CIRCUIT BREAKER

Abstract

A circuit breaker protects an electric low-voltage circuit. The circuit breaker has a housing with grid-side connections and load-side connections for conductors of the low-voltage circuit and a series circuit containing a mechanical separating contact unit and an electronic interruption unit. The separating contact unit is paired with the grid-side connections, and the interruption unit is paired with the load-side connections. The mechanical separating contact unit has a handle for closing and opening contacts. A current sensor is arranged in a conductor path between the separating contact unit and the interruption unit, for ascertaining the level of the current of the low-voltage circuit. The circuit breaker is configured such that when current thresholds and/or current/time thresholds are exceeded, a process for preventing current flow in the low-voltage circuit is initiated. A power supply is connected to conductors of the low-voltage circuit between the grid-side connection and the separating contact unit.

Claims

1-25. (canceled)

26. A circuit breaker for protecting an electrical low-voltage AC circuit, the circuit breaker comprising: a housing with grid-side and load-side terminals for conductors of the electrical low-voltage AC circuit; an electronic interruption unit connected to said load-side terminals and having semiconductor-based switching elements; a mechanical isolating contact unit having contacts and connected to said grid-side terminals and also connected to said electronic interruption unit, so that closed said contacts of said mechanical isolating contact unit and a low-impedance state of said semiconductor-based switching elements of said electronic interruption unit permit a flow of current in the electrical low-voltage AC circuit, or open said contacts of said mechanical isolating contact unit permit an electrical isolation preventing the flow of the current in the electrical low-voltage AC circuit and/or a high-impedance state of said semiconductor-based switching elements preventing the flow of the current in the electrical low-voltage AC circuit, said mechanical isolating contact unit having a handle for closing and opening said contacts; a current sensor disposed in a conductor downstream of said mechanical isolating contact unit, to determine a level of a current in the electrical low-voltage AC circuit; a controller connected to said current sensor, said electronic interruption unit and said mechanical isolating contact unit, wherein the circuit breaker is configured such that current limits and/or current-time limits being exceeded results in prevention of the flow of the current in the electrical low-voltage AC circuit being initiated; and a power supply for supplying power to the circuit breaker, which is connected to the conductors of the electrical low-voltage AC circuit between said grid-side terminals and said mechanical isolating contact unit.

27. The circuit breaker according to claim 26, further comprising a voltage sensor, connected to said controller, for determining a level of a voltage between the conductors of the electrical low-voltage AC circuit between said mechanical isolating contact unit and said electronic interruption unit.

28. The circuit breaker according to claim 26, wherein said mechanical isolating contact unit has a position sensor for a position of said contacts.

29. The circuit breaker according to claim 26, further comprising a display connected to said controller.

30. The circuit breaker according to claim 26, further comprising a communication unit, connected to said controller, that facilitates in a wireless communication capability.

31. The circuit breaker according to claim 26, further comprising a differential current determination unit, connected to said controller, for determining a differential current in the conductors of the electrical low-voltage AC circuit.

32. The circuit breaker according to claim 26, wherein the circuit breaker is configured such that operation of said mechanical isolating contact unit by way of said handle results in a signal being sent to said controller before said contacts open, so that said controller puts said semiconductor-based switching elements of said electronic interruption unit into the high-impedance state.

33. The circuit breaker according to claim 26, wherein said mechanical isolating contact unit is configured such that said contacts are opened by said controller but not closed.

34. The circuit breaker according to claim 26, wherein the circuit breaker is configured such that said controller can put said mechanical isolating contact unit into a blocked state, so that said contacts are prevented from being closed by way of said handle.

35. The circuit breaker according to claim 34, wherein said controller puts said mechanical isolating contact unit into an unblocked state, said contacts not being closed, but said contacts being able to be closed by way of said handle.

36. The circuit breaker according to claim 34, wherein said mechanical isolating contact unit is configured such that there is provision for a bistable blocking state, so that the blocked state or an unblocked state of said mechanical isolating contact unit is maintained even in an event of a power failure in the electrical low-voltage AC circuit.

