WO2018069009A1

WO2018069009A1 - Device and method for detecting an arcing fault in an electric power supply circuit

Info

Publication number: WO2018069009A1
Application number: PCT/EP2017/073728
Authority: WO
Inventors: Josef Bauer; Vicente Garcia Alvarez; Werner Schiemann; Soheil Mohseni; Gerd Lorenz
Original assignee: Robert Bosch Gmbh
Priority date: 2016-10-12
Filing date: 2017-09-20
Publication date: 2018-04-19
Also published as: DE102016219849A1

Abstract

The invention relates to a device (10) for detecting an arcing fault in an electric power supply circuit (20). To this end, a voltage fed at the input end is compared with a voltage available at the output end in the electric power supply circuit. Any difference between the voltages at the input and the output of the electric power supply circuit that exceeds a predefined threshold value is an indication that there might be an arcing fault.

Description

DEVICE AND METHOD FOR DETECTING A BROWTH ARC IN ONE

ELECTRICAL ENERGY SUPPLY

The present invention relates to an apparatus and a method for

Detection of an arc fault. Furthermore, the present invention relates to an electrical power supply with a device for detecting a

Arc fault.

State of the art

In electrical applications with higher voltages put so-called

Error or fault arcs is a non-negligible hazard potential. An arc fault, for example, at a defective location of a

electrical line, such as a loose cable clamp or

due to a cable break occur. Therefore, electrical systems with a voltage above a critical value must be monitored. In

Vehicles, especially in electric or hybrid vehicles must due to the large mechanical and thermal load with potential errors

can be calculated, which can lead to a fault arc. Due to the danger potential emanating from such an arc, the arc must be reliably detected, and then a reliable shutdown of the affected power grid must be done.

The document 10 2013 001 612 AI discloses an arrangement for plant and personal protection. The arrangement comprises a switching element which can be triggered by an arc fault detection. This results in the electrical

Energy for triggering the switching element exclusively from the energy of the fault arc occurring. Disclosure of the invention

The present invention discloses an apparatus for detecting an arc fault according to claim 1 and a method for detecting an arc fault according to claim 7. Further, the present invention discloses an electrical power supply according to claim 6.

Accordingly, it is provided:

An apparatus for detecting an arc fault between a first position and a second position in an electrical power supply. The device comprises a first voltage detector, a second voltage detector

Voltage detector and an arc detector. The first voltage detector is configured to detect a first voltage at the first position of the electrical power supply. The second voltage detector is configured to detect a second voltage at the second position of the electrical power supply. The arc detector is configured to compare the detected first electrical voltage with the detected second electrical voltage. Furthermore, the arc detector is configured to output a signal for a detected arc fault when a difference between the first voltage and the second voltage is greater than a predetermined threshold.

It is also provided:

An electrical power supply with an electrical line and a device according to the invention for detecting an arc fault. The electrical line is at a first position with an electrical

Energy source connectable. Furthermore, the electrical line is connectable at a second position with an electrical load.

Furthermore, it is provided: A method for detecting an arc fault in an electrical

Power supply. The method includes a step of detecting a first electrical voltage at a first position of the electrical

Power supply and a step for detecting a second electrical voltage at a second position of the electrical power supply. Further, the method includes a step of detecting a fault arc in the electrical power supply when a difference between the first electrical voltage and the second electrical voltage exceeds a predetermined threshold.

Advantages of the invention

The present invention is based on the finding that a not inconsiderable electrical voltage drops across an active arc fault. Therefore, if a fault arc occurs at a fault location of an electrical power supply, a voltage drop will be recorded at this fault location with the fault arc. This voltage drop is usually greater than a voltage drop along a fault-free line of the electrical energy supply without arc fault.

It is therefore an idea of the present invention to take into account this finding and to provide a detection for an arc fault, which identifies the significant voltage drop across an arc fault. For this purpose, it is provided in particular to compare an input-side voltage with an output-side voltage in an electrical power supply. If there is a significant difference between the input-side and the output-side voltage, a voltage drop exists between the input and the output of the power supply. This voltage drop can be used as an indication of a possible arc fault in the electrical

Power supply between the input and the output are interpreted.

