Solid state circuit breaker module for integration into power converter

Abstract

A solid state circuit breaker module (17) for integration into a power converter, the circuit breaker module (17) having a housing (19) containing: a. A semiconductor switch (7) acting as a main overcurrent protection means; b. An electromechanical protection relay (9) serving as a fallback over-current protection device; c. A fuse (35) serving as a final overcurrent protection device; d, a current sensor used for detecting overcurrent; e. A controller for tripping the semiconductor switch (7) and the protective relay (9) when the current sensor detects an overcurrent; and f. A sealed gas chamber (29) filled with an arc extinguishing gas, the gas chamber (29) housing the semiconductor switch (7), the protective relay (9) and the fuse (35).

Description

Technical Field

[0001] The present disclosure relates to the field of solid-state circuit breakers. More particularly, the present invention relates to solid-state circuit breakers used as devices for protecting power supplies in a DC power distribution network from electrical faults such as overloads and short circuits. Background Art

[0002] Figure 1 A typical direct current or DC power distribution network 100 is shown, which can be implemented in an office building or a residential building. Such a DC network 100 has one or more power sources, such as the battery of an electric vehicle 102, the public grid 104, storage batteries 106, or photovoltaic panels 108. The DC network 100 also has a central distribution bus 110 to distribute power from the power sources 102, 104, 106, 108 to various loads 112. Each power source 102, 104, 106, 108 is connected to the central bus 110 via a power converter 114. Each power converter 114 converts the current delivered by the corresponding power source to match the rated voltage of the central bus 110.

[0003] The power sources 102, 104, 106, 108 must be protected from overcurrents, which may typically be caused by overloads and short circuits in the DC network 100. To this end, a circuit breaker 116 is connected between each power source 102, 104, 106, 108 and the central bus 110, i.e. to the output of each power converter 114.

[0004] It would be advantageous to integrate the circuit breakers 116 with their corresponding power converters 114. This would reduce the number of separate components of the DC network 100, making it more compact and easier to set up. Summary of the Invention

[0005] In view of the above, an object of the present disclosure is to provide a compact circuit breaker that is well suited for overcurrent protection of power supplies in DC power distribution networks. In particular, the proposed circuit breaker should be easy to integrate into existing power converters.

[0006] According to the present disclosure, the object is achieved by a solid-state circuit breaker module for integration into a power converter, the circuit breaker module having a housing containing a semiconductor switch serving as a main overcurrent protection device, an electromechanical protection relay serving as a fallback overcurrent protection device, a fuse serving as a limit overcurrent protection device, a current sensor for detecting overcurrent, a controller for tripping the semiconductor switch and the protection relay when the current sensor detects overcurrent, and a sealed gas chamber filled with arc extinguishing gas, the gas chamber containing the semiconductor switch, the protection relay and the fuse.

[0007] In fact, by arranging the primary overcurrent protection device, the fallback overcurrent protection device and the final overcurrent protection device, i.e., the semiconductor switch, the protection relay and the fuse, in a single sealed gas chamber, a compact circuit breaker module can be obtained, which can be directly installed in the power converter. In this way, the circuit breaker becomes an integral part of the power converter. By using the circuit breaker module of the present disclosure, it is thus possible to replace the power converter with a single power converter with a protected output. Figure 1 Each component pair 114, 116 in.

[0008] The following features can optionally be implemented individually or in combination with each other:

[0009] - The controller is located outside the sealed gas chamber;

[0010] - an input / output connector on the housing for communicating between the controller and an external device connected to the circuit breaker module via the input / output connector;

[0011] - an inductor which delays the current rise in the event of an overcurrent, the inductor being arranged inside the gas chamber;

[0012] - A fuse is a bonding wire that interconnects a semiconductor switch and a protective relay. The bonding wire is designed to melt in the presence of a sustained overcurrent.

