Load disconnecting switchgear, switchgear cabinet, automation system and method for operating load disconnecting switchgear

Abstract

The invention relates to a load disconnecting switch device, a switch cabinet, an automation system and a method for operating a load disconnecting switch device. A small size load disconnect switchgear for a busbar system. The load cut-off switchgear includes a shunt resistor disposed proximate to a connection to the bus system. The voltage drop across the shunt resistor is analyzed to determine a value of current flowing through the load disconnect switchgear.

Description

Technical Field

[0001] The invention relates to a load disconnection switchgear, in particular a load disconnection switchgear for a busbar system. The invention also relates to a switch cabinet arrangement and an automation system having the load disconnection switchgear. In addition, the invention relates to a method for operating the load disconnection switchgear. Background Art

[0002] Switchgear, in particular switch breakers, can be used in industrial environments to switch power to a load, for example, to an electrical device. A switch breaker is designed to interrupt an electrical connection even if current is flowing through the switch.

[0003] During the operation of a system with such a switch breaker, it is often desirable to measure and monitor the current flowing through the switch breaker. For example, current measurement may be useful for capturing the power consumption of electrical systems, building units, and individual consumers such as motors. In particular, the measured current can be used as a basis for billing the consumed electricity. In addition, the monitoring of the current can be used to detect changes in power consumption, for example for predictive maintenance. The monitored current can also be used to identify the critical state of the device itself and the connected consumer. However, previously known methods (such as Rogowski coils, current transformers or Hall sensors) are relatively complex and expensive or require a large installation space. In addition, these methods are also very sensitive to interference, which requires further measures to protect the sensing element from external interference.

[0004] In view of this, a solution with a simple and reliable concept for measuring current in a switch circuit breaker which requires only a small installation space is desired. In particular, a switch circuit breaker is desired in which the current measurement can be realized by small-sized and preferably low-cost components. Furthermore, a current measurement in a switch circuit breaker is desired which is robust against interferences. Summary of the invention

[0005] The present invention therefore takes the above needs into account and provides a load shedding switchgear, a method for operating a load shedding switchgear, a switch cabinet arrangement and an automation system having the features of the independent claims. Further advantageous embodiments are subject matter of the dependent claims.

[0006] According to a first aspect, a load disconnection switch device is provided. The load disconnection switch device comprises a first connector unit, a second connector unit, a load disconnection unit and at least one shunt resistor. The first connector unit comprises at least one first terminal. In particular, a separate first terminal can be provided for each terminal of a power supply or a load that should be connected to the first connector unit. For example, the first connector unit can comprise a separate first terminal for each busbar of a busbar system. Thus, each first terminal can be used to connect to one busbar of the busbar system.

[0007] The second connector unit comprises at least one second terminal. In particular, the number of the second terminals may correspond to the number of the first terminals. In particular, each second terminal is used for connecting to an electrical connection of an external electrical device. The external electrical device may be, for example, an electrical load, such as a motor or the like. However, the electrical device may also be a power source, such as an inverter of a regenerative energy system or the like.

[0008] The load disconnection unit is used to disconnect the electrical connection between the first terminal of the first connector unit and the corresponding second terminal of the second connector unit. In particular, the load disconnection unit is used to disconnect the electrical connection even if current is flowing through the load disconnection unit.

[0009] A shunt resistor is arranged in each current path between the first terminal of the first connector unit and the second terminal of the second connector unit. In particular, the shunt resistor is arranged between the first connector unit and the load disconnection unit. In other words, the shunt resistor is arranged electrically close to the first terminal of the first connector unit.

[0010] Furthermore, the fuse unit is provided in a current path between each first terminal of the first connector unit and a corresponding second terminal of the second connector unit.

[0011] According to a second aspect, a switch cabinet device is provided. The switch cabinet device includes a busbar system and a load disconnect switch device according to the first aspect. In particular, the busbar system includes at least one busbar electrically connected to a first connector unit of the load disconnect switch device. The busbar system is used to connect to a power source. For example, the power source can be an inverter, such as an inverter of a regenerative energy system (such as a photovoltaic device). Additionally or alternatively, the busbar system can be connected to a power sink. For example, the busbar system can receive electrical energy from a power source connected to the second connector unit and provide energy to a power grid, a battery, etc.

[0012] According to a third aspect, an automation system is provided. The automation system comprises a busbar system, an electrical device and a load shedding switchgear, in particular the load shedding switchgear according to the first aspect. The busbar system is used to be connected to a power source. Additionally or alternatively, the load shedding switchgear can be connected to the power source. For example, the power source can be an inverter, for example an inverter of a regenerative energy system such as a photovoltaic device. The electrical device of the automation system is electrically connected to the load shedding switchgear. In particular, the electrical device can be connected to a second connector unit of the load shedding switchgear.