37. The circuit breaker according to claim 26, further comprising a protective element connected upstream of said power supply.

38. The circuit breaker according to claim 26, wherein said power supply has electrical isolation.

39. The circuit breaker according to claim 26, wherein the circuit breaker is configured such that when the circuit breaker is first started up in a de-energized state of the electrical low-voltage AC circuit said semiconductor-based switching elements of said electronic interruption unit are in the high-impedance state and said mechanical isolating contact unit is in a blocked state, and: when power is supplied in the electrical low-voltage AC circuit the circuit breaker is supplied with power by said power supply; and said controller performs a first checking function of the circuit breaker, a successful outcome of the first checking function resulting in said mechanical isolating contact unit being unblocked, so that it is possible for said contacts of said mechanical isolating contact unit to be closed by way of said handle.

40. The circuit breaker according to claim 39, wherein after the first checking function has had a successful outcome and said mechanical isolating contact unit has been unblocked, said mechanical isolating contact unit is unblocked even after a power failure.

41. The circuit breaker according to claim 39, wherein after the first checking function has been successful and said mechanical isolating contact unit has been unblocked, said semiconductor-based switching elements of said electronic interruption unit are in the high-impedance state after said contacts of said mechanical isolating contact unit have been closed by means of said handle, a second checking function is performed, in that said semiconductor-based switching elements of said electronic interruption unit are put into the low-impedance state after a successful outcome of the second checking function.

42. The circuit breaker according to claim 39, wherein the first checking function includes a self-test of the functionality of the circuit breaker, which involves at least one component of a unit of the circuit breaker being checked, and if the at least one component of the unit is functional then the first checking function is terminated with a successful outcome.

43. The circuit breaker according to claim 39, wherein the first checking function encompasses a check on at least one electrical parameter of a grid-side terminal of said terminals.

44. The circuit breaker according to claim 41, wherein the second checking function includes a self-test of a functionality of the circuit breaker in accordance with the first checking function and/or encompasses a check on at least one electrical parameter of a load-side terminal of said terminals.

45. The circuit breaker according to claim 26, wherein the circuit breaker is configured such that initiated opening of said contacts by means of said handle results in a signal being sent to said controller before said contacts open, so that said semiconductor-based switching elements of said electronic interruption unit are put into the high-impedance state.

46. The circuit breaker according to claim 26, wherein the circuit breaker is configured such that a current limit value or/and current-time limit value being exceeded results in said semiconductor-based switching elements of said electronic interruption unit being put into the high-resistance impedance to prevent the flow of the current in the electrical low-voltage AC circuit, in that, depending on an adjustable configuration of the circuit breaker, further: said contacts of said mechanical isolating contact unit are opened; or said semiconductor-based switching elements remain in the high-impedance state and the high impedance state is indicated; or said semiconductor-based switching elements change to the low-impedance state after a first period of time or after a check on said load-side terminal.

47. The circuit breaker according to claim 30, wherein the circuit breaker is configured such that detection of a fault in a unit of the circuit breaker results in said semiconductor-based switching elements of said electronic interruption unit being put into the high-impedance state to prevent the flow of the current in the electrical low-voltage AC circuit, and: said contacts of said mechanical isolating contact unit are opened and said mechanical isolating contact unit is put into a blocked state, so that said contacts are prevented from being closed by way of said handle; and detection of a fault is communicated by way of said communication unit.

48. The circuit breaker according to claim 26, wherein the circuit breaker is configured such that a power failure in the electrical low-voltage AC circuit results in said mechanical isolating contact unit remaining in its switching state, so that closed said contacts and a subsequent power failure result in said contacts still being closed after the power supply has been restored.

49. The circuit breaker according to claim 26, wherein said controller has a microcontroller.

50. An operating method, which comprises the steps of: providing the circuit breaker according to claim 26; operating the circuit breaker.

Description

[0107] In the drawing:

[0108] FIG. 1 shows a block diagram of a circuit breaker.

