Retractable hybrid switching device

Abstract

To provide a drawable type hybrid switching device capable of overcoming or alleviating a known technical problem.SOLUTION: A switching device for power distribution grid includes: a drawable first switching unit with one or more first electric poles; a drawable second switching unit having one or more second electric poles and electrically connected in series to the first switching unit; and a controller mounted with control countermeasures orientated to improve the safety of an operation of withdrawing the first and second switching units.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a switching device for a power distribution grid, such as a circuit breaker or a device of the same type.

Background Art

[0002] As is known, low-voltage switching devices are used in electrical circuits or power distribution grids, enabling the precise operation of specific electrical circuit parts or specific power distribution network parts. For example, these devices are used to ensure the availability of the nominal current required for some equipment, enable the proper plugging and disconnection of electrical loads, and protect the power distribution grid and the set electrical loads against fault events such as overloads and short circuits (especially circuit breakers).

[0003] Most conventional switching devices include an electromechanical switching unit having one or more electrical poles, each of which has a pair of electrical contacts provided to connect or disconnect, enabling or blocking the line current along the electrical pole. Although they have proven to be very robust and reliable, electromechanical switching devices exhibit relatively long interruption times mainly at relatively high voltages (DC, between 1 kV and 1.5 kV) with DC application. As a result, the electric arc that occurs between the usually separated electrical contacts can last for a relatively long time. This often causes a serious wear phenomenon of the electrical contacts, resulting in a significant decrease in operational reliability and electrical durability.

[0004] To overcome these technical problems, they are designed as switching devices (also called solid-state circuit breakers "SSCBs") that include a switching unit having one or more solid-state switches for each electrical pole, i.e., semiconductor-based transistors or thyristors adapted to operate in a conducting state that enables current flow or a blocking state that interrupts current flow. The main advantage of SSCBs lies in their potentially unlimited electrical endurance, as the interruption operation is performed without forming an electric arc. Furthermore, their interruption time is significantly shorter compared to that of electromechanical switching devices. A significant drawback of solid-state switchbacks (SSCBs) is that they generally cannot provide electrical insulation between the line conductors connected to each other. In fact, when a voltage is applied to the power terminals of a solid switch (e.g., the collector and emitter terminals of an IGBT), leakage current typically flows even when the switch is in the blocked position.

[0005] Recently, these have evolved into switching devices that include both SSCB-type switching units and electromechanical-type switching units, which are electrically connected in series. These switching devices (commonly called "hybrid switching devices") allow for the full utilization of all the advantages offered by SSCBs in terms of reliability and reduced interruption time, in addition to enabling electrical isolation between the line conductors connected to each other. Many hybrid switching devices are of the "pull-out" type. In this case, both the SSCB unit and the electromechanical switching unit can move relative to the fixed part of the switching device. Specifically, each switching unit is mounted on a trolley so that it can move reversibly between an inserted position and a pulled-out position relative to the fixed part of the switching device. The "pull-out" type of hybrid switching device has several advantages in terms of efficiency of use. [Overview of the project] [Problems that the invention aims to solve]

[0006] However, these switching devices have several aspects that could be improved, particularly regarding the coordinated control of the SSCB switching unit and the electromechanical switching unit during operation. With the control measures currently in place, these switching devices cannot operate in a completely safe manner, especially when the SSCB switching unit needs to be withdrawn for any reason. The main objective of the present invention is to provide a drawable type hybrid switching device that can overcome or mitigate the aforementioned problems of known technologies. [Means for solving the problem]

[0007] Within the scope of this objective, the present invention aims to provide a switching device that ensures a high level of safety and efficiency in operation. Another object of the present invention is to provide a switching device whose operation can be easily controlled without requiring complex and expensive control resources. Yet another object of the present invention is to provide a switching device that is relatively easy and inexpensive to manufacture at an industrial level. [Effects of the Invention]

[0008] These objectives and their results are achieved by the switching device of the present invention according to claim 1 and its dependent claims presented below, together with other objectives evident from the following description and accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] A diagrammatic illustration of the switching device according to the present invention is shown. [Figure 2] The operation of the switching device according to the present invention is illustrated diagrammatically. [Figure 3] The operation of the switching device according to the present invention is illustrated diagrammatically. [Modes for carrying out the invention]

[0010] The switching device of the present invention is One or more first line terminals provided to be electrically connected to the corresponding first line conductor of the electric wire, One or more second line terminals provided to be electrically connected to the corresponding second line conductor of the aforementioned electric wire, A first switching unit having one or more first electric poles, A second switching unit having one or more second electric poles, A first actuator provided to move the first switching unit during an operation to pull out the first switching unit based on activation by the user, A second actuator is provided to operate the second switching unit during an operation to pull out the second switching unit based on activation by the user, The system includes a control device provided to control the operation of the switching device.

[0011] Each first electric pole comprises a first pole contact, a second pole contact, and one or more solid switches, which are electrically connected to the corresponding first line terminals, and which are configured to operate to allow current to flow when conducting and to interrupt current when blocking. The first switching unit can reversibly switch between a closed state and an open state, where the solid switch is conductive in the closed state and blocked in the open state. The first switching unit can move reversibly between an inserted state and an extended state. In the inserted state, the first pole contact is connected to the first line terminal, and in the extended state, the first pole contact is separated from the first line terminal.

[0012] Each second electric pole comprises a third pole contact provided to be electrically connected to a corresponding second pole contact of the first switching unit, a fourth pole contact provided to be electrically connected to a corresponding second line terminal, and electrical contacts provided to be electrically connected to the third and fourth pole contacts, wherein the electrical contacts are provided to operate in a connected state (connected state) in which current can flow or in a disconnected state (unconnected state) in which current cannot flow. The second switching unit can reversibly switch between a closed state and an open state, where the electrical contacts are connected in the closed state and separated in the open state. The second switching unit can move reversibly between an inserted state and an extended state. In the inserted state, the fourth pole contact is connected to the second line terminal, while in the extended state, the fourth pole contact is not connected to the second line terminal.

