Warning device and method for detecting an approach towards an electrical facility

Abstract

The invention relates to a warning device (W) for detecting an approach towards an electrical facility, the warning device having at least one component (K) to which a voltage (U) is applied, in particular an electrical line (L), the component being surrounded by an electrical field (E). The warning device (W) has at least two sensor units (SE1, SE2), each of which detects the electrical field (E) in the form of a measurement signal (M1, M2). Furthermore, the warning device comprises an evaluation unit (AW) which is designed to evaluate a difference between the measurement signals (M1, M2) detected by the at least two sensor units (SE1, SE2) and a reference variable which can be derived from the measurement signals (M1, M2) detected by the at least two sensor units (SE1, SE2), to estimate a respective current hazard potential on the basis of the evaluation result, and to actuate an output of at least one warning signal (WS) in accordance with the respective estimated hazard potential.

Description

[0001] Warning device and method for detecting an approach to an electrical installation

[0002] The present invention relates generally to the field of safety equipment, in particular to the area of ​​personal protection in the vicinity of electrical installations. Specifically, the present invention relates to a warning device for detecting an approach to an electrical installation, which has at least one or more live components, in particular electrical conductors, surrounded by an electric field. The warning device comprises at least two sensor units, each of which detects the electric field in the form of a measurement signal, an evaluation unit for evaluating the measurement signals detected by the sensor units, and an alarm unit for issuing at least one warning signal. Furthermore, the invention relates to an associated method for detecting an approach to an electrical installation.

[0003] State of the art

[0004] Electrical power supply systems are widespread. Besides voltage conversion (e.g., substations, transformer stations, etc.), they also serve to transmit electrical energy over long distances (e.g., high- and medium-voltage networks or sections thereof) and to distribute energy to consumers (e.g., low-voltage networks or sections thereof) to supply power to buildings, machinery, or industrial plants. Typically, a number of different electrical systems are used in power supply. Electrical systems usually comprise a variety of components used for converting electrical energy, such as power transformers, switchgear, etc., and / or for transmitting and distributing electrical energy, such as transmission and distribution lines (e.g., cables and / or overhead lines), high-voltage cable terminations, etc.They are used. Such components carry current or are under voltage, which, depending on the application of the component, can be in the medium or high voltage range, such as in transmission lines, or in the low voltage range, such as in distribution lines.

[0005] Electrical power supply systems, with their numerous components, especially electrical lines for power transmission and distribution, require regular inspection, maintenance, and repair, and potentially expansion. These tasks are carried out by qualified personnel—sometimes even during the operation of the electrical systems or power supply system. This entails an inherent risk to these personnel, as unintentional proximity to live and / or energized components, particularly electrical lines, and / or unintentional contact with such components can result in a life-threatening electric shock or at least the risk of serious injury.Furthermore, there are usually people in the vicinity of an electrical installation who, in the event of incorrect behavior or a fault in the electrical system, may also be at risk, for example, of suffering an electric shock. Such a potential hazard can, of course, exist not only with electrical installations of a power supply system, but also during work (e.g., commissioning, maintenance and / or repair work, rescue operations, renovation work, etc.) in the vicinity of or near other installations with live and / or energized components, such as industrial plants, production machines, etc. This also applies to work with construction machinery such as cranes, excavators, etc., in the vicinity of components of electrical installations of an energy supply system, especially in the vicinity of transmission lines or distribution lines in the form of overhead lines or cables, there is a risk that, for example, a work machine may get too close to the line and / or unintentionally damage it.

[0006] Typically, safety regulations and practices are in place in sectors such as energy and industry to reduce the risk to people from electrical installations and to prevent accidents involving live components or damage to components caused by machinery. Especially in industrial settings, it is common for electrical installations to have an emergency stop function to de-energize the system, for example, if a live component is touched. While this increases the safety of people working near live components, particularly from electric shock due to accidental contact, at least one other person must be present to activate the emergency stop in case of a fault and, if necessary, call for help.This hardly prevents unintentional damage to electrical components, especially transmission lines (e.g. overhead lines, cables), caused by machinery.

[0007] Warning devices offer a way to increase the safety of people working in or near electrical installations, especially power supply systems, who are therefore at risk of dangerously close contact with live components, such as live wires. Various warning devices are available today, designed for personal use and intended for individuals working in or around electrical installations. These devices protect against unintentional dangerous approaches to electrical components and electric shocks, particularly in medium- and high-voltage networks, but also in low-voltage networks. Typically, these warning devices detect the electric field generated by a live component, such as a power line.The electrical conductor is surrounded by a field whose strength and magnitude are proportional to the voltage level of the respective component, or, in the case of a current conductor, the magnetic field. These devices monitor, for example, compliance with exposure limits for electric fields and generate a warning signal when such limits or thresholds are exceeded, in order to prevent, for example, a dangerous approach and / or an electrical accident. Ideally, these warning devices are designed as compact, easily portable warning devices. The warning device can be designed, for example, to be attached to and worn on the wrist, work clothing, and / or a helmet so as not to hinder the person in their work.

[0008] Such a warning device is known, for example, from EP 1 296 150 A1, which can be worn by a person, e.g., on a helmet. This warning device has a housing in which a sensor circuit and an alarm circuit coupled to the sensor circuit are arranged. The sensor circuit detects an electric field and generates a signal that is proportional to the strength of the detected electric field. The alarm circuit generates an audible warning signal, the repetition rate of which is proportional to the strength of the detected electric field, and a visual warning signal, whereby the audible signal can be manually muted and reactivates after a predetermined period of time.

[0009] Another portable warning device is known, for example, from EP 4 276 478 A1, which also uses two sensor units to detect an electric field, in particular the electric field of a high-voltage line. This warning device emits an acoustic or visual warning signal that indicates to the wearer the strength and a general direction of the detected electric field. With this device as well, the acoustic warning signal can be muted by the user, and it reactivates after a predetermined period.

[0010] Ideally, such warning devices should reliably warn the wearer of a dangerous approach to a live component, particularly an electrical line, at a safe distance. However, the functionality of these devices does not guarantee this completely. The electric field strength detected by the warning device can, for example, be the same at a dangerous distance from a low-voltage component (e.g., a conductor system with three live conductors or a single conductor or live conductor in the range of 230 volts to approximately 1000 volts AC) as it is at a relatively safe distance from a medium- or high-voltage component (e.g., an electrical line or conductor system with a voltage above approximately 1 kV AC). Thus, for example, at an already dangerous distance of approximately...At a distance of 20 cm from an electrical component in the low-voltage range, approximately the same field strength value (e.g., approx. 250 V / m) can be measured as at a safe distance (e.g., approx. 4 m) from an electrical component or line in the 10 kV medium-voltage range, or at a relatively large distance (e.g., approx. 150 m) from a high-voltage component or line in the 420 kV range, when it is taken into account that the electric field results, for example, from a relationship between voltage and distance to the electrical component. For an infinitely long conductor, the electric field, for example, is calculated as a function of the distance to the conductor using the following formula: where E represents the electric field or electric field strength, U the voltage, d a distance to the electrical conductor under voltage, and R a radius of the electrical conductor.

[0011] Warning devices that only consider a single detected field strength cannot, for example, distinguish between a dangerous approach to a low-voltage component and the electric field of a medium- or high-voltage component at a safe or even distant distance. With these devices, an alarm is triggered, for instance, when a field strength exceeding a predefined threshold is detected. Therefore, warning signals are often unnecessarily issued to the user, which can lead to the user muting the warnings or not using the device at all. Consequently, such devices are often set to specific voltage ranges within which they reliably issue warnings. However, this can mean that, for example,A person performing maintenance, servicing, repair, and / or inspection work on electrical components, particularly electrical wiring, must carry various warning devices suitable for the respective voltage range and must know the voltage range of the electrical component in order to use the appropriate warning device. Furthermore, there are warning devices, such as those described in WO 2018 / 111474 A1, where, for example, the detection sensitivity and thus the alarm, especially a threshold for the audible alarm, can be adjusted to the ambient electric field strength upon arrival at an electrical component. This can be done, for example, by pressing a button on the warning device. The alarm remains silent as long as the measured electric field strength is below this value.The device remains constant and is only activated once the measured values ​​exceed the threshold or the measured field strength increases. This means that, in the worst case, the warning device must be recalibrated for each electrical component, which represents an additional effort and could potentially be a source of error (e.g., setting an incorrect threshold) and thus a safety risk.

[0012] It would therefore be desirable if a warning device could reliably detect a dangerous approach (e.g., falling below a certain safety distance) to an electrical component, regardless of its voltage range, without additional effort and / or without changing the device, thereby increasing the safety for a user of the warning device.

[0013] Description of the invention

[0014] The object of the present invention is therefore to provide a warning device and an associated method with which a dangerous approach to a component of an electrical system or the reaching and / or possible falling below a respective safety distance is reliably detected in a simple manner, regardless of the voltage range of the component.

[0015] This problem is solved by a device for detecting an approach to an electrical component and an associated method according to the independent claims. Advantageous embodiments of the present invention are described in the dependent claims.

[0016] According to the invention, the problem is solved by a warning device of the type specified above, wherein the warning device at least comprises:

[0017] - at least two sensor units, each of which detects the electric field of at least one component of the electrical system in the form of a measurement signal; and an evaluation unit, which is configured to evaluate a difference between the measurement signals detected by the at least two sensor units and a reference value that can be derived from the measurement signals detected by the at least two sensor units, to estimate a current hazard potential based on an evaluation result, and to trigger the output of at least one warning signal according to the estimated hazard potential.

[0018] The main aspect of the warning device according to the invention is that a potential hazard, e.g., for a person and / or a machine (e.g., crane, excavator, etc.), is reliably detected in a simple manner, independent of the component's voltage range, by measuring and evaluating the electric field surrounding the component of the electrical system. In the event of a dangerous approach to the component and / or a possible breach of a certain safety distance to the component, the evaluation unit can trigger the output of a warning signal, based on the estimated hazard potential, to indicate the current danger. By estimating the hazard potential based on the difference between the measurement signals acquired by the sensor units and a reference value derived from the measurement signals, the output of the warning signal is always adapted to the current situation (e.g.,Distance to the component, voltage range of the component, etc.) are controlled and adjusted accordingly without additional effort. This avoids unnecessary warning signals, as a distinction can be made between a component in the medium and / or high voltage range at a greater and therefore safer distance and a component in the low voltage range at a shorter distance.

[0019] Furthermore, it is advantageous if the evaluation unit is configured to use a first measurement signal acquired by a first sensor unit (of at least two sensor units), a second measurement signal acquired by a second sensor unit (of at least two sensor units), or an average of the measurement signals acquired by the at least two sensor units as a reference value. The reference value to which the difference of the measurement signals is related (e.g., in the simplest case by division) should ideally reflect the magnitude of the electric field surrounding the live component being approached. Therefore, as an alternative to the first or second measurement signal, or the average of the measurement signals, a maximum, a minimum, a median, or a similar value derived by calculation from the measurement signals of the at least two sensor units could also be used as the reference value.The current hazard potential can then be easily estimated from the relationship between the difference between the measurement signals and the reference value.

[0020] Ideally, the warning device also includes an alarm unit, which can be controlled by the evaluation unit and is configured to output at least one warning signal as a visual, audible, and / or vibration alarm. The volume, frequency, and / or intensity of the warning signal can be adjusted by the evaluation unit to the assessed hazard potential. This means that the alarm unit—controlled by the evaluation unit—emits a warning signal according to the current hazard potential, with its form—i.e., volume, frequency, and / or intensity—adapted to the assessed hazard potential. For example, a warning signal can become louder, or its frequency and / or intensity can increase with rising hazard potential or as the person approaches the live component.

[0021] In a preferred embodiment of the warning device, the evaluation unit is configured to compare the estimated hazard potential with at least one predefined threshold. The evaluation unit then controls the alarm unit to output at least one warning signal when the estimated hazard potential exceeds this threshold. The comparison result can then be easily used to control the output of the warning signal. Thus, by comparing the hazard potential with the threshold, it is very easy to determine when the alarm unit should activate or deactivate the output of the warning signal.

[0022] Furthermore, the warning signal can be designed to activate an emergency stop function if, upon comparison of the estimated hazard potential with at least one predefined threshold, the evaluation unit determines that the estimated hazard potential exceeds the predefined threshold. In this way, for example, a lifting platform with a worker approaching a live component, such as an electrical line, or a machine (e.g., crane, crane arm, excavator, etc.) approaching a live component, such as an electrical line, can be quickly stopped if, for example, there is a risk of the safe distance to the live component being breached.

[0023] It is further advantageous if the evaluation unit is configured to compare the first recorded measurement signal and / or the second recorded measurement signal and / or the average of the measurement signals recorded by the at least two sensor units with at least one predefined calculation limit, whereby below this at least one calculation limit, the respective current hazard potential is classified as low. This means that below the calculation limit, no further considerations or calculations (e.g., determining the difference between the measurement signals, determining the relationship between the difference and a reference value) are performed in the evaluation unit, thereby saving hardware resources and / or computing power – especially in the evaluation unit. Since the hazard potential is considered low below the predefined calculation limit, the output of a warning signal is also omitted.The evaluation unit does not activate the output of the warning signal.

[0024] It is also advantageous if the warning device has a local memory unit in which at least adaptation parameters for adjusting the output of the at least one warning signal to the respective estimated hazard potential are stored. The evaluation unit can then very easily access the adaptation parameters for the warning signal stored in the memory unit (e.g., regarding frequency, volume, intensity, etc.) to adjust the output of the at least one warning signal to the respective estimated hazard potential, thus controlling the output of the warning signal very easily and simply. Furthermore, at least one threshold value and at least one calculation limit value can be stored in the local memory unit.

[0025] Furthermore, the warning device advantageously includes a filter unit to filter the evaluation result and / or the respective estimated hazard potential. Ideally, the filter unit is designed as a low-pass filter. In this way, short-term fluctuations in the evaluation result or the hazard potential can be easily filtered out. Such fluctuations can occur, for example, due to short-term fluctuations in the measurement signals, which can arise, for instance, when moving the warning device in the vicinity of the live component, and / or due to errors in acquiring the measurement signals by the sensor units or due to interference. A short-term fluctuation in at least one of the measurement signals, a measurement error, and / or interference thus do not lead to an incorrectly estimated hazard potential and the output of warning signals.

[0026] A practical design of the warning device provides that it is a mobile device that can be attached to a helmet or article of clothing, or worn on the wrist. This allows the warning device to be easily used by a person, for example, during maintenance, repair, or inspection work in the vicinity of an electrical system or a component of an electrical system, particularly an electrical cable, to provide early and reliable warning of a hazard. Alternatively, the mobile warning device can be designed so that it can be attached to a piece of machinery. This allows, for example, the timely detection of a piece of machinery (e.g., crane, excavator, etc.) approaching the component, particularly an electrical cable, and thus potentially preventing damage to the component and / or the machinery. (Brief description of the figures)

[0027] The present invention is explained in more detail below with reference to Figure 1, which shows exemplary, schematic, and non-limiting advantageous embodiments of the invention. Figure 1 shows an embodiment of the warning device according to the invention for detecting an approach to an electrical installation with at least one component.

[0028] Implementation of the invention

[0029] The invention relates to a warning device W with which an approach to an electrical installation of a power supply system or to a component L of an electrical installation of a power supply system that is under voltage U can be detected.

[0030] Figure 1 shows an example of a component L, which is under a voltage U and therefore surrounded by an electric field E. This component is an electrical conductor or conductor system, such as a cable or overhead line, or a section thereof, shown in cross-section. The voltage U can vary depending on whether the electrical conductor belongs to an electrical installation or a transmission and / or distribution network in the high, medium, or low voltage range. For a low-voltage conductor or conductor system, which consists, for example, of three phase conductors, a neutral conductor, and a protective conductor, the voltage U is in the range of 230 V to 400 V, depending on whether the voltage U is considered between a phase conductor and the neutral and protective conductors, or between two phase conductors. However, it can reach up to approximately 1 kV.In a medium-voltage network, the voltage U between the conductors can range from 1 kV to approximately 50 kV or 60 kV, with medium-voltage networks for the transmission and distribution of energy typically operating at, for example, 10 kV or 20 kV. In a high-voltage network, the voltage U between the conductors can range from approximately 50 kV or 60 kV to over 400 kV, with high-voltage networks in Western Europe typically operating at 110 kV, 220 kV, or 380 kV, and occasionally at 420 kV.

[0031] The warning device W can also be used in the vicinity of another component L of an electrical installation, such as a transformer, switchgear, etc., which is surrounded by an electric field E, to detect a dangerous approach. When approaching the live component U, e.g., an electrical conductor, or when the distance d to component L is reduced, for example, during maintenance, repair, and / or inspection work, there is a potential hazard from component L, e.g., that a person gets too close to component L, receives an electric shock, or possibly unintentionally touches component L, especially an electrical conductor. This potential hazard can also exist when using machinery (e.g., crane, excavator, etc.).Getting too close to component L can lead to damage to component L and / or the machine being worked on, a short circuit, and malfunctions in the electrical system, etc. Therefore, it is important that both people and machines maintain a certain safety distance from component L to minimize hazards (e.g., electric shock, accidental contact, damage, etc.). Depending on the voltage range – i.e., low, medium, or high voltage – of component L, different safety distances may be necessary. For example, for electrical cables, the required distance might be approximately 0.5 m for a low-voltage cable with a voltage U of 230 V or 400 V, approximately 1.5 m for a medium-voltage cable with a voltage U of 10 kV between the conductors, and approximately 5 m for a high-voltage cable with a voltage U of 420 kV between the conductors.When approaching component L, especially when a distance d to component L reaches or falls below this safety distance, the potential for danger to a person from component L or for damage and / or disruption of component L by a working machine increases.

[0032] The warning device W, shown schematically and by way of example in Fig. 1, is located in the vicinity of a live component U, such as an electrical line, and is moved there, for example, by the person wearing the warning device W or by a machine to which the warning device W is attached, within a reference coordinate system with an x-axis, a y-axis, and a z-axis. The reference coordinate system is assumed, for example, such that a plane formed by the x-axis and y-axis is parallel to component L, and the z-axis is perpendicular to component L. This means that, for example, when the warning device W moves in the direction of the x-axis or y-axis, the distance d to component L remains largely constant, whereas when the warning device W moves in the direction of the z-axis, the distance d to component L changes, for example, becoming smaller or larger.

[0033] The warning device W, shown schematically and by way of example in Fig. 1, is therefore designed to warn of the potential hazard posed by component L during an approach to component L, especially before a safety distance is reached or breached – regardless of the voltage range of the voltage U of component L. For this purpose, the warning device W, as shown by way of example in Fig. 1, has at least two sensor units SE1, SE2, each of which detects the electric field E surrounding component L in the form of a measurement signal M1, M2. The electric field E is detected by a first sensor unit SE1 of the at least two sensor units SE1, SE2 in the form of a first measurement signal M1, and by a second sensor unit SE2 in the form of a second measurement signal M2.Ideally, a large number of sensor units SE1, SE2 can be distributed in the warning device W, each of which detects the electric field E of component L or the electric field strength E.

[0034] Each of the sensor units SE1, SE2 can comprise at least one sensor, and usually several, to detect the electric field E omnidirectionally. Using this at least one sensor, each sensor unit SE1, SE2 can detect the electric field E in the form of a measurement signal M1, M2, which surrounds the component L under voltage U, thus determining the strength and extent of the electric field E. The at least one sensor of each sensor unit SE1, SE2 can, for example, be a capacitive sensor, consisting, for instance, of two conductors arranged in space (e.g., plates of conductive material) between which a voltage is measured. The measurement signals M1, M2 detected by the at least two sensor units SE1, SE2 are then transmitted—possibly after appropriate amplification by an amplifier unit—to an evaluation unit AW of the warning device W.

[0035] The evaluation unit AW of the warning device W is designed to calculate the difference between the measurement signals M1 and M2 acquired by the at least two sensor units SE1 and SE2, and to relate this difference to a reference value and evaluate it. Based on the evaluation result, the evaluation unit AW can estimate the current hazard potential and trigger the output of at least one warning signal corresponding to the estimated hazard potential.

[0036] The evaluation unit AW can therefore be microprocessor-based hardware running appropriate software. However, the evaluation unit AW can also be implemented as an integrated circuit, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). Other implementations are also conceivable. The reference value, which can be derived from the measurement signals M1 and M2 and to which the difference between the measurement signals M1 and M2 is related, should approximately correspond to the electric field E or electric field strength E that can be measured absolutely with the warning device W (i.e., all sensor units SE1 and SE2) at a distance d. For example, the first measurement signal M1 of the first sensor unit SE1, the second measurement signal M2 of the second sensor unit SE2, or an average of the measurement signals M1 and M2 can be used as the reference value.It is also conceivable that, for example, a maximum, a minimum, a median, or similar value could be derived from the measurement signals M1 and M2 by calculation and used as a reference value. The difference between the measurement signals M1 and M2 is then related to this reference value. In the simplest case, this is done, for example, by dividing the difference between the measurement signals M1 and M2 by the reference value. The resulting dimensionless quantity represents the evaluation result used to estimate the current hazard potential. For example, the hazard potential is considered greater the larger the evaluation result is—regardless of the voltage U of component L.

[0037] Alternatively, a table can be stored in the warning device W, for example in a local storage unit SP or directly in the evaluation unit AW, which establishes the relationship between the difference between the measurement signals M1 and M2 and the reference value. This table can then be used, for example, for evaluating and estimating the hazard potential. Such a table can contain, for example, different field strength values ​​as reference values, which can be recorded, for example, by the first sensor unit SE1 as the first measurement signal M1 or by the second sensor unit SE2 as the second measurement signal M2, or which can be assumed to be the average of the measurement signals M1 and M2. These reference values ​​can be linked by the table, for example, to different difference values ​​between the measurement signals M1 and M2 and a possible hazard potential – in the simplest case, in Boolean form, such as no hazard, hazard. The evaluation unit AW determines, for example,The reference value (e.g., the currently measured (absolute) field strength value) is determined from the measurement signals M1 and M2, and the difference between the measurement signals M1 and M2 is calculated to estimate the hazard potential using the table. For example, the table can be used to determine whether a given combination of reference value and the difference between the measurement signals M1 and M2 poses a hazard or not.

[0038] Furthermore, the evaluation unit AW can also be configured to compare the first measurement signal M1 and / or the second measurement signal M2 and / or the average of the measurement signals M1, M2 acquired by at least two sensor units SE1, SE2 with at least one predefined calculation limit, which can be stored, for example, in the evaluation unit AW or in the local storage unit SP. Below the calculation limit, the respective current hazard potential is classified as low, and the evaluation unit AW does not perform any evaluation or calculations. That is, the evaluation unit AW does not calculate the difference between the measurement signals M1, M2, nor does it relate this difference to the reference value. Since the hazard potential is classified as low below the predefined calculation limit, no warning signal WS is issued.Only when the specified calculation limit value of the first measurement signal M1 and / or the second measurement signal M2 and / or the mean value of the measurement signals M1, M2 recorded by the at least two sensor units SE1, SE2 is exceeded, is an evaluation carried out and thus an estimation of the respective current hazard potential based on the difference of the recorded measurement signals M1, M2 and the specified reference value.

[0039] Based on the assessed hazard potential, the evaluation unit AW then controls the output of at least one warning signal WS. The warning signal WS can, for example, be output via an alarm unit AL of the warning device W. The alarm unit AL is controlled by the evaluation unit AW in such a way that the output of the warning signal WS is adjusted depending on the assessed hazard potential.

[0040] The alarm unit AL is then configured – controlled by the evaluation unit AW – to issue a correspondingly adapted warning signal WS in order to warn according to the hazard potential assessed by the evaluation unit AW. The alarm unit AL can, for example, output the warning signal WS as a visual alarm, an audible alarm, and / or a vibration alarm. The alarm unit AL can, for example, have a visual indicator, such as an LED or a small display. The LED or display can, for example, flash at a frequency that the evaluation unit AW adjusts to the respective assessed hazard potential from component L by means of appropriate control of the alarm unit AL. That is, if the evaluation unit AW determines a high or increasing hazard potential from component L, because, for example,When a person wearing the warning device W approaches component L or is already very close to it, the flashing frequency of the LED or display increases. If the perceived hazard potential from component L decreases, for example because the person moves away from it, the flashing frequency can be reduced accordingly, or the visual alarm can be deactivated until the perceived hazard potential increases again.

[0041] Furthermore, the alarm unit AL can include an acoustic output unit, such as a loudspeaker. Similar to a visual alarm, the volume, pitch, and / or repetition frequency of an acoustic alarm can be adjusted by component L according to the estimated hazard potential. This means that the volume, pitch, and / or repetition frequency can be changed according to the estimated hazard potential – for example, increased when the hazard potential is high and decreased when it is low. If the estimated hazard potential is very low, it is possible, for example, to mute the acoustic alarm temporarily.

[0042] Additionally or alternatively, the AL alarm unit can also have a vibration motor for issuing a vibration alarm, whereby, for example, the frequency and / or intensity of the vibration alarm can be adapted to the respective estimated hazard potential via appropriate control of the AW evaluation unit.

[0043] Additionally, the evaluation unit AW can be configured to compare the estimated hazard potential with at least one predefined threshold, which may be stored, for example, in the evaluation unit AW or in the local storage unit SP. If the estimated hazard potential exceeds at least one predefined threshold, the evaluation unit AW determines that the alarm unit AL must activate the output of the warning signal WS, provided that the alarm unit AL is not already outputting the warning signal WS. If the estimated hazard potential falls below at least one predefined threshold, the evaluation unit AW can control the alarm unit AL to, for example, deactivate an activated warning signal WS. This means that the evaluation unit AW controls the alarm unit AL in such a way that the warning signal WS, for example,The visual and / or audible alarm and / or vibration alarm is only activated when the predefined threshold is exceeded by the estimated hazard potential. If the hazard potential is below the threshold, the AL alarm unit does not issue a warning signal (WS) or switches off an existing warning signal (WS).

[0044] Alternatively or additionally, the warning signal WS can also be designed to activate an emergency stop function if the evaluation unit AW detects that the assessed hazard potential exceeds the predefined threshold. This allows, for example, a lifting platform with a worker approaching a live component L (e.g., an electrical line) to be stopped, thus preventing injury to the person or ensuring a safe distance. Furthermore, the warning signal, triggered when the predefined threshold for the assessed hazard potential is exceeded, can also be used to stop a piece of machinery, such as a crane, crane arm, excavator, etc., via an emergency stop function. This prevents damage to a live component L (e.g., an electrical line).For example, a safe distance must be maintained.

[0045] Furthermore, the warning device W can have a local storage unit SP. The local storage unit SP can, for example, contain at least one predefined threshold value for comparison with the estimated hazard potential, as well as at least one predefined calculation limit value. Furthermore, the local storage unit SP can also contain adjustment parameters for adapting the warning signal WS. For example, adjustment parameters for the warning signal WS can be stored in the storage unit SP for different magnitude ranges of the difference between the measurement signals M1 and M2. These parameters adjust the output warning signal WS, for example, in volume, frequency, and / or intensity, to the estimated hazard potential of component L. The adjustment parameters can, for example,in the form of a table in the storage unit SP, whereby a specific adjustment setting for the warning signal WS is assigned to each predefined size range of the difference between the measurement signals M1, M2.

[0046] The warning device W can additionally include a filter unit F, which filters the respective evaluation result and thus the estimated hazard potential. The filter unit F can, for example, be designed as a low-pass filter and prevent, for example, short-term deviations in the evaluation result, due to, for example, momentary measurement fluctuations and / or errors in the acquisition of the measurement signals M1, M2 by the sensor units SE1, SE2, from leading to an incorrect assessment of the hazard potential and thus an incorrect activation of the warning signal WS output.

[0047] Furthermore, the warning device W can have a power supply, such as a suitable battery, accumulator, or similar. This power supply primarily provides the evaluation unit AW and the alarm unit AL with the necessary energy.