[0013] - a rotatable key socket on the housing, which can be rotated by inserting a hand key therein and turning it to reset the protection relay if it trips;

[0014] - a protection relay comprising two spaced-apart fixed contacts, a displaceable contact, and a displaceable device, wherein the displaceable contact is displaceable between a closed state and an open state, wherein in the closed state, the displaceable contact contacts the two fixed contacts and thereby establishes an electrical connection between the two fixed contacts, and in the open state, the displaceable contact is separated from the two fixed contacts so that the two fixed contacts are electrically isolated, and the displaceable device is used to displace the displaceable contact from its closed state to its open state, wherein the displaceable device comprises a rotatable rod, a coil spring, and an electromagnetic coil, wherein rotation of the rotatable rod displaces the displaceable contact, the coil spring urges the rotatable rod to rotate to a position corresponding to the open state of the displaceable contact, and the electromagnetic coil, when energized, resists the urging of the coil spring to maintain the rotatable rod in a position corresponding to the closed state of the displaceable contact, and wherein the controller trips the protection relay by de-energizing the electromagnetic coil;

[0015] - the rotatable rod comprises a ferromagnetic material and is positioned adjacent to a wall of the gas chamber, the circuit breaker module further comprising a rotatable permanent magnet positioned adjacent to the rotatable rod on an opposite side of the gas chamber wall, and when the protection relay is reset by rotating the key socket, the permanent magnet follows the rotation of the key socket, thereby magnetically inducing rotation of the rotatable rod across the gas chamber wall, thereby displacing the movable contact to its closed state against the urging of the coil spring;

[0016] The gas chamber is delimited by a rigid housing and an elastic sealing bellows arranged in the rigid housing, the bellows being in mechanical contact with the protection relay to allow the protection relay to be reset from outside the gas chamber by a mechanical action on the bellows. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] These and other features, details and advantages will be set forth in the following detailed description and accompanying drawings, in which:

[0018] [ Figure 1 ] shows a known DC power distribution network in which the circuit breaker module of the present disclosure can be implemented.

[0019] [ Figure 2 ] is a diagram of an electrical circuit that may be implemented in a circuit breaker module according to the present disclosure.

[0020] [ Figure 3 ] is a top view of a circuit breaker module according to the present disclosure.

[0021] [ Figure 4 ]yes Figure 3 Cutaway side view of a circuit breaker module.

[0022] [ Figure 5 ]yes Figure 3 Another cross-sectional side view of a circuit breaker module, showing the arrangement inside the gas compartment.

[0023] [ Figure 6 ] means Figures 3 to 5 Schematic diagram of the components of the shifting device of the protective relay of the circuit breaker module.

[0024] [ Figure 7 ] can be Figures 3 to 5 Illustration of a bond wire fuse used in a circuit breaker module.

[0025] [ Figure 8 ]and[ Figure 9 ] shows different embodiments of the present disclosure having an elastic sealing bellows that allows the protection relay to be reset from outside the gas chamber. DETAILED DESCRIPTION

[0026] The solid-state circuit breaker modules, now described in detail, are stand-alone electrical units designed to be integrated into larger electrical devices. In a preferred application, these solid-state circuit breaker modules can be integrated into a power converter. More specifically, by assembling the solid-state circuit breaker modules of the present disclosure between the DC link capacitor and the output terminals of the power converter, the output of the power converter can be protected from overcurrent. The solid-state circuit breaker modules of the present disclosure can, for example, be mounted on a printed circuit board of the power converter to be protected.

[0027] When used as protection devices in a power distribution network, solid-state circuit breaker modules as described herein would each be installed next to the source they protect. This distributed / decentralized protection architecture is advantageous because it eliminates the need for a traditional central distribution cabinet housing many individual circuit breakers.

[0028] The solid-state circuit breaker module of the present disclosure generally has the following features: Figure 2 The circuit shown. This circuit 1 (delimited by the dashed rectangle) is a DC circuit with two inputs, L+IN and L-IN, and two outputs, L+OUT and L-OUT. It is a protection circuit that protects a source 3 connected to its inputs, L+IN and L-IN, from overcurrent. Protection circuit 1 provides bidirectional protection, meaning it not only protects source 3 from overcurrent but also protects load 5 connected to its outputs, L+OUT and L-OUT. This will be explained in more detail further below.