[0109] FIG. 1 shows a representation of a circuit breaker SG for protecting an electrical low-voltage circuit, in particular low-voltage AC circuit, comprising: [0110] a housing GEH with grid-side L1, N1 and load-side L2, N2 terminals for conductors of the low-voltage AC circuit,
the grid-side terminals comprise a grid-side neutral conductor terminal N1 and a grid-side phase conductor terminal L1,
the load-side terminals comprise a load-side neutral conductor terminal N2 and a load-side phase conductor terminal L2,
an energy source, for example, is connected to the grid-side terminals or the grid-side Grid,
(at least) one load, for example, is connected to the load-side terminals or the load-side Load, [0111] a mechanical isolating contact unit MK connected to the grid-side L1, N1 terminals, which is also connected to an electronic interruption unit EU that is also connected to the load-side terminals L2, N2,
i.e. a series circuit formed by a mechanical isolating contact unit MK and an electronic interruption unit EU, wherein the mechanical isolating contact unit MK is associated with the grid-side terminals L1, N1 or the grid Grid and
the electronic interruption unit EU is associated with the load-side terminals L2, N2 or the load-side Load, [0112] so that closed contacts KL, KN of the isolating contact unit MK and a low-resistance state of semiconductor-based switching elements T1, T2 of the electronic interruption unit EU permit a flow of current in the low-voltage circuit, or
open contacts KL, KN of the isolating contact unit MK permit an electrical isolation preventing a flow of current in the low-voltage circuit or/and a high-resistance state of the switching elements T1, T2 of the electronic interruption unit EU permits a flow of current to be prevented in the low-voltage circuit, [0113] the mechanical isolating contact unit MK has a handle for closing and opening the contacts KL, KN that is accessible on the outside of the housing, so that it can be manually operated by a user, [0114] a current sensor unit SI arranged in a conductor between the isolating contact unit MK and the interruption unit EU, to determine the level of the current in the low-voltage circuit,
in the example the current sensor unit SI is arranged in the phase conductor, [0115] a control unit SE, which is connected to the current sensor unit SI, the electronic interruption unit EU and the mechanical isolating contact unit MK, wherein the circuit breaker SG is designed
such that current limits or/and current-time limits being exceeded results in prevention of a flow of current in the low-voltage circuit being initiated,
this can be accomplished as a result of the switching elements T1, T2 of the electronic interruption unit EU changing to a high-resistance state or/and as a result of the contacts KL, KN of the mechanical isolating contact unit MK opening, [0116] a power supply unit NT for supplying power to the circuit breaker SG, in particular the control unit SE, which is connected to conductors of the low-voltage circuit between the grid-side (L1, N1) terminals and the mechanical isolating contact unit (MK). This encompasses a connection that encompasses a direct connection to the grid-side (L1, N1) terminals or the mechanical isolating contact unit (MK). The power supply unit NT is electrically connected upstream of the mechanical isolating contact unit (MK), so that it is supplied with power by the grid-side terminals (provided that the grid-side terminals supply power/voltage) irrespective of the switching state of the contacts of the mechanical isolating contact unit (MK).

[0117] The power supply unit is thus normally (provided that the grid side or energy source supplies power) constantly supplied with power. It is therefore possible for protective and monitoring functions to be (more or less) constantly performed in the circuit breaker or by the control unit.

[0118] The power supply unit may have a protective element, in particular a fuse SICH (as shown in FIG. 1), or/and a switch connected upstream of it.

[0119] The circuit breaker SG in the example further has a voltage sensor unit SU, connected to the control unit SE, for determining the level of the voltage between the conductors of the low-voltage circuit between the isolating contact unit MK and the interruption unit EU.

[0120] The circuit breaker SG in the example has a differential current determination unit ZCT, which is connected to the control unit and arranged on the conductors of the low-voltage circuit between the isolating contact unit MK and the interruption unit EU, for determining a differential current in the conductors of the low-voltage circuit.