[0013] According to the present invention, the control device of the switching device is configured to prevent the first actuator from moving the first switching unit from the inserted state to the pulled-out state, even if the user starts it up, when at least one of the first switching unit and the second switching unit is in the closed state. According to the present invention, the control device of the switching device is configured such that, when both the first switching unit and the second switching unit are in an open state, the first actuator allows the first switching unit to move from an inserted state to an extended state based on activation by the user.

[0014] Preferably, the first actuator of the switching device comprises a first actuator means operably connected to a first switching unit, a first command means that can be activated by a user to issue a command to the first actuator means to move the first switching unit from an inserted state to an unplugged state, and a first enable means provided to enable or disable the first command means in response to a control signal received by the control device.

[0015] Preferably, the first actuating device comprises activation detection means for supplying a detection signal indicating activation (activation) of the first command means by the user to the control device. Preferably, the second actuating device of the switching device is provided to move the second switching unit from the inserted state to the withdrawn state based on activation (activation) by the user only when the second switching unit is in the open state.

[0016] Preferably, the second actuating device includes second actuating means operably connected to the second switching unit, second command means that can be activated by the user to issue a command to the second actuating means to move the second switching unit from the inserted state to the withdrawn state, and second enabling means provided to enable or disable the second command means according to the operating state of the electrical contacts of the second switching unit.

[0017] Preferably, the second enabling means is provided to disable the second command means when the electrical contacts of the second switching unit are in the connected state, and to enable the second command means when the electrical contacts of the second switching unit are in the separated state.

[0018] According to one aspect of the present invention, the control device of the switching device is provided to control the operating states of the first switching unit and the second switching unit so that the first switching unit and the second switching unit operate in a combination according to the first, second or third operation modes. The first operation mode corresponding to the closed state of the switching device is an operation mode in which both the first switching unit and the second switching unit are in the closed state. The second operation mode corresponding to the standby state of the switching device is an operation mode in which the first switching unit is in the open state and the second switching unit is in the closed state. The third operation mode corresponding to the open state of the switching device is an operation mode in which both the first switching unit and the second switching unit are in the open state.

[0019] Preferably, when the first switching unit and the second switching unit are operating in a combination according to the first operation mode or the second operation mode, the control device is configured to prevent the first operating device from moving the first switching unit from the inserted state to the pulled-out state. When the first switching unit and the second switching unit are operating in a combination according to the third operation mode, the control device is configured to permit the first operating device to move the first switching unit from the inserted state to the pulled-out state based on activation by the user.

[0020] Preferably, the second operating device of the switching device is provided to move the second switching unit from the inserted state to the pulled-out state based on activation by the user only when the first switching unit and the second switching unit are operating in a combination according to the third operation mode.

[0021] According to one aspect of the present invention, the control device of the switching device includes an interface unit including one or more input ports provided to receive an input command indicating a desired operating state for the switching device.

[0022] Preferably, the switching device includes a human machine interface provided to be communicable with the interface unit. The human machine interface is provided to supply the input command based on interaction with the user. Preferably, the interface unit can receive the input command from a remote computer device. According to one aspect of the present invention, the control device of the switching device is included in the first switching unit.

[0023] Further features and advantages of the present invention will become more apparent from the description of preferred but non-exclusive embodiments, which are described purely as illustrative and not limited to the accompanying drawings.

[0024] Referring to the aforementioned drawings, the present invention relates to a switching device 100 for a power distribution grid, such as a circuit breaker, disconnector, contactor, or the like. The switching device 100 is particularly suitable for installation in low-voltage power distribution grids or systems. However, it may also be successfully adopted in a medium-voltage distribution grid or system. For the purposes of this invention, the term "low voltage" (LV) refers to operating at voltages lower than 1 kV AC and 1.5 kV DC, while the term "medium voltage" (MV) refers to higher operating voltages up to several tens of kV, for example, up to 72 kV AC and 100 kV DC.

[0025] Generally, the switching device 100 is provided to be electrically connected to the electric wire 50. The electric wire 50 comprises one or more first line conductors 51 and one or more second line conductors 52, the first line conductors 51 can be electrically connected to an equivalent power source (e.g., a power supply system or a power generation system or a part of a power distribution grid), and the second line conductors 52 can be connected to an equivalent electrical load (e.g., an electrical system or electrical equipment or a part of a power distribution grid). In the embodiment shown in the referenced drawings, the electric wire 50 is of a three-phase type. However, in principle, it can include a different number of phases.

[0026] The switching device 100 includes one or more first line terminals 91 provided to be electrically connected to the corresponding first line conductor 51 of the electric wire 50, and one or more second line terminals 92 provided to be electrically connected to the corresponding second line conductor 52 of the electric wire 50. Conveniently, the first line terminal 91 and the second line terminal 92 are housed in a fixed section (not shown) of the switching device, which is conveniently defined by a support frame (not shown) of the switching device.

[0027] The switching device 100 comprises an SSCB type first switching unit 1 and an electromechanical type switching unit 2, which are electrically connected in series between the line terminals 91 and 92 described above during operation. The SSCB switching unit 1 comprises one or more first electric poles 1A. The number of electric poles of the SSCB switching unit 1 can be varied as needed. In the embodiment shown in the cited drawings, the SSCB switching unit is of the three-phase type and comprises three electric poles. However, according to other embodiments of the present invention (not shown), the SSCB switching unit may include a different number of electric poles.

[0028] Each electric pole 1A is provided to be electrically connected to the corresponding first line conductor 51 of the electric wire 50, and also to be electrically connected to the electric pole of the electromechanical switching unit 2. Each electric pole 1A is equipped with a first pole contact 11 and a second pole contact 12, the first pole contact being provided to be electrically connected to the corresponding first line terminal 91 of the switching device, and the second pole contact being provided to be electrically connected to the corresponding pole contact 23 of the electromechanical switching unit 2. Each electric pole 1A is equipped with one or more solid switches 10 that are configured to allow current to flow when conducting and to interrupt the current when blocking.