[0013] According to another aspect, a method for operating a load disconnect switch device, in particular a load disconnect switch device according to the first aspect, is provided. The method comprises the step of measuring a voltage drop across a shunt resistor, in particular a voltage drop across a shunt resistor in a current path between one of the first terminals of a first connector unit and the load disconnect unit. The method comprises the step of determining a current in a corresponding current path between one of the first terminals of the first connector unit and the load disconnect unit. The current is determined based on the measured voltage drop across the corresponding shunt resistor. Furthermore, the method comprises the step of providing an output signal indicative of the determined current.

[0014] The invention is based on the following finding: currently known concepts for current measurement in switch circuit breakers require rather complex hardware elements, such as current transformers, Hall sensors or Rogowski coils. Since these existing concepts are relatively sensitive to interference, in particular to interfering magnetic fields, these solutions require additional measures for protecting the current sensing element from such interference. These additional measures and the relatively large volume of the sensor itself require a large assembly volume for the current sensing device in the switch circuit breaker.

[0015] Therefore, the present invention takes this discovery into account and aims to provide an improved load shedding switch device with current sensing capability. In particular, the present invention aims to provide a load shedding switch device with current sensing capability, which can be implemented with a reduced assembly volume and which can provide current measurement that is robust against external interference such as magnetic fields.

[0016] In order to achieve the above requirements, the present invention uses a shunt resistor for current sensing. If current flows through such a shunt resistor, the voltage drop across the terminals of the shunt resistor is generally proportional to the current flowing through the shunt resistor. Therefore, the current flowing through the shunt resistor can be easily determined based on the voltage drop across the shunt resistor.

[0017] The shunt resistor may be any kind of resistor suitable for current sensing purposes. For example, the shunt resistor may be implemented based on a suitable conductive material such as a metal or an alloy such as a copper-nickel-manganese alloy or a nickel-chromium alloy. For example, the shunt resistor may be implemented based on a material with a small thermal coefficient. Typically, the shunt resistor has a fairly small resistance, in particular a resistance below 1 ohm, in particular a resistance in the range of 0.025 up to 0.1 milliohms. In this way, the power loss through the shunt resistor is low.

[0018] When analyzing the inventive concept of using a shunt resistor for current measurement in a load shedding switchgear, it has been found that it is advantageous that the shunt resistor can be located close to the busbar system. In other words, the shunt resistor should preferably be located between the load shedding unit and the first connector unit, in particular near the first connector unit of the load shedding switchgear or even within the first connector unit of the load shedding switchgear. In this way, a very compact, small-sized and robust configuration for current measurement in a load shedding switchgear can be achieved.

[0019] In one possible embodiment of the load disconnection switchgear, the fuse unit can be used to receive fuses with rated currents in the range of NH000 to NH03 or of equivalent types. Therefore, the concept according to the present invention makes it possible to realize a compact and small-sized load disconnection switchgear including fuses with relatively high rated currents. For example, the load disconnection switchgear can include a fuse with a maximum rated voltage of up to 1000 volts. For example, the fuse can be any suitable fuse, for example, according to the UL or IEC field. The fuse can be an NH fuse (NH000 until NH3), a UL fuse (CC class, J class, CF class, etc.) or a cylindrical fuse (such as D0, D01, D02, 22x58, 10x85, 14x51), etc. However, any other suitable fuse with the same or at least almost similar rated current is also possible. The fuse can have a cylindrical shape that matches the compartment of the fuse receiving element.

[0020] Therefore, the proposed concept for current measurement can be used even in switch breakers with a small assembly volume. Furthermore, the proposed concept can be implemented by simple elements such as shunt resistors which result in low cost and can perform very robust and reliable current measurement.

[0021] The busbar system to which the load shedding switchgear is connected may include one or more busbars. For example, in the case of an AC application with a single phase, the busbar system may include only a single busbar. Alternatively, for an application with multiple phases, the busbar system may include more than one busbar. For example, the busbar system may include three busbars (L1, L2, L3) for a three-phase AC system. However, the busbar system may also be a busbar system for DC applications. In this case, the busbar system may include, for example, two busbars (a positive busbar and a negative busbar). However, the present invention is not limited to the above examples. Furthermore, any other number of busbars is also possible.