[0121] The circuit breaker SG in the example has an indicator unit AE, connected to the control unit SE, for indicating status information relating to the circuit breaker, in particular the control unit SE.

[0122] The circuit breaker SG in the example has a communication unit COM, connected to the control unit SE. Said communication unit can facilitate a wired or wireless communication capability, or both.

[0123] The control unit SE has a microcontroller MCU to control the circuit breaker. The microcontroller MCU or the control unit SE may have a computer program product CPP. The computer program product CPP comprises commands that, when the program is executed by the microcontroller MCU, cause the latter to instigate said functions for a circuit breaker.

[0124] There may be provision for a computer-readable storage medium that stores the computer program product CPP. Similarly, there may be provision for a data carrier signal that transmits the computer program product CPP. As such, the computer program product CPP or a new computer program product CPP can reach the circuit breaker by way of the communication unit COM.

[0125] In the example shown in FIG. 1, the control unit SE comprises the microcontroller MCU along with the computer program product CPP, the indicator unit AE, the communication unit CPP, the current sensor unit SI, the voltage sensor unit SU and the differential current determination unit ZCT. This is only one example; the units may also be separate or grouped differently.

[0126] The electronic interruption unit EU in the example shown in FIG. 1 has two semiconductor-based switching elements T1, T2, such as transistors, field effect transistors, IGBTs or the like. The semiconductor-based switching elements T1, T2 can be controlled by a driver unit Drv. The driver unit Drv in the example is in turn controlled by the control unit SE. The electronic interruption unit EU may have an energy absorber EA, to prevent destructive voltage spikes or absorb switching energies.

[0127] The electronic interruption unit EU in the example is in single-pole form (for one conductor of the low-voltage circuit). In the example, the electronic interruption unit EU is arranged in the phase conductor.

[0128] The mechanical isolating contact unit MK in the example is of two-pole design (in both conductors, of the single-phase AC circuit in the example). With a two-pole design, safe electrical isolation is possible provided that the mechanical isolating contact unit MK is designed with isolator switch properties in accordance with the standard (distances, minimum air gaps, etc.).

[0129] The mechanical isolating contact unit MK has a position indicator unit POSA that indicates the (switching) position of the contacts of the mechanical isolating contact unit MK. The position indicator unit is of mechanical design, so that the contact position can be indicated even in the off-circuit state (no power from the grid-side Grid).

[0130] The circuit breaker or the mechanical isolating contact unit MK is designed such that operation of the mechanical isolating contact unit MK by way of the handle HH results in an (operating) signal AS being sent to the control unit SE before the contacts KL, KN are opened. The circuit breaker SG or the control unit SE is designed such that the semiconductor-based switching elements T1, T2 of the electronic interruption unit EU are then put into a high-resistance state, thus permitting zero-power switching with the mechanical isolating contact unit MK.

[0131] The circuit breaker or the mechanical isolating contact unit MK is designed such that the contacts KL, KN can be opened by the control unit SE, for example by way of an opening signal OPEN, but not closed. Specifically, the contacts can be opened even if the handle is blocked (for example, contrary to customary use, is permanently operated for On/contacts closed).

[0132] In one embodiment, the circuit breaker or the mechanical isolating contact unit MK is designed such that in particular the control unit SE can put the mechanical isolating contact unit MK into a blocked state, so that the contacts are prevented from being closed by way of the handle.

[0133] Further, in particular the control unit SE can put the mechanical isolating contact unit MK into an unblocked state, the contacts not being closed, in particular by the control unit, [0134] but the contacts being able to be closed by way of the handle.

[0135] Furthermore, the circuit breaker, specifically the mechanical isolating contact unit MK, is designed such that there is provision for a bistable blocking state, so that the blocked state or the unblocked state of the mechanical isolating contact unit MK is maintained even in the event of a power failure in the low-voltage circuit.

[0136] There may be provision for other units, such as a switch lock unit SS or a combined opening block unit O/B.

