Meter, apparatus, terminal block and process for measuring electric current

Abstract

Meter (1) configured to measure electric current, which comprises at least one printed circuit board (2) including a plurality of electrical and / or electronic components electrically connected to each other via conductive tracks to form at least one electrical circuit configured to measure electric current through a non-contact measurement and to generate an electrical signal that varies according to the intensity of the measured electric current, wherein the printed circuit board (2) comprises one or more Hall effect sensors (3, 3', 3") and at least one amplifier (4) configured to amplify and / or buffer the signal generated by the Hall effect sensors (3, 3', 3"), so that the meter (1) can be easily placed at the base of a terminal block due to its small size, while still offering sufficient sensitivity to perform electric current measurements. This description also relates to an apparatus comprising this meter, a terminal block comprising this meter and / or this apparatus, as well as a process that can be carried out by this apparatus.

Description

[0001] Meter, apparatus, terminal block and process for measuring electric current

[0002] Technical field

[0003] The present description concerns a meter for measuring electric current, in particular a meter that can be used to measure alternating current in a multi-pole terminal block. The present description also concerns an apparatus comprising this meter, a terminal block comprising this meter and / or this apparatus, as well as a process that can be carried out by this apparatus.

[0004] Background of the description

[0005] Known multi-pole terminal blocks, for example for low-voltage three-phase current (380-400 V), are attached to the exterior walls of buildings, poles, or towers, or inside containers or distribution cabinets installed in private areas or on public land to connect one or more electrical cables of an electrical network to one or more electrical cables of an electrical network or subnetwork. These known terminal blocks may also comprise disconnect switches to interrupt or restore the electrical connection between the cables connected to them.

[0006] In recent years, the need to monitor the proper functioning of these terminal blocks has arisen. However, installing known current meters, such as ferromagnetic or Rogowski coils, near a terminal block is difficult due to their relatively large size and the limited space available inside a distribution container or cabinet, or to the external and / or difficult-to-reach location of the terminal block, especially if it is installed in a location visible to the public and / or at a considerable distance from the ground.

[0007] Furthermore, known meters are relatively unsafe, as they must be mounted in direct contact with the poles of a terminal block, resulting in the risk of short circuits or leakage if their insulating protection is damaged.

[0008] In fact, the insulation of meters relies solely on their insulating protection, and the cables connecting them must maintain the same level of protection. On the other hand, reinforced insulating protections on cables and meters make the meters bulkier and the cables more rigid.

[0009] Placing meters in contact with the poles of a terminal block exposes these meters to increased stress due to operating temperatures and the potential risk of damage to the insulating protections during operating activities.Known meters are also relatively expensive due to the modifications required for their installation in terminal blocks, especially considering the number of meters required for a complete monitoring of all poles of a terminal block.

[0010] Document WO 2016 / 028710 A1 describes a known meter.

[0011] Summary of the description

[0012] The object of the present description is therefore to provide a meter that solves these problems. This object is achieved with a meter, an apparatus, a terminal block, and a process, the main characteristics of which are specified in the attached claims, which are to be considered an integral part of the present description.

[0013] Thanks to its particular printed circuit board comprising at least one Hall effect sensor and at least one amplifier, the meter according to this description takes up little space, can be mass-produced at low cost, provides relatively precise measurements, with respect to the object of the present description (indicatively with an error less than 1.5% on the full scale), and can be easily installed near or even inside a known terminal block.

[0014] The meter is also safer than known meters since it does not have to be installed in contact with the poles of a terminal block or other live conductors but at a distance from them, preferably with an insulating element placed between them, such as the support of a terminal block.

[0015] Preferably, the meter comprises additional components that improve its performance and / or more Hall effect sensors arranged in specific positions and orientations on a same side of the printed circuit board, so as to improve measurement accuracy, especially when more meters are arranged close to each other in a terminal block.

[0016] The apparatus according to the present description is relatively compact, so it can be easily attached to a terminal block.

[0017] The apparatus may also comprise a particular modular structure that offers numerous advantages in terms of simplicity of manufacturing, production costs, reliability over time and safety in use.

[0018] This modular structure may comprise a particular power supply module that can be powered directly from the terminal blocks and comprise a buffer power supply to ensure continuity of operation of the apparatus for a certain period of time even in the event of a power failure from the terminal block.This modular structure may also comprise a particular measurement module configured to generate digital signals based on the electrical signals generated by one or more meters according to the present description, and which preferably comprises one or more specific processing sections configured to amplify, differentiate, and / or process the electrical signal generated by the meter connected to it. This differentiated signal may be processed by an external device as if the meters were Rogowski meters, thus maintaining compatibility with pre-existing systems.

[0019] The measuring module may comprise a special processing section that can transmit to a communication module of the modular system a series of detailed information on the operation of a terminal block, such as instantaneous, minimum, average and / or maximum current values detected by the meters and / or alarm signals in the event of overload, short circuit, anomaly and / or absence of voltage detected by the meters.