[0029] The solid-state switches 10 ("SSCBs") may include, for example, MOSFETs, insulated-gate bipolar transistors ("IGBTs"), gate turn-off thyristors ("GTOs"), integrated gate commutation thyristors ("IGCTs"), or the same. Each solid switch 10 of the electric pole 1A is electrically connected between pole contacts 11 and 12, for example, in a series configuration or by other more complex, well-known types of circuit configurations. In operation, the SSCB switching unit 1 can reversibly switch between a closed state (ON) and an open state (OFF). In the closed state, the solid switch 10 of the electric pole 1A is in a conductive state, and in the open state, the solid switch 10 of the electric pole 1A is in a blocked state.

[0030] When switching unit 1 is in the closed state (ON), line current can flow along the electrical pole 1A. On the other hand, when switching unit 1 is in the open state (OFF), line current cannot flow along the electrical pole 1A. However, the leakage current that is normally expected to affect the solid switch in the blocked state will still flow. The transition from the closed state ON to the open state OFF constitutes the operation of opening the switching unit 1, while the transition from the open state OFF to the closed state ON constitutes the operation of closing the switching unit 1. When the switching unit 1 receives the first trip signal T1 from the control device 3, it may perform an opening or closing operation. Preferably, the switching unit 1 includes one or more first drive circuits (not shown) that receive a first trip signal T1 and drive a control terminal (e.g., gate terminal or base terminal) of the solid switch 10 in response to the first trip signal.

[0031] Switching unit 2 is equipped with one or more second electric poles 2A. In this case, the number of electric poles 2A of switching unit 2 may vary as needed. Generally, the number of electric poles 2A corresponds to the number of electric poles 1A of SSCB switching unit 1. Each electric pole 2A is electrically connected in series with the corresponding electric pole 1A of the SSCB switching unit 1 and is also electrically connected to the corresponding second line conductor 52 of the electric wire 50. Accordingly, each electric pole 2A is provided with a third pole contact 23 and a fourth pole contact 24, the third pole contact 23 is provided to be electrically connected to the corresponding second pole contact 12 of the SSCB switching unit 1, and the fourth pole contact 24 is provided to be electrically connected to the second line terminal 92 of the switching device. Each second electric pole 2A is provided with an electrical contact 20 that can conduct current when connected or interrupt current when disconnected.

[0032] Conveniently, each electrical pole 2A's electrical contact 20 includes a fixed electrical contact and a movable electrical contact (not shown). Each movable contact can move to connect to or away from the fixed contact. In operation, the electromechanical switching unit 2 can reversibly switch between a closed state (ON) and an open state (OFF). When the closed state (ON) is active, the electrical contacts 20 of the electric pole 2A are connected, and when the open state (OFF) is active, the electrical contacts 20 of the electric pole 2A are disconnected. When switching unit 2 is in the closed state (ON), line current can flow along electric pole 2A. On the other hand, when switching unit 2 is in the open state (OFF), line current cannot flow along electric pole 2A. The transition from the closed state ON to the open state OFF constitutes the operation of opening the switching unit 2, while the transition from the open state OFF to the closed state ON constitutes the operation of closing the switching unit 2.

[0033] Preferably, the electromechanical switching unit 2 includes one or more trip actuators 25 (which may be of known type) provided to cause the movable contacts of the switching unit to actuate in order to perform the opening and closing operations described above. As an example, the trip actuator 25 may include an open coil actuator and a close coil actuator, the open coil actuator being configured to activate the movable contact of the electric pole 2A and perform an opening operation, and the close coil actuator being configured to activate the movable contact of the electric pole 2A and perform a closing operation. The trip actuator 25 can be operationally connected to a suitable operating mechanism (not shown) provided to move the movable contacts of the second switching unit. Such an operating mechanism (which may be of a known type) is conveniently designed to move the movable contacts of the second switching unit 2 based on the activation by the trip actuator described above. The electromechanical switching unit 2 may perform an opening or closing operation based on the receipt of a trip signal T2 from the control device.

[0034] Preferably, the electromechanical switching unit 2 may include one or more second drive circuits (not shown) that receive the trip signal T2 and drive the trip actuator 25 based on the trip signal. When driven according to the trip signal T2, the trip actuator 25 activates the aforementioned operating mechanism, which moves the movable contacts of the electromechanical switching unit to perform a closing or opening operation of the electromechanical switching unit.

[0035] Preferably, the electromechanical switching unit 2 includes one or more contact detection means 26 provided to supply a detection signal S2 indicating the operating state of the electromechanical switching unit 2 to a control device. For example, the detection means 26 may include a closed microswitch (which may be of a known type) provided to send a signal indicating the closed state ON of the switching unit 2, and an open microswitch (which may be of a known type) provided to send a signal indicating the open state OFF of the switching unit 2.

[0036] Preferably, the electromechanical switching unit 2 may include one or more enable devices 27 provided to supply an enable signal E to a control device to allow or prevent the electromechanical switching unit 2 from operating in the closed state ON. As an example, the enable device 27 may include a power outlet microswitch (which may be of a known type).

[0037] According to the present invention, the switching device 100 is of the pull-out type. Therefore, both the SSCB unit 1 and the electromechanical switching unit 2 can be pulled out from their normal operating positions to connect to or disconnect from the electric wire 50. The SSCB switching unit 1 can move reversibly between an inserted state A and an extended state B, where in inserted state A the first pole contact 11 is connected to the first line terminal 91, and in extended state B the first pole contact 11 is separated from the first line terminal 91. Preferably, when in insertion state A, the second pole contact 12 of the SSCB switching unit 1 is connected to the third pole contact 23 of the electromechanical switching unit 2. Preferably, when in the extended state B, the second pole contact 12 of the SSCB switching unit 1 is separated from the third pole contact 23 of the electromechanical switching unit 2.

[0038] The transition from inserted state A to pulled-out state B constitutes the operation of pulling out the switching unit 1, while the transition from pulled-out state B to inserted state A constitutes the operation of inserting the switching unit 1. When in the extended state B, the SSCB switching unit 1 may also be in the test position. In the test position, the SSCB switching unit 1 is electrically connected to the auxiliary power supply of the switching device. Also, when in the extended state B, the SSCB switching unit 1 is electrically disconnected from all electrical circuits when fully extended.

[0039] Preferably, the switching device 100 includes a first trolley (not shown) on which the SSCB switching unit 1 is mounted. Conveniently, such a first carriage is slidably connected to the support frame of the switching device 100. In this way, both the first switching unit 1 and the first carriage can move relative to the fixed part of the switching device.