[0029] The protection circuit 1 includes a main overcurrent protection device, namely one or more semiconductor switches 7, a fallback overcurrent protection device, namely an electromechanical protection relay 9, a current sensor 11 for detecting overcurrent, a current rise delay / timing inductor 13, and a controller 15 connected to the semiconductor switch 7, the current sensor 11 and the protection relay 9.

[0030] exist Figure 2 In the protection circuit 1 shown, the main overcurrent protection device includes two semiconductor switches 7.1 and 7.2. Each semiconductor switch 7.1 and 7.2 is implemented as a transistor, here an N-channel MOSFET in depletion mode. Other transistors or other semiconductor devices can be used instead. The first semiconductor switch 7.1 protects the source 3 from overcurrent, and the second semiconductor switch 7.2 protects the load 5 from overcurrent. In practice, as shown in FIG. Figure 2 It can be clearly seen that the two transistors 7.1, 7.2 are connected in anti-series. The controller 15 can act on the gates of the transistors 7.1 and 7.2 to trip one or the other or both in the event of an overcurrent.

[0031] like Figure 2As shown in the bottom panels A and B, the primary overcurrent protection device can also have a single semiconductor switch 7.1 instead of two semiconductor switches. The single semiconductor switch 7.1, which can also preferably be a transistor, will then only protect the source 3 from overcurrent, without protecting the load 5. As is clear from panel A, a diode 8 can be added in series with the single transistor 7.1 to ensure that power can flow in only one direction, from the source 3 to the load 5.

[0032] Returning to the protection circuit 1, a current sensor 11 is connected in series with the semiconductor switches 7.1 and 7.2. The current sensor 11 can be implemented as a resistor. The controller 15 monitors the voltage across the resistor 11 and thus the current.

[0033] The protection relay 9 is connected downstream of and in series with the transistors 7.1 and 7.2 and the current sensing resistor 11. When the current sensor 11 detects an overcurrent, the controller 15 trips the protection relay 9 simultaneously with the first transistor 7.1 and / or the second transistor 7.2.

[0034] A time-buyer inductor 13 is connected in series between the protective relay 9 and the output L+OUT. In the event of an overcurrent, the time-buyer inductor 13 delays the current rise so that the current interruption components, i.e. the semiconductor switches 7.1, 7.2 and the protective relay 9 (if applicable), have sufficient time to react and open the circuit.

[0035] refer to Figures 3 to 5 , we will now describe the physical layout of an exemplary solid-state circuit breaker module according to the present disclosure.

[0036] Figures 3 to 5 The solid-state circuit breaker module 17 shown in FIG is a stand-alone device that can be purchased separately. It can be mounted on a printed circuit board along with other modules or electronic components.

[0037] Solid-state circuit breaker module 17 includes Figure 2 Protection circuit 1.

[0038] The circuit breaker module 17 is defined by a housing 19. A pair of input terminals 21.1 and 21.2 are arranged at one end of the housing 19. A pair of output terminals 23.1, 23.2 are arranged at the other end of the housing 19. A source 3 can be connected to the input terminal 21, and a load 5 can be connected to the output terminal 23 (see FIG. Figure 3). Under normal operating conditions, power flows from the source 3 to the load 5 via the circuit breaker module 17. However, in the event of an overcurrent, the circuit breaker module 17 will interrupt the flow of current from the source 3 to the load 5. In other words, the circuit breaker module 17 is arranged between the source 3 and the load 5 and can disconnect the load 5 from the source 3, for example, in the event of a short circuit or if the load 5 overloads the source 3.

