阅读说明：本技术 接地导线监控 (Ground lead monitoring ) 是由 弗兰克·塞尔克 扬·里瓦尔德 于 2019-07-11 设计创作，主要内容包括：一种接地导线监控装置,具有：a)至少一个接地导线接头,其设置用于连接接地导线电位,b)至少一个第一电位接头,其设置用于连接第一电位,所述第一电位与接地导线电位不同,c)至少一个第二电位接头,其设置用于连接第二电位,所述第二电位与第一电位不同并且与接地电位不同,d)至少一个电开关装置,其设置用于,可选地根据电控制信号,在第一电位接头和接地导线接头之间建立电连接(连接状态)或中断电连接(中断状态),e)至少一个控制单元,其设置用于,将控制信号自动地发送至电开关装置。(An earth conductor monitoring device having: a) at least one earth conductor connection provided for connecting an earth conductor potential, b) at least one first potential connection provided for connecting a first potential, which is different from the earth conductor potential, c) at least one second potential connection provided for connecting a second potential, which is different from the first potential and different from the earth potential, d) at least one electrical switching device provided for establishing an electrical connection (connected state) or an interrupted electrical connection (interrupted state) between the first potential connection and the earth conductor connection, optionally in dependence on an electrical control signal, e) at least one control unit provided for automatically sending the control signal to the electrical switching device.)

1. An earth conductor monitoring device (7) having:

a) at least one earth conductor connection (13) which is provided for connecting an earth conductor Potential (PE),

b) at least one first potential connection (12) which is provided for connecting a first potential (0V) which is different from the ground conductor Potential (PE),

c) at least one second potential connection (11) which is provided for connecting a second potential (U)_b) The second potential being different from the first potential (0V) and different from the ground Potential (PE),

d) at least one electrical switching device (14) which is provided for selectively establishing an electrical connection (connected state) or interrupting an electrical connection (interrupted state) between the first potential connection (12) and the earth conductor connection (13) as a function of an electrical control signal,

e) at least one control unit (8) which is provided to automatically send a control signal to the electrical switching device (14).

2. The earth conductor monitoring device according to claim 1,

it is characterized in that the preparation method is characterized in that,

the control device (8) is provided for evaluating an electrical signal at the earth conductor terminal (13) at least in the interruption state.

3. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the control device (8) is provided for automatically switching the electrical switching device (14) between a switching state, i.e. a connected state and an interrupted state, at predetermined regular and/or irregular time intervals by means of a control signal generated by the control unit (8).

4. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the connected state is triggered more frequently on a time average than the interrupted state.

5. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the evaluation of the electrical signal at the earth conductor connection (13) is carried out without measuring the current in the earth conductor.

6. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the earth conductor monitoring device (7) is provided to identify, on the basis of the evaluated electrical signal at the earth conductor connection (13): whether the ground conductor is connected to the first potential (0V) and/or whether the ground conductor is connected to the second potential (U)_b) And (4) connecting.

7. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the electrical switching device (14) is designed as a semiconductor switch.

8. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the ground conductor monitoring device (7) has an optical signal device (6), and when the ground conductor monitoring device (7) recognizes that the ground conductor is connected to the first potential (0V) and/or the ground conductor is connected to the second potential (U)_b) When connected, an optical signal can be automatically emitted through the optical signal device.

9. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the ground conductor monitoring device (7) has an output interface (20) which, when the ground conductor monitoring device (7) detects that the ground conductor is connected to the first potential (0V) and/or the ground conductor is connected to the second potential (U)_b) Upon connection, a warning signal can be automatically issued via the output interface.

10. The earth conductor monitoring device according to claim 9,

it is characterized in that the preparation method is characterized in that,

the output interface (20) has a potential-free output connection.

11. The earth conductor monitoring device according to claim 2,

it is characterized in that the preparation method is characterized in that,

the earth conductor monitoring device (7) has an evaluation circuit via which an electrical signal at the earth conductor connection (13) can be evaluated by means of the control device (8) at least in the interruption state.

12. The earth conductor monitoring device of claim 11,

it is characterized in that the preparation method is characterized in that,

the evaluation circuit has at least one first voltage detection device (17) connected between the ground line connection (13) and the first potential connection (12) and/or at least one second voltage detection device (16) connected between the ground line connection (13) and the second potential connection (11).

13. The earth conductor monitoring device of claim 12,

it is characterized in that the preparation method is characterized in that,

the first and/or second voltage detection device (16, 17) is designed as a photo coupler (32, 35) or as a photo coupler (32, 35).

14. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the earth conductor monitoring device (7) has a power supply device (10) which is provided to supply at least the control unit (8) and the electrical switching device (14) with electrical energy required for operation, wherein the power supply device (10) draws electrical energy from the first and second potential connections (11, 12) and outputs it in a buffered manner by means of a buffer circuit.

15. An earth conductor monitoring device according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the earth conductor monitoring device (7) is designed as a rail-mounted terminal (1) or is arranged in or on the rail-mounted terminal (1).

16. Computer program with program code means, which is provided for executing, when the computer program is executed on a computer, a method for monitoring a ground conductor of an electrical device that is grounded by means of the ground conductor, the electrical device being grounded by means of a first potential (0V) and a second potential (U |)_b) Providing and/or being supplied with electrical energy, the first potential being different from a ground conductor Potential (PE), the second potential being different from the first potential (0V) and from the ground conductor Potential (PE):

a) automatically switching, by means of at least one electrical switching device (14), at predetermined regular and/or irregular time intervals, between a switching state, i.e. a connection state in which an electrical connection between the first potential (0V) and the ground conductor is established by means of the electrical switching device (14), and an interruption state in which the electrical connection between the first potential (0V) and the ground conductor is interrupted by means of the electrical switching device (14);

b) detecting and evaluating an electrical signal at the ground conductor at least in the interruption state;

c) identifying, from the evaluated electrical signal at the ground conductor: whether the ground conductor is connected to the first potential (0V) and/or whether the ground conductor is connected to the second potential (U)_b) And (4) connecting.