[0040] The switching device 100 includes a first actuator 7 that is configured to move the SSCB switching unit 1 based on activation by the user, in order to perform at least the operation of pulling out the switching unit. Preferably, the first actuator 7 comprises a first actuator 70 operably connected to the SSCB switching unit 1 for moving the SSCB switching unit 1. Such actuator may include an electric motor or electromagnetic actuator operably connected to the switching unit 1 and the support frame of the switching device via a kinematic chain suitable for the switching device.

[0041] Preferably, the first actuator 7 includes a first command means 71 which can be activated by the user to issue a command to the first actuator means 70 to perform an unplugging operation and move the SSCB switching unit 1 from an inserted state A to an unplugged state B. Preferably, the command means 71 is configured to send an appropriate command signal to operate the first actuation means 70 as soon as the command means 71 is manually activated by the user. Preferably, the first command means 71 includes a command button that the user can press to command the actuator means 70. According to other solutions, the first command means 71 may include a more advanced human-machine interface (for example, a touchscreen device that generates the aforementioned command signals based on user interaction).

[0042] Preferably, the first actuator 7 includes a first enable means 72 configured to enable or disable the first command means 71 in response to a control signal C received from the control device of the switching device. As an example, the first enable means 72 may include an actuator (e.g., a coil actuator) operably connected to the first command means 71 and configured to mechanically allow or prevent the user from activating the command means upon receiving a control signal C from the control device. As a further example, the first enable means 72 may include a switch circuit operably connected to the first command means 71 to electrically or electronically allow or prevent the command means from transmitting a command signal to the first actuator 70 upon receiving a control signal C from the control device. Preferably, the first actuator 7 includes an activation detection means 73 (e.g., a microswitch) that supplies a detection signal S1 to the control device of the switching device indicating that the user has activated the first command means 71. According to possible embodiments of the present invention, the enabling means 72 and / or detection means 73 may be included in the operating means 70.

[0043] According to a preferred embodiment of the present invention, the first actuator 7 is configured to move the SSCB switching unit 1 based on user activation in order to perform an operation to insert the SSCB switching unit. In this case, the first actuator 7 includes additional command means (not shown) that can be activated by the user to issue a command to the first actuator 70 to perform the insertion operation and move the SSCB switching unit 1 from a disconnected state B to an inserted state A. Such additional command means may be designed according to known types of solutions. According to another embodiment of the present invention, the operation of inserting the switching unit 1 may be performed directly by the user, for example, using a mechanical tool that can be operably connected to a suitable kinematic chain operably connected to the switching unit 1 and the support frame of the switching device.

[0044] With respect to the electromechanical switching unit 2, the electromechanical switching unit 2 can move reversibly between an inserted state A and an extended state B. In the inserted state A, the fourth pole contact 24 is connected to the second line terminal 92, and in the extended state B, the fourth pole contact 24 is not connected to the second line terminal 92. Preferably, when in insertion state A, the third pole contact 23 of the electromechanical switching unit 2 is connected to the second pole contact 12 of the SSCB switching unit 1. Preferably, when in the extended state B, the third pole contact 23 of the electromechanical switching unit 2 is separated from the second pole contact 12 of the SSCB switching unit 1.

[0045] The transition from inserted state A to pulled-out state B constitutes the operation of pulling out the switching unit 2, while the transition from pulled-out state B to inserted state A constitutes the operation of inserting the switching unit 2. When in the extended state B, the switching unit 2 may also be in the test position. In the test position, the switching unit 2 is electrically connected to the auxiliary power supply 4 of the switching device, and the switching unit 2 is powered by the auxiliary power supply 4. Also, when in the extended state B, the switching unit 2 is electrically disconnected from all electrical circuits when fully extended.

[0046] Preferably, the switching device 100 includes a second trolley (not shown) on which the switching unit 2 is mounted. Conveniently, such a second carriage is slidably connected to the support frame of the switching device 100, and as a result, the second carriage can move relative to the fixed part of the switching device (together with the second switching unit 2).

[0047] The switching device 100 includes a second actuator 8 that is configured to move the electromechanical switching unit 2 based on activation by the user, at least during the operation of pulling out the electromechanical switching unit 2. Preferably, the second actuator 8 comprises a second actuator 80 operably connected to the electromechanical switching unit 2 for moving the electromechanical switching unit 2. Such actuator may include an electric motor or electromagnetic actuator operably connected to the switching unit 2 and the support frame of the switching device via a suitable kinematic chain.

[0048] Preferably, the second actuator 8 includes a second command means 81 that can be activated by the user to issue a command to the second actuator means 80 to perform an extraction operation and move the electromechanical switching unit 2 from an inserted state A to an extracted state B. Preferably, the second command means 81 is configured to send an appropriate command signal to operate the second actuation means 80 as soon as the second command means 81 is manually activated by the user. Preferably, the second command means 81 includes a command button that the user can press. According to other solutions, the second command means 81 may include a more advanced human-machine interface (for example, a touchscreen device that generates the aforementioned command signals based on user interaction).

[0049] Preferably, the second actuator 8 includes a second enabling means 82 that enables or disables the second command means 81 depending on the operating state of the electrical contacts 20 of the electromechanical switching unit 2, and in particular depending on the operating position of the movable contacts of the electrical poles 2A of the switching unit 2. As an example, the second enabling means 82 may include a blocking mechanism that is operably connected to the second command means 81 and is configured to mechanically prevent or allow activation by the second command means 81 depending on the operating state of the electrical contacts 20 of the electromechanical switching unit 2, particularly depending on the operating position of the movable contacts. Such a blocking mechanism can be designed to mechanically lock the second command means 81 when the movable contacts of the switching unit 2 are connected to the corresponding fixed contacts, and to mechanically unlock the second command means 81 when the movable contacts of the switching unit 2 are separated from the corresponding fixed contacts.

[0050] According to some embodiments of the present invention, the second actuator 8 is configured to move the electromechanical switching unit 2 based on user activation in order to perform an insertion operation of the electromechanical switching unit 2. In this case, the second actuator 8 includes additional command means (not shown) that can be activated by the user to issue a command to the second actuator 80 to perform the insertion operation and move the electromechanical switching unit 2 from a disconnected state B to an inserted state A. Such additional command means may be designed according to known types of solutions.

