Protection switch device and method

Abstract

The invention relates to a protective switching device for protecting a multi-phase low-voltage AC circuit, comprising:-a housing having a grid-side phase connection and a load-side phase connection for phase conductors of the low-voltage AC circuit,-a series circuit of mechanical phase contacts and electronic switches, wherein each series circuit electrically connects one of the network-side phase connections to one of the load-side phase connections,-the mechanical phase contacts can be switched in such a way that they open together to avoid a current flow or closed together for a current flow, switching the electronic switch by means of a semiconductor-based switching element to a high-resistance state of the switching element to avoid the current flow or to a low-resistance state of the switching element for the current flow, determining the magnitude of the current of the respective phase conductor in each series circuit, when at least one first current threshold value or current-time limit value is exceeded in the phase conductor, the avoidance of the current flow is initiated, and the electronic switch can be switched into a high-resistance state or a low-resistance state by means of the control input.

Description

Technical Field

[0001] The present invention relates to the technical field of protective switching devices for multi-phase low-voltage AC circuits having electronic switches and a method for protective switching devices for multi-phase low-voltage AC circuits having electronic switches. Background Art

[0002] Low voltage refers to voltages up to 1000 V AC or 1500 V DC. Specifically, low voltage refers to voltages greater than minimum voltage, which is 50 V AC or 120 V DC.

[0003] A low-voltage circuit, low-voltage network, or low-voltage system is a circuit with a rated or nominal current of up to 125 amperes, more particularly up to 63 amperes. A low-voltage circuit is particularly a circuit with a rated or nominal current of up to 50 amperes, 40 amperes, 32 amperes, 25 amperes, 16 amperes, or 10 amperes. The current values ​​mentioned are particularly the rated current, the nominal current, and / or the cut-off current, i.e., the maximum current conducted through the circuit under normal circumstances, or the current normally interrupted by the circuit, for example, by a protective device such as a protective switchgear, a circuit breaker, or a circuit breaker. The rated current can be further graded, from 0.5 A through 1 A, 2 A, 3 A, 4 A, 5 A, 6 A, 7 A, 8 A, 9 A, 10 A, etc., up to 16 A.

[0004] Circuit breakers are long-known overcurrent protection devices used in low-voltage circuits in electrical installation technology. They protect circuits from damage caused by overcurrent and / or short-circuit-induced heating. They automatically disconnect circuits in the event of an overload and / or short-circuit. They are non-self-resetting fuses.

[0005] Unlike circuit breakers, circuit breakers are rated for currents greater than 125 amperes, sometimes starting at 63 amperes. Consequently, circuit breakers are simpler and more compact. They typically have a mounting option for top-hat rails (supporting rails, DIN rails, TH35).

[0006] Circuit breakers are electromechanical. They contain mechanical switching contacts or operating current triggers within their housings for interrupting (triggering) the current. Typically, a bimetallic protective element or bimetallic element is used to trigger (interrupt) the circuit in the event of a prolonged overcurrent (overcurrent protection) or thermal overload (overload protection). An electromagnetic trigger with a coil is used for short-term triggering when the overcurrent limit is exceeded or a short circuit occurs (short-circuit protection). One or more arc extinguishing chambers or arc extinguishing devices are provided. Furthermore, connection elements for the conductors of the circuit to be protected are provided.

[0007] Protection switchgear with electronic interruption units or switches is a relatively recent development. These devices have semiconductor-based electronic interruption units or switches. That is, the current in the low-voltage circuit is directed through the semiconductor device or switch, which can interrupt the current or switch it into conduction mode. Protection switchgear with electronic interruption units also typically have a mechanical disconnect contact unit, which has disconnection characteristics, particularly in accordance with relevant standards for low-voltage circuits. The contacts of the mechanical disconnect contact unit are connected in series with the electronic interruption unit, meaning that the current in the low-voltage circuit to be protected is directed through both the mechanical disconnect contact unit and the electronic interruption unit.

[0008] The present invention relates in particular to a (polyphase) low-voltage AC circuit having an AC voltage, which is typically a time-dependent sinusoidal AC voltage with a frequency f. The time dependence of the instantaneous voltage value u(t) of the AC voltage is described by the following equation:

[0009] u(t)=U*sin(2π*f*t)

[0010] in:

[0011] u(t) = instantaneous voltage value at time t

[0012] U = voltage amplitude

[0013] A harmonic AC voltage can be represented by the rotation of a pointer, where the length of the pointer corresponds to the voltage amplitude (U). Here, the instantaneous deflection is the projection of the pointer onto the coordinate system. The oscillation period corresponds to a full rotation of the pointer, and its full angle is 2π (2Pi), or 360°. The angular frequency is the rate of change of the phase angle of this rotating pointer. The angular frequency of a harmonic oscillation is always 2π times its frequency, i.e.:

[0014] ω = 2π * f = 2π / T = angular frequency of the AC voltage (T = duration of the oscillation cycle)

[0015] The specification of angular frequency (ω) is often preferred to frequency (f) because many vibration theory formulas can be expressed more compactly in terms of angular frequency due to the presence of trigonometric functions, which, by definition, have a period of 2π:

[0016] u(t)=U*sin(ωt)

[0017] In the case of an angular frequency that is not constant over time, the term instantaneous angular frequency is also used.

[0018] In the case of a sinusoidal, in particular temporally constant, alternating voltage, the time-dependent value as a function of the angular velocity ω and the time t corresponds to a time-dependent angle φ(t), which is also called the phase angle φ(t).

[0019] That is, the phase angle φ(t) periodically passes through the range of 0...2π or 0°...360°. That is, the phase angle periodically assumes values ​​between 0 and 2π or 0° and 360° (φ=n*(0...2π) or φ=n*(0°...360°), abbreviated to: φ=0...2π or φ=0°...360° due to the periodicity).

[0020] The instantaneous voltage value u(t) therefore refers to the instantaneous value of the voltage at the time t, i.e. in the case of a sinusoidal (periodic) alternating voltage, to the value of the voltage about the phase angle φ (φ=0...2π or φ=0°...360° for the respective period). Summary of the Invention

[0021] The object of the present invention is to improve a circuit breaker device of the type mentioned at the outset, in particular to achieve greater flexibility and new features for the circuit breaker device.

[0022] The aforementioned object is achieved by a protective switching device having the features of patent claim 1 and by a method according to patent claim 20 .

[0023] According to the present invention, a protective switch device for protecting a multi-phase low-voltage AC circuit is provided, which comprises:

[0024] - a housing having a line-side phase connection and a load-side phase connection for the phase conductors of a polyphase low-voltage AC circuit,

[0025] - a series circuit of mechanical phase contacts and electronic switches,

[0026] The series circuit electrically connects one of the grid-side phase connections to one of the load-side phase connections.

[0027] - mechanical phase contacts can be switched in such a way that they open together to prevent current flow or close together for current flow,

[0028] - electronic switches can switch, with the aid of semiconductor-based switching elements, into a high-resistance state of the switching element to prevent current flow or into a low-resistance state of the switching element to allow current flow,

[0029] - A current sensor unit is provided for each series circuit,

[0030] Used to determine the current size of the corresponding phase conductor,

[0031] In particular, there is an instantaneous current value,

[0032] - providing a control unit connected to the current sensor unit, the mechanical phase contacts and the electronic switch,

[0033] The protective switching device is designed such that the prevention of the current flow is initiated when at least one first current threshold value and / or current-time limit value is exceeded in a phase conductor.

[0034] Especially when it is started by an electronic switch,

[0035] - A control input is provided on the protective switchgear,

[0036] - The protective switching device is designed so that the electronic switch can be switched to the high-resistance state or the low-resistance state via a control input.

[0037] In particular, all electronic switches can be switched simultaneously to a high-resistance state or a low-resistance state via a control input.

[0038] This has the advantage that a control input is provided for the multi-phase circuit breaker, with which the electronic switches can be switched unambiguously. Normally, mechanical (phase) contacts can only be switched via a handle accessible on the circuit breaker. External (control input) switchability of the electronic switches is usually not provided. The present invention makes this possible externally and offers the possibility of expanding the functionality of the circuit breaker.

[0039] Further advantageous embodiments of the invention are specified in the dependent claims and exemplary embodiments.

[0040] In an advantageous embodiment of the invention, the circuit breaker device is designed such that the electronic switches can be switched independently of one another into a high-resistance state or a low-resistance state by means of control inputs.

[0041] Alternatively or additionally, each electronic switch can be switched individually (or in pairs), for example by means of a (particularly configurable) switching sequence; this can in particular be configurable.

[0042] This has the particular advantage that the flexibility of the protective switching device is increased due to the phase-dependent switchability (the electronic switch can be switched to a high-resistance state or a low-resistance state independently of one another per phase), thereby making it possible to implement new functions.

