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Title:
CIRCUIT BREAKER DEVICE
Document Type and Number:
WIPO Patent Application WO/2017/122142
Kind Code:
A1
Abstract:
Circuit breaker device (100) comprising an instantaneous electric power measurement unit (110), a processing unit (140), and a relay unit (180) connected to a unbalancing resistor (190) the ends of which are configured to be connected to a phase conductor and to a neutral conductor of a single phase power line (400), wherein the instantaneous electric power measurement unit (110) is configured to measure an instantaneous electric power corresponding to an AC voltage between the phase conductor and the neutral conductor and to an AC current flowing through the phase conductor or the neutral conductor, the instantaneous electric power measurement unit (110) being configured to provide the processing unit (140) with a digital signal indicating an instantaneous electric power measured by the instantaneous electric power measurement unit (110), wherein the processing unit (140) is configured to activate the relay unit (180) when said measured instantaneous electric power is higher than a tolerance threshold PTOL for a delay time period TDLY, the activation of the relay unit (180) being such that, when the ends of the unbalancing resistor (190) are connected to the phase conductor and to the neutral conductor, respectively, and an end is connected upstream of and the other end is connected downstream of a residual current circuit breaker (300) the two branches of which are connected to the phase conductor and to the neutral conductor, it causes a current to flow through the unbalancing resistor (190) and through only one of the two branches of the residual current circuit breaker (300) resulting into an interruption of the residual current circuit breaker (300).

Inventors:
RICCIARDIELLO, Antonio (Viale J. F. Kennedy 161, Pescara, 65123, IT)
CHIAVAROLI, Piero (Via di Pian Savelli 134, Roma, 00134, IT)
Application Number:
IB2017/050144
Publication Date:
July 20, 2017
Filing Date:
January 12, 2017
Export Citation:
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Assignee:
RICCIARDIELLO, Antonio (Viale J. F. Kennedy 161, Pescara, 65123, IT)
CHIAVAROLI, Piero (Via di Pian Savelli 134, Roma, 00134, IT)
International Classes:
H01H83/14; H01H83/18
Foreign References:
GB2376360A2002-12-11
EP0748016A21996-12-11
EP0403216A21990-12-19
Attorney, Agent or Firm:
SCILLETTA, Andrea (IP Sextant s.r.l, Via Antonio Salandra 18, Roma, 00187, IT)
Download PDF:
Claims:
CLAIMS

1. Circuit breaker device (100) comprising an instantaneous electric power measurement unit. (110), a processing unit (140), and a relay unit (180) connected to a unbalancing resistor (190) the ends of which are configured to be connected to a phase conductor and to a neutral conductor of a single phase power line (400), wherein the instantaneous electric power measurement unit (110) is configured to measure an instantaneous electric power corresponding to an AC voltage between the phase conductor and the neutral conductor and to an AC current flowing through the phase conductor or the neutral conductor, the instantaneous electric power measurement unit (110) being configured to provide the processing unit (140) with a digital signal indicating an instantaneous electric power measured by the instantaneous electric power measuremen unit (110), wherein the processing unit (140) is configured to activate the relay unit (180) when said measured instantaneous electric power is higher than a tolerance threshold PTOL for a delay time period TDLY, the activation of the relay unit (180) being such that, when the ends of the unbalancing resistor (190) are connected to the phase conductor and to the neutral conductor, respectively, and an end is connected upstream of and the other end is connected downstream of a residual current circuit breaker (300) the two branches of which are connected to the phase conductor and to the neutral conductor, it causes a current to flow through the unbalancing resistor (190) and through only one of the two branches of the residual current circuit breaker (300) resulting into an interruption of the residual current circuit breaker (300).

2. Circuit breaker device (100) according to claim 1, further comprising a display (150) configured to be controlled by the processing unit (140) so as to visually signal a value of said measured instantaneous electric power.

3. Circuit breaker device (100) according to claim 2, wherein the display (150) is a LED display comprising one or more LEDs, wherein the processing unit (140) is optionally configured to control said one or more LEDs so that they flash at an increasing frequency when said measured instantaneous electric power is higher than the tolerance threshold PTOL.

4. Circuit breaker device (100) according to any one of the preceding claims, further comprising a buzzer (160) configured to be controlled by the processing unit (140) so as to acoustically signal a value of said measured instantaneous electric power, wherein the processing unit ( 140) is optionally configured to control the buzzer (160) so that it emits one or more acoustic signals of increasing intensity when said measured instantaneous electric power is higher than the tolerance threshold PTOL.

