Method for interrupting currents with adaptive switching times and medium and / or high voltage switchgear for interrupting currents with adaptive switching times

Abstract

Method for switching off currents with a medium and / or high-voltage switchgear (1) with adaptive switching times, wherein the medium and / or high-voltage switchgear (1) comprises: - at least one medium and / or high voltage switch (10) with at least one vacuum interrupter (15) per phase, - at least one protective device (50) for triggering a switching operation of the medium and / or high voltage switch(es), and - at least one current sensor (100) per phase for determining the current flow in the respective phase, wherein ▪ in response to a shutdown signal (1000) or a shutdown detection of the protective device (50), the current flow through the respectively assigned vacuum interrupters (15) is determined by means of the at least one current sensor (100) per phase, ▪ a direct current component of the respective current flow per phase and a temporal progression of the direct current components are determined from the respective current flows per phase, ▪ a decay curve of the direct current components and a switch-off time (1200) are determined from the time courses of the direct current components determined for each phase, ▪ a switching delay (1400) is determined from the switch-off time (1200), which causes a switch-off at the specific switch-off time (1200), and ▪ Tripping the medium and / or high voltage switch (10) with the switching delay (1400) determined in this way, so that the medium and / or high voltage switch(es) (10) switch(es) off the current at the switch-off time (1200), characterized in that a plausibility and / or threshold check (1500) of the respective current flows per phase determined by the current sensors (100) and / or of the respective direct current components and / or of the respective time profiles of the direct current components and / or of the respective decay profiles is carried out and in the event of a negative plausibility and / or threshold check (1500) the medium and / or high voltage switch(es) (10) is switched off with a predetermined switching delay (1450).

Description

The present disclosure relates to a method for switching off currents with a medium- and / or high-voltage switchgear with adaptive switching times, to additional electronics for medium- and / or high-voltage switchgear for switching off currents with adaptive switching times, to a protective device for medium- and / or high-voltage switchgear for switching off currents with adaptive switching times, and to a medium- and / or high-voltage switchgear for switching off currents with adaptive switching times.Medium-voltage and / or high-voltage switches, in particular circuit breakers or vacuum interrupters, or vacuum switches for short, for alternating current have the task of rapidly, reliably and repetitively interrupting the electrical energy flow. Said vacuum interrupters are frequently used as switching elements; the current is interrupted by opening the switching contacts of the vacuum interrupter; in the next zero current passage, the arc formed between the switching contacts then breaks. The switching contacts of the vacuum interrupter are often a fixed contact and a moving contact per vacuum interrupter.A distinction is made between switching off a "normal" load current for operation guidance within the power distribution grid and switching off a fault current for protection of the operating means of the power distribution grid. Causes of such errors are short or earth faults in the operating means. Short-circuit currents are significantly higher than the rated currents. Circuit breakers are rated according to the rated currents and short-circuit currents. Circuit breakers according to their product standard must be able to carry the rated short-circuit current for a few seconds without being damaged.If short-circuit currents flow, a decaying DC component in the current will flow to the AC current depending on the impedance of the energy distribution grid. This direct component often exceeds the amplitude of the alternating current, so that the total current does not have a zero crossing and thus the arc between the open contacts of a vacuum interrupter does not break. The energy released by the arc can then damage the switching contacts of the vacuum interrupter.In order to ensure reliable switching off of the current in the event of a fault with a direct component in the current, the intrinsic time of the circuit breaker is selected to be so great that the direct component has decayed to such an extent at the opening time of the switching contacts that a zero crossing occurs in the current flow and the arc can extinguish. The decay of the DC component is also described as decay behavior or decay profile. Within the meaning of this disclosure, the characteristic time of a medium- and / or high-voltage switch, in particular a power switch, is to be understood as meaning the time period between the triggering of the medium- and / or high-voltage switch with a triggering signal and the complete disconnection of the switching contacts of the medium- and / or high-voltage switch, at which time period and distance of the switching contacts the arc can quench and a sufficient disconnection path between the switching contacts of the medium- and / or high-voltage switch is achieved. Typical