[0043] In an advantageous embodiment of the invention, the protective switching device is designed such that, when at least one first current threshold value is exceeded in a phase conductor, the prevention of a current flow in the relevant phase conductor is initiated by the relevant electronic switch, in particular for a first period of time.

[0044] This has the particular advantage that, when a defined current threshold or current-time threshold is exceeded (i.e. the current threshold is exceeded for a defined duration), only the affected conductor (or the conductor being affected) is selectively interrupted. Current flow is still permitted in the other conductors (non-affected conductors) of the polyphase low-voltage AC circuit.

[0045] By avoiding the first time period, it is advantageously switched on again or becomes low-impedance after the first time period, thereby further ensuring power supply safety or enabling further checking whether a current threshold is exceeded. This is advantageously performed by the housing by evaluating the instantaneous value of the current magnitude.

[0046] This advantageously increases the power supply safety, since a complete current avoidance is not activated, but only a phase-dependent current avoidance is activated. In addition, short-term current peaks can be intercepted and, if there is no fault in the low-voltage circuit, false shutdowns can be avoided.

[0047] In an advantageous embodiment of the present invention, the first time period is less than 20 ms, in particular less than 10 ms.

[0048] This has the particular advantage that a voltage or current interruption in an AC circuit lasts for one half-wave or full-wave, for example 20ms or 10ms at a 50Hz network frequency, so that power supply security is restored during the next full-wave or half-wave. In particular, after the interruption, low resistance can occur in the next zero crossing region (at the zero crossing or in the region 1ms before or after the zero crossing).

[0049] In an advantageous embodiment of the invention, the mechanical phase contact is associated with the load-side connection, and the electronic switch is associated with the grid-side connection. In particular, the mechanical phase contact can be actuated by a mechanical handle to open or close the contact. In particular, the mechanical phase contact is part of a mechanically disconnectable contact unit that switches the phase contacts together.

[0050] This has the particular advantage of providing a structure for a protective switching device that is functional even when the contacts of the mechanically disconnected contact unit are open. This provides an advantageous design that supports phase-dependent switching of the electronic switch and enables self-testing (in particular self-testing of the electronic switch) even with open contacts. Furthermore, the energy supply to the protective switching device is ensured even with open contacts.

[0051] Furthermore, there is the particular advantage of simultaneously achieving complete galvanic isolation of all phase conductors (compared to the electronic switch becoming high-impedance to prevent phase-dependent current flow). The handle allows for compatible behavior with classic electromechanical protective switchgear.

[0052] In an advantageous embodiment of the invention, the control input has a particularly safe galvanic isolation, in particular between the control input and the phase conductors. More particularly, there is a safe galvanic isolation between the control input and the low-voltage circuit (the voltage of the low-voltage circuit in the device).

[0053] Furthermore, more particularly, there is a particularly safe galvanic isolation between the control input and the control unit.

[0054] For example, safe galvanic isolation can be achieved by means of optocouplers or relays. Alternatively, safe galvanic isolation can be achieved by inductive or capacitive galvanic isolation.

[0055] This has the particular advantage of allowing universal use of the control inputs in a potential-free manner or providing safe galvanic isolation from the phase conductors (or from the control unit). Since the phase conductors (or control unit) are at mains voltage (e.g., 230 V (AC)) during operation, this galvanic isolation allows for safe use of the control inputs. This prevents electric shock to the connected cables and devices connected thereto, as well as so-called residual voltage. In the case of residual voltage, potential is unintentionally transferred to the cables or other devices.

[0056] This has the particular advantage that the circuit breaker device can be used universally in a potential-free manner or provides a safe galvanic isolation with respect to the phase conductors (or with respect to the control unit).

[0057] In an advantageous embodiment of the present invention, the electronic switches can be switched to the low-impedance state by means of the control input only when a release condition exists. In particular, if a high-impedance state of the electronic switches is caused by a (particularly external) protection function of the protective switching device, these electronic switches (alternatively, all electronic switches, i.e., a plurality of electronic switches) cannot be switched to the low-impedance state by means of the control input (particularly, cannot be switched to the low-impedance state for at least a first duration after the high-impedance state is established).

[0058] The first duration may be 10 seconds or longer.

[0059] This has the particular advantage that the basic protective function of the protective switching device, providing protection, is unaffected by the control inputs. For example, a defective protective switching device (without a release condition) cannot be forced closed by the control inputs, i.e., supplying unprotected energy to the low-voltage circuit. Furthermore, particularly in cases where the protective function of the protective switching device results in a high-impedance state for one or more electronic switches (e.g., when / after a current limit value and / or a current-time limit value is exceeded), this high-impedance state cannot be changed by the control inputs, i.e., a (immediate) return to a low-impedance state cannot be forced. Consequently, the protective switching device cannot simply switch back to a low-impedance state after the protective function.

[0060] In an advantageous embodiment of the invention, the test function on the protection switching device side

[0061] a) switching the electronic switch from a high-resistance state to a low-resistance state for a first period of time, or (and)

[0062] b) switching the electronic switch from the low-resistance state to the high-resistance state for a second period of time,

[0063] Ability to be independent of control inputs (i.e., execution of the check function does not depend on (the state of) a control input).

[0064] This has the particular advantage that the test function of the protective switching device is not influenced by the control input and thus functional reliability is ensured in particular by the test function of the protective switching device (during operation).

[0065] The first time period is, for example, a short time period ranging from μs or ms to one second, such as 100 μs ... 200 μs ... 300 μs ... 600 μs ... 700 μs ... 800 μs ... 1 ms ... 10 ms ... 20 ms ... 40 ms ... 50 ms ... 100 ms ... 200 ms ... 500 ms ... 1s (any possible intermediate value).

[0066] The second time period is, for example, a short time period in the range of μs or ms to one second, such as 100 μs ... 200 μs ... 300 μs ... 600 μs ... 700 μs ... 800 μs ... 1 ms ... 10 ms ... 20 ms ... 40 ms ... 50 ms ... 100 ms ... 200 ms ... 500 ms ... 1 s (any possible intermediate value).

[0067] In an advantageous embodiment of the invention, the phase contacts can be opened by means of a control input, in particular it can be configured whether the phase contacts can be opened by means of the control input.

[0068] a) can switch the electronic switch to a high-resistance state or a low-resistance state, or

[0069] b) The phase contacts can be opened (possibly mechanical separation of the phase contacts of the contact unit).

[0070] Alternatively or additionally, one or the other state can be initiated, for example, further by a (particularly configurable) switching sequence; this can be configurable in particular.

[0071] This has the particular advantage that it provides for further flexibility and functional expansion of the protective switching device.

[0072] In an advantageous embodiment of the invention, the control input is accessible on the housing side. In particular, the control input has a plurality of connecting terminals, in particular two, three or four connecting terminals, wherein these connecting terminals are connected to at least one optocoupler within the protective switching device.

[0073] Furthermore, the control input provides a wired interface (particularly a two-wire, three-wire, or four-wire wired communication interface) such that quasi-delayless signaling (substantially no latency) is provided via the control input. Quasi-delayless refers to direct signaling, i.e., without overhead information processing, such as occurs in principle in LAN / WLAN connections by using communication protocols such as MAC addresses, TCP / IP communication, or OSI communication.

[0074] This has the particular advantage of providing a simple method for connecting the control inputs. Furthermore, for example, each electronic switch can be switched independently (and directly) with four connection terminals, which is advantageous, for example, in three-phase AC circuits (a common variant of polyphase low-voltage AC circuits).

[0075] In an advantageous embodiment of the invention, a display unit connected to the control unit is provided, which has a display device visible on the protective switching device for displaying the high-resistance state or the low-resistance state of the electronic switch.

[0076] The state of each electronic switch can be displayed. Alternatively, the overall state of the electronic switches (high resistance / low resistance) can be displayed, which is a common state based on a specified standard or when the electronic switches are switched together (only the overall state: high resistance or low resistance is displayed).

[0077] This has the particular advantage that a visualization of the states of the electronic switches (or their common switching state) is provided.

[0078] In an advantageous embodiment of the present invention, the protective switching device is designed to:

[0079] When a control input initiates (changes to) a standby state (Standby state), all electronic switches in this standby state are in a high-impedance state (with closed contacts). This high-impedance state is established at the zero current crossing of the current of the corresponding electronic switch. This means, for example, in a three-phase AC circuit with an ohmic load, it is established sequentially (120° phase shifted) at the corresponding current zero crossings. At the current zero crossing (in the region of the current zero crossing) means directly at or near the current zero crossing, i.e., for example, at a current instantaneous value that is less than a first current limit, e.g., less than 5 amperes to 1 ampere (any intermediate values ​​are possible; the first current limit depends on the nominal current of the low-voltage circuit or protective switchgear, e.g., 20% to 15% to 10% to 5% to 1% or less of the nominal current).

[0080] This has the particular advantage of supporting quasi-powerless switching and thus reducing the load on the electronic switch, in particular its semiconductor-based switching elements.