[0051] According to some embodiments of the present invention, the operation of inserting the switching unit 2 may be performed directly by the user, for example, using a mechanical tool that can be operably connected to a suitable kinematic chain operably connected to the switching unit 2 and the support frame of the switching device. Generally, switching units 1 and 2 may include multiple additional elements arranged at an industrial level using known types of solutions. In the following, for the sake of brevity, these will not be explained in further structural details.

[0052] According to the present invention, the switching device 100 includes a control device 3 provided to control the operation of the switching device 100, particularly the operation of the switching units 1 and 2. According to some embodiments of the present invention (Figure 1), the control device 3 is a standalone device not included in either the switching units 1 or 2. According to another embodiment of the present invention (not shown), the control device 3 is included in one of the switching units 1, 2, preferably in the SSCB switching unit 1. In this case, the control device 3 is more precisely the control device of the switching unit 1 and is appropriately configured to perform the functions described below (in addition to other functions of known types that are specifically provided for the SSCB switching unit 1). Preferably, the control device 3 includes a data processing unit 31 provided to process and supply data or control signals for implementing the requested function. Generally, the data processing unit 31 may include, for example, one or more digital or analog data processing resources such as a microprocessor or DPS.

[0053] Preferably, the control device 3 includes a trip unit 32 that exchanges information with the data processing unit 31 in order to generate trip signals T1 and T2 for controlling the operation of the switching units 1 and 2. Generally, the trip unit 32 may include, for example, one or more digital or analog data processing resources such as a microprocessor or DSP.

[0054] Preferably, the control device 3 is provided to receive and process input commands CM1, CM2, and CM3 (for example, generated by appropriate control signals) that indicate a desired operating state for the switching device 100 in order to control the operation of the switching units 1 and 2. Preferably, the control device 3 includes an interface unit 33 that includes one or more input ports for receiving input commands CM1, CM2, and CM3. Preferably, the switching device 100 includes a human-machine interface 5 that communicates with the interface unit 33 of the control device 3. The human-machine interface 5 is provided to supply input commands CM1, CM2, and CM3 based on interaction with the user. As an example, the human-machine interface 5 may include appropriate buttons that the user can press to generate input commands CM1, CM2, and CM3.

[0055] As another example, the human-machine interface 5 may include a touchscreen with appropriate graphic resources (e.g., digital buttons) that the user can use to generate input commands CM1, CM2, and CM3. As an additional example, the human-machine interface 5 may exchange information with the user's computer equipment (for example, wirelessly) to generate input commands CM1, CM2, and CM3. Preferably, the human-machine interface 5 is a standalone device not included in either of the switching units 1 or 2.

[0056] According to another embodiment of the present invention (not shown), the human-machine interface 5 is included in one of the switching units 1 and 2, preferably in the SSCB switching unit 1. In this case, the human-machine interface 5 may be a human-machine interface of the switching unit 1 that is appropriately configured to perform the functions described above (in addition to other functions provided for the SSCB switching unit 1). According to some embodiments of the present invention, the interface unit 33 of the control device 3 is provided to communicate with a remote computer device 9 (generally not part of the switching device 100), such as a digital relay. Conveniently, the interface unit 33 may receive input commands CM1, CM2, and CM3 from the computer device 9.

[0057] Preferably, the switching device 100 includes an auxiliary power supply 4, which can be electrically connected to an external low-voltage power supply (not shown) and is provided to supply a power supply PS that is appropriately supplied to the control device 3 and to other possible electrical or electronic components of the switching device, such as the actuators 7, 8 of the switching device and the aforementioned drive circuits included in the switching units 1, 2. Preferably, the auxiliary power supply 4 is a standalone device. However, those skilled in the art may also utilize different types of devices. Generally, the control unit 3, the human-machine interface 5, and the auxiliary power supply 4 can be arranged at an industrial level according to known types of hardware solutions. Therefore, for the sake of brevity, these will not be described in further structural or circuit details below.

[0058] In general, the operation of pulling out or inserting the SSCB switching unit 1 or the electromechanical switching unit 2 may be performed independently; that is, it is not necessary for the same operation to be performed on the other switching unit. Therefore, one of the switching units 1 or 2 may be the target of a specific operation without the need to involve the other switching unit. Accordingly, the switching device 100 can take on multiple operating modes depending on whether the switching units 1 or 2 are the target of the pulling out or inserting operation.

[0059] Figure 2 schematically illustrates the operating modes that the switching unit 100 can take when the switching units 1 and 2 are pulled out or inserted. According to Embodiment #1, both switching units 1 and 2 are in insertion state A. According to embodiment #2, switching unit 1 is in the extended state B, and switching unit 2 is in the inserted state A. In this case, switching unit 1 may be in the test position or in the fully extended position as needed. To transition the switching device from configuration #1 to configuration #2, it is necessary to pull out only the SSCB switching unit 1. To transition the switching device from configuration #2 to configuration #1, it is necessary to insert only the SSCB switching unit 1.

[0060] According to Embodiment #3, switching unit 1 is in the inserted state A, and electromechanical switching unit 2 is in the extended state B. In this case, electromechanical switching unit 2 may be in the test position or in the fully extended position, depending on the need. To transition the switching device from configuration #1 to configuration #3, it is necessary to perform an operation to pull out only the electromechanical switching unit 2. To transition the switching device from configuration #3 to configuration #1, it is necessary to perform an operation to insert only the electromechanical switching unit 2.

[0061] According to configuration #4, both switching units 1 and 2 are in the extended state B. In this case, each of switching units 1 and 2 may be in the test position or in the fully extended position, depending on the need. In order for the switching device to transition from configuration #2 to configuration #4, it is necessary to perform an operation to pull out only the electromechanical switching unit 2. In order for the switching device to transition from configuration #4 to configuration #2, it is necessary to perform an operation to insert only the electromechanical switching unit 2. In order for the switching device to transition from configuration #3 to configuration #4, it is necessary to perform an operation to pull out only the SSCB switching unit 1. In order for the switching device to transition from configuration #4 to configuration #3, it is necessary to perform the operation of inserting only the SSCB switching unit 1.