5. Circuit breaker device (100) according to a ny one of the preceding claims, further comprising a phase visual indicator (144), optionally a LED, configured to be controlled by the processing unit (140) so as to signal when the ends of the unbalancing resistor (190) are connected to the phase conductor and to the neutral conductor, respectively, and an end is connected upstream of and the other end is connected downstream of the residual current circuit breaker (300) the two branches of which a re connected to the phase conductor and to the neutral conductor.

6. Circuit breaker device (100) according to any one of the preceding claims, wherein:

- the tolerance threshold PTOL is selectable by means of a tolerance threshold selection unit (142), optionally provided with a plurality of dip-switches, configured to be read by the processing unit (140) and/or by means of an external selection device configured to be connected, through a wired or wireless connection, to the processing unit (140) for setting the operation of the latter; and/or

the delay time period TDLY is selectable by means of a delay time period selection unit (146), optionally provided with a plurality of dip-switches, configured to be read by the processing unit (140) and/or by means of an external selection device configured to be connected, through a wired or wireless connection, to the processing unit (140) for setting the operation of the latter.

7. Circuit breaker device (100) according to any one of the preceding claims, wherein the processing unit (140) is configured to activate the relay unit (180) when said measured instantaneous electric power is higher than an intervention threshold PINT higher than the tolerance threshold PTOL, whereby PINT > PTOL, wherein the intervention threshold PINT is optionally selectable by means of an intervention threshold selection unit, more optionally provided with a plurality of dip-switches, configured to be read by the processing unit (140) and/or by means of an external selection device configured to be connected, through a wired or wireless connection, to the processing unit (140) for setting the operation of the latter.

8. Circuit breaker device (100) according to any one of the preceding claims, wherein the instantaneous electric power measurement unit (110) comprises a first operational amplifier (112), the two inputs of which are configured to be respectively connected to the phase conductor and to the neutral conductor, whereby the first operational amplifier (112) is configured to output an analog signal of measurement of said AC voltage, and a second operational amplifier (114), the two inputs of which are respectively connected to the ends of a shunt resistor (170) configured to be connected in series to the phase conductor or to the neutral conductor, whereby the second operational amplifier (114) is configured to output an analog signal of measurement of said AC current, the instantaneous electric power measurement unit (110) further comprising two ADC converters (116; 118) configured to receive and sample the analog signal of measurement of said AC voltage and the analog signal of measurement of said AC current, respectively, so as to output at respective outputs two sampled voltage and current signals, respectively, the instantaneous electric power measurement unit (110) still comprising a digital phase correction block (120) downstream of one of the two ADC converters (116; 118) and configured to correct a phase difference of the sampled voltage signal with respect to the sampled current signal or a phase difference of the sampled current signal with respect to the sampled voltage signal, an output of the digital phase correction block (120) being connected, through a high-pass digital filter (122), to a multiplier unit (124) to which the output of the other one of the two ADC converters (116; 118) is also connected and which is configured to calculate an instantaneous digital effective power and to output an instantaneous digital effective power signal, a low-pass digital filter (126) being connected downstream of the multiplier unit (124) and being configured to eliminate digital noises from the instantaneous digital effective power signal, a power-to-frequency converter (128) being connected downstream of the low-pass digital filter (126) and being configured to generate at an output (130) of the instantaneous electric power measurement unit (110), that is connected to the processing unit (140), a digital pulsed signal having frequency that is function of the measured instantaneous digital effective power signal, whereby said digital signal indicating an instantaneous electric power measured by the instantaneous electric power measurement unit (110) consists of said digital pulsed signal.

9. Circuit breaker device (100) according to any one of the preceding claims, wherein the processing unit is a microprocessor (140).

10. Circuit breaker device (100) according to any one of the preceding claims, wherein the relay unit is a bidirectional thyristor (180), having a control input configured to be controlled by the processing unit (140).

11. Circuit breaker device (100) according to any one of the preceding claims, configured to be mounted on a standard DIN rail.

Description:
CIRCUIT BREAKER DEVICE

* * *

The present invention concerns a circuit breaker device allowing in a manner that is simple, reliable, efficient, inexpensive, safe and comfortable to users to inform the users on the energy consumption and to interrupt the connection to the mains through the activation of a conventional residual current circuit breaker, the device being easily installable inside a conventional distribution board, possibly already existing inside a house or an office, without requiring particular modifications to the existing electrical wiring.