[0020] Preferably, the communication module not only transmits this information remotely, for example to control centers, but can also receive parameters for configuring the apparatus, in particular the processing section.

[0021] This information can therefore also provide useful indications on the operation of networks or subnetworks connected via a terminal block, thus facilitating fault finding and improving the quality of the network service, reducing the probability of failures and limiting their impact on end users.

[0022] In particular, the apparatus can transmit an alarm message in “last gasp” mode containing essential information sufficient to identify the apparatus in the network and the situation detected at the time of a power outage. This feature is crucial for the operator of the network containing the apparatus, as it allows the operator to both identify a section of the network without power and effectively trace the path of the current that caused the fault. In the specific case of a fault downstream of the apparatus, the latter is no longer powered following the opening of an upstream circuit breaker. Before shutting down, the apparatus therefore transmits an alarm message in “last gasp” mode, reporting both the power loss and the alarm condition, for example the detection of a short circuit, as well as the last current value detected. This information is crucial for a network operator as it allows him to quickly locate the section of the network affected by the fault.

[0023] The process according to the present description can be carried out by the apparatus to provide such information in a simple, precise and fast manner.Brief description of the drawings

[0024] Further advantages and features of the meter, the apparatus, the terminal block and the process according to the present description will become apparent to those skilled in the art from the following detailed description of some embodiments, to be considered nonlimiting examples of the claims, with reference to the attached drawings in which:

[0025] figure 1 is a top perspective view of an embodiment of the meter;

[0026] figure 2 is an electrical diagram of the meter of figure 1 ;

[0027] figure 3 is a top view of an embodiment of the terminal block;

[0028] figure 4 is a bottom view of the terminal block of figure 3;

[0029] figure 5 is a front view of the terminal block of figure 3;

[0030] figure 6 is an exploded view of the terminal block of figure 5;

[0031] figure 7 is section VII-VII of the terminal block of figure 5;

[0032] figure 8 is a top view of an embodiment of the apparatus for the terminal block of figure 3;

[0033] figure 9 is a bottom view of the terminal block of figure 3 without the apparatus; figure 10 is a partial and enlarged sectional view of the terminal block of figure 3; figures 11 and 12 are partial and enlarged sectional views of the terminal block of figure 3 with two further embodiments of the meter;

[0034] figure 13 is a block diagram of the apparatus;

[0035] figure 14 is an electrical circuit of a treatment section of the apparatus; figure 15 is a flowchart of operational steps of an embodiment of the process.

[0036] Exemplary embodiments

[0037] Figures 1-2 show an embodiment of the meter 1 for measuring electric current according to the present description, which comprises at least one printed circuit board 2 that includes a plurality of electrical and / or electronic components, which are electrically connected to each other via conductive tracks to form at least one electrical circuit, as shown in figure 2. Said electrical circuit is configured to measure electric current through a contactless measurement, i.e. through a measurement of a magnetic field generated by an electrical conductor crossed by this current, and generate an electrical signal that varies as a function of the intensity of the measured current.

[0038] For this purpose, the printed circuit board 2 of the meter 1 comprises at least one Hall effect sensor 3, in particular a linear ratiometric sensor, for example a DRV5055-Q1A1sensor from Texas Instruments in TO-92 configuration, which protrudes from an upper side of the printed circuit board 2.

[0039] The electrical circuit of the meter 1 is also configured to amplify and / or buffer the electrical signal generated by the Hall effect sensor 3. For this purpose, the printed circuit board 2 of the meter 1 also comprises at least one amplifier 4, in particular a rail-to-rail operational amplifier, which is connected to at least one connector 5 of the meter 1 to provide the signal amplified by the amplifier 4 to the outside of the meter 1. Preferably, the amplifier 4 is an MCP6281 integrated circuit from Microchip Technology.

[0040] The signal generated by the meter 1 is preferably a voltage signal variable as a function of the magnetic field detected by the Hall effect sensor 3, in particular an analog signal variable between 0.2 and 4.5 V and proportional to the magnetic field detected by the Hall effect sensor 3. The connector 5 may also comprise ground and / or power pins for the meter 1, in particular to power the meter 1 with a voltage of 5 V direct current.

[0041] The printed circuit board 2 of the meter 1 may also comprise at least one power supply block 6 which comprises the amplifier 4 and may be connected to the power pins of the connector 5 to power the amplifier 4, and / or comprise a regulator 7 , in particular a linear regulator LP2985IM5-4.5 from Texas Instruments, which is configured to convert and stabilize input voltages of the Hall effect sensor 3, the amplifier 4 and / or the power supply block 6, compensating for variations in the voltage at the connector 5. For this purpose, the power supply block 6 is also connected to the regulator 7.

[0042] The printed circuit board 2 of the meter 1 may comprise additional electrical and / or electronic components, such as resistors, capacitors and ground terminals arranged and sized as in the electrical circuit of figure 2, which are necessary or preferable for the operation of the meter 1.