[0039] The circuit breaker module 17 may include a cooling plate 22, which may be arranged at the bottom of the housing 19. The cooling plate 22 may be implemented as a metal substrate. The function of the cooling plate 22 is to absorb the heat generated by the protection circuit 1 during operation of the circuit breaker module 17. When the circuit breaker module 17 is integrated into a larger device, such as a power converter, its cooling plate 22 may be in contact with a heat sink 24 of the larger device, see Figure 5 In such a configuration, the heat generated by the circuit breaker module 17 is dissipated by the larger device's heat sink 24. Thus, the circuit breaker module 17 can be designed without any heat sink.

[0040] The circuit breaker module 17 may also have an input-output connector 25 located on the housing 19. The input-output connector 25 includes a set of connection pins 27. The input-output connector 25 is an interface that allows communication between the circuit breaker module's controller 15 and an external device (e.g., a microcontroller of a power converter into which the circuit breaker module 17 is integrated). Thus, an external device can be connected to the circuit breaker module 17 via the input-output connector 25. The pins 27 of the input-output connector 25 can be used, for example, to supply power to the circuit breaker module 17, synchronize the voltage with the voltage of the power grid to which the circuit breaker module 17 is connected, indicate an error (overload, overcurrent, overvoltage, overtemperature) to an external device, or switch the circuit breaker module 17 on or off.

[0041] refer to Figure 4 The sealed gas chamber 29 filled with arc extinguishing gas is located inside the housing 19. The sealed gas chamber 29 is located inside the housing 19. Figure 2 The arc extinguishing gas in the gas chamber 29 may be an inert gas, such as sulfur hexafluoride (SF6).

[0042] According to the present disclosure, the gas chamber 29 contains the main components of the circuit breaker module 17 related to interrupting the current, in particular one or more semiconductor switches 7 and the protection relay 9. Preferably, the time delay inductor 13 is also arranged inside the single gas chamber 29. By concentrating the main current interruption components in a single gas chamber, the circuit breaker module 17 becomes very compact. The resulting small size of the circuit breaker module 17 allows it to be easily integrated into, for example, a power converter. Figure 2 and Figure 4As can be clearly seen in FIG, the controller 15 is located inside the housing 19, but outside the sealed gas chamber 29. The controller 15 can be located on top of the sealed gas chamber 29.

[0043] Preferably, a rotatable key socket 31 is arranged on the housing 19. The hand key 33 (see Figure 4 and Figure 5 ) can be inserted into the rotatable socket 31. Turning the inserted hand button 33 causes the rotation of the socket 31, and when the protection relay 9 is tripped, the socket 31 resets the protection relay 9.

[0044] In the illustrated embodiment, see Figure 5 The sealed gas chamber 29 also contains a fuse 35 which serves as a final overcurrent protection device. If one or more semiconductor switches 7 and the protection relay 9 fail to open the circuit in the event of an overcurrent, the fuse 35 will blow.

[0045] Preferably, the fuse 35 is implemented as a bond wire interconnecting the one or more semiconductor switches 7 and the protection relay 9. The bond wire 35 is designed to melt in the presence of a sustained overcurrent. Figure 7 An exemplary wire bond fuse 35 is shown in FIG. This particular wire bond 35 has a section 37 of reduced cross-section. If an excess current I flows through the wire bond fuse 35, the thinner section 37 will overheat and melt. Consequently, the wire bond 35 will be cut in two, and current will cease to flow therethrough.

[0046] We will now refer to Figure 5 and Figure 6 The setting of the protection relay 9 is described.

[0047] from Figure 5 As can be clearly seen in the figure, the protection relay 9 includes two spaced-apart fixed contacts 39.1 and 39.2, a displaceable contact 41, and a displacement device for displacing the displaceable contact 41. Although the present embodiment discloses two fixed contacts 39.1 and 39.2, it should be understood that the protection relay may include more than two fixed contacts, for example, 2xn contacts, where n is an integer greater than 1. When the protection relay 9 trips, having more contacts allows the displacement device to have a reduced travel relative to the required dielectric insulation.