[0022] The load disconnect switchgear can be electrically coupled to the busbars of the busbar system via a first connector unit. For this purpose, a separate connecting element (first terminal) can be provided in the first connector unit for each busbar to be connected. The connecting element can be configured in such a way that a reliable electrical connection can be established when the terminal of the first connector unit is connected to the busbar of the busbar system. For example, the first terminal can include a spring or the like in order to provide an appropriate force towards the busbar. However, any other suitable measures for a reliable electrical connection are also possible.

[0023] For each first terminal of the first connector unit, a corresponding second terminal of the second connector unit can be provided. For example, an electrical device such as a load (in particular a motor or the like) can be electrically connected to the second connector unit of the load disconnect switch device. For this purpose, the wire can be connected to the second terminal of the second connector unit by means of a clamp connection or a screw connection. The electrical connection at the second connector unit can also be established in any other way.

[0024] The load disconnection unit of the load disconnection switch device is electrically arranged between the first connector unit and the second connector unit. In this way, if the corresponding switching element of the load disconnection unit is closed, the load disconnection unit can establish an electrical connection between the first terminal of the first connector unit and the corresponding second terminal. Alternatively, if the corresponding switching element of the load disconnection unit is opened, the electrical connection between the first terminal and the corresponding second terminal is interrupted. In particular, the load disconnection unit can interrupt the electrical connection even when current is flowing through the load disconnection unit.

[0025] In a possible embodiment, the fuse unit can be used to receive cylindrical fuses, especially fuses such as D0, D01, D02, D02, 22x58, 10x85, 14x51, etc.

[0026] In a possible embodiment, the load disconnection switch device includes a monitoring unit. The monitoring unit is used to determine at least one current in a current path between one of the first terminals of the first connector unit and the load disconnection unit based on a voltage drop across the shunt resistor in the corresponding current path. For example, the monitoring unit may include a voltage measuring unit for measuring the voltage drop across the shunt resistor and a processing unit for determining the current through the shunt resistor based on the measured voltage drop. Since the current is generally proportional to the voltage drop, the current can be easily calculated by dividing the voltage drop by the resistance of the shunt resistor. For this purpose, the resistance of the shunt resistor can be predetermined. However, any other scheme for determining a factor that specifies the relationship between the voltage drop and the resulting current is also possible.

[0027] In a possible embodiment, the monitoring unit is arranged to measure the voltage at the connection point between one of the first terminals of the first connector unit and the load disconnection unit. In this case, the monitoring unit can also be arranged to determine the power flow and / or the current direction based on the sensed current and the measured voltage. In case of an alternating current, the monitoring unit can take into account the phase shift between the determined current and the voltage. Thus, the direction of the current / power flow and / or the active power / reactive power can be determined.

[0028] In a possible embodiment, the monitoring unit includes a communication interface. The communication interface can be used to establish a communication link, particularly a communication link with a remote device. The communication interface can also be configured to output data for specifying a determined current value. The communication interface can be, for example, a communication interface such as Modbus / RTU, Modbus / TCP / IP, CAN-bus, IO-Link or any other appropriate communication standard. The communication of the communication interface can also use, for example, a power LAN technology such as a power line. In this way, communication can be performed, for example, via a power line connected to the first connector unit and / or the second connector unit, or via other auxiliary devices of the (DC) power supply and / or load disconnection switch device of the monitoring unit. Additionally or alternatively, wireless communication can also be performed. For example, the communication interface can use WLAN, Bluetooth, NFC, Zigbee or any other known or upcoming communication standard.

[0029] In a possible embodiment, the monitoring unit is used to trigger the load disconnection unit. In particular, the monitoring unit can be used to trigger the load disconnection unit to interrupt the electrical connection between the first terminal of the first connector unit and the corresponding second terminal of the second connector unit. If at least one determined current exceeds a predetermined threshold value, the connection can be interrupted. In this way, an overcurrent protection based on the sensed current value can be achieved.

[0030] In a possible embodiment, each terminal of the first connector unit comprises a connecting element for connecting the respective first terminal to the associated busbar of the busbar system. In this case, the shunt resistor in the current path between the first terminal of the first connector unit and the load disconnection unit can be connected directly to the connecting element of the first connector unit, respectively. Alternatively, the shunt resistor can even be integrated in the first connector unit. Thus, the shunt resistor can be arranged very close to the connection of the busbar.

[0031] In a possible embodiment, each fuse in the fuse unit has a maximum rated current of at least 160 amperes. In particular, the maximum rated current may even be at least 250 amperes, 355 amperes, 500 amperes or at least 800 amperes. Such a maximum rated current may be achieved, for example, using the above-mentioned NH fuse or a similar fuse with a corresponding rated current.