[0043] The printed circuit board 2 of the meter 1 may have a substantially rectangular shape, with one or more Hall effect sensors 3 arranged on the same side of the printed circuit board 2. The dimensions of the printed circuit board are preferably: height 1-2 mm, width 14-16 mm and / or length 45-55 mm. Alternative embodiments of the meter 1 may comprise larger printed circuit boards comprising two or more printed circuit boards 2 of the type described above, in particular four printed circuit boards 2 arranged side by side.

[0044] Figures 3-9 show a terminal block 11, specifically a terminal block comprising one or more poles 12, more specifically four poles 12 configured for a three-phase low-voltageconnection to a neutral pole. The poles 12 are mounted on a support 13 configured to be attached to a wall W (partially shown in Figure 7). The wall W may, for example, be the back wall of a container, for example made of plastic, which in turn may be attached to the wall of a building or other structure. At least one pole 12 comprises connectors 14, 15 which are configured to be connected to one or more electrical cables 16, for example by means of a screw terminal, and are electrically connected to each other by at least one conductive bar 17 which may be provided with a jumper bar 18 which can be removed to prevent the passage of electrical current between the connectors 14, 15. At least one pole 12 may have an elongated shape, in particular substantially parallelepiped, which extends along a longitudinal axis L. The connectors 14, 15 may be arranged at two opposite ends of a pole 12 along the longitudinal axis L. The support 13 may comprise one or more barriers 19 arranged next to a pole 12 and / or between two poles 12 to prevent accidental contacts, as well as holes 20 for attaching the support to the wall W by means of screws 21 (shown with dashed lines in figure 7).

[0045] A cover 22, preferably transparent and removable, may at least partially cover the terminal block 11, in particular the upper side with the poles 12. For this purpose, the support 13 comprises one or more threaded pins 23 which can pass through respective holes 24 obtained in the cover 22 and be coupled with threaded elements 25, for example knurled bushings 25, so that a threaded element 25 screwed onto a threaded pin 23 can removably lock the cover 22 on the support 13. The cover 22 has openings 26 for the passage of the electrical cables 16.

[0046] With particular reference to figure 8, an embodiment of the apparatus 31 according to the present description comprises one or more meters 1, in particular four meters 1, so that each meter 1 can measure the three phases and the neutral of a three-phase current. The meters 1 of the apparatus 31 are arranged, preferably one next to the other, on a base 32 configured to be applied to a terminal block, in particular under the terminal block 11. The base 32 can be provided with fixing means to be fixed to the support 13 of the terminal block 11. In particular, such fixing means comprise openings 33 arranged in positions substantially corresponding to the positions of the holes 20 on the support 13, so that the base 32 can be attached to the wall Wwith the same screws 21 , each passing through a hole 20 of the support 13 of the terminal block 11 and an opening 33 of the base 32 of the apparatus 31, as shown in figure 7. The support 13 of the terminal block 11 is therefore arranged between the poles 12 of the terminal block 11 and the meters 1 of the apparatus 31. In this way, a terminal block 11 without the apparatus 31, as shown in figure 9, can be removed from the wall W to which it is attached, the apparatus 31 canbe arranged between the terminal block 11 and the wall W and the terminal block 11 can be re-attached to the wall W. If desired, the cover 22 can be replaced with a similar, but higher cover 22 as shown in the figures, to compensate for the difference in height of the terminal block 11 when the apparatus 31 is applied to it.

[0047] The base 32 preferably comprises a seat 34 open upwards, i.e. towards the terminal block 11, in which electrical and / or electronic components for the operation of the apparatus 31 are arranged, including the meters 1. In particular, the apparatus 31 comprises multiple printed circuit boards which are arranged on the base 32 and are connected to each other via connectors C and / or interfaces DI to create a modular system. Alternative embodiments of the apparatus 31 may comprise a single printed circuit board which creates all the modules of the apparatus 31. The modular system of the apparatus 31 preferably comprises at least one measuring module MM configured to generate digital signals based on the electrical signals generated by the meters 1 , at least one communication module CM to transmit the signals generated by the measuring module MM outside the apparatus 31, and / or at least one power supply module PM to power the measuring module MM and / or the communication module CM.

[0048] The base 32 of the apparatus 31 has an external profile, in particular a rectangular external profile, width and / or height substantially equal to the external profile, width and / or height of the support 13 of the terminal block 11.

[0049] At least one meter 1 has an elongated shape, in particular substantially rectangular, which extends along a longitudinal axis substantially parallel to the longitudinal axis L of the poles 12 of the terminal block 11 when the apparatus 31 is applied to the terminal block 11.

[0050] With reference also to figure 10, the Hall effect sensor 3 of at least one meter 1 is preferably arranged in contact or almost in contact, in particular at a distance of less than 5 mm, with a lower surface of the support 13 of the terminal block 11, so that the Hall effect sensor 3 is arranged as close as possible, in particular at a distance of less than 10 mm, to a pole 12 of the terminal block 11 to measure the magnetic field induced by the passage of the current in this pole 12. Preferably, the Hall effect sensor 3 is arranged substantially on the median plane M of the pole 12 and / or has a measurement axis F of the magnetic field flux that is substantially perpendicular to the median plane M of the pole 12 and / or substantially perpendicular to the longitudinal axis L of the pole 12. The median plane M is a plane that is substantially parallel to the longitudinal axis L of the pole 12 and divides the pole 12 into two substantially equal or mirror parts. Preferably,the measurement axis F of the magnetic field flux of the Hall effect sensor 3 is substantially parallel to the surface of the printed circuit board 2 on which the Hall effect sensor 3 is mounted.