[0137] The novel circuit breaker SG according to the invention is designed such that when the circuit breaker is first started up in the de-energized (in the example off-circuit) state of the low-voltage circuit the switching elements of the electronic interruption unit are in the high-resistance state and the mechanical isolating contact unit is in a blocked state. When power is supplied (in the example voltage is supplied) in the low-voltage circuit the circuit breaker is supplied with power by the power supply unit. The circuit breaker, in particular the control unit, performs a first checking function of the circuit breaker. A successful outcome of the first checking function results in the mechanical isolating contact unit being unblocked, so that it is possible for the contacts of the mechanical isolating contact unit to be closed by way of the handle.

[0138] After the first checking function has been successful and the mechanical isolating contact unit has been unblocked the switching elements of the electronic interruption unit are (as previously) in a high-resistance state after the contacts of the mechanical isolating contact unit have been closed by means of the handle (which is now possible).

[0139] A second checking function is performed. The switching elements of the electronic interruption unit are put into a low-resistance state after a successful outcome of the second checking function.

[0140] This step concludes the switch-on process, in particular.

[0141] The first and second checking functions comprise, for example, a self-test of the functionality of the circuit breaker. The self-test of the functionality of the circuit breaker involves: [0142] at least one component, in particular multiple components, of a unit, in particular multiple units, [0143] of the circuit breaker being checked.

[0144] If the at least one component, in particular multiple components, [0145] of a unit, in particular multiple units, is/are functional [0146] then the first (or second) checking function is terminated with a successful outcome.

[0147] The first checking function is, for example, specifically directed to a self-test of the control unit SE, since the latter is supplied with power.

[0148] The second checking function may be, for example, specifically directed to a self-test of the electronic interruption unit EU, since this is now supplied with power/voltage is applied.

[0149] An unsuccessful outcome of the first checking function results in the contacts of the mechanical isolating contact unit remaining in a blocked state, so that they cannot be closed by way of the handle.

[0150] An unsuccessful outcome of the second checking function results, depending on the fault, in the contacts of the mechanical isolating contact unit being able to be opened and put into a blocked state. Alternatively, depending on the fault, the electronic interruption unit may merely remain in a high-resistance state.

[0151] The checking functions encompass a check on at least one electrical parameter of the load-side or grid-side terminal. In particular, the checking function performs a check on at least one, in particular multiple or all, of the following parameters: [0152] check for a, in particular grid-side, first overvoltage value or/and second overvoltage value or/and third overvoltage value being exceeded, [0153] check for a, in particular grid-side, first undervoltage value being underrun, [0154] check for a first temperature limit value or/and second temperature limit value or/and third temperature limit value being exceeded, [0155] check for parameters of the load-side terminal, in particular for a load-side first or/and second resistance value or load-side first or/and second impedance value being underrun.

[0156] The first checking function can encompass the check for a grid-side first overvoltage value or/and second overvoltage value or/and third overvoltage value being exceeded. Further, a check for a grid-side first undervoltage value being underrun. The second checking function can involve the check for parameters of the load-side terminal, in particular for a load-side first or/and second resistance value or load-side first or/and second impedance value being underrun. This allows switching on to a short circuit to be avoided.

[0157] Further, depending on the checked parameters: [0158] if the first overvoltage value is exceeded, overvoltage information is provided, [0159] if the second overvoltage value is exceeded, the electronic interruption unit is prevented from changing to a low-resistance state, [0160] if the third overvoltage value is exceeded, the contacts open, [0161] if the first undervoltage value is underrun, undervoltage information is provided or/and the electronic interruption unit remains in a high-resistance state, in particular if the voltage level is greater than a second undervoltage value, [0162] if the first temperature limit value is exceeded, temperature information is provided, [0163] if the second temperature limit value is exceeded, the electronic interruption unit remains in a high-resistance state, [0164] if the third temperature limit value is exceeded, the contacts open, [0165] if the load-side first resistance value or load-side first impedance value is underrun, impedance information is provided, [0166] if the load-side second resistance value or load-side second impedance value is underrun, the electronic interruption unit remains in a high-resistance state.