[0048] like Figure 5 As shown by the double arrow F in FIG. 4 , the displaceable contact 41 can be moved up and down. More specifically, the displaceable contact 41 can be displaced between a closed state and an open state. In the closed state, the displaceable contact 41 contacts the two fixed contacts 39.1 and 39.2 and thus establishes an electrical connection between the two fixed contacts, as shown in FIG. Figure 5As shown, in the open state, the displaceable contact 41 is separated from the two fixed contacts 39.1 and 39.2, electrically isolating the two fixed contacts. Under normal operating conditions, the displaceable contact 41 is in the closed state, allowing current to flow through the circuit breaker module 17. In the event of an overcurrent, the controller 15 trips the protective relay 9, causing the displaceable contact 41 to move from the closed state to the open state. When the displaceable contact 41 is in the open state, no current can flow through the circuit breaker module 17. Any arc generated when the displaceable contact 41 moves away from the fixed contacts 39.1 and 39.2 is extinguished by the inert gas in the sealed gas chamber 29.

[0049] The shifting device of the protective relay 9 includes a rotatable rod 43, a coil spring 45, an electromagnetic coil 47, and a locking bolt 49. The rotatable rod 43 is mechanically connected to the displaceable contact 41, so that rotation of the rotatable rod 43 causes the displaceable contact 41 to move between its open state and its closed state. The coil spring 45 pushes the rotatable rod 43 to rotate to a position corresponding to the open state of the displaceable contact 41. Thus, the rotatable rod 43 can rotate between a reeled position corresponding to the closed state of the displaceable contact 41 and an unreeled position corresponding to the open state of the displaceable contact 41.

[0050] The function of the locking bolt 49 is to keep the rotatable rod 43 in the reeled position and thereby keep the protection relay 9 in the closed position. In order to keep the rotatable rod 43 in the reeled position, the locking bolt 49 is inserted into a complementary groove 51 of the rotatable rod 43 .

[0051] The protection relay 9 can be tripped by removing the locking bolt 49 from the groove 51 in the rotatable rod 43. In fact, when the locking bolt 49 is removed from the groove 51, the rotatable rod 43 will rotate to the extended position under the urging of the coil spring 45, which in turn will cause the displaceable contact 41 to enter the open state.

[0052] The insertion and removal of the locking bolt 49 into the groove 51 are controlled by the electromagnetic coil 47. Figure 6 As can be clearly seen, the electromagnetic coil 47 surrounds the locking bolt 49. The locking bolt 49 acts like a plunger inside the electromagnetic coil 47. When the electromagnetic coil 47 is energized, it pushes the locking bolt 49 into the corresponding groove 51. When the controller 15 de-energizes the electromagnetic coil 47, the locking bolt 49 falls back into the coil 47, as shown in FIG. Figure 6 Therefore, when energized, the coil 47 holds the rotatable rod 43 at a position corresponding to the closed state of the displaceable contact 41 against the urging force of the coil spring 45. In summary, the controller 15 trips the protection relay 9 by deenergizing the electromagnetic coil 47.

[0053] The rotatable rod 43 of the displacement device just described cooperates with a rotatable permanent magnet 53 (for example a bar magnet) which is fitted onto the rotatable key socket 31, see Figure 5 The permanent magnet 53 rotates in unison with the key socket 31 . Therefore, twisting of the hand key 33 causes a corresponding rotation of the key socket 31 and the permanent magnet 53 .

[0054] from Figure 5 , it can be clearly seen that the permanent magnet 53 is close to the rotatable rod 43 of the protective relay 9. In fact, the permanent magnet 53 and the rotatable rod 43 are located on opposite sides of the upper wall 55 of the gas chamber 29. More precisely, the permanent magnet 53 is arranged near the gas chamber wall 55, outside the gas chamber 29, and the rotatable rod 43 is also arranged near the gas chamber wall 55, but inside the gas chamber 29. In other words, the permanent magnet 53 and the rotatable rod 43 face each other while being separated by the gas chamber wall 55.

[0055] The rotatable rod 43 comprises a ferromagnetic material. Therefore, the rotatable rod 43 is susceptible to the magnetic force exerted by the permanent magnet 53 through the gas chamber wall 55.

[0056] refer to Figure 5 The contact sensor 44 is arranged in the gas chamber 29 above the protection relay 9. The contact sensor 44 is adapted to detect the current state of the protection relay 9, i.e., whether the relay 9 is in the operating state or the tripped state. The contact sensor 44 may be, for example, a device that monitors the current drawn by the electromagnetic coil 47.

[0057] We will now explain how the protection relay 9 can be reset by means of the hand key 33 and the rotatable key socket 31 once the protection relay 9 has tripped.

[0058] The protective relay 9 is reset as follows: the user inserts the hand key 33 into the key socket 31 and rotates it. This causes the key socket 31 to rotate, and the permanent magnet 53 follows this rotation. The rotation of the permanent magnet 53 magnetically induces the rotation of the rotatable rod 43 through the gas chamber wall 55. The rotation of the rotatable rod 43 then causes the displaceable contact 41 to move to its closed state, overcoming the urging force of the coil spring 45. This reestablishes the electrical connection between the two fixed contacts 39.1 and 39.2, and the protective relay 9 is reset.

[0059] It should be noted that the arrangement just described with the external permanent magnet 53 acting on the magnetic rod 43 inside the gas chamber 29 is particularly advantageous since it allows resetting the protection relay 9 from outside the gas chamber 29 without compromising the sealing of the gas chamber 29. Thanks to this arrangement, the protection relay 9 can be located inside the sealed gas chamber 29 and still be controlled from the outside.

[0060] Now go to Figure 8 and Figure 9 , these two figures show a second embodiment, which also has a protective relay 9 within a sealed gas chamber 29 and a mechanism for resetting the protective relay 9 from outside the gas chamber 29, which maintains the sealing of the gas chamber 29. In this second embodiment, the permanent magnet 53 and the magnetic rod 43 are replaced by a resilient sealing bellows 57. Here, the gas chamber 29 is bounded by a rigid housing 59 and the resilient sealing bellows 57 disposed within the rigid housing 59. The bellows 57 is in mechanical contact with the protective relay 9, allowing the protective relay 9 to be reset from outside the gas chamber 29 by mechanical action on the bellows 57.

[0061] Figure 8 The bellows 57 and the protective relay 9 are shown in a normal operating state, wherein the protective relay 9 is closed. According to one embodiment, a mechanical latch (not shown) can be used instead of the electromagnetic coil 47 to maintain the displaceable contact 41 in a closed state with the fixed contact 39, thereby allowing for reduced electromagnetic power consumption.

[0062] Figure 9 The bellows 57 and the protective relay 9 are shown in the tripped state, wherein the protective relay 9 is open. To move from the normal operating state to the tripped state, the coil spring 45 pushes the displaceable contact 41 away from the fixed contact 39. The stiffness of the coil spring 45 can be designed to find a trade-off between sufficient opening speed for movement from the normal operating state to the tripped state and reduced power consumption of the electromagnetic coil 47.

[0063] Since the force exerted by the coil spring 45 on the movable contact 41 is greater than the force exerted by the bellows 57 , a gap remains between the movable contact 41 and the fixed contact 39 in the tripped state.

[0064] To reset the displaceable contact 41 back to the normal operating state, a mechanical action may be applied to the displaceable contact 41 from outside the sealed gas chamber 29. When the bellows 57 and the electromagnetic coil 47 (or a mechanical latch) apply a cumulative force on the displaceable contact 41 that is greater than the cumulative force from the coil spring 45, the displaceable contact 41 remains in the normal operating state.

[0065] Due to the elastic sealing bellows 57 , one can reconcile the two conflicting aims of keeping the gas chamber 29 sealed and being able to control the protective relay 9 from the outside.

[0066] Furthermore, in an embodiment, the module 17 may include a mechanical position indicator to indicate the state of the protection relay 9. This indicator may be a bellows 57 that is directly visible through the housing 59. This arrangement thus allows the position of the bottom of the bellows 57 to directly and mechanically reflect the state of the displaceable contact 41.