[0051] With reference to figure 11 , a second embodiment of the meter 1 may comprise two Hall effect sensors 3, 3’, wherein the first Hall effect sensor 3 is the same as that of the first embodiment, while the second Hall effect sensor 3’ is a sensor mounted on the printed circuit board 2 in SOT-23 configuration. The second Hall effect sensor 3’ has a measurement axis F’ of the magnetic field flux that is substantially perpendicular to the measurement axis F of the magnetic field flux of the first Hall effect sensor 3 and / or substantially parallel to the median plane M of the pole 12 and / or substantially perpendicular to the longitudinal axis L of the pole 12. The second Hall effect sensor 3’ also serves to measure the magnetic fields generated by the adjacent poles 12 to correct the measurement of the first Hall effect sensor 3. Preferably, the measurement axis F’ of the magnetic field flux of the second Hall effect sensor 3’ is substantially perpendicular to the surface of the printed circuit board 2 on which the second Hall effect sensor 3’ is mounted.

[0052] With reference to Figure 12, a third embodiment of the meter 1 may comprise three Hall effect sensors 3, 3’, 3”, wherein the first two Hall effect sensors 3, 3’ are the same as those of the second embodiment, while the third Hall effect sensor 3” is a second sensor mounted on the printed circuit board 2 in TO-92 configuration like the first sensor. The third Hall effect sensor 3” has a measurement axis F” of the magnetic field flux that is substantially parallel to or aligned with, but oriented in an opposite direction, the measurement axis F of the magnetic field flux of the first Hall effect sensor 3. The third Hall effect sensor 3” serves to obtain a measurement opposite to the measurement of the first Hall effect sensor 3 to improve the accuracy of the latter measurement. Preferably, the measurement axis F” of the magnetic field flux of the third Hall effect sensor 3” is substantially parallel to the surface of the printed circuit board 2 on which the third Hall effect sensor 3” is mounted.

[0053] With reference also to figure 13, the power supply module PM of the apparatus 31 is configured to reliably and safely power the apparatus 31 and any external devices connected to it, in particular by drawing alternating current from two poles 12 of the terminal block 11. The thin arrows in figure 13 show the electrical connections for powering the components of the apparatus 31, while the thicker arrows show theelectrical connections for transmitting signals among the components of the apparatus 31.

[0054] For this purpose, the power supply module PM comprises one or more external connectors EC connected by conductors (not shown in figures 1-12) to a connector 14 or 15 of at least two poles 12. The external connectors EC are connected to an converter ACDC configured to transform an alternating voltage / current into a direct voltage / current, for example 24 V, suitable for powering the components of the apparatus 31.

[0055] One of the two external connectors EC may be connected to a neutral pole 12, for example to obtain a 230 V alternating current, or to a phase pole 12, for example to obtain a 400 V alternating current, so as to exclude potential problems related to incorrect connections or malfunctions in the electrical network connected to terminal block 11. This flexibility in the power supply of the power supply module PM allows for safer and more reliable operation of the apparatus 31. Indeed, the installation of the apparatus 31 does not necessarily have to take into account the position of the neutral pole in terminal block 11 and possible deviations in the voltage on the neutral pole, if used, due to malfunctions in the electrical network.

[0056] The power supply module PM preferably comprises a buffer power supply BPS, in particular comprising a supercapacitor, which is configured to ensure the continuity of operation of the apparatus 31 for a period of time following a possible interruption of the power supply at the external connectors EC, in which case the buffer power supply BPS would provide a continuous voltage to a last gasp device LGP of the communication module CM, i.e. a device capable of carrying out a last action after a power interruption, using a secondary accumulator, as will be described below.

[0057] The measuring module MM is also configured to process the electrical signals generated by the meters 1 and transmit to the communication module CM instantaneous, minimum, average and / or maximum current values detected by the meters 1, in particular in time intervals determined and / or settable by a user, and / or alarm signals in the event of overload, short circuit and / or anomalies detected by the meters 1.

[0058] The measurement module MM also comprises a signal treatment device STD which is connected to the meters 1 and is configured to acquire and process the electrical signals generated by the meters 1.The signal treatment device STD comprises, for each meter 1 connected to the measurement module MM, a treatment section TS configured to amplify and / or differentiate the signal generated by the meter 1 connected to it.

[0059] As shown in figure 14, at least one treatment section TS comprises at least one input connector IN comprising at least one pole connected to a line ML which is in turn connected to a meter 1 to receive the signal generated by this meter 1.