The regulations of many countries, among which Italy, require that, for a house or office, an electrical energy meter, provided with a main thermal magnetic circuit breaker, is installed by the electricity supplier in a distribution board external to the house or office, while inside the house or office there is an internal distribution board comprising a residual current circuit breaker and one or more secondary thermal magnetic circuit breakers connected downstream of the meter; in particular, each secondary thermal magnetic circuit breaker is connected upstream of a specific group of electrical loads (e.g., lights, power sockets, air conditioners). The meter measures the electrical energy supplied by the mains and used by the electrical loads installed in the house or office, the main thermal magnetic circuit breaker protects users from short circuits and overloads (in this case by interrupting the connection to the mains of all the electrical loads of the house or office), the residual current circuit breaker protects users from possible current leakage detected by the same (by interrupting the connection to the meter and, hence, to the main of all electrical loads of the house or office), and the secondary thermal magnetic circuit breakers protect users from short circuits and overloads due to respective specific groups of electrical loads (each secondary thermal magnetic circuit breaker interrupting the connection to the meter and, hence, to the mains of only the respective specific group of electrical loads connected downstream of the same).

In recent years, the electrical energy electromechanical meters, which require a direct reading of the measurement, have been increasingly replaced with electronic meters which are remotely readable.

The main thermal magnetic circuit breakers of the electrical energy electromechanical meters have wide tolerances, whereby, when the instantaneous power absorption is higher than the instantaneous power limits established by the electricity supply contract, they rarely interrupt the connection to the mains. This entails that, on the one hand, users rarely realise to have electrical loads which consume an overall instantaneous power higher than the contractual limits and, on the other hand, users equally rarely a re forced to go to the external distribution board of the electricity supplier to reset the main thermal magnetic circuit breaker and to supply electrical energy to the electrical loads of the house or office. I n this regard, the contractual limit PCON of instantaneous power established by a contract is connected to the contractual limit of supplied electrical energy; by way of example, in Ita ly the contractual limit of supplied electrical energy is usua lly expressed in KW-h (where 1 KW-h = 3,6 χ 10 6 J) and the contractual limit PCON of instantaneous power is equal to the same value expressed in KW, whereby, for instance, in case of a contractual limit of supplied electrica l energy equal to 1,5 KW-h, the contractual limit PCON of instantaneous power is equal to 1,5 KW.

The electrical energy electronic meters allow the electricity suppliers to avoid to employ staff in order to visit in person houses and offices to control the measurements of the electrical energy consumptions. Also, the electronic meters are provided with main thermal magnetic circuit breakers much more sensitive with respect to those of the electromechanical meters, whereby the former are capable to carry out a m uch more precise control of the instantaneous power consumptions, avoiding to exceed the contractual limits PCON of instantaneous power for periods longer than a threshold that generally ranges from few seconds to few minutes.

Document GB 2376360A discloses an electrical energy meter provided with a prior art circuit breaker device.

However, the electronic meters suffer from some drawbacks, especially for domestic users.

I n fact, such electronic meters interrupt the connection of all loads of the house or office to the mains (at most) already after few minutes of small exceeding of the contractual limit of instantaneous power, whereby the user is forced to personally intervene to reset the main thermal magnetic circuit breaker of the electronic meter, getting to the external distribution board of the electricity supplier that is usually placed outside the user's house (or office), on a street or in a courtyard of a condominium.

This causes significant discomforts for the end users, especially for domestic users, for instance in the case where who is inside the house at the moment of electrical energy interruption does not know where the external distribution board of the electricity supplier is placed and/or does not know the modes to reset the breakers of the main electronic meter.

Also, the external distribution boards are usually inserted in locked cabinets and, in case of electrical energy interruption, the user could not have a key of the cabinet. Finally, users who are older people or people with physical disabilities may have significant difficulties to get to the external distribution boa rd and to reset the breakers of the electronic meter.

Some solutions to such drawbacks have been developed in prior art, which comprise apparatuses, dedicated to an industrial use and installed in the premises where the users are, which apparatuses may carry out measurements and breaks of sections of electrical systems. However, even such solutions suffer from some drawbacks, mainly due to the fact that the related breaking apparatuses are very expensive and complex to control a nd they need equally complex and expensive systems.

Therefore, it is an object of the present invention to allow in a manner that is simple, reliable, efficient, inexpensive, safe and comfortable to users to inform the users on the consumption of the instantaneous power a nd to maintain such consumption within the contractual limits.