[0032] In a possible embodiment, the load disconnection unit is arranged in the current path between the first connector unit and the fuse unit. Additionally or alternatively, the load disconnection unit can be arranged in the current path between the fuse unit and the second connector unit. Therefore, by using two load disconnection units in each current path, the two terminals of the fuse unit can be electrically separated by one of the two load disconnection units. The two load disconnection units can be switched synchronously, that is, the two load disconnection units can be opened and closed at the same time. Alternatively, the two load disconnection units can be switched separately.

[0033] In a possible embodiment, the load disconnect switch device comprises a sensor element. The sensor element may be used to sense a physical property of the shunt resistor. For example, the sensor element may sense a temperature in the vicinity of the shunt resistor. Thus, the monitoring unit may be used to determine a current in a current path between one of the first terminals of the first connector unit and the load disconnect unit based on the physical property sensed by the sensor element. For example, the determined current value may be compensated based on the sensed physical property, for example a temperature compensation of the resistance of the shunt resistor may be applied. In this case, the sensor element may comprise a thermal sensor.

[0034] In a possible embodiment, the monitoring unit is configured to output an alarm signaling. In particular, an alarm signaling may be output if at least one of the determined currents exceeds a predetermined threshold. The signaling may be an optical, acoustic and / or tactile signaling. Additionally or alternatively, an electrical signal may be provided. For example, the signaling may be forwarded to another device, in particular a remote device. In this way, a user may be informed of an impending problem, such as a current that is currently approaching a limit.

[0035] In a possible embodiment, the load disconnection unit is used to interrupt the electrical connection between the first terminal of the first connector unit and the corresponding second terminal of the second connector unit under load conditions. In other words, the load disconnection unit can interrupt the electrical connection between the first terminal of the first connector unit and the associated second terminal of the second connector unit even if current is flowing through the load disconnection unit. This makes it possible, for example, to perform switching actions even for loads with high inductance or capacitance, such as electric motors. In particular, the load disconnection switch can perform switching actions for loads according to IEC 60947-3 up to AC-23B.

[0036] In a possible embodiment, the load disconnect switch device has an outer width of at most 27 mm, in particular at most 22.5 mm. Thus, the load disconnect switch device is realized with very small dimensions and assembly volume. In particular, a load disconnect switch device with such dimensions appropriately provides the required distance with respect to the leakage current requirement as required (e.g. according to the pending UL specification). In this context, the width is considered to be the extent between two side faces. These side faces usually extend parallel to each other. The width may refer to a grid size or a similar feature of the load disconnect switch assembly. In particular, the width may be the smallest extent of the assembly in one spatial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In the following, possible embodiments of different aspects of the present invention are described in more detail with reference to the accompanying drawings.

[0038] Figure 1 is a schematic diagram of a load shedding switchgear according to an embodiment;

[0039] Figure 2 is a schematic diagram of a monitoring unit for a load shedding switchgear according to an embodiment;

[0040] Figure 3 is a schematic diagram of a monitoring unit for a load shedding switchgear according to another embodiment;

[0041] Figure 4 is a schematic illustration of a load shedding switchgear in a switchgear arrangement according to an embodiment; and

[0042] Figure 5 is a flow chart illustrating a method for operating a load shedding switchgear according to an embodiment. DETAILED DESCRIPTION

[0043] Figure 1 A schematic block diagram illustrating a load shedding switch device 1 according to an embodiment is shown. The load shedding switch device 1 may include a first connector unit 10, a second connector unit 20, and a load shedding unit 30.

[0044] The load disconnect switchgear 1 can be electrically (and mechanically) connected to the busbar system 3. For this purpose, the first connector unit 10 can include one or more first terminals 11, 12, 13. Each first collecting terminal 11, 12, 13 can be connected to a corresponding busbar 3a, 3b, 3c of the busbar system 3. For this purpose, the first terminal 11, 12, 13 can include appropriate connecting elements for reliable connection with the corresponding busbar 3a, 3b, 3c. For example, the first terminal 11, 12, 13 can have a shape that matches the corresponding element of the busbar 3a, 3b, 3c.

[0045] Although the invention is described here and in the following embodiments in connection with a busbar system 3 comprising three busbars 3a, 3b, 3c, the invention is not limited to busbar systems comprising three busbars. Furthermore, any other suitable number of busbars, in particular one busbar, two busbars or more than three busbars, is also possible. For example, the invention may also be applied to AC applications with only a single phase requiring only a single busbar. Furthermore, the invention may also be applied to DC applications.

[0046] In another configuration, the load disconnect switch device 1 can be connected at the first connector unit 10 in any other way instead of using the busbar system 3. For example, the load disconnect switch device 1 can be directly mounted on a mounting plate or a top-hat rail. In such a configuration, the first terminals 11, 12, 13 of the first connector unit 10 can be coupled with the corresponding wires 3a, 3b, 3c of the electrical system 3.