By detecting the input-side and the output-side voltage can in this way a particularly simple and reliable detection of otherwise difficult to detect so-called serial arc along the arc paths of the electrical power supply will be realized. Voltage detectors for detecting the relevant

Electrical voltages in the electrical energy supply can be realized easily, inexpensively and with a relatively small space. Therefore, the cost of a Störlichtbogendetektion can be kept low.

According to one embodiment, the first position in the electrical

Power supply, where the first voltage detector is an electrical

Voltage detected, coupled with an electrical energy source. This electrical energy source may be, for example, a

DC source, in particular a high-voltage battery, such as a traction battery of an electric or hybrid vehicle act. In addition, it may also be in the electrical energy source

AC source act, for example, a

Energy supply network, to which, for example, a domestic installation

connected.

According to one embodiment, the second position of the electrical

Power supply, at which the second voltage detector detects the second electrical voltage, coupled to an electrical load. To this

Way, the electrical power supply can be checked up to this electrical load on an arc out. In particular, for example, the cable routes in an electrical device, in particular a consumer electronics device, between a

Connection point at which the electrical device is coupled to a power supply and monitored the electrical load within the device to detect an arc fault.

According to one embodiment, the arc detector is adapted to adjust the predetermined threshold in response to an electric current through the electrical power supply. Additionally or alternatively, the arc detector can also adjust the predetermined threshold value as a function of electrical power of a connected electrical load. In this way, occurring voltage drops in the electrical energy supply due to ohmic resistors or Impedances considered and eliminated if necessary. As a result, the reliability of the arc fault detection can be increased.

In one embodiment, the predetermined threshold is at least 15 volts. In particular, the predetermined threshold may be 30 volts or more. As for the ignition of a fault arc between two

Copper contacts an electrical voltage of at least about 12 volts is required, at a lower voltage drop no arc can be ignited. Furthermore, an electric arc voltage of 20 volts or more is usually required for maintaining an arc fault.

The above embodiments and developments can, as far as appropriate, combine arbitrarily. Further refinements, further developments and implementations of the invention also include combinations of previously or below that are not explicitly mentioned with respect to FIG

Embodiments described features of the invention. In particular, the person skilled in the art will also consider individual aspects as improvements or

Add additions to the respective basic forms of the present invention.

Brief description of the drawings

The present invention will be explained in more detail with reference to the exemplary embodiments indicated in the schematic figures of the drawings. Showing:

Figure 1: a schematic representation of an apparatus for detecting a

Arc fault according to one embodiment; and

FIG. 2 is a schematic representation of a flowchart, such as FIG

Method according to one embodiment is based.

Embodiments of the invention FIG. 1 shows a schematic representation of a device 10 for detecting an arc fault in an electrical energy supply 20 according to an embodiment. The electrical energy supply 20 includes, for example, a first supply line 21 and a second supply line 22. The electrical energy supply 20 can be coupled, for example, on the input side to an energy source 30. This electrical energy source 30 may be, for example, a DC voltage source, such as a high-voltage battery, in particular a traction battery of an electric or hybrid vehicle. Furthermore, the electrical energy source 30 can be any other electrical energy source, in particular a single-phase or multi-phase AC voltage source. For example, the electrical energy source 30 may be an energy supply network which can be connected, for example, to a domestic installation or the like. Furthermore, a single- or multi-phase socket within a domestic installation can be considered as an electrical energy source 30, which feeds an electrical energy supply of an electrical appliance, in particular a consumer electronics device.

Accordingly, the electrical connection between a connection point of the energy source 30 and an electrical load 40 within an electrical appliance can be understood as the electrical energy supply 20. In particular, for example, in an electrical appliance, such as a household electrical appliance, such as a washing machine, a tumble dryer, an electric heater, a television, etc., the electrical conduction paths between a connection to a power outlet of the home network and the electrical loads within the device , such as an electric motor and / or a heater of a washing machine, are monitored. In addition, for example, the

Conduits are monitored in an electric or hybrid vehicle between a high-voltage battery (traction battery) and the electric drive system or other consumers of the vehicle.

The electric power source 30 may be connected to the electric power supply 20 or disconnected from the electric power supply 20, for example, by means of a circuit breaker 23 or the like. On the output side, the electrical power supply 20 can be connected to one or more consumers 40, for example. For example, these consumers may be an electric drive system of an electric or hybrid vehicle. In addition, of course, any other electrical consumers are possible. For example, the consumers 40 may also be electrical consumers within an electrical appliance. In particular, as an electrical load 40, for example, an electric drive or a heating of a washing machine come into question. Also, a plurality of electrical loads 40 may be connected in parallel or at different locations of the electrical power supply 20 to the electrical power supply 20.

To protect the electrical energy supply 20, in particular for the detection of an arc fault 24, a device 10 for detecting an arc fault 24 may be provided in the electrical power supply 20. For this purpose, for example, a first voltage detector 11 may be provided at a first position of the electrical power supply 20. This first position in the electrical power supply 20 may, for example, be at a terminal of the electrical power supply 20 at which the electrical energy source 30 feeds electrical energy into the electrical power supply 20. In this case, the first voltage detector 11 may, for example, be provided directly at the point at which the electrical energy source 30 is coupled to the electrical energy supply 20. Furthermore, the first voltage detector 11 may also be provided at a different location of the electrical energy supply 20, in particular at a location in the vicinity of the connection of the electrical energy source 30.

Furthermore, a second voltage detector 12 is provided. This second voltage detector 12 is provided at a second position, which is preferably located at a location of the electrical power supply 20 to which the electrical load 40 is connected. However, it is also possible, the second voltage detector 12 at a different location, in particular a location in the vicinity of the terminal of the electrical

Consumers 40 provide. The first voltage detector 11 and the second voltage detector 12 each detect an electric voltage at the corresponding location of the electric power supply 20. For example, the first voltage detector 11 can detect a voltage difference between the first position in the electric power supply 20 and a reference potential. Similarly, the second voltage detector 12 may detect a voltage difference between the second position in the electrical power supply 20 and the reference potential. In this case, the reference potential may be any potential, in particular the potential formed by a supply line 21 or 22. In this case, the first voltage detector 11 detects a voltage difference between the first supply line 21 and the second supply line 22 at the first position. Similarly, the second voltage detector 12 detects a voltage difference between the first

Supply line 21 and the second supply line 22 at the second position. Thus, by the first voltage detector 11, for example, the input-side voltage is detected, which is fed by the electric power source 30 in the electric power supply 20. For example, the output voltage that is provided at the electrical load 40 can be detected by the second voltage detector 12.

In the case of a faultless electrical power supply 20, during operation a relatively small voltage drop will be established between the voltage provided on the input side and the electrical voltage applied to the output side of the load 40. This low voltage drop is among other things due to the electrical losses in the supply lines

21, 22 reasons.

In the event of a fault in the electrical energy supply 20, for example an interruption in the first or second supply line 21, 22, a sufficiently high electrical voltage can occur at this fault location

Set fault arc 24. In this case, such a fault arc 24 is set in particular when at the fault point between two points an electrical voltage is applied, which is sufficient to ignite a fault arc 24. For example, between two points of a copper line, a voltage of at least 12 volts is required to a Initiate arc fault. Thereupon must at the error place with the

Arc fault also for the continued maintenance of the arc fault a sufficiently high electrical voltage, which is usually several tens of volts. Thus, a correspondingly high voltage drop will set at the fault with the arc fault 24.

Due to the voltage drop across the arc fault 24, the electrical voltage at the second position, which by the second

Voltage sensor 12 is detected to be smaller than the voltage at the first position, which is detected by the first voltage detector 11. For a detection of a fault arc 24 in the electrical

Power supply 20 can therefore be provided by the first voltage detector 11 and the second voltage detector 12 each have an output signal to an arc detector 13. The output signals from the first voltage detector 11 and the second voltage detector 12 correspond to the detected electric voltages. Of the

Arc detector 13 may then determine a voltage difference between the first position and the second position based on the output signals provided by the first voltage detector 11 and the second voltage detector 12. If this voltage difference lies above a predetermined threshold value, this is an indication that an arc fault 24 has occurred between the first voltage detector 11 and the second voltage detector 12, which causes a voltage difference. As a result, the arc detector 13, a signaling for a

Output arc fault when a sufficiently large voltage difference has been detected.

This signaling for an arc fault 24 can be used, for example, to separate the electrical power supply 20 from the electrical energy source 30. In this way, no further electrical energy is fed into the fault arc 24 and the arc fault 24 will go out. For example, by the output of the

Arc detector 13 of the circuit breaker 23 are triggered to separate the electrical energy source 30 from the electrical power supply 20. Optionally, the arc detector 13 may also sense and evaluate an electrical current in the electrical energy supply 20. For example, for this purpose, a current sensor (not shown) may be provided in the electrical energy supply 20, in particular between the first position and the second position. Based on this detected electrical current, the arc detector 13 may consider possible voltage drops due to the electrical losses in the electrical power supply 20 when evaluating the voltage drop between the first voltage detector 11 and the second voltage detector 12. As with an increasing electric current in the electric power supply 20 between the input and the output of the electric

Power supply 20 will set an increasing voltage drop even if there is no fault arc 24, the predetermined threshold for the voltage difference between the first voltage detector 11 and the second voltage detector 12 in response to an electric current through the electrical power supply 20 can be adjusted.

In addition, it is also possible that the arc detector 13 at a known power consumption of the connected load 40 estimates a possible voltage drop within the electrical power supply 20 and depending on the known power, in particular a known maximum power consumption of the connected load 40, an estimate for a threshold for the voltage drop to detect the fault arc 24 makes. For example, this can be a

corresponding signaling about the current power of the electric

Consumer 40 are provided to the arc detector 13.

In addition, of course, any other possibilities for adjusting the threshold value for the voltage drop between the first voltage detector 11 and the second voltage detector 12 for detecting an arc fault 24 in the electrical energy supply 20 are possible.

FIG. 2 shows a schematic representation of a flowchart, such as a method for detecting an arc fault in an electric arc Power supply 20 according to one embodiment is based. In step S1, a first electrical voltage is detected at a first position of the electrical energy supply 20. In step S2, a second electric

Voltage detected at a second position of the electrical power supply 20. Then, in step S3, an arc fault 24 in the

Direct voltage network 20 detects when a difference between the first electrical voltage and the second electrical voltage a

exceeds the predetermined threshold.

In summary, the present invention relates to the detection of a

Arc fault in an electrical power supply. For this purpose, a voltage supplied on the input side is compared with a voltage provided in the electrical energy supply on the output side. If this voltage difference between the input and the output of the electrical energy supply exceeds a predetermined threshold value, then this is an indication of a possible arc fault.

Claims

claims

A device (10) for detecting an arc fault (24) between a first position and a second position in an electrical

A power supply (20) comprising: a first voltage detector (11) configured to detect a first voltage at the first position of the power supply (20); a second voltage detector (12) adapted to apply a second voltage at the second position of the second voltage detector

To capture energy supply (20); and an arc detector (13) configured to compare the detected first electrical voltage with the detected second electrical voltage and signaling for a detected one

To output arc fault (24) if a difference between the first electrical voltage and the second electrical voltage is greater than a predetermined threshold.

2. Device (10) according to claim 1, wherein the electrical

Power supply (20) at the first position with an electrical energy source (30) can be coupled.

3. Device (10) according to claim 1 or 2, wherein the electrical

Power supply (20) at the second position with an electrical load (40) can be coupled.

4. Device (10) according to one of claims 1 to 3, wherein the

Arc detector (13) is adapted to the given

Adjust threshold value in response to an electric current through the electrical power supply (20) or electrical power of a connected load (40).

5. Device (10) according to one of claims 1 to 4, wherein the

predetermined threshold is at least 15V.

An electrical power supply (20), comprising: an electrical lead (21, 22) connectable at a first position to an electrical energy source (30) and connectable at a second position to an electrical load (40); and a device (10) for detecting an arc fault (24) according to one of claims 1 to 5.

7. A method for detecting an arc fault (54) in an electrical power supply (20), comprising the steps of:

Detecting (S1) a first electrical voltage at a first position of the electrical power supply (20);

Detecting (S2) a second voltage at a second position of the electrical power supply (20); and

Detecting (S3) an arc fault (24) in the electrical

Power supply (20) if a difference between the detected first electrical voltage and the detected second electrical voltage exceeds a predetermined threshold.