[0048] Furthermore, the warning device W can be designed as a mobile device. For this purpose, the warning device W can have a housing in which the sensor units SE1, SE2, the evaluation unit AW, the alarm unit AL, the local storage unit SP, and the power supply are arranged. As a mobile device, the warning device W can, for example, be attached to a person's helmet or clothing, or worn on the wrist, to detect a potential hazard from the live component U to the person and to warn the person of a dangerous approach (e.g., when a safety distance is reached or breached). Furthermore, the warning device W can also be mounted on a work machine, such as...a crane or an excavator, in particular an excavator bucket, in order to detect when the working machine comes dangerously close to component L, to send at least a warning signal WS and, if necessary, e.g. by means of a control signal from the evaluation unit AW of the warning device W to stop the working machine.

Claims

Patent claims 1. Warning device (W) for detecting an approach to an electrical installation which has at least one live component (L), in particular an electrical conductor surrounded by an electric field (E), wherein the warning device (W) at least comprises: - at least two sensor units (SE1, SE2) which each detect the electric field (E) of at least one component (L) in the form of a measurement signal (M1, M2); and - an evaluation unit (AW) which is set up to evaluate a difference of the measurement signals (M1 , M2) recorded by the at least two sensor units (SE1 , SE2) in relation to a reference value which can be derived from the measurement signals (M1 , M2) recorded by the at least two sensor units (SE1 , SE2), to estimate a current hazard potential on the basis of an evaluation result and to control an output of at least one warning signal (WS) according to the respective estimated hazard potential.

2. Warning device (W) according to claim 1, characterized in that the evaluation unit (AW) is configured to use as a reference variable a first measurement signal (M1) detected by a first sensor unit (SE1) of the at least two sensor units (SE1 , SE2) or a second measurement signal (M2) detected by a second sensor unit (SE2) of the at least two sensor units (SE1 , SE2) or an average of the measurement signals (M1 , M2) detected by the at least two sensor units (SE1 , SE2).

3. Warning device (W) according to one of claims 1 to 2, characterized in that the warning device further comprises an alarm unit (AL) which can be controlled by the evaluation unit (AW) and which is configured to output the at least one warning signal (WS) as a visual alarm and / or acoustic alarm and / or vibration alarm, wherein, by means of control by the evaluation unit (AW), a volume and / or frequency and / or intensity of the at least one warning signal (WS) can be adapted to the respective estimated hazard potential.

4. Warning device (W) according to claim 3, characterized in that the evaluation unit (AW) is configured to compare the estimated hazard potential with at least one predetermined threshold, wherein the evaluation unit (AW) controls the alarm unit (AL) to output at least one warning signal (WS) when the estimated hazard potential exceeds the at least one predetermined threshold.

5. Warning device (W) according to one of claims 1 to 4, characterized in that the evaluation unit (AW) is configured to compare the estimated hazard potential with at least one predetermined threshold, wherein the at least one warning signal (WS) is designed to activate an emergency stop function if the estimated hazard potential exceeds the at least one predetermined threshold.

6. Warning device (W) according to one of claims 2 to 5, characterized in that the evaluation unit (AW) is further configured to compare the first detected measurement signal (M 1 ) and / or the second detected measurement signal (M2) and / or the mean value of the measurement signals (M1 , M2) detected by the at least two sensor units (SE1 , SE2) with at least one predetermined calculation limit value, wherein below the at least one calculation limit value the respective current hazard potential is classified as low.

7. Warning device (W) according to one of claims 1 to 6, characterized in that the warning device (W) has a local storage unit (SP) in which at least adaptation specifications for adapting the output of the at least one warning signal (WS) to the respective estimated hazard potential are stored.

8. Warning device (W) according to claim 7, characterized in that the at least one predetermined threshold value and the at least one predetermined calculation limit value are further stored in the local storage unit (SP).

9. Warning device (W) according to one of claims 1 to 8, characterized in that the warning device (W) comprises a filter unit (F), in particular a low-pass filter.

10. Warning device (W) according to one of claims 1 to 9, characterized in that the warning device (W) is designed as a mobile device which can be attached to a helmet or to a piece of clothing or worn on the wrist, or which is designed such that the warning device can be attached to a work machine.

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