[0047] The second connector unit 20 may include one or more second terminals 21, 22, 23. In particular, the number of the second terminals corresponds to the number of the first terminals 11, 12, 13. Each second terminal 21, 22, 23 can be connected to the external electrical device 2. For this purpose, each second terminal 21, 22, 23 can receive an electric wire for connecting the corresponding second terminal 21, 22, 23 to the external electrical device 2. For example, the second terminals 21, 22, 23 may include a clamping mechanism or any other suitable component for receiving and fastening the electric wire. In this way, the busbars 3a, 3b, 3c can be electrically connected to the external electrical device 2 via the internal structure of the load disconnection switch device 1.

[0048] The external electrical device 2 can be any kind of suitable electrical device. For example, the electrical device 2 can be an electrical load, such as a motor, an actuator of an automation system, or any other component that requires power. However, the external electrical device 2 can also be a power source, such as an inverter of a photovoltaic system, or any other device that provides power. In this way, the power of the external electrical device 2 can be provided to the bus system 3.

[0049] The load disconnection switch device 1 includes a load disconnection unit 30 that can establish or interrupt the electrical connection between the first terminal 11, 12, 13 and the corresponding second terminal 21, 22, 23. For this purpose, the load disconnection unit 30 may include a plurality of switch elements 31, 32, 33. Specifically, a separate switch element 31, 32, 33 is provided for each current path between the first terminal 11, 12, 13 and the corresponding second terminal 21, 22, 23. The operation of the separate switch elements 31, 32, 33 can be controlled by a common single mechanism. Therefore, the switch elements 31, 32, 33 are all in a closed state or an open state. The switch elements 31, 32, 33 can be switch elements that can interrupt the connection between the first connection terminal 11, 12, 13 and the second connection terminal 21, 22, 23 even if the current is flowing through the switch elements 31, 32, 33. In other words, the switch elements 31, 32, 33 can be disconnected under load conditions.

[0050] The load cut-off switchgear 1 further comprises a shunt resistor 61, 62, 63 in each current path between the first terminals 11, 12, 13 of the first connector unit 10 and the associated switching elements 31, 32, 33 of the load cut-off unit 30. In other words, the shunt resistors 61, 62, 63 are arranged close to the busbars 3a, 3b, 3c of the busbar system 3. In particular, the shunt resistors 61, 62, 63 are arranged close to the first connector unit 10 or even within the first connector unit 10.

[0051] The shunt resistors 61, 62, 63 may have a relatively low resistance. In particular, the resistance of the shunt resistors 61, 62, 63 may be less than 1 ohm. Preferably, the resistance of the shunt resistors 61, 62, 63 may be in the range of 0.025 to 0.1 milliohms. The shunt resistors 61, 62, 63 may include a resistance element such as a metal or an alloy. Preferably, the shunt resistors 61, 62, 63 may have a resistance element with a small thermal coefficient.

[0052] The shunt resistors 61, 62, 63 may include cooling elements for dissipating power losses of the respective shunt resistors 61, 62, 63. Additionally or alternatively, the shunt resistors 61, 62, 63 may have a suitable mechanical structure or shape that supports heat dissipation of the shunt resistors 61, 62, 63.

[0053] In such a configuration having the shunt resistors 61, 62, 63 in each current path between the first terminals 11, 12, 13 of the first connector unit 10 and the associated second terminals 21, 22, 23 of the second connector unit 20, the current in the current path causes a voltage drop across the corresponding shunt resistors 61, 62, 63. The voltage drop is almost proportional to the resistance of the corresponding shunt resistors 61, 62, 63. Therefore, the current value in the corresponding current path can be easily determined based on the voltage drop across the shunt resistors 61, 62, 63 and the resistance value of the shunt resistors 61, 62, 63.

[0054] In order to determine the current through the shunt resistors 61, 62, 63, a monitoring unit 50 is provided in the load disconnect switchgear 1. The monitoring unit 50 can measure the voltage drop across the shunt resistors 61, 62, 63 and determine the corresponding current value. For this purpose, appropriate data such as the values ​​of the respective shunt resistors 61, 62, 63 can be stored in the monitoring unit 50.

[0055] The resulting values ​​of the determined currents through the shunt resistors 61, 62, 63 can be further used for any appropriate measurement. For example, the determined current values ​​can be used in order to trigger the load disconnection unit 30. For example, if at least one of the determined current values ​​through the shunt resistors 61, 62, 63 exceeds a predetermined threshold, the switching elements 31, 32, 33 of the switching unit 30 can be disconnected. In this way, overcurrent protection can be achieved.