It is specific subject matter of the present invention a circuit breaker device comprising an instantaneous electric power measurement unit, a processing unit, and a relay unit connected to a unbalancing resistor the ends of which are configured to be connected to a phase conductor and to a neutral conductor of a single phase power line, wherein the instantaneous electric power measurement unit is configured to measure an instantaneous electric power corresponding to an AC voltage between the phase conductor a nd the neutral conductor and to an AC current flowing through the phase conductor or the neutral conductor, the instantaneous electric power measurement unit being configured to provide the processing unit with a digital signal indicating an instantaneous electric power measured by the instantaneous electric power measurement unit, wherein the processing unit is configured to activate the relay unit when said measured instantaneous electric power is higher than a tolerance threshold Ρτοί ίθΓ a delay time period TDLY, the activation of the relay unit being such that, when the ends of the unbalancing resistor are connected to the phase conductor a nd to the neutra l conductor, respectively, and an end is connected upstream of and the other end is connected downstream of a residual current circuit breaker the two branches of which are connected to the phase conductor and to the neutral conductor, it causes a current to flow through the unbalancing resistor and through only one of the two branches of the residual current circuit breaker resulting into an interruption of the residual current circuit breaker.

According to another aspect of the invention, the circuit breaker device may further comprise a display configured to be controlled by the processing unit so as to visually signal a value of said measured instantaneous electric power.

According to a further aspect of the invention, the display may be a LED display comprising one or more LEDs.

According to an additional aspect of the invention, the processing unit may be configured to control said one or more LEDs so that they flash at a n increasing frequency when said measured instantaneous electric power is higher than the tolerance threshold PTOL.

According to another aspect of the invention, the circuit breaker device may further un buzzer comprise a buzzer configured to be controlled by the processing unit so as to acoustically signal a value of said measured instantaneous electric power.

According to a further aspect of the invention, the processing unit may be configured to control the buzzer so that it emits one or more acoustic signals of increasing intensity when said measured instantaneous electric power is higher than the tolerance threshold PTOL.

According to an additional aspect of the invention, the circuit breaker device may further comprise a phase visual indicator configured to be controlled by the processing unit so as to signal when the ends of the unbalancing resistor are connected to the phase conductor and to the neutral conductor, respectively, and an end is connected upstream of and the other end is connected downstream of the residual current circuit breaker the two branches of which a re connected to the phase conductor and to the neutral conductor.

According to another aspect of the invention, the phase visual indicator may be a LED.

According to a further aspect of the invention, the tolerance threshold PTOL may be selectable by means of a tolerance threshold selection unit, optionally provided with a plurality of dip-switches, configured to be read by the processing unit and/or by means of a n external selection device configured to be connected, through a wired or wireless connection, to the processing unit for setting the operation of the latter.

According to an additional aspect of the invention, the tolerance threshold selection unit may be provided with a plurality of dip-switches.

According to another aspect of the invention, the delay time period TDLY may be selectable by means of a delay time period selection unit, optionally provided with a plurality of dip-switches, configured to be read by the processing unit and/or by means of a n external selection device configured to be connected, through a wired or wireless connection, to the processing unit for setting the operation of the latter. According to a further aspect of the invention, the delay time period selection unit may be provided with a plurality of dip-switches.

According to an additional aspect of the invention, the processing unit may be configured to activate the relay unit when said measured instantaneous electric power is higher than an intervention threshold PINT higher than the tolerance threshold PTOL, whereby PINT > PTOL.

According to another aspect of the invention, the intervention threshold PINT may be selectable by means of a n intervention threshold selection unit, more optionally provided with a plurality of dip-switches, configured to be read by the processing unit and/or by mea ns of an external selection device configured to be connected, through a wired or wireless connection, to the processing unit for setting the operation of the latter.

According to a further aspect of the invention, the intervention threshold selection unit may be provided with a plurality of dip-switches.

According to an additional aspect of the invention, the instantaneous electric power measurement unit may comprise a first operational amplifier, the two inputs of which are configured to be respectively connected to the phase conductor and to the neutral conductor, whereby the first operational amplifier is configured to output an analog signal of measurement of said AC voltage, and a second operational amplifier, the two inputs of which are respectively connected to the ends of a shunt resistor configured to be connected in series to the phase conductor or to the neutral conductor, whereby the second operational amplifier is configured to output an analog signal of measurement of said AC current, the instantaneous electric power measurement unit further comprising two ADC converters configured to receive and sample the analog signal of measurement of said AC voltage and the analog signal of measurement of said AC current, respectively, so as to output at respective outputs two sampled voltage and current signals, respectively, the instantaneous electric power measurement unit still comprising a digital phase correction block downstream of one of the two ADC converters and configured to correct a phase difference of the sampled voltage signal with respect to the sampled current signal or a phase difference of the sam pled current signal with respect to the sampled voltage signal, a n output of the digital phase correction block being connected, through a high-pass digital filter, to a multiplier unit to which the output of the other one of the two ADC converters is also connected and which is configured to calculate an instantaneous digital effective power and to output an instantaneous digital effective power signal, a low-pass digital filter being connected downstream of the multiplier unit a nd being configured to eliminate digital noises from the instantaneous digital effective power signal, a power-to-frequency converter being connected downstream of the low-pass digital filter and being configured to generate at an output of the instantaneous electric power measurement unit, that is connected to the processing unit, a digital pulsed signal having frequency that is function of the measured instantaneous digital effective power signal, whereby said digital signal indicating an instantaneous electric power measured by the instantaneous electric power measurement unit consists of said digital pulsed signal.