intrinsic times for the short-circuit case in circuit breakers with vacuum interrupters are 35 ms to 50 ms.For the disconnection of "normal" load currents, it is expedient in the sense of an optimum operating control to choose the intrinsic time as short as possible. Desirable intrinsic times are in the range below 20 ms. Because of their mechanical construction, vacuum circuit breakers with spring-loaded drives cannot be influenced in their movement sequence and thus their mechanical intrinsic time after the release by, for example, an electromagnet as a release.In order to realize different intrinsic times, in particular in the case of spring-loaded drives, different rapid triggers can be used. Due to the mechanical construction, max. 3 different triggers are installed, thus the max. 3 different intrinsic times can be realized. In practice, only 2 triggers of different speeds are used, since the third trigger is installed for redundancy reasons, in the case that one of the other triggers does not operate as intended.The actuation of the trigger of different speeds is usually effected via a suitably designed protective device which decides on the basis of the measured currents whether a rapid disconnection, for example for a "normal" load current, or a delayed disconnection for a short-circuit current with a direct current component is to take place.As a result of the network topologies of the energy distribution networks with variable energy flow direction becoming more and more complex as a result of decentralized energy generation, different settings, parameter sets, must be active depending on the load flow direction in the protective device in order to ensure reliable operation even in the event of a short circuit. The selection of the appropriate parameter set takes place dynamically in the protective device or on request by a higher-order device.The specification and activation of the respectively matching parameter set is complex and, due to the limited number of possible parameter sets in the protective device and the methods for selecting the parameter set matching the operating case, is not always satisfactorily detachable in practice.For safety reasons, the delay of the switching command is always selected in the parameter set of the protective device to be so great that damage to the circuit breaker is prevented even under the worst case network conditions. Thus, the set delay of the switching command is generally greater than is necessary for safe operation control and possibly impedes the optimum operation control in the energy distribution network.DE 40 05 532 A1 discloses a generator circuit breaker which shifts the switching time to a zero current crossing by means of a zero current relay.U.S. Pat. No. 3,292,047 A1 discloses a control circuit for an alternating voltage switch which enables switching at the zero crossing even in the case of a DC component.DE 38 12 734 A1 shows a high-voltage switching device with state monitoring.From JP S61-173 424 A a circuit breaker is known which delays the opening of the switch.DE 10 2016 116 008 A1 shows an overcurrent protection arrangement.DE 10 2021 203 192 A1 discloses the determination of a state of aging of an auxiliary switch.DE 10 2018 216 475 A1 discloses a high-voltage switching system which has a sensor array for monitoring the state.It is an object of the invention to provide an improved or alternative method and apparatus.The object is achieved by the independent claims and the claims dependent on the independent claims.A first aspect relates to a method for switching off currents with a medium-voltage and / or high-voltage switching installation with adaptive switching times, wherein the medium-voltage and / or high-voltage switching installation has:at least one medium-voltage and / or high-voltage switch having at least one vacuum interrupter per phase,at least one protective device for triggering a switching process of the medium-voltage switch or switches and / or high-voltage switches, andat least one current sensor per phase for determining the current flow in the respective phase,wherein▪ in response to a switch-off signal or a switch-off detection of the protective device, the current flow through the respectively assigned or assigned vacuum interrupters is determined per phase by means of the at least one current sensor,▪ from the respective current flows per phase a direct current component is determined at the respective current flow per phase and a time profile of the direct current components,▪ from the time curves of the DC components determined per phase, a decay curve of the DC components and a switch-off time are determined,▪ from the switch-off time a switching delay is determined which causes a switch-off at the previously determined switch-off time, and Triggering of the medium- and / or high-voltage switch, with the switching delay determined in this way, so that the medium- and / or high-voltage switch or switches shut off the current at the switch-off time.Furthermore, a plausibility and / or threshold value check of the respective current flows determined with the current sensors per phase and / or of the determined respective DC current components and / or of the respective time curves of the DC current components and / or of the respective decay curves is carried out, and in the case of a negative plausibility and / or threshold value check, the medium-voltage switch or switches