component originating from the region of the multi-core steel wire armored cable.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for contactless measurement of current in a multi-core cable. In some examples, the multi-core cable may be armored. In some examples, the multi-core cable may be used to supply a net current. Background Art

[0002] A magnetically permeable casing surrounding a current-carrying cable attenuates the magnetic field around the cable generated by the current flowing through it, making it impractical to measure any current in the cable other than the net current running in the center of the cable. This net current is measured using a conventional current transformer or Rogowski coil placed around the cable. Consequently, information about (among other things) the differential current and the positioning of the conductors within the cable is lost in the external magnetic field.

[0003] Prior art related to the present invention:

[0004] WO2013 / 068360A1 (2013) discloses a device for measuring the current in the conductors of an armored cable of a multiphase network. The invention comprises at least six magnetic field sensors arranged around a central hole. The cable to be measured passes through the central hole, and the number of conductors in the cable must be less than the number of magnetic field sensors. The invention comprises a computing device and a matrix library that associates the measured field with the current in the conductor when the conductor configuration is known. A procedure is described for selecting the optimal matrix, optimizing it, and adapting it to the set of conductors to be measured. WO2013 / 068360A1 offers significant advantages over documents such as EP0874244B1: the total current is not limited to zero, the number of sensors is not constrained to be equal to the number of conductors minus 1, and it allows adaptation to unexpected conductor configurations within certain limits.

[0005] Thus, methods for inferring the current in an unarmoured multi-core cable from the magnetic field are known in the art. An example is disclosed in patent application WO 2013 / 068360 A1.

[0006] The invention disclosed in this specification solves the need for measuring current in steel wire armored multi-core cables that has not been solved in the prior art.

[0007] Single-conductor current sensors based on Gauss's law and the current magnetic field (e.g., current transformers and Rogowski coil units) have long been the mainstay of electrical measurement. They rely on Faraday's law, requiring the sensor to be placed around each conductor, and provide accurate readings of the net current enclosed, regardless of the material used in the cable (magnetic or otherwise).

[0008] Systems for simultaneously measuring multiple conductors in the same cable have been demonstrated. However, conventionally, this requires separating each conductor and measuring the current in each conductor—CT, Rogowski, shunt, etc. Methods for sensing current in multiple conductors in the same cable without separating the conductors have been discussed in US Pat. No. 5,473,244 A, US Pat. No. 7,755,347 B1, and EP 0 874 244 A2. Summary of the Invention

[0009] This specification relates in part to methods and apparatus for applying a magnetic field to saturate the magnetically permeable shell of an armored multi-core cable, reducing its effective magnetic permeability and allowing the magnetic field generated by the current distribution within the cable to reach the exterior. In this manner, techniques for calculating the internal current distribution based on external field measurements can be employed.

[0010] Typical armored cables use steel wire wrapped around the conductor to provide a partially magnetically conductive enclosure and attenuate and distort the magnetic field generated by the current distribution within the cable. As described herein, magnetically saturating the steel wire reduces (or effectively eliminates) this effect, allowing accurate and repeatable measurement of the field generated by the current distribution within the cable. Based on the magnetic field, the current distribution can be calculated, resulting in derived parameters such as (but not limited to) the time domain current in one or more individual cores, conductor current, differential current, phase, harmonics, the number and / or geometry of cores within a multi-core steel wire armored cable and / or unarmored multi-core cable, and the like.

[0011] According to a first aspect of the present invention, a device for coupling to a multi-core steel wire armored cable is provided. The device includes one or more magnets and one or more magnetic field sensors. The device is configured such that, when coupled to the multi-core steel wire armored cable, a magnetic field corresponding to the one or more magnets is applied to a region of the multi-core steel wire armored cable. The device is configured such that, when coupled to the multi-core steel wire armored cable, each magnetic field sensor is oriented to detect a magnetic field component originating from that region of the multi-core steel wire armored cable.

[0012] The magnets may be rare earth magnets (eg, samarium cobalt (SmCo) and / or neodymium (NdFeB)) and / or other non-rare earth magnets.

[0013] Because magnets can be fragile, they may need to be protected from mechanical shock or impact. The magnets may be coated with rubber or other polymers. One or more magnets may be overmolded with a polymer; or assembled with one or more rigid polymer or metal (magnetic or non-magnetic) covers that protect the surface of the magnets that would otherwise be exposed to impact.

[0014] In this way, the magnetic field from one or more magnets saturates or at least partially saturates the steel wire armor (typically in the form of wire wrapped around the periphery of the multi-core cable). As a result, the magnetic permeability of the steel wire armor is reduced, allowing a greater portion of the magnetic field generated by the current within the cores of the cable to couple to the magnetic field sensor. This can improve the accuracy and reliability of the measured magnetic field generated by the differential current between two or more cores (or conductors) of the multi-core steel wire armor cable. As a result, derived quantities calculated based on the measured magnetic field can also be improved. Examples of derived quantities can include (but are not limited to) time domain current in one or more individual cores, current, differential current, phase, harmonics, the number and / or geometry of the cores within the multi-core steel wire armor cable, and the like.

[0015] Each magnetic field sensor can be oriented to detect a magnetic field component originating from current flowing through one or more cores of the multi-core steel wire armored cable within a region to which a magnetic field corresponding to one or more magnets is applied. The magnetic field sensor can be configured to measure a magnetic field generated by a differential current between two or more cores of the multi-core steel wire armored cable.

[0016] Alternatively, a multi-core cable may be referred to as a multi-conductor cable (these terms should be interpreted interchangeably).

[0017] The magnetic field corresponding to the one or more magnets corresponds to a superposition of the magnetic fields generated by each of the one or more magnets.

[0018] The coupling may include mechanical coupling and / or connection. The coupling may include linking magnetic flux generated by or within the multi-core steel wire armored cable and / or its core. The coupling does not include DC electrical connection.

[0019] When the device is coupled to a multi-core steel wire armored cable, within a region, the magnetic field corresponding to the one or more magnets may include a component parallel to the axial direction of the multi-core steel wire armored cable. The component parallel to the axial direction of the multi-core steel wire armored cable may be the maximum component of the magnetic field at each point within the region. The component parallel to the axial direction of the multi-core steel wire armored cable may be the maximum total component of the magnetic field.

[0020] At least one of the one or more magnets may include a permanent magnet or take the form of a permanent magnet. Two or more of the magnets may include a permanent magnet or take the form of a permanent magnet. All of the one or more magnets may include a permanent magnet or take the form of a permanent magnet.

[0021] At least one of the one or more magnets may include an electromagnet or take the form of an electromagnet. Two or more of the magnets may include an electromagnet or take the form of an electromagnet. All of the one or more magnets may include an electromagnet or take the form of an electromagnet.

[0022] At least one of the one or more magnetic field sensors may include a coil or take the form of a coil. Two or more of the magnetic field sensors may include corresponding coils or take the form of corresponding coils. All of the one or more magnetic field sensors may include corresponding coils or take the form of corresponding coils. The coils may be prefabricated, inserted into the cable, or wrapped around the cable in situ, or connected in situ around the cable, or placed in situ around the cable. The coils may be mounted radially, tangentially, or along other axes relative to the longitudinal axis of the sensor. A mix of coil orientations may be used, such as, but not limited to, radial and tangential within a single sensor. The coils may be wound around a core of magnetically conductive material. The coils may be so-called "air core" coils, which do not include a core of magnetically conductive material. The "air core" coils may be wound around a support structure formed of a non-magnetic conductive material (e.g., plastic, glass, etc.).

[0023] At least one of the one or more magnetic field sensors may include a solid-state magnetic field sensor device or take the form of a solid-state magnetic field sensor device. Each solid-state magnetic field sensor can sense magnetic fields along one axis, two axes, three axes, or more axes. The solid-state magnetic field sensor device may include a semiconductor magnetic sensor, a magnetoresistive sensor, a giant magnetoresistive sensor, or an anisotropic magnetoresistive sensor or take the form of a semiconductor magnetic sensor, a magnetoresistive sensor, a giant magnetoresistive sensor, or an anisotropic magnetoresistive sensor. The solid-state magnetic field sensor device may include a giant magnetoimpedance (GMI) sensor or take the form of a giant magnetoimpedance (GMI) sensor. The solid-state magnetic field sensor device may include a superconducting quantum interference detector (SQUID) or take the form of a superconducting quantum interference detector (SQUID). The solid-state magnetic field sensor device may include a magneto-optical sensor or take the form of a magneto-optical sensor. The solid-state magnetic field sensor device may include a fluxgate or take the form of a fluxgate. The solid-state magnetic field sensor device may include a chip or an integrated circuit or take the form of a chip or an integrated circuit. The solid-state magnetic field sensor device may include a Hall effect sensor or take the form of a Hall effect sensor.

[0024] Two or more of the magnetic field sensors may include or take the form of corresponding solid-state magnetic field sensing devices (of any type described herein). All of the one or more magnetic field sensors may include or take the form of corresponding solid-state magnetic field sensing devices (of any type described herein).

[0025] The magnetic field corresponding to the one or more magnets may have a magnitude of at least 5 mT within the region. The magnetic field corresponding to the one or more magnets may have a magnitude of at least 12 mT within the region. The magnetic field corresponding to the one or more magnets may have a magnitude of at least 50 mT within the region.

[0026] The magnetic field corresponding to one or more magnets can vary over time. The time-varying magnetic field can correspond to at least some of the one or more magnets in the form of electromagnets. At least some of the electromagnets can be driven by alternating current. At least some of the electromagnets can be energized during an active period (active period) and de-energized during an inactive period (inactive period). The device can be configured to compare the magnetic field measurement results between the active period and the inactive period to identify and preferably compensate for the residual shielding effect of the steel wire armor. The active period and the inactive period can be sequenced according to a predetermined plan. Additionally or alternatively, the device can be configured to energize at least some of the electromagnets in response to a trigger condition, a received signal, etc.

[0027] The device can be configured so that the magnetic field corresponding to one or more magnets is constant. Constant may mean that, when powered and operated correctly, the magnetic field is not time-varying. The constant magnetic field can be provided by permanent magnets, electromagnets powered by DC current, or a combination of the two.

[0028] The device can be configured to mechanically couple to a multi-core steel-armored cable using a magnetic force generated by applying a magnetic field to the steel armor layer. The one or more magnets can be primarily configured to apply a magnetic field to an area to at least partially saturate the steel armor layer. However, this will always generate a certain magnetic force between the device and the multi-core steel-armored cable. Through appropriate design choices, this magnetic force can also be used to secure the device to the coupled multi-core steel-armored cable. For example, the weight of the device can be designed to be less than the magnetic force generated when the multi-core steel-armored cable is contained within the area.

[0029] The device may also include a structure supporting one or more magnets and one or more magnetic field sensors. The structure may include a channel configured to accommodate a multi-core steel wire armored cable. In other words, the structure may be a channel-defining structure. The cross-section of the channel may have a circular or arc-shaped shape. The cross-section of the channel may have a non-circular shape that does not correspond to an arc of a circle. The channel may be open so as to accommodate a multi-core steel wire armored cable. The structure may define the cross-section of the channel as a C-shape or a U-shape. The cross-section may be taken in a plane perpendicular to a direction corresponding to the axial direction of the channel, and when the multi-core steel wire armored cable is connected to the device, the multi-core steel wire armored cable will be accommodated along the axial direction of the channel.

[0030] The passage can be defined by first and second components of a structure configured to enclose the multi-core steel wire armored cable when the multi-core steel wire armored cable is received within the passage. The first and second components can be urged together by a spring. The first and second components can be urged by magnetic forces from at least some of the one or more magnets to enclose the multi-core steel wire armored cable. The first and second components of the structure can provide a clamp. Once the multi-core steel wire armored cable is enclosed, the first and second components can be secured together by a latch, a lock, or a similar fastening device.

[0031] The structure may include or take the form of two or more components configured to enclose or wrap around a multi-core steel wire armored cable to define a passageway. The two or more components may be urged together by a spring. Once enclosed around the multi-core steel wire armored cable, the two or more components may be secured together by one or more latches, locks, or similar fastening devices.

[0032] The device may also include a net current sensor configured to measure a net current flowing through the multi-core steel wire armored cable when the device is coupled to the multi-core steel wire armored cable. The net current sensor may include or take the form of a Rogowski coil. The net current sensor may include or take the form of a current transformer. One or more magnetic field sensors may be disposed within a transformer coil of the current transformer.

[0033] At least one of the one or more magnetic field sensors may include or be in the form of a coil. Each coil may be wound around a sensing pole piece. Two or more of the magnetic field sensors may be provided by corresponding coils. The two or more coils providing the magnetic field sensors may be wound around corresponding portions of a single sensing pole piece. Alternatively, the two or more coils providing the magnetic field sensors may be wound around corresponding separate sensing pole pieces.

[0034] The circumferential sensing pole piece may extend around all or part of the circumference of the multi-wire armored cable when it is housed and may include two or more inward radial projections. A coil providing a magnetic field sensor may be wound around each inward radial projection.

[0035] At least one of the one or more magnets may include or take the form of an electromagnet. Each electromagnet may be wound around a pole piece. Two or more of the magnets may be provided by electromagnets. Two or more electromagnets may be wound around respective portions of a single pole piece. Alternatively, two or more coils providing magnetic field sensors may be wound around respective individual pole pieces.

[0036] The apparatus may comprise a common pole piece having one or more coils wound on respective portions providing the magnetic field sensors and one or more electromagnets wound on other portions.

[0037] The device may include two or more magnetic field sensors. The device may include three or more magnetic field sensors. The device may include four or more magnetic field sensors. The device may include five or more magnetic field sensors. The device may include six or more magnetic field sensors. The device may include ten or more magnetic field sensors.

[0038] The magnetic field sensors may be located at equal angular intervals around the passageway housing the multi-core steel wire armored cable.

[0039] The one or more magnets may include or take the form of a first set of magnets including a plurality of first magnets and a second set of magnets including a plurality of second magnets. When coupled to the device, the first set of magnets and the second set of magnets may be positioned on either side of the one or more magnetic field sensors along a direction corresponding to an axial direction of the multi-wire armored cable. In other words, the first set of magnets and the second set of magnets may sandwich or interpose the magnetic field sensors along the length of the coupled / received multi-wire armored cable.

[0040] The device may include a pair of magnets corresponding to each magnetic field sensor. Each pair of magnets may be arranged on either side of the corresponding magnetic field sensor along a direction corresponding to the axial direction of the multi-core steel wire armored cable (when coupled to the device). In other words, each pair of magnets may clamp or interpose the corresponding magnetic field sensor along the length of the coupled / received multi-core steel wire armored cable.

[0041] The one or more magnetic field sensors may include a first set of first magnetic field sensors and a second set of second magnetic field sensors.The first set of magnetic field sensors and the second set of magnetic field sensors may be arranged to be spaced apart along an axial direction of the multi-core steel wire armored cable (when coupled to the device).

[0042] In this way, differences in magnetic field measurements made using the first and second sets of magnetic field sensors may be used to compensate for different twisting rates between different multi-core cables, as further discussed in relation to the apparatus of the third aspect.

[0043] The sensor may comprise the apparatus of the first aspect and a controller. The controller may be connected to one or more magnetic field sensors and configured to calculate one or more derived quantities based on magnetic field components measured by the magnetic field sensors for some or all cores of the multi-core steel wire armored cable.

[0044] One or more derived quantities may include (but are not limited to): the current in each core (the core current may be an AC differential current or a DC differential current between the cores), the phase between the cores, harmonics, the time domain current in one or more independent cores, the number and / or geometry of the cores in a multi-core steel wire armored cable; or the cores / conductors in a magnetic conduit or pipe or cable tray, etc.

[0045] At least a portion of an apparatus containing at least one sensor can be moved relative to a magnetic core or conductor of interest to provide additional data, thereby enabling improved determination of a derived quantity. At least one sensor can be moved between two defined positions relative to a conductor of interest to provide additional magnetic field data, thereby enabling determination of the geometry of the current-carrying conductor and other derived quantities.

[0046] Two or more turns of magnetic field sensors may be axially spaced apart. Additionally or alternatively, one or more of the turns may be offset from the central axis of the sensor assembly to provide additional magnetic field data to determine the geometry of the current carrying conductor / core and other derived parameters.

[0047] The magnetic sensor array can be arranged in any predetermined geometric shape during measurement, such as a ring, a two-piece clamp, or a clamshell, or any shape used by conventional single current probes, or a fixed or open rectangular shape (suitable for conductors arranged in rectangular ducts or cable tray sections), or an elliptical shape (fixed or open), or an open shape such as a "C" or "U", or a self-returning shape. The relative position of the sensors must not change during the measurement process.

[0048] The described apparatus and methods may also be applied to wire cores, cables, or conductors that are grouped together but not necessarily housed in a single multi-core cable.

[0049] Steel wire armored multi-core cable is a subset of multi-core cable.

[0050] The described device and method can be used to saturate partially permeable steel or soft magnetic (conduit or pipe or cable containing conductors) parts.

[0051] One or more magnets and one or more magnetic field sensors may be mounted within a soft magnetic housing or channel-defining structure. The soft magnetic channel-defining structure provides magnetic immunity to external current-carrying conductors that are near or adjacent to the device.

[0052] If magnets are not used, the channel-defining structure may be made of a non-magnetic (i.e., non-magnetically conductive) material. If magnets are used, the channel-defining structure may be made of a non-magnetic (i.e., non-magnetically conductive) material. If magnets are used, the channel-defining structure may be made of a magnetic (i.e., magnetically conductive) material.

[0053] Magnetic immunity can be achieved using magnetic field sensors, for example, by using the known relative position and orientation of the magnetic field sensors to distinguish between magnetic field sources inside a multi-core cable and external magnetic field sources.

[0054] The controller may include one or more digital electronic processors communicatively coupled to a memory. The controller may include a memory storing computer program code that, when executed by the one or more digital electronic processors, implements one or more of the following:

[0055] A controller obtains magnetic field measurements using one or more magnetic field sensors;

[0056] ●The controller controls the power supply status of one or more electromagnets;

[0057] • The controller calculates one or more derived quantities.

[0058] The computer program may be an algorithm or a series of algorithms. The computer program may operate on the same principles as the cited prior art; and / or may use a series of principles developed by:

[0059] Immunity the derived quantity from external magnetic fields (e.g., caused by adjacent current-carrying conductors external to the sensor); and / or

[0060] Makes derived quantity calculations independent of the twist associated with multi-core cables

[0061] The sensor may include the device of the first aspect. The device may also be configured to generate one or more signals based on the output of one or more magnetic field sensors. Each signal may be proportional to the differential current between the cores of a multi-core steel wire armored cable (when coupled to the device). Each signal may be proportional to the individual core currents of the individual cores of the multi-core cable. The sensor may also include a link corresponding to each signal for connecting to a control and / or measurement system.

[0062] Part or all of the links may be in the form of wired links. Part or all of the links may be in the form of low-power wireless links (eg, Bluetooth (RTM), RFID, etc.).

[0063] Any sensor may also include one or more voltage sensors, and the one or more derived quantities may include one or more power values. The one or more power values ​​may include the power delivered by each core and / or the total power delivered by the multi-core steel wire armored cable.

[0064] The system may include any sensor coupled to provide input to a measurement device. The measurement device may receive one or more derived quantities from the sensor. The measurement device may receive one or more signals based on outputs of one or more magnetic field sensors.

[0065] The measuring device may be a power quality analyzer, which may also be called a "power quality monitor."

[0066] The measuring device may be a power quality recording device. The power quality recording device may be in the form of a power recorder or an energy recorder.

[0067] According to a second aspect of the present invention, a method is provided, the method comprising coupling an apparatus according to the first aspect, or coupling an apparatus comprised by a sensor or system, to a multi-core steel wire armored cable, such that a magnetic field corresponding to one or more magnets is applied to a region of the multi-core steel wire armored cable. The method further comprises measuring, using one or more magnetic field sensors, a component of the magnetic field originating from the region of the multi-core steel wire armored cable.

[0068] The magnetic field corresponding to one or more magnets can saturate the magnetic field of the steel wire armor layer in the area. The magnetic field corresponding to one or more magnets can saturate (all or part) the magnetic field of the steel wire armor layer in the area.

[0069] The magnetic permeability of a magnetic material such as steel wire armour can be defined as the gradient of the magnetic flux with respect to the magnetic field, i.e.:

[0070]

[0071] Where μ is the magnetic permeability of the steel wire armor layer, B is the magnetic flux (unit is Tesla, T), and H is the magnetic field strength (unit is Ampere / meter, Ampere / meter). -1 ).

[0072] If the magnetic permeability μ is less than or equal to 20% of the peak value, the magnetic field in the steel wire armor layer can be considered saturated. If the magnetic permeability μ is less than or equal to 15% of the peak value, the magnetic field in the steel wire armor layer can be considered saturated. If the magnetic permeability μ is less than or equal to 10% of the peak value, the magnetic field in the steel wire armor layer can be considered saturated. If the magnetic permeability μ is less than or equal to 5% of the peak value, the magnetic field in the steel wire armor layer can be considered saturated.

[0073] Alternatively, the magnetic field in the steel wire armor layer can be considered to be saturated if, when the same current is supplied in each case via the cores of each cable, the magnetic field measured by the one or more magnetic field sensors is attenuated by no more than 10% compared to a multi-core cable that is identical to a multi-core steel wire armored cable system except that the steel wire armor layer is omitted.

[0074] The method may further include calculating one or more derived quantities based on the magnetic field components measured by the magnetic field sensor for some or all cores of the multi-core steel wire armored cable. The one or more derived quantities may include (but are not limited to): current in each core, differential current between cores, phase between cores, harmonics, time domain current in one or more individual cores, the number and / or geometry of cores in the multi-core steel wire armored cable, and the like.

[0075] The method may include features corresponding to any features of the apparatus of the first aspect and / or a sensor or system including the apparatus of the first aspect (and / or its features). Definitions applicable to the apparatus of the first aspect and / or a sensor or system including the apparatus of the first aspect (and / or its features) may also apply to the method of the second aspect (and / or its features).

[0076] According to a third aspect of the present invention, a device for coupling to a multi-core cable is provided. The device includes a first group of one or more first magnetic field sensors. The device also includes a second group of one or more second magnetic field sensors. The device is configured so that when the device is coupled to the multi-core cable, each first magnetic field sensor is oriented to detect a magnetic field component originating from a first region of the multi-core cable. The device is configured so that when the device is coupled to the multi-core cable, each second magnetic field sensor is oriented to detect a magnetic field component originating from a second region of the multi-core cable. The device is configured so that when the device is coupled to the multi-core cable, the first region is spaced apart from the second region along the length of the multi-core cable.

[0077] The apparatus of the third aspect may include features corresponding to any features of the apparatus of the first aspect and / or the method of the second aspect (and / or its features). Definitions applicable to the apparatus of the first aspect and / or the method of the second aspect (and / or its features) may also apply to the apparatus of the third aspect (and / or its features).

[0078] When coupled to a multi-core cable, the number and arrangement of the first magnetic field sensors relative to the multi-core cable may be the same as the number and arrangement of the second magnetic field sensors relative to the multi-core cable.

[0079] The individual cores of a multi-core cable are typically twisted with each other to increase the mechanical compliance of the cable as a whole and to facilitate cable routing, winding, and the like. When the measurement results of the magnetic field generated by the cores are used to infer the current in the cores and / or the relative phase between the cores, some assumptions need to be made about the relative position and twist rate of the cores. However, if an unknown cable is measured, this geometric factor is not available without disassembling the cable and without violating the purpose of non-invasive measurement. Using the device of the third aspect, the relative position of each core will change between the first group of magnetic field sensors and the second group of magnetic field sensors, while the current remains unchanged between the first area and the second area. In this way, the difference in the magnetic field measurement results obtained using the first group of magnetic field sensors and the second group of magnetic field sensors can be used to compensate for the different twist rates between different multi-core cables. For example, the magnetic field measurement rotation rate detected by the magnetic field sensor may be related to the twist / rotation rate of the cores of the multi-core cable.

[0080] The apparatus of the third aspect may further comprise one or more magnets arranged such that when the apparatus is coupled to the multi-core cable, magnetic fields corresponding to the one or more magnets are applied to the first and second regions of the multi-core cable.

[0081] The magnetic field corresponding to the one or more magnets can be applied substantially equally to the first and second regions of the multi-core cable. Substantially equally can mean that the magnetic fields in the first and second regions are approximately symmetrical about a mirror plane equidistant between the first and second regions and oriented perpendicular to the axial direction of the multi-core cable (when coupled). Approximately symmetrical can mean that the magnetic field components (e.g., x, y, z components) at any point in the first region differ by no more than 10% from the reflection point in the second region.

[0082] According to a fourth aspect of the present invention, a device for coupling to a multi-core cable is provided, the device comprising a current transformer coil and one or more magnetic field sensors. The device is configured such that, when the device is coupled to the multi-core cable, a region of the multi-core cable passes through the current transformer coil. The device is configured such that, when the device is coupled to the multi-core cable, the one or more magnetic field sensors are at least partially disposed between the magnetic core of the current transformer coil and the multi-core cable. At least one of the magnetic field sensors is oriented to detect a magnetic field component originating from the region of the multi-core cable.

[0083] The current transformer coil may also be referred to as a "CT" coil. The current transformer coil may be configured to measure a net current flowing through a multi-core cable. One or more magnetic field sensors may be arranged and configured to measure one or more derived quantities based on magnetic field components measured by the magnetic field sensors for some or all cores of the multi-core cable. These derived quantities may include any or all derived quantities specified with respect to the apparatus according to the first aspect and / or the method according to the second aspect.

[0084] The apparatus according to the fourth aspect may include features corresponding to any features of the apparatus according to the first and / or third aspects. Definitions applicable to the apparatus according to the first and / or third aspects (or their features) may also apply to the apparatus according to the fourth aspect (or their features).

[0085] The current transformer coil can be short-circuited via a resistor. This resistor is sometimes referred to as a "shunt resistor," "burden resistor," or "load resistor." The resistor can be between 0.1Ω and 100Ω. Preferably, the resistor is between 1Ω and 10Ω. The voltage measured across the "burden resistor" is proportional to the net current flowing through the multi-core conductors of the current transformer coil.

[0086] One or more magnetic field sensors may be disposed at least partially within an inner diameter of the current transformer coil.

[0087] The magnetic core of the current transformer coil can include or be in the form of a magnetically conductive material. The magnetically conductive material can be soft iron. The current transformer coil can be wound directly onto the magnetically conductive core. The current transformer coil can be wound onto a bobbin (or similar support), and one or more regions of the magnetically conductive material can be housed within the bobbin (or similar support). For example, the current transformer coil can be wound onto a bobbin having a through hole, and the magnetically conductive core can be inserted into the through hole, thereby being disposed within the current transformer coil.

[0088] The bobbin may be flexible and / or segmented. In this way, the current transformer coil may be wound on the bobbin in a flat configuration and the bobbin may then be bent and / or folded to form a toroidal shape (or a portion thereof).

[0089] The current transformer coil may include or take the form of two or more sub-coils. These two or more sub-coils may be connected together. Two, a subset, or all of the sub-coils may be connected in series. Two, a subset, or all of the sub-coils may be connected in parallel.

[0090] The apparatus may be configured such that the region of the multi-core cable accommodated by the current transformer coil is oriented in an axial direction. The current transformer coil may extend in the axial direction on both sides of the one or more magnetic field sensors. The magnetic core of the current transformer coil may extend in the axial direction on both sides of the one or more magnetic field sensors.

[0091] The length of the current transformer coil extending in the axial direction may be greater than or equal to half the inner diameter of the current transformer coil. The length of the current transformer coil extending in the axial direction may be greater than or equal to the inner diameter of the current transformer coil. The length of the current transformer coil extending in the axial direction may be greater than or equal to twice the inner diameter of the current transformer coil. One or more magnetic field sensors may be disposed at a midpoint along the axial length of the current transformer coil.

[0092] At least one of the one or more magnetic field sensors may include or take the form of a sensor coil. Each sensor coil may be wound around a sensing pole piece. Each sensor coil may be wound around a portion or protrusion of the magnetic core of a current transformer coil. Two or more of the magnetic field sensors may include or take the form of corresponding sensor coils. All of the one or more magnetic field sensors may include or take the form of corresponding sensor coils. The sensor coils may be prefabricated and inserted into a multi-core cable, or wound in situ around a multi-core cable, or attached in situ around a multi-core cable, or placed in situ around a multi-core cable. The sensor coils may be mounted radially, tangentially, or along other axes relative to the longitudinal axis of the device (along which the multi-core cable is configured to be received). A mix of sensor coil orientations may be used, such as, but not limited to, radial and tangential within a single device. The sensor coils may be wound around a core of magnetically conductive material. The sensor coils may be so-called "air-core" coils, which do not include a core of magnetically conductive material. "Air-core" sensor coils may be wound around a support structure formed of a non-magnetic conductive material (e.g., plastic, glass, etc.). The sensor coils may be wound around a bobbin. The skeleton can be shared with the current transformer coil.

[0093] At least one of the one or more magnetic field sensors may include a solid-state magnetic field sensor device or take the form of a solid-state magnetic field sensor device. Each solid-state magnetic field sensor can sense magnetic fields along one axis, two axes, three axes, or more axes. The solid-state magnetic field sensor device may include a semiconductor magnetic sensor, a magnetoresistive sensor, a giant magnetoresistive sensor, or an anisotropic magnetoresistive sensor or take the form of a semiconductor magnetic sensor, a magnetoresistive sensor, a giant magnetoresistive sensor, or an anisotropic magnetoresistive sensor. The solid-state magnetic field sensor device may include a giant magnetoimpedance (GMI) sensor or take the form of a giant magnetoimpedance (GMI) sensor. The solid-state magnetic field sensor device may include a superconducting quantum interference detector (SQUID) or take the form of a superconducting quantum interference detector (SQUID). The solid-state magnetic field sensor device may include a magneto-optical sensor or take the form of a magneto-optical sensor. The solid-state magnetic field sensor device may include a fluxgate or take the form of a fluxgate. The solid-state magnetic field sensor device may include a chip or an integrated circuit or take the form of a chip or an integrated circuit. The solid-state magnetic field sensor device may include a Hall effect sensor or take the form of a Hall effect sensor.

[0094] Two or more of the magnetic field sensors may include or take the form of corresponding solid-state magnetic field sensing devices (of any type described herein). All of the one or more magnetic field sensors may include or take the form of corresponding solid-state magnetic field sensing devices (of any type described herein).

[0095] The device may include a structure that supports the current transformer coil and one or more magnetic field sensors. The structure may include or take the form of a skeleton around which the current transformer coil and / or one or more sensor coils are wound. When the device includes one or more magnets, the structure may also support the one or more magnets.

[0096] The structure may comprise a channel configured to accommodate a multi-core cable. In other words, the structure may take the form of a channel-defining structure.

[0097] The cross section of the channel may have the shape of a circle or an arc of a circle.

[0098] The cross section of the channel may have a shape that is non-circular and does not correspond to an arc of a circle.

[0099] The channel can be open. An open channel can accommodate a multi-core cable. The structure can define the channel as being self-reflective in cross-section. The structure can define the channel as being C-shaped or U-shaped in cross-section. The cross-section can be taken in a plane perpendicular to the axial direction of the channel. When a multi-core cable is connected to the device, the multi-core cable will be accommodated along the axial direction of the channel.

[0100] The passageway can be defined by first and second components of a structure configured to enclose the multi-core cable when received within the passageway. The first and second components can be urged together by a spring. The first and second components of the structure can provide a clamp. Once the multi-core cable is enclosed, the first and second components can be secured together by a latch, a lock, or a similar fastening device.

[0101] The structure may include two or more components configured to enclose or wrap around a multi-core cable to define a passageway. The two or more components may be urged together by a spring. Once the multi-core cable is enclosed, the two or more components may be secured together by one or more latches, locks, or similar fastening devices. The structure may be segmented, wherein the two or more components may be joined together by a flexible material or joined together using hinges aligned with an axial direction.

[0102] The device may comprise two or more magnetic field sensors.

[0103] The device may further include one or more magnets. The device may be configured such that when the device is coupled to the multi-core cable, a magnetic field corresponding to the one or more magnets is applied to a region of the multi-core cable passing through the current transformer coil.

[0104] In this manner, the apparatus according to the fourth aspect can be applied to a steel wire armored multi-core cable in the same manner as the apparatus according to the first aspect, and the same effects and advantages are obtained.

[0105] The one or more magnetic field sensors may include a first set of first magnetic field sensors and a second set of second magnetic field sensors.The first set of magnetic field sensors and the second set of magnetic field sensors may be arranged spaced apart along an axial direction of the multi-core cable (when coupled to the device).

[0106] The sensor may include the apparatus according to the fourth aspect. The sensor may also include a controller connected to the one or more magnetic field sensors. The controller may be configured to calculate one or more derived quantities based on the magnetic field components measured by the magnetic field sensors for some or all cores of the multi-core cable.

[0107] The controller may be further configured to calculate a net current through the multi-core cable based on measurements using the current transformer coils.

[0108] One or more derived quantities may include (but are not limited to): the current in each core (the core current may be an AC differential current or a DC differential current between the cores), the phase between the cores, harmonics, the time domain current in one or more independent cores, the number and / or geometry of the cores in a multi-core cable; or the cores / conductors in a magnetic conduit or pipe or cable tray, etc.

[0109] The sensor may comprise an apparatus according to the fourth aspect. The apparatus may also be configured to generate one or more signals based on the output of one or more magnetic field sensors. Each signal may be proportional to the differential current between the cores of a multi-core cable (when coupled to the apparatus). Alternatively, each signal may be proportional to the individual core currents of the individual cores of the multi-core cable. The sensor may also comprise a link corresponding to each signal for connection to a control and / or measurement system. The apparatus comprising the sensor may also be configured to generate a net current signal based on the output from a current transformer coil.

[0110] The sensor may also include one or more voltage sensors. The one or more derived quantities may include one or more power values. The sensor may be configured to correctly assign phases to cores of the multi-core cable using the one or more voltage sensors.

[0111] Using a current transformer coil, the sensor can be powered by the net current running through the multi-core cable.

[0112] The system may include the aforementioned sensor coupled to provide input to a measurement device. The measurement device may be a power quality analyzer. The measurement device may be a power quality recorder. The measurement device may be an energy meter. The measurement device may be an electricity meter.

[0113] According to a fifth aspect of the present invention, a method is provided, comprising coupling the apparatus according to the fourth aspect (or a sensor / system incorporating the apparatus) to a multi-core cable such that a region of the multi-core cable passes through a current transformer coil. The method further comprises measuring, using one or more magnetic field sensors, a component of a magnetic field originating from the region of the multi-core cable.

[0114] The method according to the fifth aspect may include features corresponding to any features of the apparatus according to the first, third and / or fourth aspects. Definitions applicable to the apparatus according to the first, third and / or fourth aspects (or their features) may also apply to the method according to the fifth aspect (or its features).

[0115] The method may further include measuring a net current passing through the multi-core cable using a current transformer coil.

[0116] According to a sixth aspect of the present invention, a device for coupling to a multi-core cable is provided, the device comprising a Rogowski coil and one or more magnetic field sensors. The device is configured such that, when coupled to the multi-core cable, a region of the multi-core cable passes through the Rogowski coil, or the Rogowski coil is wrapped around the region of the multi-core cable. At least one of the magnetic field sensors is disposed proximate to the Rogowski coil and oriented to detect a magnetic field component originating from the region of the multi-core cable.

[0117] At least one of the one or more magnetic field sensors can be positioned, or at least partially positioned, within the inner diameter of the Rogowski coil. In other words, during use, the magnetic field sensor can be positioned between the Rogowski coil and the multi-core cable. At least one of the one or more magnetic field sensors can be positioned outside the Rogowski coil. In other words, the magnetic field sensor can be separated from the multi-core cable by the Rogowski coil. At least one of the one or more magnetic field sensors can be positioned adjacent to the Rogowski coil in the axial direction.

[0118] The apparatus according to the sixth aspect may include features corresponding to any features of the apparatus according to the first, third and / or fourth aspects. Definitions applicable to the apparatus according to the first, third and / or fourth aspects (or their features) may also apply to the apparatus according to the sixth aspect (or their features). BRIEF DESCRIPTION OF THE DRAWINGS

[0119] Certain embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0120] Figure 1 is a cross-sectional 3 / 4 view of a sensor assembly including two magnet arrays, a semiconductor type magnetic sensor array, a housing channel defining structure and associated electronics, connections and outputs, with a length of armored multi-core cable shown for illustrative purposes.

[0121] Figure 2 is a cross-sectional ¾ view of a sensor assembly including two magnets, a semiconductor-type magnetic sensor array, and a housing channel-defining structure, with a section of armored multi-core cable shown for illustrative purposes.

[0122] Figure 3 is a cross-sectional view of a sensor assembly, which includes a housing, two magnet arrays, a semiconductor-type magnetic sensor array mounted on a soft magnetic mounting ring, and a housing channel defining structure.

[0123] Figure 4 is a cross-sectional ¾ view of a sensor assembly including a housing, two magnet arrays, a tangential coil type magnetic sensor array, a housing channel defining structure, and associated electronics and outputs.

[0124] Figure 5is a cross-sectional ¾ view of a sensor array comprising a soft magnetic ring, multiple axial sensor coils and their associated outputs.

[0125] Figure 6 is an isometric view of a sensor assembly specifically configured as a polyphase electricity meter, the polyphase electricity meter including the sensor assembly, an associated electronics housing with a display and service port, a load under test, phase connections from the electronics housing to the load under test, and a length of armored multi-conductor cable (for illustrative purposes).

[0126] Figure 7 is an isometric view of a sensor assembly specifically configured as a power quality analyzer including the sensor assembly, a power meter, phase connections to the device under test, and three Rogowski coils grouped to illustrate an alternative approach - the armored multi-core cable under test is not shown.

[0127] Figure 8A and Figure 8B The diagrams are respectively an isometric axial cross-sectional view and an isometric sectional view of a sensor assembly comprising two magnet arrays, a radial coil type magnetic sensor array mounted on a soft magnetic mounting ring, and a housing channel defining structure.

[0128] Figure 9A and Figure 9B The diagrams are respectively an isometric axial section view and an isometric cross-sectional view of a sensor assembly comprising two magnet arrays, radial and tangential coil type magnetic sensor arrays mounted on a soft magnetic mounting ring, and a housing channel defining structure.

[0129] Figure 10A and Figure 10B They are an isometric axial cross-sectional view and an isometric cross-sectional view of a sensor assembly, which includes two magnet arrays, a radial coil type magnetic sensor array mounted on a soft magnetic mounting ring, and a shell channel defining structure with two additional radial coils on both sides of the soft magnetic mounting ring.

[0130] Figure 11 is an isometric cross-sectional view of a sensor assembly including two magnet arrays, two radial coil type magnetic sensor arrays mounted on respective soft magnetic mounting rings, and a housing channel defining structure.

[0131] Figure 12A 、 Figure 12B and Figure 12C An isometric axial cross-sectional view, a side view, and an isometric cross-sectional view, respectively, of an open sensor assembly comprising two magnet arrays, a radial coil type magnetic sensor array mounted on a soft magnetic mounting ring, and a mounting channel defining structure and housing, with a length of armored multi-core cable set shown resting on a flat surface for illustrative purposes.

[0132] Figure 13A 、 Figure 13B and Figure 13C An isometric cutaway view (open), an isometric view (closed), and an isometric cross-sectional view (open) of a 'spring clamp' type sensor assembly comprising two magnet arrays, a radial coil type magnetic sensor array mounted on a soft magnetic mounting ring, a mounting channel defining structure, and a housing assembly with a spring, with a length of armored multi-core cable shown for illustrative purposes.

[0133] Figure 14B 、 Figure 14B and Figure 14C Isometric cross-section, plan section, and isometric views, respectively, of a sensor assembly comprising two magnets, a radial sensor coil, a soft magnetic backing, and a wired connection, with a length of armored multi-core cable shown for illustrative purposes.

[0134] Figure 15A 、 Figure 15B 、 Figure 15C 、 Figure 15D and Figure 15E An isometric view (open), an isometric view (closed), a side view (closed), an isometric axial cross-sectional view (closed), and an isometric cross-sectional view of a multi-unit sensor assembly, each individual unit of which includes two magnets, a radial sensor coil, a soft magnetic backing sheet, a hinge element, and a movement limiting element, with a length of armored multi-core cable shown for illustrative purposes.

[0135] Figure 16A 、 Figure 16B and Figure 16C The diagrams are an isometric view, an isometric cross-sectional view, and an isometric axial cross-sectional view of a sensor assembly, respectively. The sensor assembly includes a soft magnetic cylindrical sensor body, an electromagnetic coil, and a radial coil type magnetic sensor array mounted on a soft magnetic mounting ring.

[0136] Figure 17A 、 Figure 17B and Figure 17C An isometric view, an axial cross-sectional view, and a cross-sectional view, respectively, of a sensor assembly comprising an electromagnetic coil, a soft magnetic armature, a hinged and / or clamp-type housing, and a radial coil type magnetic sensor array, with a length of armored multi-core cable shown for illustrative purposes.

[0137] Figure 18A 、 Figure 18B and Figure 18CIsometric cross-sectional, plan sectional, and isometric views, respectively, of a sensor assembly comprising a magnet, radial sensor coil, soft magnetic backing, and wired connections, showing, for illustrative purposes, a length of armored multi-core cable set resting against a flat surface.

[0138] Figure 19 Shows the use Figure 8A and Figure 8B The sensor assembly shown experimentally measures the current in a three-conductor multicore cable compared to measurements made by isolating one of the conductors and using a conventional current clamp probe.

[0139] Figure 20 shows the results for a series of applied currents through the Figure 19 The errors obtained from the analysis of the data are shown.

[0140] Figure 21 and Figure 22 shows the current signal for harmonic components up to the 11th harmonic Figure 19 comparable data.

[0141] Figure 21 and Figure 22 The current signal including the superposition of the fundamental frequency sine wave and its 31st harmonic is shown using Figure 19 Experimentally determined currents obtained with the same setup.

[0142] Figure 24A and Figure 24B They are respectively an isometric axial cross-sectional view and an isometric cross-sectional view of the sensor assembly, which is Figure 9A and Figure 9B A modification of the sensor assembly shown in .

[0143] Figure 25A and Figure 25B The sensor assembly includes two channel-defining structures that together form a ring. An array of solid-state magnetic field sensors is arranged around the inner surface of the ring.

[0144] Figure 26A 、 Figure 26B 、 Figure 26C and Figure 26D Axial cross-sectional, axial side, isometric, and plan views, respectively, of a sensor assembly comprising a set of radial sensor coils disposed within a channel-defining structure in the form of two semi-cylinders of magnetically conductive material. Magnets / magnet arrays are included at both ends, and end caps of magnetically conductive material help complete the magnetic circuit outside the sensing volume.

[0145] Figure 27A 、 Figure 27B and Figure 27C Shown are the 26A to 26D Plan view, axial side view and isometric view of the skeleton device in the sensor assembly.

[0146] Figure 28A 、 Figure 28B and Figure 28C Shown are the 26A to 26D Plan, axial side, and isometric views of a magnet in a sensor assembly.

[0147] Figure 29A 、 Figure 29B and Figure 29C Shown are the 26A to 26D Plan view, axial side view and isometric view of the outer core in the sensor assembly.

[0148] Figure 30A 、 Figure 30B and Figure 30C Shown are the 26A to 26D Plan view, axial side view and isometric view of the end cap in the sensor assembly.

[0149] Figure 31A and Figure 31B An isometric axial cross-sectional view and an axial cross-sectional view are shown, respectively, of a sensor assembly comprising two magnet arrays and a tangential coil-type magnetic sensor array mounted on a channel-defining structure.

[0150] Figure 32A 、 Figure 32B 、 Figure 32C and Figure 32D An isometric view of a closed sensor array, an isometric view of an open sensor array, a plan view of a closed sensor array, and a plan view of a closed sensor array are shown, respectively. The sensor array includes an array of tangential coil-type magnetic sensors mounted on a pair of channel-defining structures that form an oval shape in cross-section.

[0151] Figure 33A 、 Figure 33B 、 Figure 33C and Figure 32D An isometric view of a closed sensor array, an isometric view of an open sensor array, a plan view of a closed sensor array, and a plan view of a closed sensor array are shown, respectively. The sensor array includes a solid-state magnetic sensor array mounted on a pair of channel-defining structures that form an oval shape in cross-section.

[0152] Figure 34A 、 Figure 34B 、 Figure 34C 、 Figure 34D and Figure 34EThe sensor assembly is shown in an isometric view, an isometric axial cross-section, an axial cross-section, a plan view, and a plan cross-section, respectively. The sensor assembly includes two magnet arrays and an array of radial coil-type magnetic sensors supported within a magnetically conductive core of a current transformer. The radial coil-type magnetic sensors are disposed around protrusions of the current transformer's magnetic core.

[0153] Figure 35A and Figure 35B The isometric axial section and the planar section of the sensor assembly are shown respectively, and the sensor assembly includes two magnet arrays and a radial coil type magnetic sensor array supported in a magnetically conductive core of a current transformer. The radial coil type magnetic sensor is an air core.

[0154] Figure 36A and Figure 36B An isometric view of a flat skeleton assembly and an isometric view of the same skeleton assembly rearranged into a curved configuration are shown, respectively. Figure 36C An isometric view of a semi-cylindrical core segment for threading through a bobbin assembly in a bent configuration is shown.

[0155] Figure 37A and Figure 37B Shown are plan and isometric views, respectively, of a sensor assembly having a solid-state magnetic sensor array disposed within a transformer coil wound around a toroidal core of magnetically permeable material.

[0156] Figure 38A and Figure 38B Shown are plan and isometric views, respectively, of a sensor assembly having a solid-state magnetic sensor array disposed within windings of a transformer coil wound around a toroidal core of magnetically permeable material.

[0157] Figure 39A 、 Figure 39B 、 Figure 39C and Figure 39D An isometric view of a closed sensor array, an isometric view of an open sensor array, a plan view of a closed sensor array, and a plan view of a closed sensor array are shown, respectively. The sensor array comprises a solid-state magnetic sensor array mounted on a pair of channel-defining structures that form an oval shape in cross-section. The channel-defining structures are formed of a magnetically conductive material and serve as the magnetic core of a current transformer coil.

[0158] Figure 40A and Figure 40B An isometric view and an axial side view are shown, respectively, of a sensor array housing a multi-core cable. The sensor array includes a Rogowski coil adjacent to a radial coil type magnetic sensor array. DETAILED DESCRIPTION

[0159] Hereinafter, the same components are denoted by the same reference numerals.

[0160] Figure 1 A first sensor assembly 1 is shown comprising a soft magnetic housing 'channel defining structure' 1 made of laminated steel, sintered or bonded metal powder or any other suitable material, which partially or fully surrounds an armoured multi-core cable 6 under test.

[0161] The first sensor assembly 1 is a device for connecting to a multi-core steel wire armored cable, but can also be used with unarmored multi-core cables. The first sensor assembly 1 is formed by one, two or more soft magnetic 'channel defining structure' sections of the housing, which may be hinged downwardly along an axis parallel to the longitudinal axis of the first sensor assembly 1 to allow the sensor to be opened and closed around the multi-core steel wire armored cable 6. The armored multi-core cable 6 under test or the armored multi-conductor cable under test consists of three-phase AC current-carrying conductors 8, 9 and 10, which are armored by a 'cage' of multiple metallic non-current-carrying soft magnetic conductors 7, which are built into the outer section of the multi-core cable 6. The first sensor assembly 1 is closed around the multi-core cable 6, partially or completely enveloping the multi-core cable 6 under test. Each end of the channel defining structure 1 has one or more magnets 2 and 3 (or magnet arrays). At one end, the magnet 2 is polarized to north pole, with all north poles pointing inward from the array and toward the multi-core cable 6 under test. At the end, all magnets 3 (eg forming a magnetic array) are polarized to the south pole, and all poles are also directed toward the multi-core cable 6 under test. The magnets 2 and 3 are concentric with the multi-core cable 6 under test and generate a magnetic field from north to south along the multi-core cable 6 under test (see also Figure 3 , label 107). This in turn saturates the area of ​​the steel armor 7 section of the multi-core cable 6 where the first sensor assembly 1 is located. The magnetic field can also be generated partially or completely by an electromagnet coil installed together with the permanent magnets 2, 3 or instead of the permanent magnets 2, 3.

[0162] The magnetic field sensor array 4 is installed in the channel of the channel defining structure 1, between the two magnetic arrays 2 and 3. The magnetic field sensor array 4 is composed of a plurality of magnetic field sensors 5 aligned on the same axis. The magnetic field sensors 5 all point inward and are concentric with the armored multi-core cable 6 to be measured, forming a loop of magnetic field sensors 5 around the armored multi-core cable 6 to be measured. The first sensor assembly I uses a solid-state sensor or a semiconductor sensor (for example, a Hall sensor or a giant magnetoresistive sensor) that is mounted on a flexible PCB or flexible circuit board in close contact with the housing 1 (or "channel defining structure"). The magnetic field sensor 5 is positioned against, adjacent to, or in close proximity to the soft magnetic housing 1. The position of the magnetic field sensor 5 enables the magnetic field sensor 5 to measure the magnetic field generated by the current in the cores 8, 9, 10 of the multi-core cable 6 in the cable area saturated by the magnets 2, 3.

[0163] The signals from the magnetic field sensor 5 are processed by a processor (or controller) 12, which can be integrated with the first sensor assembly 1 or separately wired 11 to the first sensor assembly 1. The processor takes the form of an electronics housing that houses the controller 12, which is electrically connected to the first sensor assembly 1. The controller 12, processing the data, can generate three different current signal outputs, one for each of the three discrete phases 13, 14, and 15 in the multi-core cable 6 being measured. The device in the form of the first sensor assembly 1 can be used with two-core, three-core, four-core, five-core, six-core, or more cables. The number of outputs 13, 14, and 15 will be adjusted accordingly.

[0164] The electronics unit 12 (or "controller") may also include one or more connectors 16 in the form of USB or similar for power, data, updates, and other utilities.

[0165] The first sensor assembly I can also be used with non-steel wire multi-core cables (e.g., cables with a copper wire "armor layer" that can also serve as a neutral or ground wire), or with cables without any "armor layer" (i.e., just a conductive core within a plastic sheath).

[0166] Figure 2 A second sensor assembly II is shown, which is similar in design and operation to that described with respect to FIG. Figure 1 The first sensor assembly I is similarly described. The second sensor assembly II is similarly formed from one or two or more soft-magnetic "channel-defining structure" segments 21 with a sensor array 25, wherein one or more magnetic field sensors 24 surround the armor strands 27 of a multi-core cable 26 having cores 28a, 28b, and 28c under test. In this case, each end of the channel-defining structure 21 has an axially magnetized ring magnet or segment of a ring magnet 20 and 23, rather than magnet arrays 2 and 3. Magnets 20 and 23 are positioned at opposite ends of the channel-defining structure 21. Magnets 20 and 23 are oriented in the same direction, with the north poles oriented in the same direction along the axis of the multi-core cable 26 under test. Therefore, the two magnets 20 and 23 in the second sensor assembly II, facing each other sideways, have opposite magnetic poles. These two magnets 20 and 23 generate a north-to-south magnetic field 22, which in turn saturates the region of the steel armor 27 of the armored multi-core cable 26 under test where the second sensor assembly II is located.

[0167] Figure 3 A cross-sectional view of a third sensor assembly III is shown, which is similar to the third sensor assembly III described with reference to FIG. Figure 1The first sensor assembly I is described, including channel-defining structures 102 and 103 that house magnets 105, 110, 109 and 104, wherein the magnetic poles are oriented as north poles 105, 110 (radially outward) and south poles 104, 109 (radially outward) to generate magnetic fields 107, 108.

[0168] The third sensor assembly III is different in that the semiconductor or solid-state magnetic sensors 106 and 111 and other possible sensors (such as Figure 3 104 ) are mounted on a ring 101 made of laminated steel or some other soft magnetic material that is stacked / wound axially or radially. Alternatively, the ring 101 can be made of ferrite, pressed, sintered, or composite magnetic material. The ring 101 can be wide enough to accommodate the magnetic sensors 106, 111 and have separate components at each end of the channel-defining structure 102 to accommodate the magnets or arrays 105, 110, 109, and 104, or the ring 101 can be wide enough to form the entire channel, eliminating the need for channel-defining structures 102 and 103.

[0169] Figure 4 A fourth sensor assembly IV is shown, which is similar to that described with respect to Figure 1 The first sensor assembly 1 described comprises a channel defining structure 1 housing a magnet (or magnet array) 49a, 49b, wherein the magnetic poles are oriented as north and south poles at opposite ends to generate a magnetic field in the armored multi-core cable 6 under test. Figure 1 As shown in detail, the processing of the signals from the magnetic sensors 41, 42, 43, 44, 45, 46, 47, 48 is performed by a controller 50, which is integrated with the fourth sensor assembly IV or is separately wired to the fourth sensor assembly IV. The controller 50 can provide three different outputs 51, 52 and 53, one output for the multi-core cable 6 under test (for clarity, Figure 4 Each of the wire cores 8, 9, 10 in the controller 50 (not shown). The controller 50 may include one or more connectors in the form of USB or similar 54 for power, data, updates and other utilities.

[0170] The fourth sensor assembly IV differs from the first sensor assembly I in that a plurality of magnetic sensors in the form of sensor coils 41, 42, 43, 44, 45, 46, 47, and 48 are used, which are mounted in a circular form tangentially around the multi-core cable 6 under test. The sensor coils 41, 42, 43, 44, 45, 46, 47, and 48 are mounted between magnets (or magnet arrays) 49a and 49b. The sensor coils 41, 42, 43, 44, 45, 46, 47, and 48 can be replaced by solid-state magnetic field sensors in sensors on flexible circuit boards / PCB materials.

[0171] Figure 5 A fifth sensor assembly V is shown, which is connected to Figure 3 The third sensor assembly III shown is similar, but uses a plurality of sensor coils 62 instead of the semiconductor type sensor 111 on the flexible circuit board / PCB material 112, and the plurality of sensor coils 62 are radially around the armored multi-core cable 6 ( Figure 5 ) is mounted and positioned on a magnet array (e.g., Figure 3 104, 105, 109, 110 shown in the figure). The sensor coil 62 is read using a connection 63, which can be a twisted pair as shown, or a coaxial cable (or similar) to improve the suppression of interfering signals. The sensor coil 62 can include pole pieces 61 made of soft magnetic material or air core, which can be mounted on a support such as a plastic skeleton. The sensor coil 62 can be mounted on a soft magnetic ring 60, which is composed of radially stacked / wound laminated steel or ferrite, pressed, sintered or composite magnetic material. Alternatively, the fifth sensor array V can be directly mounted on the channel defining structure of the sensor assembly (not shown, but similar to Figure 1 ) in the channel formed.

[0172] Figure 6 A sixth sensor assembly VI is shown in the form of a power meter. Any version of the first to fifth sensor assemblies I to V described may be used, but is specifically configured as a multiphase electricity meter with the particular advantage of non-intrusive assembly. This can be achieved by combining the magnetic sensor assembly data obtained from the sensor assemblies 72 and 73 (arranged in first and second halves 72, 73, which are fixed around the multi-core cable 79 under test, as shown) with the additional monitoring of the phase voltages u, v and w ( Figure 6 This will include a magnet and sensor assembly 72, 73 mounted on the armored multi-core cable 79 to be measured, and a connection 75 to the meter 74. The sensor assembly 72, 73 can be connected to the previous figure ( Figures 1 to 5) are similar (or identical) to any of the first through fifth sensor assemblies I through V shown and described in connection with FIG. 1 , and variations using alternative sensors, magnets, and magnetic materials are also possible. The meter 74 includes a display 82 for meter readings and other relevant information. Flying leads 81 enable voltage input from phases u, v, and w to the meter 74. The flying leads 81 include three conductors 80, each connected to an exposed length 76 of a corresponding core 77 leading to the housing 70. The armor strands 78 are stripped to allow connection of the flying leads 81. The voltage inputs from phases u, v, and w can help correctly assign the current measured from the armored multi-core cable 79 being measured to the correct core of the cable 79. The meter 74 may include one or more connectors in the form of USB or similar 83 for power, data, updates, and other utilities.

[0173] Figure 7 A seventh sensor assembly VII in the form of a power quality analyzer is shown. The sensor assembly magnetic sensor 87 is to be mounted to the armored multi-core cable 6 ( Figure 7 The three flying leads 88, 89 and 90 are connected to the load connection point (e.g., Figure 6 The exposed length 76 shown is connected to each phase to input the voltage of each phase (u, v, w) into the power quality analyzer VII.

[0174] This solution can be lower in cost and simpler to assemble than using a set of three Rogowski coils 84, 85, or 86 (shown for illustration only and not required if sensor 87 is used). Using Rogowski coils 84, 85, 86 would require separating and spacing the three phases (e.g., cores 8, 9, 10) of the armored multi-core cable 6 under test from the armor layer (e.g., conductor 7) to leave enough space for attaching each Rogowski coil 84, 85, 86, thereby increasing component cost and installation complexity - these disadvantages can be avoided by using sensor assembly 87.

[0175] In a modified embodiment of the seventh sensor assembly VII (not shown), the output of the magnetic sensor assembly 87 can be divided into three outputs (not shown), which simulate the corresponding outputs of three current transformers or three Rogowski coils (similar to 84, 85, and 86) and are applied to the respective cores 8, 9, and 10 (when divided from a multi-core cable). In this way, the three outputs (not shown) of the magnetic sensor assembly 87 can be connected to existing power meters or power quality analyzers whose design input signals are three Rogowski coils (similar to 84, 85, and 86) or current transformers.

[0176] Figure 8A and Figure 8B The eighth sensor assembly VIII is shown. The eighth sensor assembly VIII is Figure 1 The sensor assembly I and Figure 5 The sensor assembly V shown is similar, but shows in greater detail a plurality of radial field coils 115 (magnetic sensors) mounted to a ring 114 made of laminated steel stacked / wound axially or radially, rather than semiconductor magnetic sensors mounted on a PCB / flex circuit board between the magnet arrays 117a and 117b. Alternatively, the ring 114 can be made of ferrite, pressed, sintered, or composite magnetic material. The ring 114 can extend into the center of each radial field coil 115 to form a pole piece 116, or the ring 114 can be flush with the rear edge of the coil 115 (i.e., tubular), in other words, the coil 115 can have an air core with the ring of magnetic material 114 located behind the air core. Alternatively, the radial field coils 115 can be mounted in the channel defining structure 113 without the need for an additional magnetic material mounting ring.

[0177] Figure 9A and Figure 9B The ninth sensor assembly IX is shown. The ninth sensor assembly IX has a plurality of radial sensor coils 121 and a plurality of tangential sensor coils 122, which are positioned in a ring-shaped manner on the multi-core cable 6 ( Figure 9A and Figure 9B 120b. The sensor coils 121, 122 and the magnet arrays 120a, 120b are supported by the channel defining structure 118. The sensor coils may be comprised of tangential coils 122 and radial coils 121 in a row, may be comprised of alternating tangential coils 122 and radial coils 121, or may be comprised of tangential coils 122 and radial coils 121 in any other pattern (e.g., two tangential coils, one radial coil, vice versa, etc.). The coils may have air cores and may be integrated into a ring of magnetic material 119 (e.g., Figure 9A shown) (ring 119 having radially extending protrusions to provide pole pieces / core), with separate pole pieces (not shown) or a combination of hollow core (not shown) and integrated / separate pole pieces (not shown)).

[0178] Figure 10A and Figure 10B The tenth sensor assembly X is shown. The tenth sensor assembly X is composed of magnets 128a and 128b (or arrays), sensor coils 124, and soft magnetic material 127. It is similar to some of the configurations described in the previous assemblies, but the tenth sensor assembly X adds one or two additional magnetic sensors 125, 126 (or arrays) on both sides of the main sensor array 124. These additional sensors 125 and / or 126 are used to detect the multi-core cable 6 ( Figure 10A and 10B The amount of physical twist (not shown) is determined by measuring the cable's sheathing. If the cable under test lacks a soft magnetic sheath or armor, magnets 128a and 128b are not required. Soft magnetic material ring 127 is sandwiched axially by channel-defining structure 123, and magnets 128a, 128b and additional magnetic sensors 125, 126 are supported by channel-defining structure 123. Magnetic sensor 124 is supported by (or integrally formed with) soft magnetic material ring 127.

[0179] Figure 11 An eleventh sensor assembly XI is shown. The eleventh sensor assembly XI is comprised of any of the magnets 131a, 131b and material configurations described herein, but has an auxiliary sensor array (or second sensor array) 130 in addition to the primary sensor array (or first sensor array) 129. Many features may be similar to sensor assembly VIII, but in this case with the additional looped sensors 130. Two axially spaced loops of magnetic field sensors 129 and 130 are used to detect the amount of physical twist in the three-phase conductors (e.g., cores 8, 9, 10) of the armored multi-core cable 6 or any multi-core cable (including unarmored multi-core cables) under test.

[0180] Figure 12A 、 Figure 12B and Figure 12C A twelfth sensor assembly XII is shown. The twelfth sensor assembly XII can be composed of any of the magnets 132a, 132b, magnetic sensors 133, and soft magnetic material 137 configurations described herein, but the measurement (magnetic sensor 133) and magnetic 132a, 132b arrays form an open shape or a U-shape, or a similar shape that is self-reflecting and does not form a closed loop. When the armored or unarmored multi-core cable 135 to be measured is mounted against or near the plane 134, the open shape of the twelfth sensor assembly XII allows the conductor (e.g., the multi-core cable 6) to be inserted and measured. This can take the form of a handheld device 136 for rapid deployment applications, or it can take the form of a permanent or semi-permanent device.

[0181] Figure 13A 、 Figure 13B and Figure 13CA thirteenth sensor assembly XIII is shown. The thirteenth sensor assembly XIII is comprised of any of the magnet 138a, 138b (or array), magnetic sensor 139, and soft magnetic material (channel-defining structure) 140 configurations described herein, but in the form of a clamp on the device for quick attachment and easy movement from one armored or unarmored multi-core cable 141 under test to another. The thirteenth sensor assembly XIII is comprised of two channel-defining structure sections 142 and 143 having a spring clamp mounted in a dual-handle 'spring clamp' type housing 145 and 146, wherein one or more springs 144 are compression springs, torsion springs, or any other suitable type of spring, and are positioned to hold the sensor array (i.e., channel-defining structure sections 142 and 143) closed when not opened by pinching the handles 145, 146. One or more springs 144 may be supplemented or replaced with, or used in conjunction with, latches (not shown) at the open ends of the sensor (ie, channel defining structural sections 142 and 143) to ensure that the thirteenth sensor assembly XIII is fully closed when in use.

[0182] Figure 14A 、 Figure 14B and Figure 14C The fourteenth sensor assembly XIV is shown. The fourteenth sensor assembly XIV uses Figure 1 The same technology detailed in the first sensor assembly I is shown, but consisting of a pair of magnets 150 and 151 (or, alternatively, a magnet and a feature made of a soft material) and one or more magnetic sensors 152 mounted on a soft magnetic backing member 147 (or "structure"). A fourteenth sensor assembly XIV can be composed of any of the magnet / sensor / material configurations described herein, but in a simplified single sensor / coil / magnet form as a lower cost and easier to assemble variant, or can be temporarily fixed or held against the armored multi-core cable 149 being tested.

[0183] The fourteenth sensor assembly XIV may be connected via wires 148 to sensing, monitoring, data logging or other equipment and / or may include some or all of the data processing electronics, either built-in or remotely wired / wireless.

[0184] Figure 15A 、 Figure 15B 、 Figure 15C 、 Figure 15D and Figure 15E A fifteenth sensor assembly XV is shown. The fifteenth sensor array XV is made of individual simplified sensors 153, as described 14A to 14CThe fourteenth sensor assembly XIV shown or similar thereto, but with individual simplified sensors 153 (e.g., the fourteenth sensor assembly XIV) linked together using integrated or separate hinges, clamps, or other flexible coupling elements 155 to form a flexible assembly to provide closer proximity by providing greater coverage around the circumference of the armored multi-core cable 154 under test. Figure 1 The monitoring performance of the first sensor assembly 1 and its variants are shown. Each simplified sensor 153 includes a magnet 157, 158 and a magnetic sensor 159. The fifteenth sensor assembly XV (or array) can be spring-loaded for quick attachment and can have a stop to naturally spring closed to form a circle 156 to minimize off-axis inaccuracies.

[0185] Multiple independent sensor modules 153 (simplified sensors) can be added or removed as needed to optimize the sensor's inner diameter (ID).

[0186] Similar to the fourteenth sensor assembly XIV described in detail in FIG. 14 , each sensor can be connected via a wire ( Figure 14B , 148) connected to sensing, monitoring, data logging or other equipment, and / or may include some or all of the built-in or remote wired / wireless data processing electronics. Alternatively, the individual sensor outputs may be centralized into a single electronics housing ( Figure 1 , 12) to process data from all sensors 153 in the fifteenth sensor array XV.

[0187] In a modification (not shown), the fifteenth sensor assembly XV (or array) may include a Figures 15A to 15E The six simplified sensors 153 shown may be more or fewer than the six simplified sensors 153. Furthermore, the modified fifteenth sensor assembly XV (or array) can be configured to utilize only an additional or fewer number of segments, and may utilize as many simplified sensors 153 as necessary to wind a given multi-core cable 154. In some embodiments of this modified fifteenth sensor assembly XV (or array), an operator can specify the number of simplified sensors 153 to be used, for example, by providing an input to a controller (not shown) or actuating a switch or similar element provided on each individual simplified sensor 153. Additionally or alternatively, the controller (not shown) can automatically determine the number of active simplified sensors 153, for example by analyzing signals received from each simplified sensor. Inactive (or redundant) simplified sensors 153 will continue to wind around / dangle detached from the cable 154 and can therefore be ignored. The relative angle of each simplified sensor 153 can be readily derived from the number of active sensors.

[0188] In another modification, the simplified sensors 153 can be connected / disconnected to each other. For example, mechanical and / or electrical connections can be made between the simplified sensors 153 using clamps, connectors, etc. This allows the operator to easily add or remove simplified sensors 153 to achieve the desired size. The number of connected simplified sensors 153 can be automatically detected. In a particularly simple example, by adding additional connectors to each simplified sensor 153 and connecting resistors in series with each connector, the total resistance can be used to automatically determine the number of simplified sensors 153 in use. The relative angle of each simplified sensor 153 can be easily derived from the number of active sensors.

[0189] Figure 16A 、 Figure 16B and Figure 16C The sixteenth sensor assembly XVI is shown. The sixteenth sensor assembly XVI is Figure 1 The sixteenth sensor assembly XVI is a one-piece sensor consisting of a cylindrical body 161 (channel defining structure) made of soft magnetic material and having electromagnetic coils wound around the outside of the magnetic poles 162 and a magnetic sensor array 163 formed in a ring shape. The magnetic sensors 163 can be radial coils (as shown), tangential coils, semiconductor type coils, or solid state type coils, and can be mounted on a separate soft magnetic ring (see Figure 3 , 101), can also be mounted directly on the cylindrical body 161, with or without separate magnetic poles, or extensions of the magnetic poles from the ring or cylindrical body 161. It is designed to be inserted as a single unit into the armored or unarmored multi-core cable 160 being tested. The electronics can be integrated with the sixteenth sensor assembly XVI or separated from the sixteenth sensor assembly XVI. If armored cables are to be evaluated, the sixteenth sensor assembly XVI can be supplemented with a magnet (not shown).

[0190] Figure 17A 、 Figure 17B and Figure 17C A seventeenth sensor assembly XVII is shown. Figure 1 、 Figure 2Similar to sensor assemblies I, II, and VIII detailed in FIG8 , a bias electromagnetic coil 165 is used to provide a magnetic field that saturates or substantially saturates the steel armor layer in the armored multi-core cable 170 under test. The magnetic field is caused to surround the armored multi-core cable under test by means of a soft magnetic armature 167, on which the electromagnetic coil 165 is axially mounted (or directly wound). The armature 167 extends toward and surrounds the armored multi-core cable 170 under test at its two poles. The armature 167 is housed in a hinged housing 168 and / or a clamp-on housing 169 on either side of the sensor array, thereby allowing it to be assembled around the armored multi-core cable 170 under test.

[0191] The magnetic sensor may be of any type described in the specification - an axial coil as shown or a tangential coil 166 or a semiconductor type coil, with or without magnetic material behind it, and with or without pole pieces.

[0192] Figure 18A 、 Figure 18B and Figure 18C An eighteenth sensor assembly XVIII is shown. The eighteenth sensor assembly XVIII is similar to the 14A to 14C Detailed description of the simplified sensor of the fourteenth sensor assembly XIV, but consisting of a single magnet or magnetic field source 174 and magnetic sensor 175. The eighteenth sensor assembly XVIII can be composed of any of the magnet / sensor / material configurations described herein; in this example, a permanent magnet and a sensor coil on a soft magnetic backing plate / support 173 (or "structure") are used. The eighteenth sensor assembly XVIII can be pressed against, fixed, or coupled to the armored or unarmored multi-core cable 171 being measured (e.g., when the multi-core cable 171 is armored with steel, it is fixed in place by the magnet or magnetic field source 174).

[0193] This lower cost variation (eighteenth sensor assembly XVIII) may be coupled via a wired connection 172 to connect to sensing, monitoring, data logging or other equipment, and / or may include some or all built-in or remote wired / wireless data processing electronics.

[0194] See also Figure 19 and Figure 20 The linearity of the sensor assembly described herein was evaluated. The eighth sensor assembly VIII was applied to a 30 mm diameter three-core steel wire armored multi-core cable. The inner diameter of the channel of the eighth sensor assembly VIII was 42 mm. Figure 19The current measured for each of the three cores (solid, dashed, and dot-dash lines) using an example of the eighth sensor assembly VIII is shown. The dashed line shows the current measured using a conventional current clamp applied directly to the second core at a point deviating from that of the example of the eighth sensor assembly VIII, which is separated from the multi-core cable and the steel wire armor. Despite the presence of the steel wire armor, very accurate consistency can be observed.

[0195] The current range of the eighth sensor assembly VIII used is from about 40 mA up to 500 A. The eighth sensor assembly VIII was tested from 25 mA to 80 A, and the measured % error is plotted on Figure 20 middle.

[0196] See also Figure 21 and Figure 22 , showing the Figure 20 Similar data is presented for the case of signals with higher harmonic components. Specifically, a square wave is applied to core 1, while a triangular wave is applied to cores 2 and 3. All waveforms include components up to the 11th harmonic. The solid, dashed, and dot-dash lines show the first, second, and third core currents measured using an example of the eighth sensor assembly VIII. Figure 21 In FIG, the dashed line shows the measurement results obtained using a conventional current clamp probe applied to the core 2 (when it is separated from the multi-core cable and the steel wire armor layer) at a position deviating from the example of the eighth sensor assembly VIII. Figure 22 Same as , except that a conventional current clamp probe is applied to Core 1 instead of Core 2. Figure 21 and Figure 22 In Figure 5, good agreement is obtained between the example of the eighth sensor assembly VIII and conventional measurements (which require physical separation of the multi-core cable assembly), even through the steel wire armor.

[0197] See also Figure 23 , showing the Figure 20 、 Figure 21 and Figure 22 Similar data is presented for the case of a three-phase current having a signal consisting of a fundamental sine wave with an amplitude of 20 A superimposed on a 31st harmonic with an amplitude of 2 A. In this case, the dashed line representing the conventional current clamp measurement is obtained from core 2. Even at the 31st harmonic, the example using the eighth sensor assembly VIII achieves good agreement with conventional measurement methods (which have the disadvantage of requiring physical separation of multi-core cables).

[0198] Figure 24A and Figure 24BA nineteenth sensor assembly XIX is shown. Nineteenth sensor assembly XIX is identical to ninth sensor assembly XIX, except that a magnetic material ring 119b and tangential sensor coils 122b have been reconfigured to improve efficiency. Specifically, the tangential sensor coils 122 of the ninth sensor assembly IX are positioned entirely within the inner radius of the channel-defining structure 118. To accommodate these tangential sensor coils 122, the magnetic material ring 119 of the ninth sensor assembly IX includes "kinks" corresponding to each tangential sensor coil 122. The ring 119 is radially inwardly bent to pass through the windings of the tangential sensor coils 122. This can be detrimental in terms of diverting the magnetic flux path within the ring 119. In contrast, in the nineteenth sensor assembly XIX, the magnetic material ring 119b has a simpler shape without kinks. The tangential sensor coils 122b are partially wound around the ring 119b, with the coils positioned partially inside and partially outside the channel-defining structure 118. In this way, the tangential magnetic flux can follow an uninterrupted circular path around the ring 119b. The radial sensor coil 121 remains wound on the inward radial protrusion of the ring 119b in the same manner as the ninth sensor assembly IX, and can be wound directly on the protrusion or can be wound on a bobbin housed on the protrusion.

[0199] Figure 25A and Figure 25B A twentieth sensor assembly XX is shown. The twentieth sensor assembly XX is similar to the first to third sensor assemblies I, II, and III, except that the twentieth sensor assembly XX is formed more compactly along the length of the multi-core cable (which can be an armored or unarmored multi-core cable 160). The twentieth sensor assembly XX includes a first channel-defining structure 180 and a second channel-defining structure 181 joined together around the armored or unarmored multi-core cable 160. The first channel-defining structure 180 and the second channel-defining structure 181 can be formed of a magnetic material (e.g., silicon steel), but this is not required. The inner surfaces of the channel-defining structures 180 and 181 support a solid-state magnetic sensor 182 directly or via a flexible circuit board or PCB. The longitudinal ends of the channel-defining structures 180 and 181 include corresponding lips 183a, 183b, 184a, and 184b that extend radially inward a distance at least equal to the height of the solid-state magnetic sensor 182. The twentieth sensor assembly XX is shown having six solid-state magnetic sensors 182 arranged at 60 degree intervals around the circumference to form a hexagonal arrangement, however, more or fewer solid-state magnetic sensors 182 may be used, and / or the angular spacing may be different or irregular.

[0200] The twentieth sensor assembly XX can be used with an unarmored multi-core cable 160 as shown. To be used with an armored multi-core cable 6, a magnet should be added ( Figure 25A and Figure 25B 184a, 184b). The magnets may be discrete or annular and may be housed on the inner surface of the channel defining structures 180, 181 and / or the lips 183a, 183b, 184a, 184b. In some examples, the lips 183a, 183b, 184a, 184b may be formed using an annular magnet.

[0201] See also 26A to 30C , showing a twenty-first sensor assembly XXI. The twenty-first sensor assembly XXI is similar to the eighth sensor assembly VIII, wherein the assembly is specifically designed to achieve compact, efficient and cost-effective manufacturing.

[0202] 26A to 26D The assembled twenty-first sensor assembly XXI is shown. Figures 27A to 27C A skeleton arrangement 185 is shown in the form of a semicircular support 186 from which three skeletons 187 extend radially inwardly. Preferably, the skeletons 187 are formed integrally with the semicircular support 186 using injection molded plastic. Alternatively, the skeletons 187 can be formed separately and attached to the semicircular support 186. The skeletons 187 are spaced 60 degrees apart from each other around the semicircular support 186 (about 30 degrees apart from either end). Each half of the twenty-first sensor assembly XXI includes a skeleton arrangement 185, thereby forming a loop around the multi-core cable 6, 160 as a whole. A radial sensor coil 188 is wound around each skeleton 187. For example, each radial sensor coil 189 can be formed from 300 turns of enameled copper wire with a diameter of 0.25 mm. Although in 26A to 26D Shown as air-core coils, in some examples, magnetic core material may be inserted into the through-holes of each bobbin 187 (before or after winding the sensor coil 188).

[0203] The bobbin device 185 formed with the winding of the sensor coil 188 is accommodated in the first outer core 189a and the second outer core 189b ( Figures 29A to 29C ( 189a, 189b ) are each formed from a semi-cylinder of magnetic material suitable for transformers (e.g., wound silicon steel strip). Preferably, the first and second outer cores 189a, 189b are formed by splitting a wound silicon steel strip cylinder in half. Pairs of magnets 190a and 190b are also housed within each outer core half 189a, 189b. Figures 28A to 28C, a single magnet 190 is shown. Magnets 190a, 190b can be magnetized ferrites, such as C5 grade ferrites used in speakers. Magnets 190a, 190b can be magnetized to provide a magnetic field substantially along the longitudinal axis, as in the second sensor assembly II, or can have opposite radial polarizations, as in the first sensor assembly I. Each end of each outer core 189a, 189b is terminated by a pair of identical end caps 191, formed, for example, from silicon steel (or other material suitable for transformer cores). Each end cap 190 is shaped like a semicircle with a semicircular cutout, the diameter of which defines the maximum size of the multi-core cable 6, 160 that can be accommodated.

[0204] The two halves of the twenty-first sensor assembly XXI are placed together and fixed together around the multi-core cable 6, 160. For example, the two halves can be hinged on one side and a latch or similar fixing mechanism can be provided on the other side.

[0205] When intended for use with unarmored multi-core cable, the magnets 190a, 190b may be omitted.

[0206] See also Figure 31A and Figure 31B , showing a twenty-second sensor assembly XXII. The twenty-second sensor assembly XXII is identical to the fourth sensor assembly IV, except that a specific design of tangential sensor coils 41b to 48b is shown instead of Figure 4 Schematic cylindrical sensor coils 41 to 48 are shown in FIG. Tangential sensor coils 41b to 48b are wound around respective bobbins and supported within the channel-defining structure 1. The tangential sensor coils 41b to 48b may be air-core coils, or magnetic material may be inserted into the coils before or after winding. The specific shape shown for the tangential sensor coils 41b to 48b (flattened in the radial direction and extending along the longitudinal axis (rounded rectangle)) can help increase the overall area of ​​the sensor coils 41b to 48b without reducing the diameter of the cable 6 that can be accommodated (compared to cylindrical sensor coils).

[0207] When intended for use with unarmored multi-core cables, the magnets 49a, 49b may be omitted.

[0208] Regardless of whether the channel is designed to enclose the multi-core cable or remain open, the first to twenty-second sensor assemblies I, ..., XXII have been described as defining a circular channel (or a portion thereof). However, the present invention is not limited to sensor assemblies whose cross-section (perpendicular to the longitudinal axis of the received multi-core cable) is circular (or a portion thereof).

[0209] For example, see also Figures 32A to 32D, a twenty-third sensor assembly XXIII is shown. Twenty-third sensor assembly XXIII is similar to twentieth sensor assembly XX, except that lips 183 and 184 are omitted, tangential sensor coil 192 is used instead of solid-state magnetic field sensor 182, and first channel-defining structure 180b and second channel-defining structure 181b are not semicircular. Instead, each channel-defining structure 180b and 181b defines a semi-oval (or "egg-shaped") shape in cross-section (or end view).

[0210] As another example, see also Figures 33A to 33D , a twenty-fourth sensor assembly XXIV is shown. Twenty-fourth sensor assembly XXIV is identical to twenty-third sensor assembly XXIII, except that solid-state magnetic field sensor 182 is used instead of tangential sensor coil 192. Alternatively, twenty-fourth sensor assembly XXVI can be considered identical to twentieth sensor assembly XX, except that lips 183 and 184 are omitted and first and second semi-oval channel-defining structures 180b and 181b are used.

[0211] In a similar manner, any of the first through twenty-second sensor assemblies I, ..., XXII may be modified to have a non-circular shape in cross-section (or end view).

[0212] Sensor assembly including current transformer

[0213] When measuring a multi-core cable (whether armored or unarmored), if there is a net current in the multi-core cable, it may cause saturation of any components of the channel-defining structure including magnetically permeable material and / or saturation of the magnetic field sensor.

[0214] As described below, this problem can be alleviated (or even avoided) by installing a sensor on the current transformer (CT) that has a sufficient internal aperture to pass the multi-core cable (armored or unarmored) through it and has a rated current appropriate to the expected network, or zero-sequence current in the multi-core cable.

[0215] See also Figures 34A to 34E, shows a twenty-fifth sensor assembly XXV. Twenty-fifth sensor assembly XXV is similar to eighth sensor assembly VIII, except that rather than having a separate ring 114 and channel-defining structure 113, twenty-fifth sensor assembly XXV has a channel-defining structure 193 in the form of a single piece (or preferably two halves) of magnetically conductive material that also provides a magnetic core for the windings of a current transformer coil 194. Current transformer coil 194 is arranged in the form of eight sub-windings 194a through 194h that are connected together and placed in series with a load resistor 195.

[0216] The magnetic core 193 of the current transformer coil 194 includes a radially inwardly extending protrusion 196, on which the radial sensor coil 115 is wound, or the radial sensor coil 115 is received on the protrusion 196 (e.g., pre-wound on a plastic bobbin). Preferably, the magnetic core 193 of the current transformer coil 194 is made of a material suitable for current transformers (e.g., silicon steel).

[0217] When it is desired to measure armored or unarmored multi-core cables, magnets 117a and 117b may be included, but if the twenty-fifth sensor assembly XXV is intended for use only with unarmored multi-core cables, magnets 117a, 117b may be omitted. Figures 34A to 34E As shown in FIG. 1 , the magnetic core 193 of the current transformer coil 194 may also include end or "lip" protrusions 197a, 197b at either end along the longitudinal axis that coincide with the magnets 117a and 117b. The end protrusions 197a, 197b help connect the return flux path between the magnets 117a and 117b.

[0218] The twenty-fifth sensor assembly XXV may be formed in two halves to provide a clip-on sensor, or may be of the pass-through type (ie, passing a multi-conductor cable through the current transformer coil 194).

[0219] The radial field entering the magnetic core 193 of the current transformer coil 194 is measured by the radial sensor coil 115. A solid-state magnetic field sensor and / or a tangential sensor coil may be used in addition to the radial sensor coil 115, or a solid-state magnetic field sensor and / or a tangential sensor coil may be used instead of the radial sensor coil 115. The magnetic field sensor (whether a radial / tangential sensor coil, a solid-state magnetic field sensor, or any other magnetic field sensor suitable for sensing the dipole moment generated by unbalanced currents (symmetrical or antisymmetrical) in a multi-core cable) may be placed between the magnetic core of the current transformer coil and the multi-core cable, or so that the magnetic core of the current transformer coil is located between the magnetic field sensor and the multi-core cable. Preferably, the magnetic field sensor (e.g., the radial sensor coil 115 shown, or an equivalent) is at least partially placed within the magnetic core 193 to provide shielding from external magnetic fields, as explained below. However, whether the magnetic field sensor is arranged between the magnetic core of the current transformer coil and the multi-core cable, or is arranged so that the magnetic core of the current transformer coil is between the magnetic field sensor and the multi-core cable, other effects can be obtained, such as preventing the magnetic core 193 of the current transformer coil from being saturated by the net current in the multi-core cable.

[0220] The current transformer coil 194 and magnetic core 193 provide four functions:

[0221] 1) Measure the net current, common mode current, or zero sequence current in the cable (based on the voltage across the load resistor).

[0222] 2) The current transformer's core 193 partially magnetically shields the dipole-sensing magnetic sensor (shown as radial sensor coil 115) from magnetic fields induced by cable currents (or other magnetic field sources) that do not pass through the sensor. The degree of shielding is primarily driven by the aspect ratio of the core 193. A longer core 193 (compared to its inner diameter) is expected to provide more effective shielding than a shorter core 193 with a larger inner diameter.

[0223] 3) The magnetic core 193 of the current transformer increases the sensitivity of the dipole sensing magnetic sensor (radial sensor coil 115 as shown) by providing a low reluctance flux path around the outside of the dipole sensing magnetic circuit.

[0224] 4) Prevent the magnetic core 193 from being saturated by the net current in the multi-core cable.

[0225] It is worth noting that the use of a current transformer coil 194 for functions 2) and 3) is preferable to using only a tube of permeable material (e.g., a core 23 without a secondary winding 194). This is because the windings of the current transformer coil 194, combined with the near-short circuit provided by the load resistor 195, provide a balancing current for the net current in the multi-core cable. This prevents the core 193 from being saturated by the net current in the multi-core cable (function 4). This could otherwise easily occur using a high-permeability core 193—which is necessary to provide optimal shielding from external magnetic fields—resulting in heating of the core 193. When the core 193 saturates, a voltage step is applied to the net current in the multi-core cable, modulating the sensitivity of the dipole-sensing magnetic sensor (radial sensor coil 115, as shown). This can also introduce interference into the dipole-sensing magnetic sensor (radial sensor coil 115, as shown) from different portions of the core 193 that saturate at different times.

[0226] The shielding level provided by a long core 193 is approximately the permeability of the core 193 multiplied by the thickness / diameter of the core 193. For example, for a core 193 that is 10 mm thick, 100 mm outer diameter (and therefore 80 mm inner diameter), and has a relative permeability of 10,000, this can provide a 1000-fold improvement in shielding level. Such a large core 193 would saturate at a net current of 50 A passing through the sensor (2 Tesla). For shorter, high-permeability cores 193, the shielding improvement will be limited by the geometry (related to length / inner diameter).

[0227] Although twenty-fifth sensor assembly XXV is shown using radial sensing coils 115, these radial sensing coils 115 may be replaced with any other magnetic field sensor suitable for detecting dipole components (e.g., tangential sensing coils and / or solid-state magnetic field sensors described herein, or a combination thereof).

[0228] The magnets 117a, 117b may be omitted when no measurements are required on the armored multi-core cable 6. When the magnets 117a, 117b are omitted, the protrusions 197a, 197b may be omitted or retained to help define an aperture / channel for accommodating the multi-core cable.

[0229] Unless expressly incompatible, any optional features, modifications and / or applications of the first sensor assembly I to the twenty-fourth sensor assembly XXIV are also applicable to the twenty-fifth sensor assembly XXV.

[0230] Any of the aforementioned first sensor assemblies I to twenty-fourth sensor assemblies XXIV can be modified to include a current transformer coil 24 by, for example, replacing the corresponding channel-defining structure with a suitably shaped magnetic core and then adding the current transformer coil 24 winding. As explained, the degree of shielding obtained will depend on the aspect ratio (ratio of length to diameter) and can be improved by changing this aspect ratio. When modified in this manner to include a current transformer coil 24, any of the first sensor assemblies I to twenty-fourth sensor assemblies XXIV can omit any magnets included if measurement of armored multi-core cables is not required. Such modified first sensor assemblies I to twenty-fourth sensor assemblies XXIV will still more or less obtain the advantages / functions 1), 2) and 3) described with respect to the twenty-fifth sensor assembly XXV.

[0231] See also Figure 35A and Figure 35B , shows a twenty-sixth sensor assembly XXVI. The twenty-sixth sensor assembly XXVI is identical to the twenty-fifth sensor assembly XXV, except that the magnetic core 23 does not include the protrusion 196, so that the radial sensor coil 115 is an air-core coil.

[0232] If the end projections 197a, 197b are also omitted, the twenty-sixth sensor assembly XXVI can be produced in a particularly simple manner, also as described with reference to Figures 36A to 36C shown.

[0233] Figure 35A A skeleton assembly 198 is shown for forming the sensor coil 115 and current transformer coil 194 of the twenty-sixth sensor assembly XXVI. Skeleton assembly 198 includes a first tangential skeleton 199 interlaced with a second radial skeleton 200. Radial skeletons 200 extend perpendicular to (and are integrally formed with) a support plate 201. Tangential skeletons 199 and support plate 201 are connected by a thin, flexible hinge 202. Each tangential skeleton 199 includes a corresponding rectangular through-hole 203, and each radial skeleton 200 includes a corresponding rectangular through-hole 204.

[0234] The radial sensor coil 115 is made on a radial skeleton 200, which has a pair of first and second skeleton components 198 in a flat state (such as Figure 36A As shown in FIG. 1 , four sub-windings 194 a to 194 d of the current transformer coil 194 are fabricated on a tangential bobbin 199 of a first bobbin assembly 198 , while the remaining sub-windings 194 e to 194 h are fabricated on a tangential bobbin 199 of a second bobbin assembly 198 .

[0235] In particular, refer to Figure 36B, each of the first and second backbone assemblies 198 is bent by bending the flexible hinge section 202, as shown, and the semi-cylindrical core section 205 passes through the through hole 203 of the tangential backbone 199. Once the two halves are completed, the magnets 117a, 117b and any end caps (not shown) can be added as needed and the two halves assembled to complete the twenty-sixth sensor assembly XXVI (e.g., the two halves can be hinged on one side and secured on the other side by a latch or similar mechanism).

[0236] If it is desired that the sensing coil 115 have a magnetically conductive core, a magnetically conductive material formed into the correct shape may be inserted into the through-holes 204 of the radial bobbin before or after the radial sensor coil 115 is wound.

[0237] The backbone assembly 198 can be modified to accommodate a solid-state magnetic field sensor, which can be mounted to the support plate 201 directly or via a flexible circuit board / PCB prior to folding the backbone assembly 198 and inserting the semi-cylindrical core segment 205. Similarly, the orientation of the second backbone 200 can be changed from radial to tangential (or can be alternated) to allow other magnetic field sensor configurations to be formed.

[0238] See also Figure 37A and Figure 37B , shows a twenty-seventh sensor assembly XXVII. The twenty-seventh sensor assembly XXVII comprises a toroidal transformer core 206 on which is wound a continuous spiral transformer coil 207. The end 208 of the transformer coil is connected via a load resistor ( Figure 36A and 36B Twelve (the number can vary) solid-state magnetic field sensors 209 are supported on a substrate 210 (e.g., a flexible printed circuit board / PCB) that is positioned just inside the inner diameter of the transformer coil 207.

[0239] The twenty-seventh sensor assembly XXVII functions in the same manner as already described with respect to the twenty-fifth sensor assembly XXV and / or the twenty-sixth sensor assembly XXVI, although the twenty-seventh sensor assembly XXVII has relatively weakened shielding due to its shorter length parallel to the longitudinal direction of the multi-core cable.

[0240] For use with armored multi-core cable, a magnet may be added to the twenty-seventh sensor assembly XXVII.

[0241] See also Figure 38A and Figure 38B, showing a twenty-eighth sensor assembly XXVIII. The twenty-eighth sensor assembly XXVIII is identical to the twenty-seventh sensor assembly XXVII, except that the substrate 210 is supported on the inner diameter of the toroidal core 206 and the solid-state magnetic field sensor 209 is contained within the coil of the continuous spiral transformer coil 207.

[0242] For use with armored multi-core cable, a magnet may be added to the twenty-eighth sensor assembly XXVIII.

[0243] The cross-sectional / end-view shape of the sensor assembly including the current transformer is not limited to a circular shape. For example, see also Figures 39A to 39D , showing the twenty-ninth sensor assembly XXIX.

[0244] Sensor assembly XXIX is similar to sensor assembly XXIV, but with the addition of transformer coil sub-windings 211 surrounding first and second channel-defining structures 180b, 181b. These first and second channel-defining structures 180b, 181b are also formed from a magnetically conductive material and form the magnetic core of a transformer coil formed by connecting the transformer coil sub-windings 211 together. The transformer coil sub-windings 211 are also connected in series with a load resistor (not shown) to form a current transformer. The first and second channel-defining structures 180b, 181b are hinged on one side to allow a multi-core cable to be accommodated through the transformer coil formed by connecting the sub-windings 211. The other side can be closed and preferably secured by, for example, a latch or similar mechanism. Alternatively, a spring or similar biasing device can be included to urge the unhinged ends of the first and second channel-defining structures 180b, 181b together.

[0245] For use with armored multi-core cable, a magnet may be added to the twenty-ninth sensor assembly XXIX.

[0246] See also Figure 40A and Figure 40B , shows a 30th sensor assembly XXX. The 30th sensor assembly XXX includes a Rogowski coil 212 and a plurality of magnetic field sensors 213. For illustrative purposes, Figure 40A and Figure 40B , the magnetic field sensor 213 is shown as an air-core radial sensor coil, but types of magnetic sensors of the type described herein may be used, including but not limited to solid-state magnetic field sensors, radial sensor coils (air-core or with a core of magnetically conductive material), tangential sensor coils (air-core or with a core of magnetically conductive material), and the like.

[0247] The Rogowski coil 212 and the plurality of magnetic field sensors 213 are supported by a channel defining structure that is not in the Figure 40A and Figure 40B , but may be configured as described with respect to the aforementioned sensor assembly.

[0248] The 30th sensor assembly XXX is configured such that when the device is coupled to a multi-core cable 214 (e.g., a three-core cable as shown), a region of the multi-core cable 214 passes through the Rogowski coil 212. At least one of the magnetic field sensors 213 is positioned adjacent to the Rogowski coil and oriented to detect a magnetic field component originating from that region of the multi-core cable 214. Preferably, the magnetic field sensor 213 surrounds the multi-core cable 214 to allow sensing of the dipole field and measurement of derived quantities, as described above with respect to the first through twenty-ninth sensor assemblies XXIX. The Rogowski coil 212 is used to measure the net current.

[0249] Alternatively, in some examples, the Rogowski coil 212 may be flexible (to allow wrapping around an area of ​​the multi-core cable 214). In this case, the Rogowski coil 212 and the magnetic field sensor 213 may be supported by a flexible or articulated structure.

[0250] Placing the Rogowski coil 212 and magnetic field sensor 213 in close proximity to each other allows for direct comparison of measurements. For example, the net current measurement from the Rogowski coil 212 can be used to check the individual core currents inferred using the magnetic field sensor 213.

[0251] The exact position of the magnetic field sensor 213 relative to the Rogowski coil 212 is not limited to Figure 40A and Figure 40B The embodiment shown in FIG. 2 is a schematic diagram of a configuration in which the magnetic field sensor 213 is positioned adjacent to the Rogowski coil 212 along the axial direction of the multi-core cable 214 (when in use). For example, at least one of the one or more magnetic field sensors 213 can be positioned inside the Rogowski coil 212, or at least partially inside the Rogowski coil 212. In other words, when in use, between the Rogowski coil 212 and the multi-core cable 214. Alternatively, at least one of the one or more magnetic field sensors can be positioned outside the Rogowski coil 212. In other words, separated from the multi-core cable 214 by the Rogowski coil 212.

[0252] Although the multi-conductor cable 214 is shown as unarmored, magnets may be added to the thirtieth sensor assembly XXX for use with armored multi-conductor cables.

[0253] Revise

[0254] It will be appreciated that various modifications may be made to the embodiments described above. Such modifications may involve equivalent and other features and / or methods that are already known in the design, manufacture, and use of electrical test and measurement equipment and component parts thereof and that may be used instead of or in addition to the features already described herein. Features of one embodiment may be replaced by or in addition to features of another embodiment.

[0255] Although the claims have been expressed as specific feature combinations in this application, it should be understood that the scope of the disclosure of the present invention also includes any novel feature or any novel combination of features disclosed herein, whether explicitly or implicitly, or any generalization thereof, regardless of whether it is related to the same invention currently claimed in any claim and whether it alleviates any or all technical problems similar to the present invention. The applicant hereby notifies that during the prosecution of this application or any other application derived therefrom, new claims may be expressed for these features and / or combinations of these features.

Claims

1. A device for connecting to a multi-core steel wire armored cable, comprising: one or more magnets; as well as one or more magnetic field sensors; wherein the device is configured such that when the device is coupled to the multi-core steel wire armored cable: A magnetic field corresponding to the one or more magnets is applied to a region of the multi-core steel wire armored cable; as well as Each magnetic field sensor is oriented to detect a component of a magnetic field originating from a region of the multi-core steel wire armored cable.

2. The device according to claim 1, wherein At least one of the one or more magnets comprises a permanent magnet.

3. The device according to claim 1 or 2, wherein: At least one of the one or more magnets comprises an electromagnet.

4. The device according to any one of claims 1 to 3, wherein At least one of the one or more magnetic field sensors includes a coil.

5. The device according to any one of claims 1 to 4, wherein At least one of the one or more magnetic field sensors comprises a solid-state magnetic field sensor device.

6. The device according to any one of claims 1 to 5, wherein The magnetic field corresponding to the one or more magnets has a magnitude of at least 5 mT within the region.

7. The apparatus of any one of claims 1 to 6, configured such that a magnetic field corresponding to the one or more magnets is time-varying.

8. The apparatus according to any one of claims 1 to 6, configured such that a magnetic field corresponding to the one or more magnets is constant.

9. The device according to any one of claims 1 to 8, wherein The device is configured to mechanically couple to the multi-core steel wire armored cable using a magnetic force generated by applying the magnetic field to the steel wire armor layer.

10. The apparatus of any one of claims 1 to 9, comprising structure supporting the one or more magnets and the one or more magnetic field sensors.

11. The device according to claim 10, wherein The structure includes a channel configured to receive the multi-core steel wire armored cable.

12. The device according to claim 11, wherein The cross section of the channel has a circular or arc shape.

13. The device according to claim 12, wherein The cross section of the channel has a shape that is non-circular and does not correspond to an arc of a circle.

14. The device according to any one of claims 11 to 13, wherein The channel is open.

15. The device according to any one of claims 11 to 13, wherein The passage is defined by first and second components of the structure, the first and second components being configured to enclose the multi-conductor steel wire armored cable when the multi-conductor steel wire armored cable is received within the passage.

16. The device according to any one of claims 11 to 13, wherein The structure includes two or more components configured to enclose or wrap the multi-core steel wire armored cable to define the channel.

17. The apparatus of any one of claims 1 to 16, further comprising a net current sensor configured to measure a net current passing through the multi-core steel wire armored cable when the apparatus is coupled to the multi-core steel wire armored cable.

18. The device according to any one of claims 1 to 17, wherein At least one of the one or more magnetic field sensors includes a coil, wherein each coil is wound around a sensing pole piece.

19. The device according to any one of claims 1 to 18, wherein At least one of the one or more magnets comprises an electromagnet, wherein each electromagnet is wound around a pole piece.

20. An apparatus according to any one of claims 1 to 19, comprising two or more magnetic field sensors.

21. The device according to any one of claims 1 to 20, wherein The one or more magnetic field sensors include a first set of first magnetic field sensors and a second set of second magnetic field sensors; Wherein, the first group of first magnetic field sensors and the second group of second magnetic field sensors are arranged to be spaced apart along an axial direction of the multi-core steel wire armored cable when the multi-core steel wire armored cable is coupled to the device.

22. A sensor comprising: The device according to any one of claims 1 to 21; A controller is connected to the one or more magnetic field sensors and is configured to calculate one or more derived quantities based on the magnetic field components measured by the magnetic field sensors for some or all cores of the multi-core steel wire armored cable.

23. A sensor comprising: The apparatus of any one of claims 1 to 21, further configured to generate one or more signals based on outputs of the one or more magnetic field sensors, each signal being proportional to a differential current between cores of the multi-core steel wire armored cable when the multi-core steel wire armored cable is coupled to the apparatus; A link corresponding to each signal is used to connect to the control and / or measurement system.

24. The sensor of claim 22 or 23, further comprising one or more voltage sensors, wherein The one or more derived quantities include one or more power values.

25. A system comprising a sensor according to any one of claims 22 to 24 coupled to provide input to a measurement device.

26. The system of claim 25, wherein: The measuring device is a power quality analyzer.

27. The system of claim 25, wherein: The measuring device is a power quality recording device.

28. A method comprising: coupling the apparatus according to any one of claims 1 to 21 to the multi-core steel wire armored cable, or coupling the apparatus of the sensor according to claims 22 to 24 or the system according to claims 25 to 27 to the multi-core steel wire armored cable, such that a magnetic field corresponding to the one or more magnets is applied to a region of the multi-core steel wire armored cable; A magnetic field component originating from a region of the multi-core steel wire armored cable is measured using the one or more magnetic field sensors.

29. The method according to claim 28, wherein A magnetic field corresponding to the one or more magnets saturates the steel wire armor layer within the region.

30. The method of claim 28 or 29, further comprising calculating one or more derived quantities based on magnetic field components measured by the magnetic field sensor for some or all cores of the multi-core steel wire armored cable.

31. A device for connecting to a multi-core cable, comprising: a first set of one or more first magnetic field sensors; a second set of one or more second magnetic field sensors; wherein the device is configured such that when the device is coupled to a multi-core cable: Each first magnetic field sensor is oriented to detect a magnetic field component originating from a first region of the multi-core cable; each second magnetic field sensor being oriented to detect a magnetic field component originating from a second region of the multi-core cable; The first region and the second region are spaced apart along the length of the multi-core cable.

32. The device according to claim 31 further includes one or more magnets, and the one or more magnets are arranged so that when the device is connected to the multi-core cable, magnetic fields corresponding to the one or more magnets are applied to the first region and the second region of the multi-core cable.

33. A device for connecting to a multi-core cable, comprising: Current transformer coil; one or more magnetic field sensors; wherein the device is configured such that when the device is coupled to the multi-core cable: A region of the multi-core cable passes through the current transformer coil; The one or more magnetic field sensors are at least partially disposed between a magnetic core of the current transformer coil and the multi-core cable, and wherein at least one of the magnetic field sensors is oriented to detect a magnetic field component originating from a region of the multi-core cable.

34. The device according to claim 33 or 34, wherein The magnetic core of the current transformer coil comprises a magnetically conductive material.

35. The apparatus according to claim 33 or 34, wherein The current transformer coil includes two or more sub-coils.

36. The apparatus according to any one of claims 33 to 35, wherein The apparatus is configured such that a region of the multi-core cable accommodated by the current transformer coil is oriented in an axial direction; The current transformer coil extends along the axial direction on both sides of the one or more magnetic field sensors.

37. The apparatus according to claim 36, wherein A length of the current transformer coil extending in the axial direction is greater than or equal to half of an inner diameter of the current transformer coil.

38. The apparatus according to any one of claims 33 to 37, wherein At least one of the one or more magnetic field sensors includes a sensor coil.

39. The apparatus according to any one of claims 33 to 38, wherein At least one of the one or more magnetic field sensors comprises a solid-state magnetic field sensor device.

40. An apparatus as claimed in any one of claims 33 to 39, comprising structure supporting the current transformer coil and the one or more magnetic field sensors.

41. The apparatus according to claim 40, wherein The structure includes a channel configured to receive the multi-core cable.

42. The apparatus according to claim 41, wherein The cross section of the channel has a circular or arc shape.

43. The apparatus according to claim 41, wherein The cross section of the channel has a shape that is non-circular and does not correspond to an arc of a circle.

44. The apparatus according to any one of claims 41 to 43, wherein The channel is open.

45. The apparatus according to any one of claims 41 to 44, wherein The passage is defined by first and second components of the structure, the first and second components being configured to enclose the multi-core cable when the multi-core cable is received within the passage.

46. ​​The apparatus of any one of claims 41 to 44, wherein The structure includes two or more components configured to enclose or wrap the multi-core cable to define the channel.

47. An apparatus as claimed in any one of claims 33 to 46, comprising two or more magnetic field sensors.

48. The device of any one of claims 33 to 47, further comprising one or more magnets; in, The device is configured such that, when the device is coupled to the multi-core cable, a magnetic field corresponding to the one or more magnets is applied to a region of the multi-core cable passing through the current transformer coil.

49. The apparatus of any one of claims 33 to 48, wherein The one or more magnetic field sensors include a first set of first magnetic field sensors and a second set of second magnetic field sensors; Wherein, the first group of first magnetic field sensors and the second group of second magnetic field sensors are arranged to be spaced apart along an axial direction of the multi-core cable when the multi-core cable is coupled to the device.

50. A sensor comprising: An apparatus according to any one of claims 33 to 49; a controller connected to the one or more magnetic field sensors and configured to: For some or all of the cores of the multi-core cable, one or more derived quantities are calculated based on the magnetic field components measured by the magnetic field sensors.

51. The sensor according to claim 50, wherein The controller is further configured to calculate a net current through the multi-core cable based on the measurement using the current transformer coil.

52. A sensor comprising: The apparatus of any one of claims 33 to 49, further configured to generate one or more signals based on outputs of the one or more magnetic field sensors, each signal being proportional to a differential current between cores of the multi-core cable when the multi-core cable is coupled to the apparatus; A link corresponding to each signal is used to connect to the control and / or measurement system.

53. The sensor according to claim 52, wherein The apparatus is further configured to generate a net current signal based on the output from the current transformer coil.

54. A sensor according to any one of claims 50 to 53, further comprising one or more voltage sensors, wherein The one or more derived quantities include one or more power values.

55. The sensor of claim 54, configured to use the one or more voltage sensors to correctly assign phases to cores of the multi-core cable.

56. A system comprising a sensor according to any one of claims 50 to 55 coupled to provide input to a measurement device.

57. A method comprising: coupling the device according to any one of claims 33 to 49 to a multi-core cable, or coupling the device of the sensor according to claims 50 to 55 or the system according to claim 56 to the multi-core cable, such that a region of the multi-core cable passes through the current transformer coil; A magnetic field component originating from a region of the multi-core cable is measured using the one or more magnetic field sensors.

58. The method of claim 57, further comprising measuring a net current passing through the multi-core cable using the current transformer coil.

59. A device for connecting to a multi-core cable, comprising: Rogowski coil; one or more magnetic field sensors; wherein the device is configured such that when the device is coupled to the multi-core cable: The region of the multi-core cable passes through the Rogowski coil, or the Rogowski coil is wound around the region of the multi-core cable; At least one of the magnetic field sensors is disposed proximate the Rogowski coil and is oriented to detect a magnetic field component originating from a region of the multi-core cable.

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