[0056] Additionally or alternatively, the monitoring unit 50 may include a communication interface 51. Therefore, the communication interface 51 can send data to a remote device and / or receive data from a remote device. The communication between the communication interface 51 of the monitoring unit 50 and the remote device can be performed, for example, based on any appropriate communication standard (e.g., Modbus RTP, Modbus TCP / IP, CAN bus, IO link, etc.). However, any other standard or proprietary communication mode can also be used. The communication of the communication interface 51 can also use, for example, power LAN technology, such as power line. Communication can be performed, for example, via a power line connected to the first connector unit 10 and / or the second connector unit 20, or via other auxiliary devices of the (DC) power supply and / or load disconnection switch device 1 of the monitoring unit 50. Additionally or alternatively, wireless communication can also be performed. For example, the communication interface 51 can use WLAN, Bluetooth, NFC, Zigbee or any other known or upcoming communication standard.

[0057] The monitoring unit 50 can also measure the voltage at the terminals of the shunt resistors 61, 62, 63. For example, the voltage can be measured at the terminals of the shunt resistors 61, 62, 63 facing the first connector unit 10 or at the terminals of the shunt resistors 61, 62, 63 facing the load cut-off unit 30. Based on the measured voltage, the monitoring unit 50 can also determine the direction of the current flowing through the shunt resistors 61, 62, 63. Additionally or alternatively, the monitoring unit 50 can determine the power flow through the corresponding shunt resistors 61, 62, 63 considering the determined current value and the related voltage value. In the case of alternating current (AC) applications, the monitoring unit 50 can consider the phase shift between the current and the voltage. Based on the phase shift, the active power and the reactive power can be determined. In addition to this, the monitoring unit 50 can also determine any other appropriate value that can be determined based on the acquired current value and voltage value.

[0058] In addition, the fuse units 41, 42, 43 can be arranged in each current path between the first terminals 11, 12, 13 and the second terminals 21, 22, 23. In particular, the fuse units 41, 42, 43 are arranged between the switch elements 31, 32, 33 of the load cut-off unit 30 and the second terminals 21, 22, 23 of the second connector unit 20. However, the fuse units 41, 42, 43 can also be arranged at different positions in the current path between the first connector unit 10 and the second connector unit 20. For example, the fuse can be any suitable fuse, for example, according to the UL or IEC field. The fuse can be an NH fuse (NH000 to NH3), a UL fuse (CC class, J class, CF class, etc.) or a cylindrical fuse (such as D0, D01, D02, 22x58, 10x85, 14x51), etc. Therefore, for example, the fuse can be specified for voltages up to 1000 volts. Fuses may be rated up to 160 A, 250 A, 355 A, 500 A or up to 800 A. From these specifications the required size of the appropriate fuse can be derived.

[0059] Figure 2 A schematic diagram of a monitoring unit 50 according to an embodiment is shown. In order to simplify the illustration, only the components related to a single shunt resistor 61 are illustrated in detail. However, the explanation also applies to the elements related to the other shunt resistors 62 and 63.

[0060] The monitoring unit 50 comprises a first measuring element 511 for measuring a voltage drop across the shunt resistor 61. The measured voltage drop may be provided to an analyzing element 512. The analyzing element 512 may determine the current through the shunt resistor 61 based on the measured voltage drop across the shunt resistor 61. In particular, the current through the shunt resistor 61 may be calculated by dividing the voltage drop across the shunt resistor 61 by the resistance of the shunt resistor 61. For this purpose, the resistance of the shunt resistor 61 or any other suitable parameter specifying the relationship between the voltage drop and the resulting current may, for example, be stored in the analyzing element 512. This relationship between the voltage drop and the resulting current may be predetermined.

[0061] For example, the determined current through the shunt resistor 61 may be provided to the communication interface 51 and / or the control unit 52. For example, the control unit 52 may perform a control operation based on the determined current value through the shunt resistor 61. For example, if at least one current through the shunt resistors 61, 62, 63 exceeds a predetermined threshold, the control unit 52 may trigger the load cutoff unit 32 to disconnect the switching elements 31, 32, 33.

[0062] As in accordance with Figure 2 As further illustrated in the exemplary embodiment of , the monitoring unit 50 may receive an additional sensing signal from the sensing element 47. For example, such a sensing element 47 may be arranged close to the shunt resistors 61, 62, 63. In this way, the sensing element 47 may sense the physical properties of the shunt resistors 61, 62, 63. For example, the sensing element 47 may be a thermal sensor. Therefore, the temperature of the shunt resistors 61, 62, 63 may be sensed by the corresponding sensing element 47. In this case, when determining the current through the corresponding shunt resistors 61, 62, 63, the determined temperature of the shunt resistors 61, 62, 63 may be further considered. For example, thermal compensation may be performed taking into account the thermal coefficient of the resistance of the shunt resistors 61, 62, 63. Therefore, such thermal compensation may further improve the accuracy of the determined current through the shunt resistors 61, 62, 63.

[0063] Figure 3 FIG. 5 shows a schematic diagram of a monitoring unit 50 according to another embodiment. Figure 1 and Figure 2 The configuration of the monitoring unit 50 of the aforementioned embodiment, so the explanation provided above also applies to Figure 3 In addition, according to Figure 3 The additional features may also be applied to the above-described embodiments.

[0064] according to Figure 3The monitoring unit 50 also includes a second measuring element 513. The second measuring element 513 can measure the voltage at the terminals of the shunt resistor 61. The voltage can be measured at the terminals facing the first connector unit 10 or at the terminals facing the load disconnection unit 30. The monitoring unit 50 can also include a calculation unit 514. The calculation unit 514 can receive the determined current value through the shunt resistor 61 and the related voltage at the terminals of the shunt resistor 61. Based on the corresponding current and voltage, the calculation unit 514 can calculate the power flow through the shunt resistor 61. In the case of AC applications, the calculation unit 514 can determine the phase shift between the voltage and the current. Based on the phase shift, the active power and / or the reactive power can be calculated. In addition, the direction of the power flowing through the shunt resistor 61 can be determined.

[0065] As combined Figure 2 It has already been mentioned that the above-described elements in connection with the shunt resistor 61 also apply to the further shunt resistors 62 and 63 .

[0066] In the above example, the fuse units 41, 42, 43 are provided between the load cut-off unit 30 and the second connector unit 20, and the load cut-off unit 30 is connected to the first connector unit 10. However, in general, other configurations are possible in which the fuse units 41, 42, 43 are connected to the first connector unit 10 and the load cut-off unit 30 is connected to the second connector unit 20. In this case, the above explanation applies accordingly, whereby the skilled person will make appropriate configuration adjustments where necessary.

[0067] In another alternative embodiment, the load disconnection switch device 1 may include two load disconnection units 30. In such a configuration, the first load disconnection unit 30 may be arranged between the first connector unit 10 and the fuse units 41, 42, 43. Another second load disconnection unit 30 may be arranged between the fuse units 41, 42, 43 and the second connector unit 20. For example, the first and second load disconnection units 30 may be switched synchronously, i.e., the two load disconnection units 30 are turned on or off at the same time. However, the first load disconnection unit 30 and the second load disconnection unit 30 may also be switched independently of each other.

[0068] The load disconnect switchgear 1 can be installed, for example, in a switch cabinet having a busbar system 3. Figure 4 . Such a configuration is illustrated in FIG. For example, such a configuration can be used in an automation system. In particular, the load disconnection switch device 1 can be used to supply power to a load 2. The load 2 connected to the load disconnection switch device 1 can be, for example, a resistive, inductive or capacitive load. For example, the load can be an electric motor or the like. However, any other load, such as an actuator of an automation system or the like, is also possible.

[0069] As in Figure 4 As can be further seen in , the load shedding switch device 1 may include a housing including the above-mentioned components. In particular, the housing of the load shedding switch device 1 may have a relatively small width w. For example, the width w of the housing may be 27 mm or less. In particular, the width w of the housing may be only 22.5 mm. This makes it possible to implement a device of small size and meet the requirements of the required distance relative to the leakage current requirements as required (e.g. according to the pending UL specification or other standards). However, any other dimensions are also possible depending on further constraints of the application.

[0070] Figure 5 A flow chart illustrating a method for operating a load shedding switch device 1 according to an embodiment is shown. The method can be applied to the above-described load shedding switch device 1. Therefore, the method may include any steps for performing the operations as have been described above in connection with the load shedding switch device 1. Furthermore, the above-described load shedding switch device 1 may include any kind of device, unit or component for performing the operations as described below in connection with the method.

[0071] The method comprises a step S1 of measuring a voltage drop across a shunt resistor 61 , 62 , 63 in a current path between one of the first terminals 11 , 12 , 13 of the first connector unit 10 and the load cut-off unit 30 .

[0072] The method further comprises a step S2 of determining a current in a respective current path between one of the first terminals 11,12,13 of the first connector unit 10 and the load disconnection unit 30. In particular, the respective current may be determined based on a measured voltage drop across the shunt resistors 61,62,63.