are switched off with a predefined switching delay. Thus, safe shutdown is achieved even in the event of an erroneous determination of the shutdown time.The intrinsic time of the circuit breaker is extended or set continuously by an electronic system, for example in the protective device or by means of an additional electronic system, in accordance with the current actually flowing and the decay times, and this thus ensures that the current is always switched off as quickly as possible, but reliably, regardless of the level of the DC component in the current.This ensures that a parameter set which is incorrectly or not optimally selected in the protective device or a particular network configuration which was not pre-planned when the parameter set was created in the protective device does not lead to overloading of the vacuum interrupters in the switch, in particular circuit breakers, on account of a non-extinguishing arc.The currents or current flows are preferably fault currents which are to be switched off. The currents or fault currents are switched off by opening, disconnecting the switching contacts of the one or more vacuum interrupters.It is also preferred that this is a single-phase, a three-phase or generally polyphase medium- and / or high-voltage switching installation.In a particularly preferred variant, the medium-voltage and / or high-voltage switchgear has more than one vacuum interrupter per phase, in particular two or three vacuum interrupters per phase, as a result of which high currents are able to be switched off.The shutdown signal, in particular a fault shutdown signal, in the sense of this application is one of several possibilities for initiating a shutdown of the medium-voltage and / or high-voltage switchgear. It is particularly preferred that, in addition to the switch-off signal, manual triggering via switch-off detection also leads to adaptive switch-off, i.e. to switch-off at the specific switch-off time.It is also preferred that the switch-off time is the earliest possible switch-off time. The earliest possible switch-off time is the time at which the direct current component falls below or falls below a predetermined threshold value for the first time and thus enables reliable switch-off, in particular in which a zero crossing of the current is reached.It is also preferred that the medium and / or high voltage switch or switches are operated by means of one or more spring storage drives, and that the switching contacts of the vacuum interrupter or interrupters are disconnected by means of the spring storage drive or actuators, and thus interrupt the current flow at the switch-off time. Alternatively, instead of one or more spring-loaded drives, one or more magnetic actuators can also be provided for driving the switching contact or contacts.It is further preferred that the current flows measured with the current sensor or sensors are transmitted to the protective device and the determination of the switch-off time is carried out in the protective device and the protective device causes the triggering of the medium and / or high-voltage switch, with the determined switching delay, in such a way that the medium and / or high-voltage switch or switches switch switch off the current at the switch-off time.It is also preferred that the current flows measured with the current sensor or sensors are transmitted to the protective device and the determination of the switch-off time is carried out in the protective device and the protective device causes the triggering of the medium and / or high-voltage switch, with the determined switching delay, in such a way that the medium and / or high-voltage switch or switches switch switch off the current at the switch-off time.It is also preferred that the current flows measured with the current sensor or sensors are transmitted to an additional electronics and the determination of the switch-off time in the additional electronics is carried out in response to a switch-off signal of the protective device and the additional electronics forwards the switch-off signal of the protective device to the medium and / or high-voltage switch or switches delayed by the determined switching delay and thus causes the medium and / or high-voltage switch or switches to switch off the current at the switch-off time. Such additional electronics can also be retrofitted in particular; an existing medium- and / or high-voltage switchgear can therefore be retrofitted with such additional electronics and thus form a medium- and / or high-voltage switchgear with adaptive switching times, or make possible a method for switching off currents using a medium- and / or high-voltage switchgear with adaptive switching times.Another aspect relates to an additional electronics for medium-voltage and / or high-voltage switchgear for switching off currents with adaptive switching times, wherein the additional electronics are designed:receiving a switch-off signal or a switch-off detection at a first signal input, for example via second signal or data lines,receiving second signals from current sensors at one or more second signal inputs, for example via first signal or data lines,and determining from the second signal or signals a direct current component of the respective current flow per phase and a time profile of the direct current components,determining a decay curve of the DC components and a switch-off time, in particular an earliest possible switch-off time, from the time curves of the DC components determined per phase,determining a switching delay from the switch-off time; andAfter the specific switching delay has elapsed, a triggering signal is output to a triggering output, for example via first signal or data lines, which triggering signal is suitable for triggering and switching off one or more medium and / or high-voltage switches.Furthermore, a plausibility and / or threshold value check of the respective current flows determined with the current sensors per phase and / or of the specific respective direct current components and / or of the respective time curves of the direct current components and / or of the respective decay curves is carried out, and, in the case of a negative plausibility and / or threshold value check, a switching off of the medium and / or high-voltage switch or switches is carried out with a predefined switching delay. Thus, safe shutdown is achieved even in the event of an erroneous determination of the shutdown time.In particular, such additional electronics are designed to carry out the above-described methods with or in a medium-voltage and / or high-voltage switchgear assembly.Such additional electronics can preferably also be retrofitted; an existing medium-voltage and / or high-voltage switchgear can therefore be retrofitted with such additional electronics and thus form a medium-voltage and / or high-voltage switchgear with adaptive switching times.A further aspect relates to a protective device for medium- and / or high-voltage switchgear for switching off currents with adaptive switching times, wherein the protective device is configured to receive first signals at one or more first signal inputs and second signals at one or more second signal inputs, wherein it is to be determined from the first signal or signals and / or second signals whether a fault shutdown is required, and in the case of a required fault shutdown:▪ receive at one or more second signal inputs second signals from current sensors,▪ and from the second signal or signals determine a direct current component of the respective current flow per phase and a temporal profile of the direct current components,▪ to determine a decay curve of the DC components and a switch-off time, in particular an earliest possible switch-off time, from the time curves of the DC components determined per phase,▪ determine a switching delay from the switch-off time, and▪ after the specific switching delay has elapsed to output a triggering signal to a triggering output, which triggering signal is suitable for causing one or more medium-voltage and / or high-voltage switches to be triggered.Furthermore, a plausibility and / or threshold value check of the respective current flows determined with the current sensors per phase and / or of the determined respective DC current components and / or of the respective time curves of the DC current components and / or of the respective decay curves is carried out, and in the case of a negative plausibility and / or threshold value check, the medium-voltage switch or switches are switched off with a predefined switching delay. Thus, safe shutdown is achieved even in the event of an erroneous determination of the shutdown time.In particular, such a protective device is designed to carry out the above-described methods with or in a medium-voltage and / or high-voltage switchgear assembly.In a particular embodiment, the protective device and / or the additional electronics are constructed as a distributed system, in particular a cloud system. It is also possible here for the protective device to be partially or completely constructed and / or the additional electronics to be partially or completely constructed as a distributed system, in particular a cloud system.In the context of the invention, a cloud system is optionally spatially distributed data processor and data storage devices which are connected by means of a data communication network such as the Internet. Software which takes over tasks of the protective device and / or the additional electronics, for example, can be executed module by module as a so-called cloud application where sufficient data processor and / or data storage resources are currently available. This ensures high scalability and availability. In addition, many companies essentially do away with the need to operate their own server computers or hardware on a large scale, to wait and to protect them against hacker attacks.Another aspect relates to a medium and / or high voltage switching system for switching off currents with adaptive switching times, wherein the medium and / or high voltage switching system comprises:at least one medium-voltage and / or high-voltage switch having at least one vacuum interrupter per phase,at least one protective device for triggering a switching process of the medium-voltage switch or switches and / or high-voltage switches, andat least one current sensor per phase, wherein the protective device is a protective device according to the above embodiments and / or the medium- and / or high-voltage switching system further comprises additional electronics according to the above embodiments.With regard to the device according to the invention, all the explanations given above and below with respect to the method according to the invention and vice versa apply in a corresponding manner, in particular the device according to the invention is set up for carrying out the method according to the invention in any desired embodiment or a combination of any desired embodiments. With regard to the advantages of the device according to the invention, reference is also made to the advantages described with respect to the method according to the invention.The invention is explained in more detail below with reference to an exemplary embodiment. The specific configuration of the exemplary embodiment is not to be understood as restrictive in any way for the general configuration of the method according to the invention and of the device according to the invention; rather, individual configuration features of the exemplary embodiment can be freely combined with one another and with the features described above in any desired manner. FIG. 1 : Exemplary schematic illustration of a medium-voltage and / or high-voltage switching installation; FIG. 2 : Exemplary schematic illustration of a side view of a three-phase medium-voltage and / or high-voltage switch with a spring-loaded drive; FIG. 3 : Exemplary schematic illustration of a vacuum interrupter in elevation with switching contacts; FIG. 4 : Exemplary schematic illustration of a medium-voltage and / or high-voltage switching installation with adaptive switching times; FIG. 5 : Exemplary flow diagram of a method for switching off currents with a medium-voltage and / or high-voltage switching installation with adaptive switching times.FIG. 1 shows an exemplary schematic illustration of a medium-voltage and / or high-voltage switchgear 1 with optional display elements 4, a protective device 50 and optional additional electronics 60. In an alternative embodiment, not shown, the protective device 50 and / or the additional electronics 60 can, however, also be arranged behind a cover or door or in the interior of the medium and / or high-voltage switchgear 1.FIG. 2 shows an exemplary schematic illustration of a side view of a three-phase medium and / or high-voltage switch 10 with vacuum interrupter 15 and spring-loaded drive 40.FIG. 3 shows an exemplary schematic illustration of a vacuum interrupter 15 in elevation 20 with switching contacts 16.The switching contacts 16 are formed here by way of example by a fixed contact 17 and a moving contact 18. The moving contact 18 is movably disposed in the vacuum interrupter 15 by means of a bellows 19.FIG. 4 shows an exemplary schematic illustration of a medium-voltage and / or high-voltage switching installation 1 with adaptive switching times. The medium and / or high-voltage switchgear 1 is divided here into three regions, the low-voltage space in which the protective device 50 and optional additional electronics 60 are arranged here, wherein the additional electronics 60 are connected via first signal or data lines 61 both to a current sensor 100 in a current supply and output space 14 and to a medium and / or high-voltage switch 10 arranged in a switch space 12. Furthermore, the additional electronics 60 are connected to the protective device 50 via second signal or data lines. If the protective device 50 assumes the function of the additional electronics 60, not shown here, the protective device is connected to the first signal or data lines.The medium-voltage and / or high-voltage switch 10 here has, for example, a spring-loaded drive 40, which acts on a drive 30. The drive 30 is connected via a force transmission arrangement 35 to the moving contact 18 which is illustrated in FIG. 3. The spring-loaded drive 40 is triggered, for example, by a magnetic release, not shown. Alternatively and not shown, a magnetic actuator may also be provided instead of a spring-loaded drive 40 with magnetic trigger for driving the moving contact or contacts of the vacuum interrupter 15.The current supply and output space 14 can alternatively and not shown also be divided into two separated regions, a current supply space and an output space. The current sensor 100 can be arranged either on the current supply 80 or the current outlet 90 or else in each case on the current supply 80 and the current outlet 90. In an embodiment not shown, the current sensor 100 or the current sensors 100 can also be arranged on the vacuum interrupter, in particular arranged within a pole shell of the vacuum interrupter.In a preferred embodiment, each phase is provided with one current sensor 100 or two current sensors 100.FIG. 5 shows an exemplary flow diagram of a method for switching off currents using a medium-voltage and / or high-voltage switchgear 1 having adaptive switching times.In response to a disconnection signal 1000 or not shown upon disconnection detection of a protective device 50, in a first method step 1001, a current flow in one phase through a respectively assigned or multiple assigned vacuum interrupters 15 is determined by means of at least one current sensor 100 per phase. Furthermore, from the respective current flows per phase, a direct current component of the respective current flow per phase and a time profile of the direct current components are determined.In a second method step 1100, a decay curve of the DC components and a switch-off time 1200 are determined from the time curves of the DC components determined per phase.In a third method step 1300, a switching delay 1400 is determined from the switch-off time 1200, wherein the switching delay 1400 causes a switch-off at the previously determined switch-off time 1200.If the optional fourth method step does not take place-i.e. is not implemented or activated-the triggering step 1600 is carried out as the next step, with the determined switching delay 1400, with the triggering of the medium and / or high-voltage switch 10, with the switching delay 1400 determined in this way, so that the medium and / or high-voltage switch 10 shut off the current at the switch-off time 1200.In an optional fourth method step 1500, a plausibility and / or threshold value check 1500 of the respective current flows determined with the current sensors 100 per phase and / or the determined respective DC current components and / or the respective time curves of the DC current components and / or the respective decay curves is carried out.In the case of a positive result, that is to say in the case of plausible values for the specific current flows per phase and / or the specific respective DC components and / or the respective temporal profiles of the DC components and / or the respective decay profiles, the triggering step 1600 is carried out with the specific switching delay 1400, with the triggering of the medium- and / or high-voltage switch 10, with the switching delay 1400 determined in this way, such that the medium- and / or high-voltage switch 10 switches off the current at the switching-off time 1200.In the case of a negative plausibility and / or threshold value check 1500, the alternative triggering step 1650 carries out a switching off of the medium-voltage switch or switches 10 with the predefined switching delay 1450 with a predefined switching delay 1450.List of reference characters1 Medium- and / or high-voltage switchgear, also known as switchgear for short; 4 display element; 10 medium- and / or high-voltage switches; 11 low-voltage space; 12 switch space; 14 current supply and output space; 15 vacuum interrupter; 16 switching contacts of vacuum interrupter 15; 30 drive with spring storage drive 40; 35 force transmission arrangement between drive 30 and vacuum interrupter 15; 40 spring storage drive; 50 protective device; 60 additional electronics; 61 first signal or data lines; 62 second signal or data lines; 80 current supply; 90 output; 100 current sensor; 1000 disconnection signal; 1001 first method step; 1100 second method step; 1200 disconnection time; 1300 third method step; 1400 switching delay; 1450 predefined switching delay; 1500 plausibility and / or threshold value checking as an optional fourth method step; 1600 triggering step; 1650 alternative triggering step with the predefined switching delay 1450.

Claims

Method for switching off currents with a medium and / or high-voltage switching installation (1) with adaptive switching times, wherein the medium and / or high-voltage switching installation (1) has: - at least one medium and / or high-voltage switch (10) with at least one vacuum interrupter (15) per phase, - at least one protective device (50) for triggering a switching operation of the medium and / or high-voltage switch or switches, and - at least one current sensor (100) per phase for determining the current flow in the respective phase, wherein ▪ in response to a switch-off signal (1000) or a switch-off detection of the protective device (50), the current flow through the respectively assigned or assigned vacuum interrupters (15) is determined by means of the at least one current sensor (100) per phase, ▪ a DC component of the respective current flow per phase and a temporal profile of the DC components is determined from the respective current flows per phase, ▪ a decay profile of the DC components and a switch-off time (1200) is determined from the temporal profiles of the DC components determined per phase, ▪ a switching delay (1400) is determined from the switch-off time (1200), which delay brings about a switch-off at the determined switch-off time (1200), and ▪ triggering of the medium- and / or high-voltage switch (10) with the switching delay (1400) determined in this way, such that the medium- and / or high-voltage switch (10) switch-off the current at the switch-off time (1200), characterized in that, a plausibility check and / or threshold value check (1500) of the respective current flows determined with the current sensors (100) per phase and / or of the determined respective DC components and / or of the respective time curves of the DC components and / or of the respective decay curves is carried out, and in the case of a negative plausibility check and / or threshold value check (1500), the medium and / or high-voltage switch or switches (10) are switched off with a predefined switching delay (1450).The method of claim 1, characterized in that the shutdown time (1200) is the earliest possible shutdown time (1250).Method according to Claim 1 or 2, characterized in that the medium-voltage switch or switches and / or high-voltage switches (10) are operated by means of one or more spring-loaded drives (40) or by means of one or more magnetic actuators, and in that the switching contacts (16) of the vacuum interrupter or interrupters (15) are disconnected by means of the spring-loaded drive or switches (40) or the magnetic actuators and thus interrupt the current flow at the switch-off time (1200).Method according to one of the preceding claims, characterized in that the current flows measured with the current sensor or sensors are transmitted to the protective device (50) and the determination of the switch-off time (1200) is carried out in the protective device (50) and the protective device (50) causes the triggering of the medium and / or high voltage switch (10), with the determined switching delay (1400), in such a way that the medium and / or high voltage switch (10) switch off the current at the switch-off time (1200).Method according to one of the preceding Claims 1 to 3, characterized in that the current flows measured with the current sensor or sensors are transmitted to an additional electronics (60), and the determination of the switch-off time (1200) in the additional electronics (60) is carried out in response to a switch-off signal (1000) of the protective device (50), and the additional electronics (60) forwards the switch-off signal (1000) of the protective device (50), delayed by the determined switching delay (1400), to the medium and / or high-voltage switch or switches (10) and thus causes the medium and / or high-voltage switch or switches (10) to switch off the current at the switch-off time (1200).Method according to Claim 5, characterized in that the functionality of the additional electronics (60) is monitored by the protective device (50), and, if the functionality of the additional electronics 60 is not correct, the medium-voltage switch or switches (10) is switched off with a predefined switching delay 1450. Thus, an emergency shutdown is ensured even in the event of a failure of the additional electronics.Auxiliary electronics (60) for medium- and / or high-voltage switchgear (1) for switching off currents with adaptive switching times, wherein the auxiliary electronics (60) are designed: - to receive a switching-off signal (1000) or a switching-off detection at a first signal input, - to receive second signals from current sensors (100) at one or more second signal inputs, - and to determine a direct current component at the respective current flow per phase and a temporal profile of the direct current components from the second signal or signals, - to determine a decay profile of the direct current components and a switching-off time (1200) from the temporal profiles of the direct current components determined per phase, - to determine a switching delay (1400) from the switching-off time (1200), and - to output a triggering signal to a triggering output after the determined switching delay (1400) has elapsed, The method is suitable for causing one or more medium and / or high voltage switches (10) to be triggered and switched off, characterized in that ▪ a plausibility and / or threshold value check (1500) of the respective current flows determined with the current sensors (100) per phase and / or of the determined respective direct current components and / or of the respective time curves of the direct current components and / or of the respective decay curves is carried out, and in the case of a negative plausibility and / or threshold value check (1500), the medium and / or high voltage switch (10) is switched off with a predefined switching delay (1450).Protective device (50) for medium- and / or high-voltage switchgear (1) for switching off currents with adaptive switching times, characterized in that the protective device (50) is designed to receive first signals at one or more first signal inputs and second signals at one or more second signal inputs, it being possible to determine from the first signal or signals and / or second signals whether fault switching is required, and in the case of a required fault switching: ▪ to receive second signals from current sensors at one or more second signal inputs, ▪ and to determine from the second signal or signals a DC component at the respective current flow per phase and a temporal profile of the DC components, ▪ to determine from the temporal profiles of the DC components determined per phase a decay profile of the DC components and a switching-off time (1200), ▪ to determine a switching delay (1400) from the switch-off time (1200), and ▪ to output a trigger signal after the expiry of the determined switching delay (1400), which trigger signal is suitable for causing a triggering of one or more medium and / or high-voltage switches (10), characterized in that a plausibility and / or threshold value check (1500) of the respective current flows determined with the current sensors (100) is carried out per phase and / or of the determined respective DC components and / or of the respective temporal profiles of the DC components and / or of the respective decay profiles, and in the case of a negative plausibility and / or threshold value check (1500), a switching off of the medium and / or high-voltage switch (10) is carried out with a predetermined switching delay (1450).Medium and / or high-voltage switchgear (1) for switching off currents with adaptive switching times, wherein the medium and / or high-voltage switchgear (1) has: - at least one medium and / or high-voltage switch (10) having at least one vacuum interrupter (15) per phase, - at least one protective device (50) for triggering a switching operation of the medium and / or high-voltage switch or switches (10), and - at least one current sensor (100) per phase, characterized in that the protective device (50) is a protective device (50) according to Claim 8 and / or the medium and / or high-voltage switchgear (1) further has additional electronics (60) according to Claim 7.

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