[0060] The treatment section TS may comprise an amplification block AB configured to amplify and / or buffer the signal of the meter 1 and transmit the amplified signal to at least one pole OUT 1 of at least one output connector OUT of an output block OB of the treatment section TS.

[0061] The treatment section TS may comprise a filter block FB arranged between the amplification block AB and the output block OB to filter the signal amplified by the amplification block AB, for example by means of a low-pass filter.

[0062] The treatment section TS may comprise a derivation block DB configured to differentiate the signal amplified by the amplification block AB, preferably filtered by the filter block FB and / or calibrated by a calibration block CB, in particular comprising an adjustable amplifier, and to generate a differentiated signal which substantially corresponds to a signal that can be generated by a Rogowski coil and which can be sent to at least one pole OUT2 of a connector of the treatment section TS. The derivation block DB preferably comprises a differentiating amplifier with an operational amplifier, resistors and capacitors configured to differentiate the amplified signal and generate the differentiated signal.

[0063] The treatment section TS may comprise an integration block IB comprising an integrating amplifier with an operational amplifier, resistors, and capacitors configured to integrate the differentiated signal generated by the derivation block DB. The integration block IB is then configured to regenerate, up to a gain constant, the input signal of the derivation block DB. The signal generated by the integration block IB is transmitted through at least one pole OUT3, for example, of the output connector OUT, so that this signal can be processed by an external processor to verify whether the derivation operation performed by the derivation block DB was performed correctly.

[0064] The treatment section TS may further comprise a power supply block PB which is configured to receive from a power supply connector PC the supply current / voltage fromthe converter ACDC, which is stabilized and / or converted to power the amplification block AB, the calibration block CB and / or the meter 1 connected to the treatment section TS, preferably through the connector IN.

[0065] The blocks of the treatment section TS may comprise additional electrical and / or electronic components, such as resistors, capacitors and ground terminals arranged and sized as in the electrical circuit of figure 14, which are necessary or preferable for the operation of each block.

[0066] The output connectors OUT of the treatment sections TS are connected to a processing section PS configured to process the electrical signals generated by the meters 1 and / or by the signal treatment device STD and to generate digital measurement signals for the communication module CM.

[0067] The poles OUT2 of the treatment sections TS may also be connected to an external device ED configured to process, through processes compatible with Rogowski meters, the differentiated signals generated by the treatment section TS.

[0068] The processing section PS of the measurement module MM comprises at least one processing device which is configured to convert, by means of analog-to-digital converters, the analog signals generated by the treatment section TS, to process these signals in the digital domain by means of a program, preferably stored in a firmware of the same device, and to generate the digital measurement signals for the communication module CM .

[0069] Said processing device preferably comprises a microcontroller, such as an electronic board based on the FreeRTOS operating system.

[0070] As shown in Figure 15, the measurement process carried out by the program of the processing device of the processing section PS of the measuring module MM of the apparatus 31 comprises at least four operating steps S1, S2, S3 and S4.

[0071] In a first acquisition step S1, the processing section PS samples the signals generated by the meters 1 and / or processed by the treatment section TS, preferably by means of an asynchronous process and independently of the subsequent steps S2, S3 and S4. In this acquisition step S1, the processing section PS periodically samples, at each period p, respective series of samples containing a given number of samples, for example 50 samples at each period p having a duration of 1 ms. A series of samples acquired during a period p=pO of the acquisition step S1 is then processed in the subsequent steps S2,S3 and S4 of the process. Meanwhile, the processing section PS samples further series of samples during the subsequent periods p1, p2, p3...pn. Consequently, while the samples acquired during a period pO are processed in one step of the process, the samples acquired during one or more subsequent periods p1, p2, p3...pn are processed in a previous step of the process.

[0072] In a second processing step S2, the processing section PS processes the average, minimum, and / or maximum values of the signals sampled in one or more previous acquisition steps S1 over a given observation period T=[p0...pn], for example, 15 minutes. The values thus processed are stored in the processing device and are preferably RMS values of the acquired signals. In particular, the processing section PS processes the RMS values according to a defined periodicity, for example, every 200 ms. The RMS values detected during the observation period are then grouped according to statistical criteria to obtain representative average, maximum, and / or minimum values.

[0073] In a third control step S3, the processing section PS checks whether said average, minimum and / or maximum values exceed one or more threshold values stored in the processing device, in which case the processing section PS generates one or more alarm signals. The samples used for the comparison with the short-circuit threshold values are those obtained during the first acquisition step S1. The algorithm to detect an impulse overcurrent, i.e. a short-circuit current, considers one or more adjacent samples, in absolute value, to determine whether a threshold value has been exceeded. If the short-circuit condition persists for a defined number of consecutive samples, a short-circuit alarm is generated until the short-circuit condition is no longer present. The overload detection algorithm calculates the RMS values on a predefined number of consecutive sinusoids, for example ten sinusoids, comparing them to an overload threshold value. If the threshold value is exceeded, an overload alarm is activated and any recovery from the overload condition is monitored. Any alarms are transmitted immediately, complete with the peak current value and the alarm time. Each alarm is reset using a hysteresis criterion.