According to another aspect of the invention, the processing unit may be a microprocessor.

According to a further aspect of the invention, the relay unit may be a bidirectional thyristor, having a control input configured to be controlled by the processing unit.

According to an additional aspect of the invention, the circuit breaker device may be configured to be mounted on a standard DI N rail.

The circuit breaker device according to the invention allows to measure the instantaneous electric power a bsorbed by the electrical loads of an electrical system of a house or office, so as to inform the user in every moment on the instantaneous power consumption situation and to optically and/or acoustically wa rn of the possible exceeding of the contractual limit PCON of instantaneous power. In the case where, notwithstanding the warning of exceeding of the contractual limits PCON, the user does not reduce within a reasonable time period the instantaneous power consumption of his/her own electrical system (e.g. by disconnecting or turning off one or more electrical loads), the circuit breaker device according to the invention is configured to automatically cause the intervention of a residual current circuit breaker, that may be the one already existing in the distribution board inside the house inserted in the same electrical system, disconnecting the power and anticipating the intervention of the main thermal magnetic circuit breaker of the electrical energy meter, even when the latter is an electronic meter, of the electricity supplier, which meter is usually installed outside the house or office.

The circuit breaker device according to the invention is configured to be mounted in the same internal distribution board, even already existing, in which the residual current circuit breaker that the device according to the invention is configured to activate is mounted, i.e. in the distribution board placed inside the house (or office) in a position easily accessible by the user. Consequently, the possible intervention of the residual current circuit breaker, automatically caused by the circuit breaker device according to the invention, anticipating the intervention of the main thermal magnetic circuit breaker of the electrical energy meter placed in the external distribution board of the electricity supplier, minimises user's discomforts. In fact, in order to reactivate the supply of electrical energy, the user is not required anymore to go to the external distribution board of the electricity supplier, typically housed in a cabinet installed outside the house (or office), often in positions not easily accessible by older or disabled people.

The circuit breaker device according to the invention does not require particular modifications to the existing electrical system and its installation may be easily carried out by the same operators who install conventional electrical wirings.

The present invention will be now described, by way of illustration and not by way of limitation, according to its preferred embodiments, by particularly referring to the drawings of the annexed sole Figure, indicated as Figure 1, showing a schematic circuit diagram of a preferred embodiment of the circuit breaker device according to the invention mounted in an internal distribution board.

With reference to Figure 1, it may be observed that the preferred embodiment of the circuit breaker device according to the invention, indicated with the reference numeral 100, is configured to be mounted in a distribution board 200, usually (but not necessarily) installed inside a house (or office), in which a residual current circuit breaker 300 connected downstream of a power supply main line 400 is also mounted, in turn connected downstream of an electrical energy meter (not shown in the Figure), optionally an electronic meter, installed in an external distribution board (also not shown in the Figure) usually (but not necessarily) placed outside the house (or office); the outputs 500 of the distribution board 200 are connected downstream of the residual current circuit breaker 300 and they supply all the loads (also not shown in the Figure) of the electrical system of the house (or office), in turn connected to the outputs 500.

The circuit breaker device 100 includes an instantaneous electric power measurement unit 110 connected to a microcontroller 140.

The instantaneous electric power measurement unit 110 comprises a first operational amplifier 112 (the two inputs of which are respectively connected to the phase conductor - e.g. a wire - and to the neutral conductor - e.g. a wire) that outputs an analog signal of measurement of the instantaneous voltage of the mains, and a second operational amplifier 114 (the two inputs of which are respectively connected to the ends of a shunt resistor 170 connected in series to the phase conductor) that outputs an analog signal of measurement of the instantaneous current used (flowing through the resistor 170) by the loads of the electrical system of the house (or office) connected to the outputs 500 of the distribution board 200; the shunt resistor 170 has a known and constant value, optionally ranging from 300 microohms to 500 microohms.

The analog signal of measurement of the instantaneous voltage of the mains and the analog signal of measurement of the used instantaneous current coming from the first and second operational amplifiers 112 and 114, respectively, are sampled by two respective analog to digital converters or ADCs 116 and 118; in particular, the sampling is performed by the two ADC converters 116 and 118 on the basis of the same sampling signal (indicated in the Figure by the arrow 117). However, the components of the instantaneous electric power measurement unit 110 involved in detection and sampling of the signals of measurement of the instantaneous voltage and current introduce a slight phase difference between the two sampled voltage and current signals output, respectively, by the two ADC converters 116 and 118; consequently, one of the two signals, namely the sampled instantaneous current signal output by the ADC converter 118 is treated by a block 120 of digital phase correction (that may be carried out through a delay line and/or a digital filter) and by a digital high-pass filter or HPF 122 downstream of it that eliminates the continuous component resulting from such digital phase correction. In other embodiments of the circuit breaker device according to the invention, the digital phase correction may be carried out on the sampled instantaneous voltage signal output by the ADC converter 116.

The two sampled (i.e. digital) signals, respectively, of voltage and current, after the phase correction, are sent to a multiplier unit 124 that carries out the calculation of the instantaneous digital effective power, eliminating the reactive power component, and that outputs an instantaneous digital effective power signal. The latter is filtered by a digital low-pass filter or LPF 126, for eliminating the residual digital noise, and it is then sent to a power-to-frequency converter 128 that generates on the output 130 of the instantaneous electric power measurement unit 110 a digital pulsed signal the frequency of which is function of the (instantaneous digital effective power signal measured, i.e. of the) instantaneous electric power measured and that is input to the microcontroller 140 (to which the output 130 is connected).

It must be understood that other embodiments of the circuit breaker device according to the invention may comprise instantaneous electric power measurement units different from the one of the device 100 of Figure 1, which provide the microcontroller with a measured instantaneous electric power digital signal, optionally but not necessarily a pulsed signal the frequency of which depends on the measured instantaneous effective power, still remaining within the scope of protection of the present invention. By way of example, and not by way of limitation, such an instantaneous electric power measurement unit may be based on the MCP3911 and PIC18F85K90 devices available from the US company Microchip Technology Inc. as illustrated in document "MCP3911 and PIC18F85K90 Single-Phase Anti-Tamper Energy Meter - Reference Design" by the Microchip Technology Inc., DS52097A, 2013, or it may be based on the MSP430F6736 device available from the US company Texas Instruments Inc. as illustrated in document "Implementation of a Single-Phase Electronic Watt-Hour Meter Using the MSP430F6736" by the same Texas Instruments Inc., SLAA517C-May 2012-Revised March 2014, or it may be based on the HC9S08LH64 device available from the US company Freescale Semiconductor Inc., as illustrated in document "LH60 Single Phase Power Meter - Reference Design" by the same Freescale Semiconductor Inc., DRM133, Rev. 0, 7/2012, or it may be based on the ATxmega32A4U device available from the US company Atmel Corporation, as illustrated in document "Atmel AVR1631: Single Phase Energy Meter using XMEGA A" by the same Atmel Corporation, Rev.: 42039A-AVR-10/2012.

Returning to the circuit breaker device 100 of Figure 1, the microcontroller 140 receives the digital pulsed signal present at the output 130 of the instantaneous electric power measurement unit 110 and, on the basis of such signal, it controls a LED display 150 so as to indicate the value of the measured instantaneous power; the LED display 150 comprises a row of eight consecutive LEDs, wherein the first three LEDs are green (or yellow), followed by four orange LEDs in turn followed by a final red LED. When the microcontroller 140 controls the display 150 so as to turn on only one or more of the three green LEDs, this indicates a moderate electric power (and hence a moderate instantaneous electrical energy consumption) used by the loads connected to the outputs 500 of the distribution board 200; when the microcontroller 140 controls the display 150 so as to turn on, besides the three green LEDs, also one or more of the subsequent four orange LEDs, this indicates a significant electric power (and hence a significant instantaneous electrical energy consumption) used by the loads connected to the outputs 500 of the distribution board 200; when the microcontroller 140 controls the display 150 so as to turn on, besides the three green LEDs and the four orange LEDs, also the final red LED, this indicates an excessive electric power (and hence an excessive instantaneous electrical energy consumption) used by the loads connected to the outputs 500 of the distribution board 200. Obviously, the number and the colour of the LEDs of the display 150 are not an essential feature for the invention. ln particular, when the value of the measured instantaneous electric power exceeds a tolerance threshold PTOL, optionally slightly lower than the contractual limit PCON of instantaneous power esta blished for the electrical system of the house or office (i.e., PTOL < PCON), the microcontroller 140 controls the LED display 150 and a buzzer 160 to carry out visual and acoustic, respectively, signalling so as to draw the attention of a user; by way of example, and not by way of limitation, the microcontroller 140 may control the LED display 150 so that all the LEDs flash at an increasing frequency and it may control the buzzer 160 so as to emit one or more acoustic signals of increasing intensity, until the measured peak does not fall within the standard. In this regard, the value of the tolerance threshold PTOL may be set by an operator installer (or even by a user) by means of a tolerance threshold selection unit 142, provided with a plurality of dip-switches (even if this is not an essential feature for the invention and it could be replaced with any input interface), that is read by the microcontroller 140; by way of example, and not by way of limitation, the dip-switches of the tolerance threshold selection unit 142 may correspond to several contractual limits possible for the contracts for houses or offices, e.g. equal to 1,5 KW-h, 3 KW-h, 4,5 KW-h and 6 KW-h, so that, by selecting the value of the contractual limit PCON of instantaneous power, the microcontroller 140 automatically determines the tolerance threshold PTOL (e.g. equal to 90% or 95% of the contractual limit PCON of instantaneous power).