[0062] In principle, the switching device 100 may take any of the above-described forms as necessary. However, according to the present invention, the operation of pulling out the switching units 1 and 2 can only be performed when the switching units 1 and 2 are in a certain operating state, more specifically when they are in the open state (OFF). Conveniently, the control device 3 is configured to prevent the first actuator 7 from moving the first switching unit 1 from the inserted state A to the pulled-out state B when the first switching unit 1 is in the closed state ON. However, an important aspect of the present invention is that the control device 3 is configured to allow or prevent the operation of pulling out the switching unit 1, depending not only on the operating state of the switching unit 1 but also on the operating state of the electromechanical switching unit 2. In other words, according to the present invention, the control device 3 is configured to allow or prevent the first actuator 7 from performing the operation of pulling out the SSCB switching unit 1, depending on the operating states of both the first switching unit 1 and the electromechanical switching unit 2.

[0063] Therefore, according to the present invention, the control device 3 is When at least one of the first switching unit 1 and the second switching unit 2 is in the closed state ON, the first actuator 7 is configured to prevent the first switching unit 1 from moving from the inserted state A to the pulled-out state B, and When both the first switching unit 1 and the second switching unit 2 are in the open state (OFF), the first actuator 7 is configured to allow the first switching unit 1 to move from the inserted state (A) to the pulled-out state (B) based on activation by the user. In other words, the control device 3 is configured to prevent the first actuator 7 from performing the operation to pull out the SSCB switching unit 1 if any of the following conditions are met: -SSCB switching unit 1 is in the closed state ON. - The electromechanical switching unit 2 is in the closed state ON. -Both SSCB switching unit 1 and electromechanical switching unit 2 are in the closed state (ON).

[0064] On the other hand, the control device 3 is configured to allow the first actuator 7 to perform the operation of pulling out the SSCB switching unit 1 only when the following conditions are met: -Both SSCB switching unit 1 and electromechanical switching unit 2 are in the open state (OFF).

[0065] To prevent the first actuator 7 from moving the SSCB switching unit 1 from the inserted state A to the pulled-out state B, the control device 3 instructs the first enable means to disable the first command means 71. Therefore, even if the user attempts to activate the first command means 71, the first actuator 70 will not perform the operation to pull out the SSCB switching unit 1 without moving it.

[0066] To allow the first actuator 7 to move the SSCB switching unit 1 from inserted state A to pulled-out state B, the control device 3 commands the first enable means 72 to activate the first command means. Therefore, when the user activates the first command means 71, the first actuator 70 performs the operation to move and pull out the SSCB switching unit 1. Preferably, the control device 3 is configured to maintain the SSCB switching unit 1 in the open state OFF when the control device 3 receives a detection signal S2 from the activation detection means 73 indicating the activation of the first command means 71. In this way, when the pull-out operation is initiated or performed, the control device 3 conveniently prevents the switching unit 1 from returning to the closed state.

[0067] According to another aspect of the present invention, when the second switching unit 2 is in the open state OFF, the second actuator 8 is configured to move the second switching unit 2 from the inserted state A to the pulled-out state B based on activation by the user. Furthermore, when the electromechanical switching unit 2 is in the closed state ON, the second actuator 8 is configured not to move the electromechanical switching unit 2 from the inserted state A to the pulled-out state B, even if activated by the user.

[0068] The second enabling means 82 is configured to disable the second command means 81 when the electrical contacts 20 of the electrical pole 2A of the switching unit 2 are connected, in other words, when the movable contacts of the electrical pole 2A of the switching unit 2 are connected to the corresponding fixed contacts. Therefore, even if a user attempts to activate the second command means 81, the second operating means 80 will not perform an operation to move or pull out the electromechanical switching unit 2. The second enabling means 82 is configured to activate the second command means 81 when the electrical contacts 20 of the electrical pole 2A of the switching unit 2 are not connected, in other words, when the movable contacts of the electrical pole 2A of the switching unit 2 are separated from the corresponding fixed contacts. Therefore, when the user activates the second command means 81, the second operating means 80 performs an operation to move and pull out the electromechanical switching unit 2.

[0069] A further aspect of the present invention is that the control device 3 is configured to implement special control logic for controlling the operation of the switching device 100 by controlling the operation of the switching units 1 and 2. According to such control logic, when the switching units 1 and 2 are in insertion state A, the first switching unit 1 and the electromechanical switching unit 2 may be combined in only a specific set of operating modes, each operating mode corresponding to one predetermined operating state of the switching device 100 (Figure 3).

[0070] Preferably, the control device 3 is provided to control the switching units 1 and 2 so that they can operate in combination only in the following plurality of operating modes: - First operating mode [I] where both switching units 1 and 2 are in the closed state ON, -Second operating mode [X] in which the SSCB switching unit 1 is in the open state (OFF) and the electromechanical switching unit 2 is in the closed state (ON), -A third operating mode [O] in which both switching units 1 and 2 are in the open state OFF.

[0071] When switching units 1 and 2 are operating according to the first operating mode [I], line Current can flow through the electric poles 1A and 2A of switching units 1 and 2. Therefore, there is electrical continuity between the first line conductor 51 and the second line conductor 52 of the electric wire 50. Thus, the first operating mode [I] of switching units 1 and 2 is a switching device. This corresponds to a closed state of 100.

[0072] When switching units 1 and 2 are operating according to the second operating mode [X], the first switching unit 1 is in the open state (OFF), so line current cannot flow along the electric poles 1A and 2A of switching units 1 and 2. Therefore, the first line conductor 51 and the second line conductor 52 of the electric wire 50 are not connected. However, the electromechanical switching unit 2 is in the closed state (ON), and leakage current related to the solid switch 10 can still flow along the electric poles 1A and 2A, so line conductors 51 and 52 are not electrically isolated. The second operating mode [X] of switching units 1 and 2 corresponds to the standby state of the switching device 100, which is an intermediate state between the closed state and the open state.

[0073] When switching units 1 and 2 operate according to the third operating mode [O], both switching units 1 and 2 are in the open state (OFF), so line current and any potential leakage current cannot flow along the electric poles 1A and 2A of switching units 1 and 2. The first line conductor 51 and the second line conductor 52 of the electric wire 50 are not connected, and electrical insulation is ensured between the first line conductor 51 and the second line conductor 52. Therefore, the third operating mode [O] of switching units 1 and 2 corresponds to the open state of the switching device 100.

[0074] Preferably, the control device 3 is configured to instruct the switching units 1 and 2 to switch from one operating mode to another in response to the reception of the aforementioned input commands CM1, CM2, and CM3, which indicate a desired operating state for the switching device 100. However, according to the control logic implemented in the control device 30, the transition between the operating modes of the switching units 1 and 2 always requires the involvement of a second operating mode [X] corresponding to the standby state of the switching device 100 (Figure 3). In other words, the control device 3 is configured to control the switching units 1 and 2 to prevent a direct transition between the first operating mode [I] and the third operating mode [O] of the switching units 1 and 2.

[0075] Preferably, when the switching units 1 and 2 are in a first operating mode [I] (corresponding to the closed state of the switching device 100), the control device 3, in response to receiving input commands CM2 and CM3 indicating a desirable operating state for the switching device 100, commands the switching units 1 and 2 to switch to a second operating mode [X] (corresponding to the standby state of the switching device 100). In practice, according to the control logic implemented in the control device 3, the switching units 1 and 2 can only switch from the first operating mode [I] to the third operating mode via the second operating mode [X]. When the switching device is in a closed state (first operating mode of switching units 1 and 2 [I]), the switching device 100 can switch to an open state only via a standby state (second operating mode of switching units 1 and 2 [X]) in response to the reception of input commands CM2 and CM3 indicating a desired different operating state.

[0076] Preferably, when the switching units 1 and 2 are in a second operating mode [X] (corresponding to the standby state of the switching device 100), the control device 3, in response to receiving input commands CM1 and CM3 indicating a desirable operating state for the switching device 100, commands the switching units 1 and 2 to switch to a first operating mode [I] (corresponding to the closed state of the switching device 100) or to a third operating mode [O] (corresponding to the open state of the switching device 100). In practice, according to the control logic implemented in the control device 3, the switching units 1 and 2 can switch from the second operating mode [X] to either the first operating mode [I] or the third operating mode [O] in response to the received input commands CM1 and CM3. When the switching device is in a standby state (switching units 1 and 2 are in a second operating mode [X]), in response to receiving input commands CM1 and CM3 indicating a different desired operating state, the switching device 100 switches to either a closed state (switching units 1 and 2 are in a first operating mode [I]) or an open state (switching units 1 and 2 are in a third operating mode [O]), depending on the received input commands CM1 and CM3.

[0077] Preferably, when switching units 1 and 2 are in a third operating mode [O] (corresponding to the open state of the switching device 100), the control device 3, in response to receiving input commands CM1 and CM2 indicating a desirable operating state for the switching device 100, commands switching units 1 and 2 to switch to a second operating mode [X] (corresponding to the standby state of the switching device 100). In practice, according to the control logic implemented in the control device 3, switching units 1 and 2 can only switch from the third operating mode [O] to the first operating mode via the second operating mode [X]. When the switching device is in an open state (switching units 1 and 2 in a third operating mode [O]), the switching device 100 can switch to a closed state only via a standby state (second operating mode [X] of switching units 1 and 2) in response to the reception of input commands CM1 and CM2 indicating a desired different operating state.

[0078] Furthermore, according to the control logic described above, the operation to pull out the SSCB switching unit 1 can be performed based on user activation only when both switching units 1 and 2 are in the open state (OFF). Preferably, the control device 3 is configured to prevent the first actuator 7 from moving the first switching unit 1 from the inserted state A to the pulled-out state B when the switching units 1 and 2 are operated in combination according to the first operating mode [I] or the second operating mode [X] described above. Preferably, the control device 3 is configured to allow the first actuator 7 to move the first switching unit 1 from the inserted state A to the pulled-out state B when the switching units 1 and 2 are combined and operated according to the third operating mode [O] described above.

[0079] Furthermore, according to the control logic described above, the operation to pull out the electromechanical switching unit 2 can be performed when the electromechanical switching unit 2 is in the open state (OFF) based on activation by the user. Preferably, the second actuator 8 is provided so that when the switching units 1 and 2 are combined and operated according to the first operating mode [I] or the second operating mode [X] described above, the second switching unit 2 does not move from the inserted state A to the pulled-out state B. Preferably, the second actuator 8 is provided to move the second switching unit 2 from the inserted state A to the pulled-out state B only when the first switching unit 1 and the second switching unit 2 are operating in combination according to the third operating mode [O].

[0080] The switching device 100 of the present invention offers relevant advantages over corresponding solutions available in the current state of the art. Unlike known solutions in the current state of the art, the control device 3 of the switching device 100 is configured to also check the operating status of the electromechanical switching unit 2 in order to allow or prevent the operation of drawing out the SSCB switching unit 1.

[0081] In particular, the control device 3 is configured to allow the first actuator 7 to perform an operation to pull out the SSCB switching unit 1 only when both the SSCB switching unit 1 and the electromechanical switching unit 2 are in the open state (OFF). This solution prevents the operation to pull out the SSCB switching unit from being performed when a leakage current is flowing along the electrical pole 1A of the SSCB switching unit. This leakage current will flow even if the solid switch is in the blocked state and the switching unit 1 is in the open state (OFF), as long as the electromechanical switching unit 2 is in the closed state (ON). In this way, the undesirable discharge phenomenon at the pole contacts 11 and 12 of the SSCB switching unit, which is very dangerous for personnel working in the field, can be avoided. Thus, the switching device 100 operates at a higher level of safety than the corresponding systems of the current state of technology.

[0082] According to one aspect of the present invention, the control device 3 is configured to prevent accidental operation of closing the SSCB switching unit when an extraction operation is initiated or performed. Clearly, this solution further improves safety in the operation of the switching device.