[0167] Operation of the handle to open the contacts results in a signal being sent to the control unit before the contacts open, so that the switching elements of the electronic interruption unit are put into a high-resistance state. Further, the control unit stores at least one current value or current-time value of the flow of current in the low-voltage circuit in a grid-voltage-independent memory.

[0168] A current limit value or/and current-time limit value being exceeded results in the switching elements of the electronic interruption unit being put into a high-resistance state to prevent a flow of current in the low-voltage circuit. Depending on the adjustable configuration of the circuit breaker, a further possibility is that: [0169] the contacts of the mechanical isolating contact unit are opened or [0170] the switching elements remain in a high-resistance state and this state is indicated. In particular, the changing of the switching elements to a low-resistance state can be initiated by way of an input, or [0171] the switching elements change to a low-resistance state after a first period of time or after a check on the load-side terminal, in particular a check on at least one electrical parameter of the load-side terminal, more specifically that a threshold value of the electrical parameter is underrun or exceeded.

[0172] Detection of a fault in a unit of the circuit breaker results in the switching elements of the electronic interruption unit being put into a high-resistance state to prevent a flow of current in the low-voltage circuit. Further, the contacts of the mechanical isolating contact unit are opened and the mechanical isolating contact unit is put into a blocked state, so that the contacts are prevented from being closed by way of the handle.

[0173] The detection of the fault is also communicated by way of the communication unit.

[0174] The first/second checking function may be produced by way of the control unit, specifically the microcontroller MCU in combination with the computer program product CPP.

[0175] In the absence of functionality, the contacts of the mechanical isolating contact unit can be opened. If the functionality is absent after another (or a certain number of other, e.g. 0 to 3) switch-on process(es), the mechanical isolating contact unit can be put into a blocked state, so that renewed (further) closure of the contacts is prevented.

[0176] The circuit breaker may be designed such that a power failure in the electrical low-voltage circuit results in the mechanical isolating contact unit remaining in its switching state, so that closed contacts and a subsequent power failure result in the contacts still being closed after the power supply has been restored.

[0177] High resistance is taken to mean a state in which only a current of negligible magnitude now flows. In particular, high resistance means resistance values of greater than 1 kiloohm, preferably greater than 10 kiloohms, 100 kiloohms, 1 megohm, 10 megohms, 100 megohms, 1 gigaohm or greater.

[0178] Low resistance is taken to mean a state in which the current value specified on the circuit breaker could flow. In particular, low resistance means resistance values that are less than 10 ohms, preferably less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm or less.

[0179] The invention will be described or summarized again below using different wording.

[0180] In electronic circuit breakers according to the invention, mechanical switching contacts in combination with an electronic switch will perform the switching functions.

1.) New Concept:

[0181] Mechanical isolating contacts in both poles [0182] One pole (in particular phase conductor L) is protected by an electronic interruption unit containing semiconductor-based switching elements, e.g. power semiconductors, [0183] Relief network (energy absorber) across the switching elements [0184] Mechanical operation of the handle, which is designed such that a signal is sent to the control unit before the contacts open, and the control unit causes the interruption unit to change to a high-resistance state [0185] The mechanical isolating contact unit can be opened by the control unit, but cannot be closed [0186] The mechanical isolating contact unit can only be closed manually by way of the handle [0187] Measurement technology: [0188] Voltage measurement between L and N [0189] Current measurement in the protected pole (L) [0190] Total current measurement through L and N [0191] The power supply (=power supply unit) for the control unit taps off the voltage on L and N upstream of the contacts of the mechanical isolating contact unit.

[0192] The power supply (=power supply unit) has an electrical isolation (e.g. using a voltage transformer) in order to maintain the isolating function of the mechanical contacts in the overall concept. The electrical isolation should meet standard-compliant requirements, e.g. double insulation.