[0081] In an advantageous embodiment of the present invention, a grid-side neutral conductor connection and a load-side neutral conductor connection are provided on the housing for a neutral conductor of a multi-phase low-voltage AC circuit.

[0082] The grid-side neutral conductor connector is connected to the load-side neutral conductor connector directly or through a mechanical neutral conductor contact.

[0083] This has the particular advantage that a multi-pole circuit breaker arrangement is provided, in which the neutral conductor can also be interrupted galvanically, if necessary.

[0084] In an advantageous embodiment of the present invention, the mechanical neutral conductor contact can be opened or closed together with the phase contacts. In particular, the neutral conductor contact is closed before the phase contacts are closed, or the neutral conductor contact is opened after the phase contacts are opened.

[0085] This has the particular advantage that the neutral conductor contact always opens and closes without current flowing through it. This reduces contact wear and extends its service life. Furthermore, this prevents arcing when the neutral conductor contact opens.

[0086] In an advantageous embodiment of the present invention, a voltage sensor unit is provided between each phase conductor and the neutral conductor for determining the voltage magnitude, in particular the instantaneous voltage value, between the corresponding phase conductor and the neutral conductor. The voltage sensor unit is connected to the control unit.

[0087] In an advantageous development of this design, the protective switching device is designed so that when (all) electronic switches are activated by the control unit, in particular the control input, they become low-resistance (in particular in the absence of an overcurrent event, i.e. when the first or second current threshold is not exceeded; for example when the low-resistance is activated on the user side by the control input), (all) electronic switches become low-resistance, in particular in sequence, at corresponding zero crossings of the voltage (i.e. at voltages of less than 50 V, 25 V, in particular less than 10 V).

[0088] The (especially activated) low-resistance state of (all) electronic switches (when the contacts are closed (at the same time / simultaneously)) is also called the switched-on state or ON state.

[0089] This has the particular advantage that grid feedback effects are reduced and the switch-off load in the switch is lower. Furthermore, further quasi-powerless switching is supported and the load on the electronic switch, in particular its semiconductor-based switching elements, is thus reduced.

[0090] A voltage zero crossing (= in the region of the voltage zero crossing) means directly at or near the voltage zero crossing, i.e. for example at an instantaneous value of the voltage which is less than a first voltage limit, e.g. less than 10 Volts, 25 Volts or 50 Volts (any intermediate or smaller values ​​are possible).

[0091] In an advantageous embodiment of the present invention, the protective switch device is designed such that when (all) electronic switches activated by the control unit, in particular the control input, become high resistance (in particular in the absence of an overcurrent event, i.e. when the first or second current threshold is not exceeded; for example when the high resistance is activated by the control input on the user side), (all) electronic switches become high resistance, in particular in sequence at the corresponding zero crossing of the voltage (or at a voltage of less than 50 V, 25 V, in particular less than 10 V).

[0092] The (especially enabled) high-impedance state of (all) electronic switches (when the contacts are closed (at the same time / simultaneously)) is also called the standby state or the standby state.

[0093] The open state of mechanical contacts (especially when the electronic switch is in a high-resistance state) is also called the off state or OFF state.

[0094] This has the particular advantage that grid feedback effects are reduced and the switch-off load in the switch is lower. Furthermore, further quasi-powerless switching is supported and the load on the electronic switch, in particular its semiconductor-based switching elements, is thus reduced.

[0095] Voltage zero crossing means directly at or near the voltage zero crossing, ie for example at a voltage instantaneous value that is smaller than a first voltage limit, eg smaller than 10 Volts, 25 Volts or 50 Volts (any intermediate or smaller values ​​are possible).

[0096] In an advantageous embodiment of the present invention, the protective switchgear is designed such that when a first current threshold is exceeded in a conductor, the relevant electronic switch initiates the prevention of current flow in the relevant conductor. When the voltage crosses zero for the next or next time, the electronic switch again switches to a low resistance, allowing current flow. A control unit is connected to the current sensor unit, the voltage sensor unit, the mechanical (phase) contacts, and the electronic switch.

[0097] This has the particular advantage that increased robustness against false triggering and thus increased power supply reliability is achieved.

[0098] In an advantageous embodiment of the invention, the circuit breaker device is designed such that the control input:

[0099] a) activating a high-impedance state of one or more electronic switches upon application of a first voltage level, or activating a low-impedance state of one or more electronic switches upon application of a second voltage level, or

[0100] b) initiating a state switch between a high resistance or low resistance state and a low resistance or high resistance state of the one or more electronic switches by applying a third voltage level for a first duration, or

[0101] c) Initiating a change of the one or more electronic switches to the low-resistance state by applying a third voltage level for a second duration, and after a third, in particular adjustable, duration, the one or more electronic switches changing to the high-resistance state.

[0102] This has the particular advantage that different switching options are available, which are advantageously configurable, for example.

[0103] The voltage level refers in particular to a voltage range, for example a (low voltage) TTL voltage level, which has a voltage range of, for example, a first voltage level of 0V to 0.8V (logic zero) and a second voltage level of 2V to 3.3V (logic one).

[0104] In an advantageous embodiment of the present invention, the protective switchgear is designed such that a fault-induced high-resistance state of at least one electronic switch is detected by means of a control input, in particular the fault-induced high-resistance state is initiated by exceeding a current limit value and / or a current-time limit value in the low-voltage circuit, so that the electronic switch can subsequently switch to a low-resistance state or automatically switch to a low-resistance state in the absence of a fault. In particular, it can be configured whether the control input

[0105] a) can switch the electronic switch to a high-resistance state or a low-resistance state, or

[0106] b) Confirm the high resistance state caused by the fault.

[0107] This has the particular advantage that further functionality of the protective switching device is provided.

[0108] According to the invention, a corresponding method is claimed for a protective switching device for a multi-phase low-voltage AC circuit with electronic (semiconductor-based) switches, which has the same and further advantages.

[0109] Method for protecting a multi-phase low-voltage AC circuit with a protective switchgear comprising:

[0110] - a housing having a line-side phase connection and a load-side phase connection for the phase conductors of the low-voltage AC circuit,

[0111] - a series circuit of mechanical phase contacts and electronic switches,

[0112] The series circuit electrically connects one of the grid-side phase connections to one of the load-side phase connections.

[0113] - mechanical phase contacts can be switched in such a way that they open together to prevent current flow or close together for current flow,

[0114] - electronic switches with the aid of semiconductor-based switching elements switch to a high-resistance state of the switching element to prevent current flow or to a low-resistance state of the switching element to allow current flow,

[0115] - determine the magnitude of the current in the corresponding phase conductor in each series circuit,

[0116] In particular, there is an instantaneous current value,

[0117] - initiating the prevention of the current flow, in particular by means of an electronic switch, when at least one first current threshold value or current-time limit value is exceeded in a phase conductor,

[0118] - An electronic switch can be switched to a high-resistance or low-resistance state via a control input.

[0119] In an advantageous embodiment, the control input switches the electronic switch to the low-resistance state only when a release condition exists. In particular, if a high-resistance state of at least one electronic switch is caused by a protective function of the protective switching device, the electronic switch cannot be switched to the low-resistance state by the control input.

[0120] In an advantageous embodiment, the test function on the protection switching device side

[0121] a) switching the electronic switch from a high-resistance state to a low-resistance state for a first period of time, or

[0122] b) switching the electronic switch from the low-resistance state to the high-resistance state for a second period of time,

[0123] Not affected by control input.

[0124] All designs, whether in dependent form referring to claims 1 or 20, or referring only to individual features or combinations of features of the claims, in particular dependent device claims referring to independent method claims (and vice versa), lead to improvements in the protective switchgear, in particular functional improvements, and provide new features and concepts for the protective switchgear. BRIEF DESCRIPTION OF THE DRAWINGS

[0125] The described characteristics, features, and advantages of the present invention and their implementation will become clearer and more easily understood in conjunction with the following description of the embodiments, which are described in detail in conjunction with the accompanying drawings.

[0126] Here, in the accompanying drawings:

[0127] Figure 1 A first diagram showing a protective switchgear,

[0128] Figure 2 A second diagram showing a protective switchgear,

[0129] Figure 3 A third diagram showing a protective switchgear,

[0130] Figure 4 A fourth diagram showing a protective switchgear,

[0131] Figure 5 A diagram showing the control inputs,

[0132] Figure 6 A diagram showing functional groupings,

[0133] Figure 7 shows a diagram of a first configuration,

[0134] Figure 8 shows a diagram of a second configuration,

[0135] Figure 9 shows a diagram of a third configuration,

[0136] Figure 10 A diagram showing a fourth configuration is shown. DETAILED DESCRIPTION

[0137] Figure 1 A method for protecting a multiphase low voltage AC circuit (in accordance with Figure 1 An exemplary illustration of a 3-pole (e.g. for a three-phase conductor) protective switching device SG of a three-phase low-voltage AC circuit (in the example of FIG. 1 ), which comprises:

[0138] a housing GEH having a first, second and third grid-side phase connection LG1 , LG2 , LG3 and a first, second and third load-side phase connection LL1 , LL2 , LL3 for a first, second and third phase conductor L1 , L2 , L3 of a low-voltage AC circuit,

[0139] On the grid side, the grid is usually connected to an energy source.

[0140] On the load side, electrical consumers are usually connected.

[0141] In case of GEH:

[0142] - a first series circuit SS1 of a first mechanical phase contact K1 and a first electronic switch S1,

[0143] a second series circuit SS2 of a second mechanical phase contact K2 and a second electronic switch S2,

[0144] A third series circuit SS3 of a third mechanical phase contact K3 and a third electronic switch S3, wherein:

[0145] The first series circuit SS1 electrically connects the first grid-side phase connection LG1 to the first load-side phase connection LL1.

[0146] The second series circuit SS2 electrically connects the second grid-side phase connection LG2 to the second load-side phase connection LL2, and

[0147] The third series circuit SS3 electrically connects the third grid-side phase connection LG3 to the third load-side phase connection LL3.

[0148] The mechanical phase contacts K1, K2, K3 can be switched together, ie they are opened together to prevent current flow or closed together for current flow, ie the mechanical contacts are connected to each other via a mechanical coupling (eg a switching shaft),

[0149] The electronic switches S1 , S2 , S3 can be switched by means of semiconductor-based switching elements into a high-resistance state of the switching elements to prevent a current flow or into a low-resistance state of the switching elements for a current flow.

[0150] According to the invention, a control input CI is provided on the circuit breaker device SG. The circuit breaker device SG is designed such that the electronic switches S1, S2, S3 can be switched to a high-resistance state or a low-resistance state by means of the control input CI.

[0151] In particular (in a simple variant) all electronic switches S1 , S2 , S3 can be switched simultaneously to a high-resistance state or a low-resistance state via the control input CI.

[0152] according to Figure 1 , first, second and third current sensor units SI1, SI2, SI3 are provided. The first current sensor unit SI1 is provided or arranged in the first series circuit SS1, the second current sensor unit SI2 is provided or arranged in the second series circuit SS2, and the third current sensor unit SI3 is provided or arranged in the third series circuit SS3,

[0153] It is used to determine the current magnitude of the first, second and third phase conductors L1, L2, L3 respectively, in particular the instantaneous current value.

[0154] according to Figure 1 The first mechanical phase contact K1, the second mechanical phase contact K2, and the third mechanical phase contact K3 are part of a mechanical disconnecting contact unit MK, which jointly opens or closes the phase contacts K1, K2, and K3. The mechanical disconnecting contact unit MK can have a handle HH accessible on the protective switching device for manually opening or closing the phase contacts (operated by a person). The mechanical disconnecting contact unit MK corresponds, for example, to the conventional units known from electromechanical protective switching devices (circuit breakers, circuit breakers). However, according to the present invention, there are no elements for overcurrent or short-circuit detection, such as bimetallic trips.

[0155] The protective switching device is particularly designed so that the mechanical phase contacts or the mechanical disconnecting contact unit MK can be opened but not closed by the control unit SE. In particular, the handle HH can only close the mechanical contacts after the mechanical contacts have been released by the control unit SE. A release unit LC can be provided for this purpose. This means that the handle HH can only close the contacts when there is a release or release signal (from the control unit). In the absence of a release or release signal, the handle HH can be operated but the contacts cannot be closed ("Dauerrutscher, continuous slip"). The release unit LC can also be designed so that the contacts K1, K2, K3 of the mechanical disconnecting contact unit MK can be opened by a control signal of the control unit SE, such as Figure 1 This is indicated by an arrow from the control unit SE to the release unit LC.

[0156] according to Figure 1 , the mechanical phase contacts K1 , K2 , K3 are associated with the load-side phase connector / load-side Load, and the electronic switches S1 , S2 , S3 are associated with the grid-side phase connector / grid-side Grid.

[0157] The first electronic switch S1 , the second electronic switch S2 and the third electronic switch S3 can be part of an electronic interruption unit EU, wherein the electronic switches S1 , S2 , S3 can in particular be switched independently of one another.

[0158] The electronic interruption unit / electronic switch may have a bidirectional voltage withstand strength, in particular to provide overvoltage protection for semiconductor-based switching elements, in order to limit the voltage and thus protect the semiconductor-based switching elements.

[0159] A control unit SE is provided (as already mentioned in part), which is connected to the current sensor units SI1, SI2, SI3, the mechanical phase contacts (K1, K2, K3) or the mechanical isolating contact unit MK (as Figure 1 As shown) and electronic switches S1, S2, S3. The control input CI is connected to the control unit SE, as shown Figure 1 As shown in the example.

[0160] The current sensor units SI1 , SI2 , SI3 each determine the magnitude of the current in their respective (phase) conductor, so that in particular an instantaneous value of the current is available.

[0161] If at least one first current threshold or current-time limit value is exceeded in (at least) one conductor, current flow prevention is initiated. In one variant, current flow prevention can be performed in the conductors in which the first current threshold or current-time limit value has been exceeded. In another variant, current flow prevention can be performed in all phase conductors (or alternatively, in all conductors in which electronic switches are provided). Current flow prevention is particularly performed by causing one or more (depending on the configuration) electronic switches to have a high resistance. If at least one second (higher) current threshold or current-time limit value (a current-time value that is higher or longer than the first current-time limit value) is exceeded in (at least) one conductor, current flow prevention can be performed by opening contacts K1, K2, and K3.

[0162] The high resistance can specifically last for a first period of time. After this period, the relevant electronic switch (or multiple relevant electronic switches) can be switched back to low resistance. Overcurrent events (exceeding a current threshold) can be handled for each phase / phase conductor. This also protects the electronic switches from overload.

[0163] The change to low resistance can occur in particular at the next zero crossing of the voltage, before or after it (all three options are possible: at, before or after the zero crossing, or at a value below a voltage threshold, in particular 50V, 25V or 10V).

[0164] In particular, the first time period can be less than 20 ms, in particular less than 10 ms.

[0165] like Figure 1 As shown, a differential current sensor unit ZCT can be provided for detecting a differential current of a low-voltage AC circuit, as is known, for example, from a residual current circuit breaker. The differential current sensor unit ZCT is connected to a control unit SE.

[0166] In accordance with Figure 1 In the example shown, current sensor units SI1, SI2, and SI3 are arranged between the grid-side terminals LG1, LG2, and LG3 of the series circuit of electronic switches S1, S2, and S3 and the mechanical phase contacts K1, K2, and K3. Specifically, they are arranged between the grid-side terminals LG1, LG2, and LG3 and the electronic switches S1, S2, and S3. Current sensor units SI1, SI2, and SI3 can also be arranged in other ways, for example, between the electronic switches S1, S2, and S3 and the mechanical phase contacts K1, K2, and K3.

[0167] The first, second, and third electronic switches can be switched to a high-resistance state or a low-resistance state independently of one another. That is, the first, second, and third electronic switches can be switched to a high-resistance state or a low-resistance state independently of one another. In particular, current dependence on phase conductors can be avoided or current dependence on phase conductors can be achieved. In the embodiment of the present invention, the electronic switches can be switched to a high-resistance state or a low-resistance state independently of one another via a control input CI.

[0168] Figure 2 Shown according to Figure 1 , which has the following differences.

[0169] For the neutral conductor N of the multi-phase low-voltage AC circuit, a grid-side neutral conductor joint NG and a load-side neutral conductor joint NL are set. Figure 2 In the example of , the polyphase low-voltage AC circuit is a three-phase low-voltage AC circuit with a neutral conductor. Figure 2 , the grid-side neutral conductor connection NG is connected to the load-side neutral conductor connection NL via the neutral conductor contact KN.

[0170] Alternatively, the grid-side neutral conductor connection NG can also be connected directly (ie without switchable contacts) to the load-side neutral conductor connection NL.

[0171] In this example, no electronic switch is provided in the neutral conductor path in the housing of the protective switchgear, which means that the neutral conductor connection between the grid-side neutral connection NG and the load-side neutral connection NL has no electronic switch (no electronic switch).

[0172] The mechanical neutral conductor contact KN can advantageously be switched together with the phase contacts K1 , K2 , K3 . This means that the mechanical neutral conductor contact KN can be opened or closed together with the phase contacts K1 , K2 , K3 , as explained above for the contacts K1 , K2 , K3 .

[0173] In particular, the mechanical disconnecting contact unit MK can be designed such that the neutral conductor contact KN is closed before the phase contacts K1 , K2 , K3 are closed. Similarly, the neutral conductor contact KN can be opened after the phase contacts K1 , K2 , K3 are opened.

[0174] Furthermore, a power supply device NT, for example a power supply, is provided for supplying energy to the protective switching device SG, in particular the control unit SE.

[0175] In this example, the energy supply device NT is connected to the phase conductors L1, L2, L3 and (if necessary) to the neutral conductor N. The energy supply device NT can also be connected to only some of the conductors (at least two) for energy supply. In this example, the energy supply device NT is also connected to the control unit SE.

[0176] On the other hand, the control unit SE is combined with the electronic switches S1, S2, S3 and the current sensor units SI1, SI2, SI3, as shown Figure 2 shown.

[0177] Furthermore, a voltage sensor unit is provided between each phase conductor and the neutral conductor. A first voltage sensor unit SU1 is provided between the first phase conductor L1 and the neutral conductor N, a second voltage sensor unit SU2 is provided between the second phase conductor L2 and the neutral conductor N, and a third voltage sensor unit SU3 is provided between the third phase conductor L3 and the neutral conductor N. These units are used to determine the voltage level between the respective phase conductor and the neutral conductor, particularly the instantaneous voltage value. The voltage sensor units SU1, SU2, and SU3 are connected to a control unit SE.

[0178] When the electronic switches S1, S2, S3 are activated to low resistance by the control unit SE, in particular by the control input CI, for example:

[0179] - when the user initiates a low-impedance situation (e.g. at the device or via a control input) or

[0180] - in the case of a low-resistance activation by the protective switching device, in particular in the absence of an overcurrent event (i.e. if the first or second current threshold is not exceeded), for example if an internal check function (for internal checking) of the protective switching device activates the low-resistance activation,

[0181] => The electronic switches can advantageously become low-resistance in sequence at the corresponding zero crossing of the voltage.

[0182] In the case where the electronic switches S1, S2, S3 are activated to high resistance by the control unit SE, in particular by the control input CI, for example:

[0183] - when a high-impedance condition is initiated on the user side (e.g. at the device or via a control input), or

[0184] - in the case of a high-impedance activation by the protective switching device, in particular in the absence of an overcurrent event (i.e. if the first or second current threshold is not exceeded), for example if an internal check function (for internal checking) of the protective switching device activates the high-impedance activation,

[0185] => The electronic switches can advantageously become high-resistance in turn at the respective zero crossing of the voltage (= in the zero crossing region).

[0186] As an alternative or in addition to the use of voltage, the protective switching device can be designed so that, in the case of an activated standby state or standby state, all electronic switches (S1, S2, S3) are in a high-resistance state (or should reach a high-resistance state) in this standby state, which is established (in particular when current flows in the phase conductor) when the current of the corresponding conductor through the corresponding electronic switch passes through zero.

[0187] As already mentioned, the voltage sensor units SU1, SU2, and SU3 are connected to the control unit SE, which is also connected to the current sensor units SI1, SI2, and SI3, the mechanical phase contacts K1, K2, and K3 (or the mechanical disconnecting contact unit MK), the electronic switches S1, S2, and S3, and the control input CI. The protective switching device SG can also advantageously be designed to prevent current flow in the relevant conductor by initiating the prevention of current flow via the relevant electronic switch when at least one first current threshold value (particularly an instantaneous current value) is exceeded in the conductor. At the next or next voltage zero crossing (in the zero crossing region), the electronic switch again becomes low-impedance, allowing current flow.

[0188] This can be done multiple times until the initial number of repetitions is exceeded. You can then:

[0189] a) All electronic switches become high resistance, or (and)

[0190] b) Contacts open (galvanic isolation).

[0191] according to Figure 1 and Figure 2 Any combination (intermediate combination) of the diagrams of the exemplary protective switchgear is possible (e.g. Figure 1 in Figure 2energy supply device NT, etc.).

[0192] Figure 3 Shown according to Figure 2 , differing in that the measuring resistors R12, R13, and R23 are arranged between the phase conductors within the protective switchgear. To this end, in one embodiment, a first measuring resistor (or measuring impedance) R12 is arranged between the first phase conductor L1 and the second phase conductor L2, a second measuring resistor (or measuring impedance) R23 is arranged between the second phase conductor L2 and the third phase conductor L3, and a third measuring resistor (or measuring impedance) R13 is arranged between the first phase conductor L1 and the third phase conductor L3.

[0193] Thus, in particular even in the absence of a neutral conductor (3-pole protective switchgear), the switching behavior of the electronic switches S1, S2, S3 can be checked with the aid of a measuring resistor (which can also be embodied as a measuring impedance, i.e., for example, a resistance / capacitance and / or inductance combination), for example by briefly switching on the electronic switch (in the μs, ms or even smaller second range) when the contacts are open, wherein a measuring current corresponding to the measuring resistor (measuring impedance) can be set and checked (in the case of a corresponding instantaneous value of the voltage).

[0194] In the case of a 4-pole system, ie, for example, a three-phase AC circuit with a neutral conductor, the measuring resistor can also (alternatively) be arranged between the phase conductors and the neutral conductor.

[0195] In this example, the (optional) differential current sensor unit ZCT is not provided (but could also be provided).

[0196] High resistance refers to a state where only negligible current flows. In particular, high resistance refers to a resistance value greater than 1 kilo-ohm, preferably greater than 10 kilo-ohm, 100 kilo-ohm, 1 megohm, 10 megohm, 100 megohm, 1 gigaohm or greater.

[0197] Low resistance refers to a state in which a specified current value can flow through the protective switch device. In particular, low resistance refers to a resistance value of less than 10 ohms, preferably less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm or less.

[0198] The electronic switches S1, S2, S3 or the electronic interruption unit EU can include semiconductor elements, such as bipolar transistors, field effect transistors (FETs), insulated gate bipolar transistors (IGBTs), metal oxide field effect transistors (MOSFETs), or other (self-commutated) power semiconductors. IGBTs and MOSFETs are particularly well-suited for electronic switches (as semiconductor-based switching elements) because they have low on-resistance, high junction resistance, and good switching characteristics.

[0199] Therefore, the protective switchgear according to the present invention comprises electronic and mechanical components. The rational arrangement of all components required for safe operation is an important point. In addition, a variety of switching combinations can be realized by combining electronic switches and mechanical contacts.

[0200] In this example, the circuit breaker device has three mains-side and three load-side connections, respectively, or four mains-side and four load-side connections. In this example, the device contains a 3-pole or 4-pole mechanically disconnecting contact unit (disconnecting contact system). The contacts are mechanically coupled and can only be opened or closed together.

[0201] Electronic switches are connected in series with mechanical contacts in the phase conductors. Unlike mechanical contacts, they open and close independently of each other. In a simple variant, switching of all electronic switches is initiated via a control input, where the electronic switches themselves can switch at zero crossings of the voltage or current. Furthermore, current sensor units are placed in the phase conductors (not in the neutral conductor N).

[0202] Mechanical contacts or mechanical disconnecting contact units MK are particularly those which implement a disconnecting function (compliant with standards) via the disconnecting contact unit MK. The essential features of a disconnecting function are:

[0203] - According to the standard minimum air distance (minimum distance of contacts),

[0204] - contact position indication of the contacts of a mechanically separated contact unit,

[0205] - Actuation / interruption of the contacts of a mechanically separated contact unit (via the control unit) is always possible (it is not possible for the handle to (permanently) lock the contacts in the closed state).

[0206] Regarding the minimum air distance between the contacts of a separate contact unit, this minimum air distance depends essentially on the voltage. Other parameters are the degree of contamination, the type of field (homogeneous, non-homogeneous), and the air pressure or the height above the standard zero point.

[0207] There are corresponding regulations or standards for these minimum air or creepage distances. These regulations, for example, specify minimum air distances for surge voltage resistance in air, which apply to both inhomogeneous and uniform (ideal) electric fields, depending on the degree of pollution. Surge voltage resistance is the strength that can be withstood when a corresponding surge voltage is applied. Only when this minimum length (minimum distance) exists does the disconnecting contact unit or protective switching device have the disconnecting function (disconnector characteristic).

[0208] In this context, for the function of the separator and its characteristics, the standard series DIN EN 60947 or IEC 60947 is relevant within the meaning of the present invention and is hereby incorporated by reference.

[0209] The disconnect contact unit is advantageously characterized by a minimum air distance of the open disconnect contacts in the off position (open position, open contacts), depending on the rated impulse withstand voltage and the degree of contamination. The minimum air distance is preferably between (minimum) 0.01 mm and 14 mm. The minimum air distance is particularly advantageously between 0.01 mm at 0.33 kV and 14 mm at 12 kV, particularly for contamination degree 1 and particularly for inhomogeneous fields.

[0210] Advantageously, the minimum air distance may have the following values:

[0211] E DIN EN 60947-1 (VDE 0660-100): 2018-06

[0212] Table 13 - Minimum air distances

[0213]

[0214] The pollution degree and field type correspond to the pollution degree and field type defined in the standard. This advantageously makes it possible to achieve a standard-compliant circuit breaker device that is dimensioned according to the rated surge voltage resistance.

[0215] Mechanically isolating contact units do not in particular refer to relay contacts.

[0216] Figure 4 Shown according to Figure 1 、 Figure 2 or Figure 3 , except that the individual units are not shown and the first, second and third measuring resistors R12, R13, R23 are not arranged between the phase conductors ( Figure 3 Instead, measuring resistors are provided between the phase conductors and the neutral conductor. For this purpose, a fourth measuring resistor RA (or measuring impedance) is provided between the first phase conductor L1 and the neutral conductor N, a fifth measuring resistor RB (or measuring impedance) is provided between the second phase conductor L2 and the neutral conductor N, and a sixth measuring resistor RC (or measuring impedance) is provided between the third phase conductor L3 and the neutral conductor N.

[0217] The switching behavior of the electronic switches S1, S2, and S3 can be checked using the fourth, fifth, and sixth measuring resistors R1, R2, and R3 (which can also be designed as measuring impedances, i.e., for example, as resistance / capacitance and / or inductance combinations), for example by briefly switching the electronic switches (in the μs, ms, or even smaller second range) when the contacts are open. A measuring current corresponding to the measuring resistor (measuring impedance) can be set and checked (given the corresponding instantaneous value of the voltage). This can be done by briefly switching the electronic switches so that the measuring current is generated through the corresponding measuring resistor between the phase conductor and the neutral conductor. Alternatively or additionally, this can also be done by briefly switching both electronic switches so that the measuring current is generated via both phase conductors (two measuring resistors).

[0218] also, Figure 4 , additional or different units are shown. A (particularly wireless) communication unit COM may be provided, which is connected to the control unit SE or is part of the control unit SE. Furthermore, a display unit AE may be provided. The display unit AE may be designed as a combined display and input unit. The display unit AE (display and input unit) may be connected to the control unit SE or be part of it. The display unit AE has a display device visible on the protective switchgear, in particular for indicating the high-resistance or low-resistance state of the electronic switch or the overall state of the electronic switch.

[0219] according to Figure 4 , the control unit SE may have a microcontroller MP (microcontroller unit). The microcontroller may have different functions or routines / methods, such as

[0220] - Switching logic function SF,

[0221] - Internal protection function IPF, used to internally check and report whether the protection switchgear is fault-free,

[0222] - an external protection function CPF, which monitors the multiphase low-voltage AC circuit and reports e.g. overcurrent events, short circuits etc. in the low-voltage circuit,

[0223] A control signal configuration unit CSC, which can be used, for example, to configure whether the state of the electronic switch is changed (high resistance / low resistance) or (also) whether a mechanical (phase) contact is opened by a trip signal TRIP.

[0224] The mentioned units and functions will be discussed in more detail below.

[0225] For example, the protective switching device SG operates in principle as follows: with the contacts of the mechanically separating contact unit closed and the interruption unit low-resistance (switch-on state or ON state) and

[0226] - if the determined current exceeds a first current value, in particular within a first time limit, the electronic interruption unit EU becomes high-resistance and the mechanical separation contact unit MK remains closed, and / or

[0227] - (and / or) if the determined current exceeds a second, higher current value, in particular within a second time limit, the electronic interruption unit EU becomes high-resistance and the mechanically separating contact unit MK opens, and / or

[0228] If the determined current exceeds an even higher third current value, the electronic interruption unit becomes high-resistance and the mechanically separating contact unit MK opens.

[0229] The invention is described in more detail below in partly differentiated terms.

[0230] In new electronic protective switchgear, contacts (mechanically disconnecting contact units) are used in conjunction with electronic switches / semiconductor-based switching elements (electronic interruption units). The ability to control these switching elements via (galvanically isolated) control inputs CI offers a new possibility for expanding the functionality of the protective switchgear. At the same time, the present invention ensures that the controllability of the switching elements / electronic switches does not impair the safety-related protective functions of the protective switchgear.

[0231] The control unit SE can switch the electronic switch to a high-resistance state or a low-resistance state, ie, switch it on and off, and open the contact(s) of the mechanically separated contact unit.

[0232] Furthermore, there are handles (for opening and closing the separating contact units), current measurement, advantageously voltage measurement, and energy supply. The protective switching device can perform various external protection functions (CPF), such as short-circuit protection, overcurrent protection (overload protection), differential fault current protection, fire protection, overvoltage protection, and undervoltage protection.

[0233] It also performs different internal protection functions IPF, such as over-temperature protection.

[0234] Overload protection, for example, involves exceeding a first current limit value and / or a current-time limit value. Short-circuit protection, for example, involves exceeding a fourth (higher) current limit value and / or a current-time limit value. Differential fault current protection, for example, involves exceeding a differential current limit value (e.g., 30 mA). Fire protection, for example, involves detecting a series arc fault in a low-voltage circuit. The same applies to overvoltage protection, undervoltage protection, and overtemperature protection.

[0235] According to the present invention, a control input CI, particularly one with galvanic isolation, is added. The switching state of the electronic switches S1, S2, and S3 can be controlled via this control input CI. Since the electronic switches are particularly required to execute the external protection function CPF, the control unit SE transmits the signal for the electronic switches (synonymous: electronic interruption unit EU) to switch to low resistance via control input CI to the electronic switches only when the stored external or internal protection function CPF or IPF is fault-free (no error detected), i.e., when a release condition exists. In particular, if a fault is detected, i.e., if at least one electronic switch is in the high-resistance state, the control input cannot change this state (i.e., cannot switch to low resistance).

[0236] This means that, by means of the control input CI, the electronic interruption unit EU can only be switched to the low-resistance state when a release condition exists.

[0237] In particular, when the electronic switch is in a high-resistance state due to an external or internal protection function CPF, IPF of the protective switchgear, the electronic switch cannot be switched to a low-resistance state via the control input.

[0238] Internal faults detected in the protective switchgear are particularly faults in the protective switchgear, such as a defective current sensor unit, a defective electronic switch, or overheating. This can also occur if external faults occur, such as overvoltage or undervoltage (voltage exceeding / falling below its effective value for a certain period of time). Furthermore, this can involve an external protection function CPF, which makes it impossible or impossible to immediately "force control" to a low impedance via the control input CI after a current limit value and / or a current-time limit value has been exceeded and current flow in the low-voltage circuit is prevented.

[0239] The same applies to other internal device functions / test functions on the protective switchgear side, e.g. for device diagnostics or surge protection.

[0240] a) switching the electronic switch from a high-resistance state to a low-resistance state for a first period of time, or (and)

[0241] b) switching the electronic switch from the low-resistance state to the high-resistance state for a second period of time,

[0242] Not affected by control input.

[0243] These brief switching actions can be used, for example, to test electronic switches or to check the functionality of current sensor units.

[0244] These brief switching actions are prioritized by the control unit SE or the switching logic function SF, so that the (external) control signal ESS at the control input CI cannot prevent these brief switching actions.

[0245] Therefore, the electronic switch or (possibly) electronic interruption unit EU (its switching elements) can only be controlled via the control input CI when the protective switchgear is in a fault-free state and / or fault-free state (tripping conditions exist) at the load-side connection / connections (at the load outputs). This task is taken over by the switching logic function SF. Therefore, the control input CI cannot directly access the electronic switch (or electronic interruption unit) for control purposes, but can only send a signal ESSI to the switching logic function SF to switch the electronic interruption unit on or off. The switching logic function SF ensures that the external and internal protection functions CPF and IPF can always act primarily on the electronic switch (electronic interruption unit).

[0246] This applies not only to the external and internal protection functions CPF, IPF of the protective switching device, but also to the (partially already mentioned) test functions of the protective switching device, which in particular check the switchability of the electronic switch, for example by opening or closing the electronic switch within a (short) first or second time period.

[0247] Figure 5 The basic structure of a galvanically isolated control input CI connected to an external control unit ESE is shown.

[0248] Figure 5 The control input CI, accessible on the housing side ESE, is shown. It has multiple connection terminals, in this example two connection terminals AK1 and AK2, which are connected to at least one optocoupler OPK within the protective switchgear. In this example, the optocoupler OPK is connected on the one hand to a resistor R1, which is connected on the other hand to a voltage of 3.3 V (i.e., a positive terminal at an internal voltage of 3.3 volts). The connection between resistor R1 and optocoupler OPK is accessible {0 V; 3.3 V} {0.1}, and in this example, an internal control signal ESSI equivalent to (and galvanically isolated from) the external control signal ESS is provided for further processing in the protective switchgear. The other terminal of the optocoupler OPK is connected to another terminal at a voltage of 0 V (i.e., ground).

[0249] The two connection terminals AK1, AK2 are connected outside the housing to a two-wire line having a first conductor LT1 and a second conductor LT2. The two-wire line is also connected to an external control unit ESE. The external control unit ESE optionally provides a voltage signal 24V, which drives an optocoupler via a control input CI to set the electronic interruption unit to the (desired) high or low resistance.

[0250] This means that an optocoupler OPK with corresponding galvanic isolation is provided. The external (remote) control unit ESE sends the voltage to transmit the control signal ESS.

[0251] Instead of an optocoupler, a relay or other element may be provided or used for galvanic isolation, such as an element based on capacitive or inductive galvanic isolation.

[0252] In a similar manner, in particular, three or four (or more) connecting terminals can be provided so that each electronic switch can be switched individually via the corresponding connecting terminal. In this case, a common connecting terminal can be provided, and the first, second, or third electronic switch can then be switched via the second, third, and fourth connecting terminals, respectively.

[0253] Figure 6 The functional grouping of the microcontroller MP is shown again. The microcontroller MP has a connection to a control input CI, to which signals from the control inputs SCI and ESSI are fed. These signals are fed to the control signal configuration unit CSC. Optionally, for example, it can be configured that the mechanical contacts (mechanically disconnecting contact unit MK) are opened via a trip signal TRIP (opening one or more contacts) via the control input CI. The signals from the control inputs are further fed to the switching logic function SF. The switching logic function is also connected to protection functions, in this example to an internal protection function IPF for internally checking and reporting the absence of faults in the protective switchgear, and an external protection function CPF, which monitors the multi-phase low-voltage circuit and reports overcurrent events, short circuits, and other events in the low-voltage circuit.

[0254] If there are no internal faults in the protective switching device (reported by the internal protection function IPF) and no external faults in the low-voltage circuit to be protected (reported by the external protection function CPF), both messages are sent to the switching logic function SF, the release condition exists and the electronic switch (electronic interruption unit) can be switched to the low-impedance state or the high-impedance state via the control input CI (connection of the switching logic function SF to the electronic interruption unit EU (arrow pointing there)).

[0255] The switching logic function SF ensures in the protective switching device that the protection functions IPF, CPF, which depend on the controllability of the electronic switches (electronic interruption units EU), can always switch them safely when necessary.

[0256] If the external protection function CPF is activated, one or more electronic switches cannot be controlled via the control inputs. If no protection status is active (release condition), the electronic interruption unit can be controlled again via the control inputs.

[0257] The same principle applies to internal device functions / test functions on the protective switching device side, or internal protection functions IPF. This internal protection function IPF also accesses the electronic interruption unit. A test function on the internal device function / protective switching device side, which only performs brief switching operations, such as for device diagnostics, also preferentially accesses one or more electronic switches. If this function is executed, control via the control inputs is not possible.

[0258] Therefore, individual phases can be briefly disconnected (made high-impedance), e.g. for testing purposes.

[0259] The control signal configuration unit CSC can be configured as to what is / should be done with the (digital) control signal.

[0260] For example, an electronic switch (electronic interruption unit EU), or a mechanical contact (mechanically separating contact unit), or both can be controlled.

[0261] This can be done by different levels, time offsets or sequences of the external control signal ESS.

[0262] The following is an example of parameterization and configuration.

[0263] 1.) Simple on / off switching

[0264] When the external control signal ESS is 1, the electronic switch is in low resistance, and when the external control signal ESS is 0, the electronic switch is in high resistance.

[0265] 2.) Simple on / off switching (reverse)

[0266] When the external control signal ESS is 1, the electronic switch is in high resistance, and when the external control signal ESS is 0, the electronic switch is in low resistance.

[0267] [1 or 2 generally: when a first voltage level is applied, a high-impedance state is initiated, or when a second voltage level is applied, a low-impedance state is initiated]

[0268] 3.) Current shock switching

[0269] The electronic switch changes state when a rising (or falling) edge of the signal occurs at the control input. This means that the change of state of the electronic switch is initiated by applying the third voltage level for the first duration.

[0270] 4.) Current surge switching with timing / timer

[0271] The electronic switch switches to the on state when a rising (or falling) signal edge occurs at the control input. The electronic switch automatically switches to the high-impedance state after an (adjustable) time. In other words, by applying a third voltage level for a second duration, the electronic switch switches to the low-impedance state, and after a third, particularly adjustable, duration, the electronic switch switches to the high-impedance state.

[0272] 5.) Delayed connection

[0273] The electronic switch switches as in point 1 or point 2, but with an adjustable switch-on delay.

[0274] 6.) Delayed shutdown

[0275] The electronic switch switches as in point 1 or 2, but with an adjustable turn-off delay.

[0276] Other parameterization options are:

[0277] 7.) Only mechanical contacts are opened. For example, when the control signal (or signal sequence) changes edge, the separating contacts open.

[0278] This is Figure 7 It is shown schematically in FIG. Figure 7 The figure shows that the external protection function can control the parameter configuration of 3 states.

[0279] Al = One or more mechanical contacts are open, and the electronic switch is high resistance (disconnected or OFF state)

[0280] S1 = One or more mechanical contacts are closed, and the electronic switch is high resistance (standby state)

[0281] El = One or more mechanical contacts are closed, and the electronic switch is low resistance (connected state or ON state)

[0282] The protective switching device is configured so that the contacts are opened by means of the control input CI. This means that the external / internal control signal ESS / ESSI leads to the state A1.

[0283] Figure 8 Shown according to Figure 7 The difference is that the external / internal control signal ESS / ESSI causes a simple on / off state, i.e. a low-resistance / high-resistance state of the electronic switch, by means of the switching logic function SF, wherein the high-resistance state occurs when a "positive" logic-one control signal ESS / ESSI is applied. Figure 8 The low-resistance state should be activated when the control signal ESS / ESSI is not applied, i.e., logic zero. Figure 8 is marked by status 0.

[0284] Figure 9 Shown according to Figure 8 The diagram differs in that it shows that the protective switchgear is designed or configured such that the electronic switch switches between high-resistance and low-resistance states via control signals ESS / ESSI, for example, via a logic zero or logic one state, alternatively via a first sequence of zero / one states. On the other hand, the contacts can also be opened, for example, via a second sequence SEQB. In this example, the circuit of the mechanical contacts is identified by the control signal configuration unit CSC. This means that the electronic switch can be switched between high-resistance and low-resistance via the control input CI. Simultaneously, the contacts (of the mechanically disconnecting contact unit) can be opened using a (switching) sequence stored in the protective switchgear.

[0285] Figure 10 Shown according to Figures 7 to 9 The difference is that it shows that the protective switching device is designed to confirm the fault state via the control signal ESS / ESSI.

[0286] This means that if the protective switching device is in state S1 due to exceeding the current limit value and / or the current-time limit value, this state can be acknowledged and reset via control input CI. Thus, the protective switching device can switch from state S1 to state E1 after a fault (when the fault has been eliminated again). This can be done remotely; the device does not have to be on site to switch to state E1.

[0287] This means that the protective switching device SG can be designed such that a fault-induced high-impedance state of the electronic interruption unit is detected by means of the control input CI, in particular the fault-induced high-impedance state is triggered by exceeding a current limit value and / or a current-time limit value in the low-voltage circuit.

[0288] The electronic switch can then switch / transfer to a low-impedance state or automatically switch to a low-impedance state without a fault, in particular with or without the aid of a control input.

[0289] a) can switch an electronic switch to a high-resistance state or a low-resistance state, or

[0290] b) Confirm the high resistance state caused by the fault.

[0291] Furthermore, the protective switching device can be designed such that the control input CI:

[0292] a) a high-impedance state is initiated when a first voltage level is applied, or a low-impedance state is initiated when a second voltage level is applied, or

[0293] b) changing the state by applying a third voltage level for a short time (e.g., less than 1 second). More specifically, changing to a low-resistance state by applying the third voltage level for a short time (e.g., less than 1 second), and changing back to a high-resistance state by applying a subsequent third voltage level.

[0294] The display unit has a display device visible on the protective switching device for displaying (showing) the high-resistance state or the low-resistance state of the electronic switch, for example, by means of an LED display.

[0295] The indication of the contact position of the mechanically disconnecting contact unit is achieved by means of the handle; this indication by the handle does not indicate the switching state of the electronic interruption unit.

[0296] In particular, the switching state of the electronic switch should be indicated when the switching state has been changed / switched on or off via the control input CI.

[0297] Although the present invention has been illustrated and described in detail through the embodiments, the present invention is not limited to the disclosed examples, and those skilled in the art may derive other variations therefrom without departing from the scope of protection of the present invention.

Claims

1. A protective switchgear (SG) for protecting a multi-phase low-voltage AC circuit, comprising: a housing (GEH) having line-side phase connections (LG1, LG2, LG3) and load-side phase connections (LL1, LL2, LL3) for phase conductors (L1, L2, L3) of a low-voltage AC circuit, - a series circuit (SS1, SS2, SS3) of mechanical phase contacts (K1, K2, K3) and electronic switches (S1, S2, S3), in, The series circuits (SS1, SS2, SS3) electrically connect one of the grid-side phase connections (LG1, LG2, LG3) to one of the load-side phase connections (LL1, LL2, LL3). - the mechanical phase contacts (K1, K2, K3) can be switched in such a way that they are opened together to prevent current flow or closed together for current flow, - the electronic switches (S1, S2, S3) can be switched by means of semiconductor-based switching elements to a high-resistance state of the switching elements to prevent current flow or to a low-resistance state of the switching elements to allow current flow, - A current sensor unit (SI1, SI2, SI3) is provided for each series circuit (SS1, SS2, SS3), Used to determine the current size of the corresponding phase conductor (L1, L2, L3) respectively, - providing a control unit (SE) connected to the current sensor units (SI1, SI2, SI3), the mechanical phase contacts (K1, K2, K3) and the electronic switches (S1, S2, S3), The circuit breaker device is designed to initiate the prevention of the current flow when at least one first current threshold value and / or current-time limit value is exceeded in a phase conductor. - setting the control input (CI) on the protective switching device (SG), - The protective switchgear is designed to: The electronic switches (S1, S2, S3) can be switched to a high-resistance state or a low-resistance state by means of the control input (CI).

2. The protective switchgear (SG) according to claim 1, It is characterized by: The circuit breaker device is designed such that the electronic switches (S1, S2, S3) can be switched independently of one another into a high-resistance state or a low-resistance state by means of the control input (CI).

3. The protective switchgear (SG) according to claim 1 or 2, It is characterized by: The protective switching device is designed such that, when at least one first current threshold value is exceeded in a phase conductor, the prevention of the current flow in the relevant phase conductor is initiated by the relevant electronic switch, in particular for a first period of time.

4. A protective switchgear (SG) according to claim 1, 2 or 3, It is characterized by: The mechanical phase contacts (K1, K2, K3) are associated with the load-side phase connectors, and the electronic switches (S1, S2, S3) are associated with the grid-side phase connectors. In particular, the mechanical phase contacts (K1, K2, K3) can be operated by a mechanical handle in order to switch the phase contacts open or the phase contacts closed. In particular, the mechanical phase contacts (K1, K2, K3) are part of a mechanical disconnect contact unit (MK) which switches the phase contacts together.

5. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: The control input (CI) has a particularly safe galvanic isolation, In particular, between the control input and the phase conductor.

6. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: Only when a release condition exists can the electronic switch be switched to a low-resistance state by means of the control input (CI). In particular, when the high-resistance state of at least one electronic switch is caused by an external protection function (CPF) of the protective switchgear, one or more electronic switches cannot be switched to a low-resistance state via the control input.

7. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: Inspection function on the protection switchgear side, a) (at least) one electronic switch in a high-resistance state switches to a low-resistance state for a first period of time, or b) (at least) one electronic switch in a low-resistance state switches to a high-resistance state for a second period of time, Not affected by the control input (CI).

8. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: The phase contacts (K1, K2, K3) can be opened by means of the control input (CI), In particular, it is possible to configure whether a) the electronic switches (S1, S2, S3) are capable of switching to a high resistance state or a low resistance state, or b) The phase contacts (K1, K2, K3) can be opened.

9. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: The control input (CI) is accessible on the housing side and in particular has a plurality of connecting terminals (AKI, AK2), in particular two, three or four connecting terminals, wherein the connecting terminals (AKI, AK2) are connected within the protective switching device to at least one element for galvanic isolation, in particular an optocoupler (OPK).

10. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: A display unit (AE) connected to the control unit (SE) is provided, the display unit having display means visible at the protective switchgear for displaying the high-resistance state or the low-resistance state of the electronic switches (S1, S2, S3).

11. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: The protective switching device is designed such that, in a standby state activated by the control input (CI), all electronic switches (S1, S2, S3) are to be in a high-resistance state, which is established in the region of a current zero crossing of the current of the corresponding electronic switch.

12. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: A grid-side neutral conductor connection (NG) and a load-side neutral conductor connection (NL) for a neutral conductor (N) of the multi-phase low-voltage AC circuit are arranged on the housing (GEH).

13. The protective switchgear (SG) according to claim 12, It is characterized by: The grid-side neutral conductor connection (NG) is connected to the load-side neutral conductor connection (NL) via a mechanical neutral conductor contact (KN).

14. The protective switchgear (SG) according to claim 13, It is characterized by: The mechanical neutral conductor contact (KN) can be opened or closed together with the phase contacts (K1, K2, K3), In particular, the neutral conductor contact (KN) is closed before the phase contacts (K1, K2, K3) are closed, or the neutral conductor contact (KN) is opened after the phase contacts (K1, K2, K3) are opened.

15. The protective switchgear (SG) according to any one of the preceding claims 12 to 14, It is characterized by: A voltage sensor unit (SU1, SU2, SU3) connected to a / the control unit (SE) is provided between each phase conductor and the neutral conductor for determining the voltage level, in particular the instantaneous voltage value, between the respective phase conductor and the neutral conductor. When the electronic switches (S1, S2, S3) are activated to low resistance by the control unit (SE), in particular the control input (CI), they are activated to low resistance in particular successively in the region of the respective zero crossings of the voltage of the respective phase conductor.

16. The protective switchgear (SG) according to claim 15, characterized in that When the electronic switches (S1, S2, S3) are activated to high resistance by the control unit (SE), in particular the control input (CI), they are activated to high resistance in particular successively in the region of the respective zero crossings of the voltage of the respective phase conductor.

17. Protection switchgear (SG) according to claim 15 or 16, characterized in that The control unit (SE) is connected to the current sensor unit (SI1, SI2, SI3), the voltage sensor unit (SU1, SU2, SU3), the mechanical contact and the electronic switch (S1, S2, S3), The protective switching device (SG) is designed to initiate the prevention of current flow in the relevant conductor by means of a relevant electronic switch when at least one current threshold value is exceeded in the conductor, When the voltage crosses zero for the next time or times after that, the electronic switch becomes low resistance again to allow current to flow.

18. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: The protective switching device is designed such that the control input (CI): a) activating a high-impedance state of the electronic switch when a first voltage level is applied, or activating a low-impedance state of the electronic switch when a second voltage level is applied, or b) initiating state switching of the electronic switch between a high resistance or low resistance state and a low resistance or high resistance state by applying a third voltage level for a first duration, or c) Initiating a change of the electronic switch into the low-resistance state by applying a third voltage level for a second duration, and after a third, in particular adjustable, duration, the electronic switch changes into the high-resistance state.

19. The protective switchgear (SG) according to any one of the preceding claims, It is characterized by: The protective switching device (SG) is designed such that a fault-induced high-impedance state of at least one electronic switch is detected by means of the control input (CI), in particular the fault-induced high-impedance state is triggered by exceeding a current limit value and / or a current-time limit value in the low-voltage circuit. The electronic switch can be switched to a low resistance state or automatically switched to a low resistance state without a fault. In particular, it is possible to configure whether a) capable of switching the electronic switch to a high-resistance state or a low-resistance state, or b) Confirm the high resistance state caused by the fault.

20. A method for protecting a protection switchgear (SG) for a multi-phase low-voltage AC circuit, the protection switchgear having: a housing (GEH) having line-side phase connections (LG1, LG2, LG3) and load-side phase connections (LL1, LL2, LL3) for phase conductors (L1, L2, L3) of a low-voltage AC circuit, - a series circuit (SS1, SS2, SS3) of mechanical phase contacts (K1, K2, K3) and electronic switches (S1, S2, S3), in, The series circuits (SS1, SS2, SS3) electrically connect one of the grid-side phase connections (LG1, LG2, LG3) to one of the load-side phase connections (LL1, LL2, LL3). - the mechanical phase contacts (K1, K2, K3) can be switched in such a way that they are opened together to prevent current flow or closed together for current flow, - the electronic switches (S1, S2, S3) can be switched by means of semiconductor-based switching elements to a high-resistance state of the switching elements to prevent current flow or to a low-resistance state of the switching elements to allow current flow, - determine the current magnitude of the corresponding phase conductor (L1, L2, L3) in each series circuit (SS1, SS2, SS3), - the prevention of the current flow is initiated when at least one first current threshold value or current-time limit value is exceeded in a phase conductor, The electronic switches (S1, S2, S3) can be switched to a high-resistance state or a low-resistance state via a control input (CI).

21. Method for protecting a switchgear (SG) according to claim 20, It is characterized by: Only when the release condition exists, the electronic switches (S1, S2, S3) are switched to the low-resistance state by means of the control input (CI). In particular, when the protection function (CPF) of the protective switchgear causes a high-resistance state of at least one electronic switch, the electronic switches (S1, S2, S3) cannot be switched to a low-resistance state by the control input.

22. Protection switchgear (SG) according to claim 20 or 21, It is characterized by: Inspection function on the protection switchgear side, a) the electronic switch in a high-resistance state switches to a low-resistance state for a first period of time, or b) the electronic switch in the low-resistance state switches to a high-resistance state for a second period of time, Not affected by the control input (CI).

Images