[0083] According to a further aspect of the present invention, the second actuator 8 is configured to perform an operation to pull out the electromechanical switching unit 2 only when the electromechanical switching unit 2 is in the open state (OFF). As a result of this solution, the operation to pull out the electromechanical switching unit 2 can be performed with an indirect and relevant safety advantage only if the electromechanical switching unit provides electrical isolation between the line conductors 51 and 52 of the wire 50.

[0084] According to one aspect of the present invention, the control device 3 of the switching device is configured to control the switching units 1 and 2 so that the switching device 100 can be in a standby state (switching units 1 and 2 in a second operating mode [X]) in addition to a closed state (switching units 1 and 2 in a first operating mode [I]) and an open state (switching units 1 and 2 in a third operating mode [O]). Such a solution makes it possible to relax the time synchronization limit between switching units 1 and 2 when the switching device 100 needs to perform an opening operation (i.e., transition from a closed state to an open state) or a closing operation (i.e., transition from an open state to a closed state). Thus, the switching device 100 can operate according to robust control logic that enables improved overall efficiency. Consequently, the switching device 100 ensures a higher level of reliability without having to perform complex and expensive control resources.

[0085] The switching device 100 is relatively easy to produce at an industrial level, and can be manufactured at a cost competitive with similar devices at the current level of technology.

Claims

1. A switching device for a power distribution grid, wherein the switching device is - One or more first line terminals provided to be electrically connected to the first line conductor of the electric wire, - One or more second line terminals provided to be electrically connected to the second line conductor of the electric wire, - A first switching unit having one or more first electric poles, - A second switching unit having one or more second electric poles, - A first actuator provided to move the first switching unit at least during an operation to pull out the first switching unit based on activation by the user, - A second actuator provided to move the second switching unit at least during the operation of pulling out the second switching unit based on activation by the user, - A control device provided to control the operation of the switching device, The first electric pole comprises a first pole contact provided to be electrically connected to a corresponding first line terminal, a second pole contact, and one or more solid switches. The solid switch is electrically connected to the first pole contact and the second pole contact, and is configured to operate by allowing current to flow when conducting and interrupting current when blocking. The first switching unit can reversibly switch between a closed state and an open state, in the closed state the solid switch is in the conductive state, and in the open state the solid switch is in the blocking state. The first switching unit can move reversibly between an inserted state and an extended state. In the inserted state, the first pole contact is connected to the first line terminal, and in the extended state, the first pole contact is separated from the first line terminal. The second electric pole comprises a third pole contact provided to be electrically connected to the second pole contact of the first switching unit, a fourth pole contact provided to be electrically connected to the second line terminal, and an electrical contact that is electrically connected to the third pole contact and the fourth pole contact. The electrical contacts are provided to operate in a connected state that allows current to flow or in a disconnected state that blocks the flow of current. The second switching unit can reversibly switch between a closed state and an open state, where the electrical contacts are in the connected state in the closed state and in the separated state in the open state. The second switching unit can move reversibly between an inserted state and an extended state, with the fourth pole contact connected to the second line terminal in the inserted state and the fourth pole contact not connected to the second line terminal in the extended state. The control device is configured such that, when at least one of the first switching unit and the second switching unit is in the closed state ON, the first actuator will not move the first switching unit from the inserted state to the pulled-out state even if the user starts it up. The switching device is characterized in that the control device is configured to allow the first actuator to move the first switching unit from an inserted state to an uninserted state based on activation by the user, but only when both the first switching unit and the second switching unit are in an open state.

2. The switching device according to claim 1, comprising: a first actuation means operably connected to a first switching unit; a first command means that can be activated by a user to issue a command to the first actuation means to move the first switching unit from an inserted state to an unplugged state; and a first enable means provided to enable or disable the first command means in response to a control signal received by the control device.

3. The switching device according to claim 2, further comprising an activation detection means for supplying a detection signal to a control device indicating activation of the first command means by a user.

4. The switching device according to any one of claims 1 to 3, wherein the second actuator is provided to move the second switching unit from an inserted state to an uninserted state based on activation by the user, but only when the second switching unit is in an open state.

5. The switching device according to claim 4, further comprising: a second operating means operably connected to a second switching unit; a second command means that can be activated by a user to issue a command to the second operating means to move the second switching unit from an inserted state to an unplugged state; and a second enabling means provided to enable or disable the second command means according to the operating state of the electrical contacts of the second switching unit.

6. The switching device according to claim 5, wherein the second enabling means is provided to disable the second command means when the electrical contacts of the second switching unit are connected, and to enable the second command means when the electrical contacts of the second switching unit are disconnected.

7. The control device is provided to control the operating states of the first switching unit 1 and the second switching unit so that the first switching unit and the second switching unit operate in combination according to the first, second, or third operating mode. The first operating mode corresponding to the closed state of the switching device is an operating mode in which both the first switching unit and the second switching unit are in a closed state. The second operating mode corresponding to the standby state of the switching device is an operating mode in which the first switching unit is in an open state and the second switching unit is in a closed state. The switching device according to any one of claims 1 to 6, wherein the third operating mode corresponding to the open state of the switching device is an operating mode in which both the first switching unit and the second switching unit are in the open state.

8. The control device is configured to prevent the first actuator from moving the first switching unit from the inserted state to the pulled-out state when the first switching unit and the second switching unit are operating in a combination according to the first operating mode or the second operating mode. The switching device according to claim 7, wherein the control device is configured to allow the first actuator to move the first switching unit from an inserted state to an uninserted state based on activation by the user when the first switching unit and the second switching unit are operating in a combination according to the third operating mode.

9. The switching device according to any one of claims 4 to 8, wherein the second actuator is provided to move the second switching unit from an inserted state to an extended state based on activation by the user, only when the first switching unit and the second switching unit are operating in a combination according to the third operating mode.

10. The switching device according to any one of claims 1 to 9, wherein the control device comprises an interface section including one or more input ports that receive input commands indicating a desirable operating state for the switching device.

11. The switching device is equipped with a human-machine interface that is capable of communicating with the interface unit. The switching device according to claim 10, wherein the human-machine interface is provided to supply the input commands based on interaction with the user.

12. The switching device according to claim 10 or 11, wherein the interface unit can receive the input command from a remote computer device.

13. The switching device according to any one of claims 1 to 12, wherein the control device is included in the first switching unit.

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