[0193] The power supply (=power supply unit) has a protected connection to L (e.g. fuse) [0194] The control unit can put the mechanical isolating contact unit into a blocked state. It is then no longer possible to close the contacts by means of the handle. The control unit can put the mechanical isolating contact unit back into an unblocked state. [0195] The device has a communication interface (preferably wireless) [0196] The contact position of the (mechanical) contacts is indicated mechanically (e.g. using Green: Off and Red: On). [0197] The device has an indicator unit that indicates the status of the device, e.g. using light-emitting diodes/LEDs, e.g. as follows: [0198] Red: On state [0199] Green: Off state, disconnected [0200] Yellow: Control state, high resistance

2.) Power-on Behavior:

[0201] When powering on, the device is switched on using the handle. [0202] a) The device receives mains voltage [0203] b) The power supply unit begins to supply the device, specifically the control unit, with power [0204] c) The device, specifically the control unit, performs a first checking function/a self-test (specifically of the electronic components) [0205] d) Successful completion results in the mechanical isolating contact unit, e.g. the switch lock, being switched from the blocked to the unblocked state (the main current path can now be mechanically switched on manually by way of the handle).

[0206] Preferably bistable states: the respective state is maintained even in the off-circuit case; changeover is actively controlled by the control unit [0207] e) The handle is used to close the contacts [0208] f) Contacts close [0209] g) The load-side output is still off circuit because the interruption unit is in a high-resistance state/in the disabled state [0210] h) Second checking function, e.g. load is checked for e.g. short circuit [0211] i) A successful test results in the interruption unit changing to a low-resistance state (without further (manual) operation)) [0212] j) Load side receives power, load is supplied with power.

3.) Power-Off Behavior:

[0213] When powering off, the device is switched off using the handle (manual operation). [0214] a) Handle is set to Off (to open contacts) [0215] b) The operating action is sent to the control unit before the contacts open [0216] c) The interruption unit changes to a high-resistance state immediately (or intelligently at the zero crossing) [0217] d) The contacts open [0218] e) The power supply for the electronics is maintained even in the isolated state (disconnected). [0219] i. In some cases the control unit is supplied with an appropriate safety extra-low voltage by the power supply unit, e.g. 3 V or 5 V [0220] ii. The power supply includes a safe electrical isolation from the mains voltage (e.g. by way of a double or extra-reinforced insulation in the voltage transformer) [0221] iii. The power supply could be isolated from the grid using a small switch.

4.) Behavior in the Event of a Fault in the Load: Short Circuit or Overload:

[0222] If a device experiences e.g. a short circuit in the load, the device reacts as follows. [0223] a) A current limit value being exceeded is detected by the relevant units [0224] b) The interruption unit is switched to the high-resistance state, so that the load is no longer supplied with power/voltage [0225] c) The device can then decide, depending on the configuration (based on fault type and/or fault current), which of the e.g. following (two) states is adopted: [0226] 1) The device automatically opens the mechanical contacts and the load is completely disconnected [0227] 2) The device remains in the high-resistance state (the contacts of the isolating contact unit remain closedthe device does not disconnect). From this state, an automatic power-on is possible again.

5.) Behavior in the Event of (Internal) Device Fault:

[0228] If a fault occurs in the circuit breaker, in particular the control unit, the device changes to a safe state from which the device cannot be switched on again. The precondition is the detection of the defect by the circuit breaker. [0229] a) The fault is detected in the circuit breaker [0230] b) The device switches the interruption unit to a high-resistance state [0231] c) The device opens the contacts of the isolating contact unit and in so doing blocks the isolating contact unit (e.g. the switch lock) so that the contacts can no longer be closed by way of the handle [0232] d) The fault is reported using the communication unit.

6.) Behavior in the Event of Grid Failure/Power Failure:

[0233] If a grid failure occurs, the circuit breaker is no longer supplied with power. The contacts remain closed/in the previous position. This means that the device can change to the previous switching state without manual operation when the grid voltage returns.

[0234] Although the invention has been illustrated and described in greater detail by way of the exemplary embodiment, the invention is not restricted by the examples disclosed and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention.