Apparatus and method for the early detection of an overload and / or for the adaptive line protection of at least one electrical line
The adaptive line protection system addresses the limitations of traditional fuses by calculating a maximum energy reserve and time interval, enabling proactive protection against electrical line overloads by considering energy history and environmental factors.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- FEP FAHRZEUGELEKTRIK PIRNA GMBH
- Filing Date
- 2025-05-09
- Publication Date
- 2026-06-04
AI Technical Summary
Existing methods for detecting electrical line overloads, such as those using traditional fuses and electronic fuses, fail to account for energy dissipation to the environment and ambient temperature changes, leading to inadequate protection against long-term overloads.
An adaptive line protection system that calculates a maximum permissible energy reserve and time interval based on the history of energy supplied and released to the environment, using sensors and a control unit to determine when to interrupt the current flow via an electronic switch.
Provides proactive early warning and rapid shutdown to prevent electrical line overloads by considering energy history and environmental factors, ensuring reliable protection against both short-term and long-term overloads.
Smart Images
Figure EP2025062792_04062026_PF_FP_ABST
Abstract
Description
[0001] STAEGER & SPERLING
[0002] PAR NERSCHAF SGESELLSCHAF MBB
[0003] FEP Fahrzeugelektrik Pirna GmbH & Co. KG
[0004] P 664 PCT
[0005] Device and method for the early detection of an overload and / or for adaptive line protection of at least one electrical line
[0006] Description:
[0007] The invention relates to a device and a method for the early detection of an overload and / or for adaptive line protection of at least one electrical line.
[0008] The so-called limit load integral l 2 The term t serves to protect lines or cables from short-term overloads, such as those that occur in the event of a short circuit. Depending on the type and diameter of the line, a permissible value for the limiting load integral l is determined. 2 t is defined or predetermined. The curve with l 2t = const indicates the maximum time t for which a specific current I may be applied before the electrical power exceeds a limit specified by the cable being protected. In the case of fuses, the constant represents a maximum permissible energy at which the fuse trips, reliably protecting the cable against overload in the event of a fault.
[0009] When using an electronic fuse, the protection encounters the limit load integral l 2There are limits to this, as an electronic fuse, compared to a traditional fuse which is subject to the same physical influences as the cable itself, generally operates on different principles. While a traditional fuse heats up and cools down with the flowing current and the ambient temperature, thus varying its melting behavior, electronic or digital monitoring is initially fixed in this respect. The calculation of the limiting load integral l 2However, the use of t in a digital safeguard has general limitations. The limiting load integral is merely an adiabatic approximation, meaning it does not consider energy dissipation from the cable to the environment. Therefore, the limiting load integral is only an adequate approximation for short pulses, and long-term monitoring of the energy in the cable is not possible. Furthermore, the effects of ambient temperature cannot be taken into account. Additionally, the cable's history is not considered, i.e., the current state determined by l. 2 t = const, the given limit is fixed or static.
[0010] The invention is therefore based on the objective of overcoming the aforementioned disadvantages and providing a device and a method for the early detection of an overload and / or for adaptive line protection of at least one electrical line, which is optimized for determining a maximum permissible energy input into an electrical line. This objective is achieved by the combination of features according to claim 1.
[0011] The basic idea of the present invention is based on the fact that adaptive line protection can be achieved by means of the limit load integral l 2The function t is provided with the aim of determining, for each calculation point in an electronic overcurrent protection device, a new maximum permissible energy value up to an overload of an electrical conductor, hereinafter referred to as the conductor's energy reserve, based on the history of the energy supplied and released to the environment. Using this energy reserve, a time interval tmax is calculated for a currently applied current I and / or voltage U, which indicates how long this current and / or voltage may be maintained before an overload of at least one conductor occurs. The calculated time interval t max It can be used as a proactive early warning signal. If the time interval becomes very small, zero, or even negative, the fuse interrupts the connection to the power supply via an electronic switch to reliably protect the line from overload.
[0012] According to the invention, a method for the early detection of an overload and / or for adaptive line protection of at least one electrical line is proposed. The at least one electrical line is arranged in an electrically conductive manner between a power source and at least one electrical load. Furthermore, an electronic overcurrent protection device is provided for interrupting and / or reducing the flow of electrical current through the at least one electrical line.The method involves detecting and / or determining at least one electric current and / or voltage in the at least one conductor using sensors. In a corresponding calculation step, the energy reserve of the at least one electrical conductor is determined based on the detected and / or determined electric current and / or determined electric voltage using a control unit for controlling and / or regulating the at least one electrical load and / or the electronic overcurrent protection device. The control unit and / or the electronic overcurrent protection device are specifically designed to process the electric current and / or voltage. Preferably, the electric current is determined from the detected and / or determined electric voltage using the control unit and / or the electronic overcurrent protection device.
[0013] In an advantageous embodiment, a threshold value is stored for the energy reserve in the control unit and / or the electronic overcurrent protection device, and a warning signal is issued by the control unit and / or the electronic overcurrent protection device when the energy reserve falls below this threshold. Additionally or alternatively, a limit value is stored for the energy reserve in the control unit and / or the electronic overcurrent protection device, and when the energy reserve falls below this limit value, the electronic overcurrent protection device interrupts the flow of electrical current through at least one electrical conductor.
[0014] In a preferred embodiment of the method, the control unit and / or the electronic overcurrent protection device uses the energy reserve to determine a time interval in the respective calculation step until an overload of the at least one electrical line occurs for the detected and / or determined electrical current and / or the determined and / or detected electrical voltage in the at least one line. In an embodiment of the invention, a threshold value is stored in the control unit and / or the electronic overcurrent protection device for at least the time interval, and a warning signal is issued by the control unit and / or the electronic overcurrent protection device when the threshold value of the time interval is undershot.Alternatively or additionally, a limit value is stored in the control unit and / or the electronic overcurrent protection device for at least the time interval, and if the limit value of the time interval is undershot, the electronic overcurrent protection device interrupts the flow of electrical current through at least one electrical line.
[0015] Preferably, if the energy reserve threshold and / or the time interval is undershot, the control unit and / or the electronic overcurrent protection device also reduces the electrical current flow through the at least one electrical conductor. This prevents the energy reserve and / or the time interval limit from being undershot.
[0016] In a further advantageous embodiment, it is provided according to the invention that the current flow through the at least one electrical line is interrupted by means of an electronic switch, in particular a MOSFET switch, of the electronic overcurrent protection device.
[0017] Furthermore, a design is advantageous in which the energy reserve of at least one electrical line is determined by means of an algorithm stored in the control unit and / or the overcurrent protection device. The following applies to the energy reserve Ei: res in the respective calculation step:
[0018] Egg, res = Emax — Ei, where Emax is a maximum permissible electrical energy reserve of the at least one electrical line and Ei is an energy determined in the corresponding calculation step, where Ei is a sum of an energy E determined in the previous calculation step, an supplied electrical energy Ei, zuand an energy output to an environment, from which amount.
[0019] The basis for the above determination is that the electrical power P introduced into the at least one electrical line ei At each point in time or calculation step, the following is calculated from the applied voltage U and the flowing current I, or the electrical resistance R of the line:
[0020] Pel = U * I = I 2 * R.
[0021] The energy input by this power in a time interval At is calculated under the assumption that At is sufficiently small to allow the power to be considered approximately constant.
[0022] AR = Per* At = R * I 2 * At.
[0023] This energy contribution AE per calculation step reduces the free energy reserve Ei, res of the line. To increase the energy reserve Ei, resTo calculate the energy in at least one electrical conductor, the energy in that conductor is arbitrarily set to zero at the assumed ambient temperature To for the intended use. This ambient temperature could, for example, be 85°C in the automotive sector. The maximum permissible electrical energy reserve E at a corresponding ambient temperature To ma x of an electrical line with permissible maximum temperature T max is then
[0024] Emax ~ Cth Tmax ~ To) with the heat capacity of the line Cth.
[0025] Using the classical limit integral method, this would yield the constant value for l. 2 t is defined as follows:
[0026] I 2 t = const.
[0027] As explained above, this value is only an approximation for short pulses, as it does not take into account energy dissipation to the environment, and only if electrical energy was not supplied to the line before the pulse.
[0028] To account for the energy supplied to the line, it is integrated starting at Eo = 0 VFs, i.e., in each calculation step i, the current h through the line is recorded and the supplied line energy is added.
[0029] Egg, zu = R * h 2 * At.
[0030] Alternatively or additionally, in each calculation step i the voltage Ui in the line is recorded and the supplied line energy is added to
[0031] Since a conductor can also release energy to the environment, terms for modeling this energy release must be defined. The influence of the ambient temperature (To) can also be considered. A general series expansion for the energy released by the conductor is as follows:
[0032] In the specific case of considering convection and radiation of heat energy, the following results:
[0033] where a is the heat transfer coefficient in E is the emissivity, <J die Stefan-Boltzmann-Konstante und A O fi is the surface area or the cladding area of a conductor sheath of at least one electrical conductor. The corresponding amount of energy released is Ei. a b is in this model
[0034] In a preferred embodiment of the invention, the following applies when determining the time interval tj.max in the respective calculation step i: ti.max ti.max where R is an electrical resistance of at least one electrical conductor, Ui is a voltage Ui determined in the respective calculation step, and h is a current h determined in the respective calculation step.
[0035] This time ti, max This indicates how long the currently flowing current h and / or the currently applied voltage Ui may continue until the energy reserve Ei. res of at least one electrical line is depleted. The adiabatic approximation of I also applies here. 2 Applying t-limit load integrals means that the energy released to the environment in the future is disregarded when calculating the permissible duration. However, this is not a major disadvantage, since the time ti, ma x is calculated in this way to be slightly shorter than it would be in reality.
[0036] In an advantageous embodiment, a predetermined fixed resistance or a temperature-dependent resistance is used to determine the electrical resistance R of at least one electrical conductor. The temperature dependence of the electrical resistance is taken into account in each calculation step i, provided that instead of a fixed electrical resistance R, the temperature-dependent resistance is used.
[0037] E-dependent resistance as well as for a line temperature — + T o in the corresponding calculation step i is applied when determining, whereby the following holds:
[0038] In a further advantageous embodiment, the invention provides that a characteristic map with value pairs L, tk is stored in the control unit for comparison with the current h determined in the respective calculation step and the corresponding time interval tj.max. The predetermined value pairs lk, tk are intended for interrupting the current flow through the at least one electrical conductor in a short-term range, preferably < 1.5 s. Here, tk defines a time range for which the corresponding current L can be present in the at least one electrical conductor until an overload of the conductor occurs. Furthermore, when the current L is present in the at least one electrical conductor and the time range tk is exceeded, the current flow through the at least one electrical conductor is interrupted. In this way, rapid shutdown times, which are determined by a software algorithm or...cannot be detected quickly enough by the algorithm, a rapid shutdown in short time intervals according to classical I. 2 t-method implemented.
[0039] If these cut-off thresholds of the value pairs are also to take into account the history of the line, i.e. the currently available energy reserve, these cut-off thresholds of the value pairs can also be adapted to the energy already introduced into at least one electrical line.
[0040] For every pair of values h, tk, l holds. k t k = const. If the energy Ei already introduced into at least one line is to be taken into account, the tk or alternatively the I must be considered. k be converted so that the following applies:
[0041] The invention further proposes a device for the early detection of an overload and / or for adaptive line protection of at least one electrical line, in particular for carrying out a method according to the preceding disclosure. The at least one electrical line is arranged in an electrically conductive manner between a power source and at least one electrical load. Furthermore, an electronic overcurrent protection device for interrupting and / or reducing an electrical current flow through the at least one electrical line, a control unit for controlling and / or regulating the at least one electrical load, and a sensor for detecting at least one electrical current in the at least one line are provided. The control unit and / or the electronic overcurrent protection device are configured to process the electrical current.Furthermore, by means of the control unit and / or the electronic overcurrent protection device, an energy reserve Ei, res of at least one electrical line can be determined in a respective corresponding calculation step i based on the detected current strength.
[0042] In an advantageous embodiment, the invention provides that the control unit and / or the electronic overcurrent protection device can be used to determine the energy reserve based on the egg. res a time interval tj.max in the respective calculation step i until an overload of at least one electrical line can be determined for the measured electrical current in the at least one line.
[0043] In a further advantageous embodiment, the electronic overcurrent protection device is an eFuse arranged on at least one electrical line. In particular, the eFuse also includes a microcontroller.
[0044] Preferably, the algorithm is stored in the control unit and / or the electronic overcurrent protection device.
[0045] Furthermore, a design is advantageous in which the device has additional sensors for detecting an ambient temperature To.
[0046] The features disclosed above can be combined in any way, provided that this is technically possible and they do not contradict each other.
[0047] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show:
[0048] Fig. 1 a schematic representation of a device for the early detection of an overload and / or for adaptive line protection of at least one electrical line; Fig. 2 a diagram of a time course of a time interval in the respective calculation step i until an overload of the at least one electrical line for the correspondingly detected electric current in the at least one line and the corresponding line temperature of the device;
[0049] Fig. 3 a diagram of solid I 2 , t pairs of values in a short-term range for the device.
[0050] The figures are schematic examples. Identical reference symbols in the figures indicate identical functional and / or structural features.
[0051] Figure 1 shows a schematic representation of a device 1 for the early detection of an overload and / or for adaptive line protection of at least one electrical line 10. The at least one electrical line 10 is arranged in an electrically conductive manner between a power source 11 and at least one electrical load 2, 2'. Furthermore, an electronic overcurrent protection device 4 for interrupting and / or reducing the flow of an electric current through the at least one electrical line 10, a control unit 5 for controlling and / or regulating the at least one electrical load 2, 2', and a sensor 3 for detecting at least one electric current h and / or one electric voltage Ui in the at least one line 10 are provided. The control unit 5 and / or the electronic overcurrent protection device 4 are configured to process the electric current h and / or the electric voltage Ui.Furthermore, an energy reserve Ei is calculated in a respective corresponding calculation step i by means of the control unit 5 and / or the electronic overcurrent protection device 4. res the at least one electrical line 10 can be determined based on the detected current h and / or the detected and / or determined electrical voltage Ui. Furthermore, the energy reserve Ei can be determined by means of the control unit 5 and / or the electronic overcurrent protection device 4. res a time interval ti.max in the respective calculation step i up to an overload of the at least one electrical line 10 for the recorded electrical current h and / or the recorded and / or determined electrical voltage Ui in the at least one line 10 can be determined.
[0052] The overcurrent protection device 4 is an eFuse arranged on at least one electrical line 10. Furthermore, an additional sensor 31 is provided for detecting an ambient temperature To.
[0053] Figure 2 shows an example of a diagram of a time course of a time interval ti.max in a respective calculation step i up to an overload of the at least one electrical line 10 of the device according to Figure 1 for the correspondingly detected and / or determined electrical current h and / or the detected and / or determined electrical voltage Ui in the at least one line 10 and the corresponding line temperature Ti of the device when using a method for early detection of an overload and / or for adaptive line protection of at least one electrical line 10.
[0054] This involves detecting and / or determining at least one electric current h and / or one electric voltage Ui in the at least one line 10 by means of a sensor 3 and determining an energy reserve Ei, res of the at least one electric line 10 in a respective corresponding calculation step i based on the detected and / or determined electric current h and / or the detected and / or determined electric voltage Ui by means of the control unit 5 and / or the electronic overcurrent protection device 4. The determination of the energy reserve Ei, res the at least one electrical line 10 is carried out by means of an algorithm stored in the control unit 5 and / or the overcurrent protection device 4, whereby for the energy reserve Ei, res in the respective calculation step i the following applies:
[0055] Egg, res = Emax —Ei, where Emax is a maximum permissible electrical energy reserve of the at least one electrical line 10 and Ei is an energy determined in the corresponding calculation step i, where Ei is a sum of an energy E determined in the previous calculation step i , an supplied electrical energy Ei, zu and an energy output to an environment, from a certain amount.
[0056] Furthermore, when determining the time interval tj.max in the respective calculation step i, the following applies: ti.max ti.max where R is an electrical resistance of at least one electrical line 10, Ui is a voltage Ui determined in the respective calculation step and h is a current h determined in the respective calculation step.
[0057] Furthermore, when determining the electrical resistance R of at least one electrical line 10, a temperature-dependent resistance is used for the determination.
[0058] For the energy reserve egg, res A threshold value S is stored in the control unit 5 and / or the electronic overcurrent protection device 4, and if the threshold value S is undershot, the energy reserve Ei is deactivated. res A pre-warning signal is issued by means of the control unit 5 and / or the electronic overcurrent protection device 4. Furthermore, at least for the energy reserve Ei, res A limit value G is stored in the control unit 5 and / or the electronic overcurrent protection device 4, and if the limit value G is undershot, the energy reserve Ei is activated. res by means of the electronic overcurrent protection device 4, an electric current flow through at least one electrical line 10 is interrupted.
[0059] Furthermore, the control unit 5 and / or the electronic overcurrent protection device 4 are used to determine the energy reserve (Ei). resA time interval ti.max is determined in the respective calculation step i until an overload of the at least one electrical line 10 occurs for the detected and / or determined electrical current h and / or voltage Ui in the at least one line 10. Furthermore, a threshold value S is stored in the control unit 5 and / or the electronic overcurrent protection device 4 for at least the time interval tj.max, and a pre-warning signal is issued by the control unit 5 and / or the electronic overcurrent protection device 4 if the threshold value S of the time interval tj.max is undershot. In addition, a limit value G is stored in the control unit 5 and / or the electronic overcurrent protection device 4 for at least the time interval tj.max, and if the limit value G of the time interval tj.max is undershot, the electronic overcurrent protection device 4 interrupts the electrical current flow through the at least one electrical line 10.
[0060] Furthermore, the current flow through at least one electrical line 10 is interrupted by means of an electronic switch 6 of the electronic overcurrent protection device 4, which is a MOSFET switch.
[0061] Figure 2 shows a time interval tj.max with a supplementary representation of the line temperature Ti for a time-varying current h and Tmax = 55°C at an ambient temperature To = 23°C. The threshold S for the time interval tj.max is 8 s, and the limit value for the time interval tj.max is 5 s. As shown in Figure 2, if the threshold value of the time interval tj.max is undershot, a warning signal is issued by the control unit 5 and / or the electronic overcurrent protection device 4, and the current h in at least one line 10 is reduced. This prevents the limit value G of the time interval tj.max from being undershot.
[0062] As can be seen in Figure 2, from the reduction of the electric current h, a corresponding time interval tj.max increases for the next calculation steps i+1 and a line temperature Ti decreases in the next calculation steps i+1, so that the electric current h can subsequently be increased again to a setpoint without the need to interrupt the current flow by means of the electronic overcurrent protection device 4.
[0063] Figure 3 shows a diagram of fixed l 2The following values are represented in a short-term range for the device 1. The control unit 5 of the device 1 contains a characteristic map with value pairs lk, tk for comparison with the current h determined in the respective calculation step and the corresponding time interval tj.max. The predetermined value pairs lk, tk are defined for an interruption of the current flow through the at least one electrical conductor 10 in a short-term range of tk < 1.5 s. Furthermore, tk defines a time range for which the corresponding current lk can be present in the at least one electrical conductor until an overload of the conductor occurs. Additionally, when the current lk is present in the at least one electrical conductor, the current flow through the at least one electrical conductor 10 is interrupted if the time range tk is exceeded.The invention is not limited in its implementation to the preferred embodiments specified above. Rather, a number of variants are conceivable which make use of the solution presented even in fundamentally different designs.
Claims
Patent claims 1. Method for the early detection of an overload and / or for adaptive line protection of at least one electrical line (10), wherein the at least one electrical line (10) is arranged in an electrically conductive manner between a power source (11) and at least one electrical load (2, 2'), wherein an electronic overcurrent protection device (4) is provided for interrupting and / or reducing an electric current flow through the at least one electrical line (10), comprising the steps of: a. detecting and / or determining at least one electric current (h) and / or one electric voltage (Ui) in the at least one line (10) by means of a sensor (3); b. determining an energy reserve (Ei, res) the at least one electrical line (10) in a respective corresponding calculation step (i) on the basis of the recorded and / or determined electrical current (h) and / or the recorded and / or determined electrical voltage (Ui) by means of a control unit (5) for controlling and / or regulating the at least one electrical consumer (2, 2') and / or the electronic overcurrent protection device (4).
2. Method according to claim 1, wherein at least for the energy reserve (Ei, res) in the control unit (5) and / or the electronic overcurrent protection device (4) a threshold value (S) is stored, wherein if the threshold value (S) of the energy reserve (Ej, re s) a warning signal is issued by means of the control unit (5) and / or the electronic overcurrent protection device (4), and / or wherein at least for the energy reserve (egg, res ) in the control unit (5) and / or the electronic overcurrent protection device (4) A limit value (G) is stored, whereby if the limit value (G) is undershot, the energy reserve (egg, res ) by means of the electronic overcurrent protection device (4) an electric current flow through the at least one electrical line (10) is interrupted.
3. Method according to claim 1 or 2, wherein the control unit (5) and / or the electronic overcurrent protection device (4) is used to determine the energy reserve (egg, res ) a time interval (tj.max) in the respective calculation step (i) up to an overload of the at least one electrical line (10) for the recorded and / or determined electrical current (h) and / or the determined and / or recorded electrical voltage (Ui) in the at least one line (10) is determined.
4. Method according to claim 3, wherein a threshold value (S) is stored in the control unit (5) and / or the electronic overcurrent protection device (4) at least for the time interval (tj.max), wherein a pre-warning signal is issued by the control unit (5) and / or the electronic overcurrent protection device (4) when the threshold value (S) of the time interval (tj.max) is undershot, and / or wherein a limit value (G) is stored in the control unit (5) and / or the electronic overcurrent protection device (4) at least for the time interval (tj.max), wherein an electrical current flow through the at least one electrical conductor (10) is interrupted by the electronic overcurrent protection device (4) when the limit value (G) of the time interval (tj.max) is undershot.
5. Method according to one of claims 2 to 4, wherein the current flow through the at least one electrical line (10) is interrupted by means of an electronic switch (6), in particular a MOSFET switch, of the electronic overcurrent protection device (4).
6. Method according to one of the preceding claims, wherein determining the energy reserve (egg, res ) the at least one electrical line (10) is controlled by means of an algorithm stored in the control unit (5) and / or the overcurrent protection device (4), wherein for the energy reserve (egg, res ) in the respective calculation step (i) the following applies: Egg, res = Emax —Ei, where Emax is a maximum permissible electrical energy reserve of the at least one electrical line (10) and Ei is an energy determined in the corresponding calculation step (i), where Ei is a sum of an energy E determined in the previous calculation step (i), an supplied electrical energy Ei, zu and an energy output to an environment, from a certain amount.
7. Method according to the preceding claims 3 and 6, wherein when determining the time interval (ti.max) in the respective calculation step (i) the following applies: ti.max ti.max where R is an electrical resistance of at least one electrical line (10), Ui is a voltage Ui determined in the respective calculation step and h is a current (h) determined in the respective calculation step.
8. Method according to claim 7, wherein, when determining the electrical resistance (R) of the at least one electrical conductor (10), a predetermined fixed resistance or a temperature-dependent resistance is used for the determination.
9. Method according to claim 7 or 8, wherein the control unit (5) contains a map with pairs of values (L, tk) for comparison with the one in the The current strength (h) determined in the respective calculation step (i) and the corresponding time interval (tj.max) are stored, wherein the predetermined pairs of values (lk, tk) are provided for an interruption of the current flow through the at least one electrical conductor (10) in a short-term range, preferably tk < 1.5 s, wherein, when determining, the current flow through the at least one electrical conductor (10) is interrupted if the time range (tk) is exceeded with a corresponding current strength (lk) applied to the at least one conductor (10).
10. Device (1) for the early detection of an overload and / or for adaptive line protection of at least one electrical line (10), in particular for carrying out a method according to one of the preceding claims, wherein the at least one electrical line (10) is arranged in an electrically conductive manner between a power source (11) and at least one electrical load (2, 2'), wherein an electronic overcurrent protection device (4) is provided for interrupting and / or reducing an electrical current flow through the at least one electrical line (10), wherein a sensor (3) is provided for detecting at least one electrical current (h) and / or one electrical voltage (Ui) in the at least one line (10), wherein a control unit (5) is used to control and / or regulate the at least one electrical load (2, 2').2') and / or the electronic overcurrent protection device (4) in a respective corresponding calculation step (i) an energy reserve (Ei, res) of at least one electrical line (10) can be determined on the basis of the detected current (h) and / or the detected and / or determined electrical voltage (Ui).
11. Device (1) according to claim 10, wherein by means of the control unit (5) and / or the electronic overcurrent protection device (4) based on the energy reserve (egg, res ) a time interval (tj.max) in the respective calculation step (i) up to an overload of the at least one electrical line (10) for the detected electrical current (h) and / or the detected and / or determined electrical voltage (Ui) in the at least one line (10) can be determined.
12. Device (1) according to claim 10 or 11, wherein the overcurrent protection device (4) is an eFuse arranged on the at least one electrical line (10).
13. Device (1) according to any one of claims 10 to 12, wherein a further sensor (31) is provided for detecting an ambient temperature (Tu).