[0074] In a fourth transmission step S4, the processing section PS transmits both the values processed in the processing step S2, in particular the average, minimum and maximum RMS values detected in an observation period T, and the alarm signals, if any, generated in the control step S3.

[0075] Steps S1 to S4 are repeated periodically at each observation period T.The processing section PS of the measuring module MM may transmit these values to the communication module CM via a digital interface DI, for example an RS485 serial interface with Modbus RTU communication protocol.

[0076] The communication module CM is configured to receive digital signals with the values generated by the processing section PS of the measurement module MM and transmit them, in whole or in part, to external devices or systems such as:

[0077] an external control system ECS, such as a SCADA (Supervisory Control And Data Acquisition) distributed control system, in particular via a network interface Nl, such as an Ethernet interface, and / or

[0078] an external receiver ER, in particular via a wireless transceiver WT with LoRaWan protocol or other radio transmission protocols, including those of cellular networks.

[0079] The communication module CM may also be configured to control the apparatus 31, in particular the parameters of the processing section PS, such as, for example, the time period over which to calculate the average values, the overcurrent and / or short circuit threshold values and other parameters, via an external control device ECD, in particular a smartphone or equivalent device via a web interface and / or dedicated application.

[0080] For this purpose, the communication module CM may comprise a digital transceiver DT equipped with a SIM or e-SIM for wireless communication. The SIM or e-SIM password may be configured, in a preliminary step, by powering the apparatus 31 with an external power supply when the apparatus 31 is not yet paired with the terminal block 11. The SIM or e-SIM number may be used to identify and authenticate the apparatus 31 in a cellular data network, for example 3G / 4G / 5G.

[0081] The external receiver ER may act as a gateway between the external control system ECS and the wireless transceiver WT and / or the digital transceiver DT.

[0082] The communication module CM may further comprise a communication section CS configured to receive and / or transmit digital signals from / to the processing section PS of the measurement module MM and to receive and / or transmit digital signals from / to the network interface Nl, the digital transceiver DT and / or the wireless transceiver WT.

[0083] The communication module CM may also comprise a wireless interface Wl, for example of the NFC type, for wireless connection with an external device equipped with another wireless interface of the same type.The network interface Nl and the digital transceiver DT provide both access to the configuration parameters of the apparatus 31 and data communication functionalities to external systems, such as SCADA control systems. The network interface Nl is implemented only in particular cases, while the digital transceiver DT is implemented if very frequent or high-throughput data exchange is required.

[0084] The wireless transceiver WT enables low-cost communications to other similar devices or data collection systems. The wireless transceiver WT does not allow configuration and / or diagnostics of the apparatus 31, so the wireless interface Wl, together with an application on an operator’s portable terminal, forexamplean NFC-enabled smartphone, allows for sufficient data exchange for the first configuration or a first diagnostics level of the apparatus 31. The wireless interface Wl also allows for configuration of the apparatus 31 from outside its container, thus without the need to access live parts.

[0085] The communication module CM may also comprise the above-mentioned last gasp device LGP, which is connected to both the converter ACDC and the buffer power supply BPS and is configured to determine a possible interruption in the power supply of the apparatus 31 and, if necessary, send an alarm signal outside, in particular via the communication section CS, the wireless transceiver WT and / or the digital transceiver DT, before the charge of the buffer power supply BPS is exhausted and therefore the apparatus 31 switches off.

[0086] The last gasp device LGP powers the communications section CS with power from the converter ACDC or, if this is absent, from the buffer power supply BPS. The communications section CS in turn powers the wireless transceiver WT, the digital transceiver DT, the wireless interface Wl, and the Nl network interface.

[0087] The communication section CS activates a “last gasp” mode when it receives the alarm signal from the last gasp device LGP, in which case the communication section CS cuts off the power to the wireless interface Wl and / or the network interface Nl, and / or stops communicating with the processing section PS, thus stopping all their energy-consuming activities, and / or sends an alarm message to the external control system ECS and / or the external receiver ER. This alarm message may be retransmitted by the communication section CS periodically n times every time period t, where n and t are parameters that can be determined by a user. During this time period t, the communication section CS preferably cuts off the power to the DT digital transceiver and / or the WT wireless transceiver. The alarm message may contain information about the apparatus, in particular the absence of power to the apparatus, an identification code for the apparatus,and / or the situation detected by the apparatus at the time of the power interruption, such as the detection of a short-circuit current.

[0088] Preferably, the communication section CS comprises a processor, for example of the ARM type with a Linux operating system, and implements the IEC61850 master / slave and / or IEC60870-5-104 slave and / or MQTT and / or Modbus TCP / RTU transmission protocols and / or other suitable protocols.

[0089] The functions of the meter 1 and / or the apparatus 31 described above may be implemented using, for example, electronic hardware, computer software, or combinations of both, depending on the specific application and the design constraints imposed on the respective overall systems.

[0090] Variations or additions may be made by those skilled in the art to the embodiments described and illustrated herein, while remaining within the scope of the following claims. In particular, further embodiments may comprise the technical features of one of the following claims with the addition of one or more technical features described in the text or illustrated in the drawings, taken individually or in any mutual combination, and comprising equivalent characteristics thereof.

[0091] Furthermore, terms used in the text and / or drawings are intended to be inclusive unless otherwise specified, so for example the terms “a”, “comprising”, “including a”, “having two” or “provided with” mean respectively “at least one”, “comprising, but not limited to”, “including at least one”, “having two or more”, or “provided with at least one”.

Claims

Claims1. A meter (1) for measuring electric current, which comprises at least one printed circuit board (2) which includes a plurality of electrical and / or electronic components electrically connected to each other via conductive tracks to create at least one electrical circuit configured to measure electric current through a noncontact measurement and to generate an electrical signal which varies according to the intensity of the measured electric current, wherein the printed circuit board (2) comprises at least one first Hall effect sensor (3) and at least one amplifier (4) configured to amplify and / or buffer the signal generated by the first Hall effect sensor (3), characterised in that at least one second Hall effect sensor (3’) is mounted on the same side of the printed circuit board (2) with the first Hall effect sensor (3), wherein the at least one first Hall effect sensor (3) is mounted on the printed circuit board (2) in TO-92 configuration and the at least one second Hall effect sensor (3’) is mounted on the printed circuit board (2) in SOT-23 configuration, wherein the at least one first Hall effect sensor (3) has a measurement axis (F) of the magnetic field flux which is substantially perpendicular to the measurement axis (F’) of the magnetic field flux of the at least one second Hall effect sensor (3’).

2. The meter (1) according to the preceding claim, wherein the printed circuit board (2) comprises at least one connector (5), a power supply block (6) and a regulator (7), wherein the power supply block (6) is connected to the connector (5) and the regulator (7) to power the amplifier (4), wherein the regulator (7) is configured to convert and / or stabilize input voltages of the at least one first Hall effect sensor (3), the amplifier (4) and / or the power supply block (6).

3. The meter (1) according to one of the preceding claims, wherein a third Hall effect sensor (3”) is mounted in TO-92 configuration on the same side of the printed circuit board (2) with the at least one first Hall effect sensor (3) and with the at least one second Hall effect sensor (3’), wherein the third Hall effect sensor (3”) has a measurement axis (F”) of the magnetic field flux that is substantially parallel to or aligned with, but oriented in an opposite direction, the measurement axis (F) of the magnetic field flux of the at least one first Hall effect sensor (3).

4. The meter (1) according to one of the preceding claims, wherein the measurement axis (F) of the magnetic field flux of the first Hall effect sensor (3) is substantially parallel to the surface of the printed circuit board (2) on which the Hall effect sensor(3) is mounted, and / or wherein the measurement axis (F’) of the magnetic field flux of the second Hall effect sensor (3’) is substantially perpendicular to the surface of the printed circuit board (2) on which the second Hall effect sensor (3’) is mounted, and / or wherein measurement axis (F”) of the magnetic field flux of the third Hall effect sensor (3”) is substantially parallel to the surface of the printed circuit board (2) on which the third Hall effect sensor (3”) is mounted.

5. An apparatus (31) for measuring electric current, which comprises one or more meters (1) according to one of the preceding claims.

6. The apparatus (31) according to the preceding claim, wherein several meters (1) are arranged next to each other on a base (32) configured to be applied to a terminal block (11).

7. The apparatus (31) according to claim 5 or 6, which comprises a modular system comprising at least one measurement module (MM) configured to generate digital signals based on the electrical signals generated by said one or more meters (1), at least one communication module (CM) configured to transmit outside the apparatus (31) the signals generated by the measurement module (MM), and / or at least one power supply module (PM) to power the measurement module (MM) and / or the communication module (CM).

8. The apparatus (31) according to the preceding claim, wherein the power supply module (PM) comprises one or more external connectors (EC) connected to at least one converter (ACDC) configured to transform an alternating voltage / current into a direct voltage / current suitable for powering the components of the apparatus (31), wherein the converter (ACDC) is connected to at least one buffer power supply (BPS) configured to ensure continuity of operation of the apparatus (31) for a period of time following a possible interruption of the power supply at the external connectors (EC).

9. The apparatus (31) according to claim 7 or 8, wherein the measurement module (MM) comprises at least one signal treatment device (STD) which is connected to said one or more meters (1) and is configured to acquire and process the electrical signals generated by these meters (1), wherein the signal treatment device (STD) comprises, for each meter (1) connected to the measurement module (MM), at least one treatment section (TS) configured to amplify and / or differentiate theelectrical signal generated by the meter (1) connected to the treatment section (TS).

10. The apparatus (31) according to one of claims 7 to 9, wherein the measuring module (MM) comprises at least one processing section (PS) configured to process the electrical signals generated by said one or more meters (1) and / or by the signal treatment device (STD) and to generate digital signals for the communication module (CM).

11. The apparatus (31) according to one of claims 7 to 10, wherein the measuring module (MM) is also configured to process the electrical signals generated by said one or more meters (1) and transmit to the communication module (CM) instantaneous, minimum, average and / or maximum current values detected by the meters (1) and / or alarm signals in the event of overload, short circuit, anomaly and / or absence of voltage detected by the meters (1).

12. The apparatus (31) according to one of claims 7 to 11 , wherein the communication module (CM) comprises at least one communication section (CS) configured to receive and / or transmit digital signals from / to the measurement module (MM) and to receive and / or transmit digital signals from / to at least one network interface (N I), a digital transceiver (DT), a wireless interface (Wl) and / or a wireless transceiver (WT).

13. The apparatus (31) according to the preceding claim, when it also depends on claim 8, wherein the communication module (CM) also comprises at least one last gasp device (LGP) which is connected to the converter (ACDC) and to the buffer power supply (BPS) and is configured to determine a possible interruption in the power supply of the apparatus (31) and, in this case, send an alarm signal to the communication section (CS) before the charge of the buffer power supply (BPS) is exhausted.

14. A terminal block (11) comprising one or more poles (12) mounted on a support (13) configured to be attached to a wall (W), wherein at least one pole (12) comprises one or more connectors (14, 15), each configured to be connected to one or more electrical cables (16), which are electrically connected to each other by at least one conductive bar (17), wherein the terminal block (11) comprises one or more meters(1) according to one of claims 1 to 4 or at least one apparatus (31) according to one of claims 5 to 13.

15. The terminal block (11) according to the preceding claim, wherein the at least one first Hall effect sensor (3) of at least one meter (1) is arranged in contact or almost in contact with a lower surface of the support (13) of the terminal block (11).

16. The terminal block (11) according to claim 14 or 15, wherein at least one pole (12) of the terminal block (11) has an elongated shape extending along a longitudinal axis (L), wherein one or more of said Hall effect sensors (3, 3’, 3”) of at least one meter (1) are arranged substantially on the median plane (M) of this pole (12) and / or have a measurement axis (F) of the magnetic field flux which is substantially perpendicular to the median plane (M) of this pole (12) and / or to the longitudinal axis (L) of this pole (12).

17. The terminal block (11) according to one of claims 14 to 16, wherein the base (32) of the apparatus (31) has an external profile, a width and / or a height which are substantially equal to the external profile, width and / or height of the support (13).

18. The terminal block (11) according to one of claims 14 to 17, wherein the base (32) of the apparatus (31) it is provided with fixing means (33) to be fixed under the support (13) of the terminal block (11), so that the support (13) is arranged between the poles (12) of the terminal block (11) and one or more meters (1) of the apparatus (31) .

19. The terminal block (11) according to one of claims 14 to 18, when also depending on claim 8, wherein one or more external connectors (EC) of the apparatus (31) are connected to at least two poles (12) of the terminal block (11).

20. A process for measuring electric current by means of the apparatus (31) according to one of claims 10 to 13, wherein the processing section (PS) of the apparatus (31):in an acquisition step (S1), samples the signals generated by the meters (1) and / or processed by the treatment section (TS);in a processing step (S2), processes and stores in a processing device the average, minimum and / or maximum values of the signals sampled in one or more acquisition steps (S1);in a control step (S3), checks whether said average, minimum and / or maximum values exceed one or more threshold values stored in the processing device, in which case the processing section (PS) generates one or more alarm signals; in a transmission step (S4), transmits both the values processed in the processing step (S2) and the alarm signals, if any, generated in the control step (S3).

21. The process according to the preceding claim, when dependent on claim 13, wherein the communication section (CS) of the apparatus (31) interrupts the power supply of the wireless interface (Wl) and / or the network interface (Nl), and / or interrupts the communication with the processing section (PS) and / or sends an alarm message to an external control system (ECS) and / or to an external receiver (ER), when the communication section (CS) receives the alarm signal from the last gasp device (LGP).

22. The process according to the preceding claim, wherein said alarm message is retransmitted by the communication section (CS) periodically for n times every time period t, wherein during a time period t the communication section (CS) interrupts the power supply of the digital transceiver (DT) and / or the wireless transceiver (WT).

23. The process according to claim 21 or 22, wherein the alarm message contains information on the apparatus, in particular the absence of power to the apparatus, an identification code of the apparatus and / or the situation detected by the apparatus at the time of the power failure.

24. The process according to one of claims 20 to 23, wherein, in the acquisition step (S1), the processing section (PS) samples the signals generated by the meters (1) and / or processed by the treatment section (TS) by means of an asynchronous process and independently of the subsequent steps (S2, S3, S4) of the method.

25. The process according to the preceding claim, wherein, in the acquisition step (S1), the processing section (PS) periodically samples series of samples containing a determined number of samples, wherein a series of samples acquired during a period of the acquisition step (S1) is then processed in the subsequent steps (S2, S3, S4) of the process, while in the meantime the processing section (PS) samples further series of samples.

26. The process according to one of claims 20 to 25, wherein said steps (S1 , S2, S3, S4) of the process are repeated periodically.

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