Other embodiments of the circuit breaker device according to the invention may have the value of the tolerance threshold PTOL that is set at the time of manufacture, e.g. by storing it in a firmware of the microcontroller 140, or it may be set through an external selection device configured to be connected, through a wired or wireless connection, to the microcontroller 140 for setting the operation of the latter.

When a delay time period TDLY is passed from the onset of the condition where the measured instantaneous electric power exceeds the tolerance threshold PTOL, the microcontroller 140 activates a bidirectional thyristor, also known as triac, 180, the control input of which is connected to one of the outputs of the microcontroller 140 (that sends a control signal to the triac 180), so that the triac 180 causes the intervention of the residual current circuit breaker 300 by interrupting the connection of the power supply main line 400 to the loads of the electrical system of the house (or office) connected to the outputs 500. To this end, the triac 180 causes an unbalance in the currents flowing through the two branches (i.e. phase and neutral) of the residual current circuit brea ker 300, by connecting an unbalancing resistor 190 between the phase conductor and the neutral conductor crossing the residual current circuit breaker 300, an end of the unbalancing resistor 190 being connected upstream of and the other one being connected downstream of the residual current circuit breaker 300. I n this way, when the microcontroller 140 activates the triac 180, a current flows through the unbalancing resistor 190 and through only one of the two branches of the residual current circuit breaker 300, ca using its unbalance and, consequently, the intervention (for magnetic effect) a nd thus interrupting the connection to the power supply main line 400. The unbalancing resistor 190 has a calibrated resistance having such a value so as to absorb a current equal to or higher than that needed to make the residual current circuit breaker 300 intervene due to magnetic effect, that typically ranges from 30 milliAm peres to 90 milliAmperes; optionally, the resistance of the unbalancing resistor 190 has such a value so as to absorb a current equal to about 100 milliAmperes.

In other words, the triac 180 operates as a relay unit that connects and disconnects the unbalancing resistor 190 between the phase conductor and the neutra l conductor which cross the residual current circuit breaker 300. Other embodiments of the circuit breaker device according to the invention may have the relay unit implemented in a different way from what illustrated for the device 100 of Figure 1; by way of exa mple, a nd not by way of limitation, the relay unit could be made with any switch, optionally a power semiconductor device, different from a single bidirectional thyristor.

The delay time period TDLY from the onset of the condition where the measured instantaneous electric power exceeds the tolerance threshold PTOL, after which the microcontroller 140 activates the triac 180, is of the order of few tens of seconds, optionally ranging from 10 to 20 seconds. I n the circuit breaker device 100 of Figure 1, the delay time period TDLY may be set by an operator installer (or even by a user) by means of a delay time period selection unit 146, provided with a plurality of dip-switches (even if this is not an essential feature for the invention and it could be replaced with a ny input interface), that is read by the microcontroller 140.

Other embodiments of the circuit breaker device according to the invention may have the delay time period TDLY that is set at the time of manufacture, e.g. by storing it in a firmware of the microcontroller 140, or it may be set through an external selection device configured to be connected, through a wired or wireless connection, to the microcontroller 140 for setting the operation of the latter.

Further embodiments of the circuit breaker device according to the invention may have the microprocessor 140 that activates the triac 180 not only after that the instantaneous electric power measured has exceeded the tolerance threshold PTOL for a delay time period TDLY, but also as soon as the instantaneous electric power measured exceeds an intervention threshold PINT, higher than the tolerance threshold PTOL (i.e. PINT > PTOL), in this case causing the immediate intervention of the residual current circuit breaker 300 and the interruption of the connection to the power supply main line 400. The value of the intervention threshold PINT may be also selectable by an operator or a user and/or it may be set at the time of manufacture and/or it may be set through an external selection device similarly to what shown for the tolerance threshold PTOL. By way of example and not by way of limitation, the intervention threshold PINT may range from 96% to 99% of the contractual limit PCON of instantaneous power.

The unbalancing resistor 190, as well as the shunt resistor 170 a nd the triac 180, are part of the circuit breaker device 100, whereby a n operator installer must only pay attention to respect the correct connections with the phase and neutral conductors upstream and downstream of the residual current circuit breaker 300. I n fact, if the correct connections were not respected, the instantaneous electric power measurement unit 110, the microcontroller 140 and the triac 180 would correctly operate, but the unbalancing resistor 190 would not cause any unbalance in the currents flowing through the two branches of the residual current circuit breaker 300 that, as a consequence, would not switch; in this case, should the instantaneous electric power exceed not only the tolerance threshold PTOL, but the contractual limit PCON of instantaneous power (in the unlikely event that the user does not react to the visual and acoustic warnings of the display 150 and the buzzer 160, respectively), after a short span of time the main thermal magnetic circuit breaker with which the electrical energy meter of the supplier is provided would intervene.

In order to assist an operator installer to respect such connections, the circuit breaker device 100 of Figure 1 further comprises a phase visual indicator 144, optionally a green LED, controlled by the microprocessor 140 so that the phase visual indicator 144 is on when the microprocessor 140 detects that the ends of the unbalancing resistor 190 are connected to the phase conductor and to the neutral conductor of the power supply main line 400 (such detection may be carried out by the microprocessor 140 by checking that an AC voltage is present across the ends of the unbalancing resistor 190). I n other words, the phase visual indicator 144 is configured to be controlled by the microprocessor 140 so as to signal when the ends of the unbalancing resistor 190 are connected to the phase conductor and to the neutral conductor, - Ir respectively, of the power supply main line 400, and an end is connected upstream of and the other end is connected downstream of the residual current circuit breaker 300 the two branches of which are connected to the phase conductor and to the neutral conductor of the power supply main line 400. Advantageously, the phase visual indicator 144 remains on, signalling that the circuit breaker device 100 of Figure 1 is ready to correctly operate.

It must be understood that other embodiments of the circuit breaker device according to the invention may be devoid of the phase visual indicator 144 of the device 100 of Figure 1, or they may be provided with a visual indicator different from a LED; by way of example, the visual indicator could be also integrated in a liquid crystal display or an alphanumeric character display that could further replace and perform the functions of the LED display 150 of the device 100 of Figure 1.

The circuit breaker device 100 of Figure 1 also comprises an optoisolated output interface 148, on which the microprocessor 140 outputs one or more digital signals indicating the measured instantaneous power, for instance one or more pulsed signals having frequency proportional to the measured instantaneous power (e.g., one or more signals identical to the digital pulsed signal present at the output 130 of the instantaneous electric power measurement unit 110). Such one or more digital signals indicating the measured instantaneous power may be used, for instance, to widen the coverage of the visual and/or acoustic signals, for instance by sending one of such digital signals to a range extender that, through a wired or wireless connection, may send such digital signal indicating the measured instantaneous power to one or more displays and/or to one or more buzzers placed in different rooms of the house or office.

Further embodiments of the circuit breaker device according to the invention may be provided of processing unit different from the microcontroller 140 of the device 100 of Figure 1, such as for instance signal processing devices (DSPs), systolic architecture devices, programmable logic devices (PLD) or ASIC devices.

Power supply for the components of the circuit breaker device according to the invention may be supplied by the same power supply main line to which the residual current circuit breaker is connected (through a conventional power supply stage), or it may be supplied by an autonomous battery of the same circuit breaker device.

It is evident from what has been illustrated above that the circuit breaker device according to the invention is configured to carry out a measurement of the instantaneous electric power used by the loads of the electrical system of the house or office, avoiding false interventions caused by reactive loads possibly present in the electrical system. In particular, when provided with a visual signalling device (such as for instance the LED display 150 of the device 100 of Figure 1), it allows to realise with just a glance how much instantaneous electric power is used by the loads of the electrical system and to have a visual feedback about the electrical energy consumptions, allowing a monitoring currently feasible only by means of a control tool inserted in the same electrical system.

Also, the circuit breaker device according to the invention may be manufactured in small size.

Advantageously, the circuit breaker device according to the invention is configured to be mounted on a standard DIN rail (e.g. with top hat-, C- or G-profile), so as to be able to be easily inserted in an already existing typical distribution board.

Finally, the circuit breaker device according to the invention may be advantageously installed to control the instantaneous power used in individual hotel rooms, thus preventing guests from activating energy consuming loads.

The preferred embodiments of this invention have been described and a number of variations have been suggested hereinbefore, but it should be understood that those skilled in the art can make other variations and changes without so departing from the scope of protection thereof, as defined by the attached claims.