[0073] Furthermore, the method comprises a step S3 of providing an output signal indicative of the determined current. The output signal can be provided, for example, by means of an appropriate communication interface 51. In particular, the output signal can be provided to a remote device via a wired and / or wireless connection. Additionally or alternatively, the output signal can be used internally in the load shedding switch device 1. For example, a switching operation of the load shedding unit 30 can be triggered based on the determined current value.

[0074] In summary, the present invention relates to a low width load shedding switchgear for a busbar system. The load shedding switchgear comprises a shunt resistor arranged close to a connection to the busbar system. The voltage drop across the shunt resistor is analyzed to determine the value of the current flowing through the load shedding switchgear.

Claims

1. A load disconnect switchgear for a busbar system, comprising: A first connector unit, the first connector unit comprising at least one first terminal, each first terminal being used to connect to a power source or a load; a second connector unit, the second connector unit comprising at least one second terminal, each second terminal being configured to connect to an electrical connection of an external electrical device; a load disconnection unit, the load disconnection unit being used to disconnect the electrical connection between the first terminal of the first connector unit and the corresponding second terminal of the second connector unit; a shunt resistor, respectively in each current path between one of the first terminals of the first connector unit and the load cut-off unit; as well as At least one fuse unit, each of the at least one fuse unit is disposed in a current path between a first terminal of the first connector unit and a corresponding second terminal of the second connector unit.

2. The load shedding switch device according to claim 1, wherein: Each fuse unit is used to receive fuses with a rated current ranging from NH000 to NH03 or equivalent types.

3. The load shedding switch device according to claim 2, wherein: Each fuse unit is used for receiving a cylindrical fuse.

4. The load cutoff switch device according to claim 1, comprising a monitoring unit for determining a current in the current path between one of the first terminals of the first connector unit and the load cutoff unit based on a voltage drop across the shunt resistor in the corresponding current path.

5. The load shedding switch device according to claim 4, wherein: The monitoring unit is for measuring a voltage at a connection between one of the first terminals of the first connector unit and the load disconnection unit and for determining a power flow and / or a current direction based on the sensed current and the measured voltage.

6. The load shedding switch device according to claim 4, wherein: The monitoring unit comprises a communication interface for establishing a communication link with a remote device and for outputting data including the sensed current.

7. The load shedding switch device according to claim 4, wherein: The monitoring unit is configured to trigger the load disconnection unit to interrupt the electrical connection between the first terminal of the first connector unit and the corresponding second terminal of the second connector unit if at least one determined current exceeds a predetermined threshold value.

8. The load shedding switch device according to claim 4, wherein: Each terminal of the first connector unit comprises a connecting element for connecting the corresponding first terminal to an associated terminal of the power source or load, and The shunt resistors in the current path between the first terminal of the first connector unit and the load disconnection unit are directly connected to the connection elements, respectively.

9. The load-cutoff switch device according to claim 4 comprises a sensor element for sensing a physical property of the shunt resistor, and wherein the monitoring unit is used to determine the current in the current path between one of the first terminals of the first connector unit and the load-cutoff unit based on the physical property sensed by the sensor element.

10. The load shedding switchgear of claim 9, wherein: The sensor element comprises a thermal sensor.

11. The load shedding switch device according to claim 4, wherein: The monitoring unit is configured to output an alarm signal if at least one of the determined currents exceeds a predetermined threshold value.

12. The load shedding switchgear of claim 1, wherein: The load disconnection unit is used to interrupt the electrical connection between the first terminal of the first connector unit and the corresponding second terminal of the second connector unit under load conditions.

13. The load shedding switchgear of claim 1, wherein: Each fuse in the at least one fuse unit has a maximum current rating of at least 160 amperes.

14. The load shedding switchgear of claim 1, wherein: The load break switchgear has an outer width of at most 27 millimeters.

15. A switch cabinet device, comprising: The load disconnect switch device according to claim 1; and A busbar system, the busbar system comprising at least one busbar, Wherein the at least one busbar is electrically connected to the first connector unit of the load disconnect switchgear.

16. An automated system comprising: The load disconnect switch device according to claim 1; and A busbar system, the busbar system comprising at least one busbar, wherein the at least one busbar is electrically connected to the first connector unit of the load-cut switchgear; and An electrical device is electrically connected to the second connector unit of the load cutoff switch device.

17. A method for operating a load shedding switchgear according to claim 1, comprising the steps of: measuring a voltage drop across the shunt resistor in the current path between one of the first terminals of the first connector unit and the load cut-off unit; determining a current in a corresponding current path between one of the first terminals of the first connector unit and the load cut-off unit based on the measured voltage drop across the shunt resistor; as well as An output signal indicative of the determined current is provided.

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