Claims

1. A solid-state circuit breaker module (17) for integration into a power converter (114), the circuit breaker module (17) having a housing (19), the housing (19) containing: a semiconductor switch (7), which serves as the main overcurrent protection device; b. an electromechanical protection relay (9) serving as a fallback overcurrent protection device; c. a fuse (35) which serves as a final overcurrent protection device; d. a current sensor (11) for detecting an overcurrent; e. a controller (15) for tripping the semiconductor switch (7) and the protection relay (9) when the current sensor (11) detects an overcurrent (I); and f. A sealed gas chamber (29) filled with arc extinguishing gas, the gas chamber (29) accommodating the semiconductor switch (7), the protection relay (9) and the fuse (35).

2. The circuit breaker module (17) according to claim 1, wherein The controller (15) is located outside the sealed gas chamber (29).

3. The circuit breaker module (17) according to any one of the preceding claims, further comprising an input / output connector (25) on the housing (19) for communicating between the controller (15) and an external device (114), the external device (114) being connected to the circuit breaker module (17) via the input / output connector (25).

4. The circuit breaker module (17) according to any of the preceding claims, further comprising an inductor (13) to delay the current rise in the event of an overcurrent (I), the inductor (13) being arranged in the gas chamber (29).

5. A circuit breaker module (17) according to any one of the preceding claims, wherein The fuse (35) is a bonding wire interconnecting the semiconductor switch (7) and the protection relay (9), the bonding wire being designed to melt in the presence of a sustained overcurrent (I).

6. The circuit breaker module (17) according to any one of the preceding claims, further comprising a rotatable key socket (31) on the housing (19) which can be rotated by inserting and turning a manual key (33) therein to reset the protection relay (9) when the protection relay is tripped.

7. A circuit breaker module (17) according to any one of the preceding claims, wherein The protection relay (9) comprises: a. two spaced apart fixed contacts (39); b. A displaceable contact (41) capable of being displaced between the following states: i. a closed state in which the displaceable contact contacts two fixed contacts (39) and thus establishes an electrical connection between the two fixed contacts, and ii. an off state in which the displaceable contact is separated from the two fixed contacts (39) so that the two fixed contacts are electrically isolated; and c. a shifting device for shifting the shiftable contact (41) from its closed state to its open state, wherein the shifting device comprises: i. a rotatable rod (43) wherein rotation of the rotatable rod causes the displaceable contact to be displaced; ii. a coil spring (45) which pushes the rotatable lever to rotate to a position corresponding to the off state of the displaceable contact (41); iii. an electromagnetic coil (47) which, when energized, holds the rotatable lever (43) in a position corresponding to the closed state of the displaceable contact (41) against the urging of the coil spring, And wherein the controller (15) trips the protection relay (9) by de-energizing the electromagnetic coil (47).

8. The circuit breaker module (17) according to claim 7 in combination with claim 6, wherein: a. The rotatable rod (43) comprises a ferromagnetic material and is located near a wall (55) of the gas chamber (29); b. The circuit breaker module (17) further comprises a rotatable permanent magnet (53) located adjacent to the rotatable rod (43) on the opposite side of the gas chamber wall (55); and c. When the protection relay (9) is reset by rotating the key socket (31), the permanent magnet (53) follows the rotation of the key socket (31), thereby magnetically causing the rotation of the rotatable rod (43) through the gas chamber wall (55), thereby overcoming the urging of the coil spring (45) and moving the movable contact (41) to its closed state.

9. The circuit breaker module (17) according to any one of claims 1 to 6, wherein: The gas chamber (29) is delimited by a rigid housing (59) and an elastic sealing bellows (57) arranged in the rigid housing, the bellows (57) being in mechanical contact with the protection relay (9) to allow the protection relay to be reset from outside the gas chamber (29) by a mechanical action on the bellows (57).

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