Technical Field

The invention relates to an earth conductor monitoring device having the features of claim 1. The invention also relates to a computer program for executing a method for monitoring a ground conductor of an electrical device that is grounded by means of the ground conductor, the electrical device supplying electrical energy and/or being supplied with electrical energy by means of a first potential that is different from the ground conductor potential and a second potential that is different from the first potential and different from the ground conductor potential.

Background

In the operation of electrical machines and installations, the safety of personnel and the safe operation of electrical devices is of the utmost importance. For this purpose, in particular fault and overcurrent protection elements are used. A prerequisite for this is that such machines and installations are connected to a ground conductor, which is also referred to as a protective conductor, in order to achieve a low-ohmic grounding. The invention thus relates to the field of connection technology for electrical devices with earth conductor connections (or protective conductor connections).

In automation technology, for example, the electrical network part in a switchgear cabinet is used to generate a supply voltage for electrical devices installed in the switchgear cabinet. Such a grid part is usually connected to the earth conductor via an earth conductor connection. In these applications, the equipment in the switchgear cabinet is usually fixed on a carrier rail. The carrier track is usually used here as a ground conductor.

In order to ensure continued safety during operation of such installations, periodic ground checks are required. In this case, it must be checked whether there is a so-called ground connection, i.e. a short circuit between one of the two supply potentials of the network part and the ground line. The supply potential of the grid part may be, for example, 0 volts and an operating voltage, for example, 24 volts dc. The ground wire disconnection terminal described so far, which has a manually actuable disconnection knife, has been used for the ground test. The normally existing connection of the 0 volt line to the ground conductor can be separated by means of a separation blade. In the disconnected state, a measurement can then be carried out, from which it can be recognized whether a ground connection is present.

Disclosure of Invention

The invention is based on the object of reducing the complexity for such a grounding test.

This object is achieved by means of a ground conductor monitoring device having:

a) at least one earth conductor connection arranged for connection to an earth conductor potential,

b) at least one first potential connection arranged for connection to a first potential, the first potential being different from the ground conductor potential,

c) at least one second potential connection, which is provided for connecting a second potential, which is different from the first potential and from the ground potential,

d) at least one electrical switching device, which is provided to establish an electrical connection (connected state) or to break an electrical connection (interrupted state) between the first potential connection and the earth conductor connection, selectively as a function of an electrical control signal,

e) at least one control unit, which is provided to automatically send a control signal to the electrical switching device.

The invention has the advantage that it is no longer necessary to carry out the earth check manually, but rather at least partially automatically by means of the earth conductor monitoring device according to the invention. This significantly reduces the personnel expenditure. Furthermore, the safety is increased, since the automatic ground fault check can be carried out significantly more frequently than was hitherto possible in manual processes. In manual inspection, ground access inspection is typically performed at three month intervals. An almost continuous ground test can be achieved by means of the ground conductor monitoring device according to the invention.

A further advantage of the invention is that even slowly occurring earthings can be detected by means of the invention. Thus, a prospective maintenance of the electrical installation can be achieved by means of the invention. In this way problematic downtime of such a facility can be avoided or at least reduced, since prospective maintenance can be performed.

In an advantageous embodiment of the invention, this can be facilitated by not only identifying a low-ohmic short of the ground line to the first or second potential, but also already identifying high-ohmic connections, for example in the range of several kilohms. Furthermore, due to the almost constant monitoring, it is possible with the aid of the invention to: intermittent grounding is identified.

The first potential can be, for example, a 0 volt potential in an automation technology in the case of an application. The second potential can be an operating voltage of a power grid part of the automation installation, for example a low voltage, in particular a direct voltage. The second potential may be, for example, a 12 volt potential, a 24 volt potential, or a 48 volt potential.

The electrical switching device can be realized in different ways. In a first variant, it is possible to realize: the use of the previous manually actuable separating blade of the grounding conductor for separating the terminals is continued and the separating blade is automatically driven by an electric drive, for example by means of an electric motor or an electromagnet. In a second variant, it is possible to: the electrical switching device is realized by an electromechanical switch, for example by a relay or a contactor. In a third variant, the electrical switching device can be embodied as a semiconductor switch, for example as a transistor, a thyristor or a switching system of transistors and/or thyristors. This has the advantage that the switching between the connected state and the disconnected state can be effected virtually without wear and without noise. Furthermore, the electrical switching system can be realized at low cost and with a very low amount of space requirement.

The electrical switching device has at least two switching states, namely a connection state and an interruption state. In the connected state, the first potential connection is connected to the earth conductor connection via an electrical switching device, and in the interrupted state the electrical connection between the first potential connection and the earth conductor connection is interrupted by means of the electrical switching device. Advantageously, the electrical switching device connects the first potential connection to the ground line connection in the connected state at a relatively low impedance. The electrical switching device can have other switching states, for example an intermediate state in which the electrical connection between the first potential connection and the ground line connection is established at a higher impedance than in the connected state.

According to an advantageous embodiment of the invention, the control device is provided for evaluating the electrical signal at the ground line connection at least in the interruption state. In this way, it is possible to perform a grounding check by means of the grounding conductor monitoring device according to the invention in a manner similar to the manual handling hitherto. The control device may additionally be provided for evaluating the electrical signal at the ground line connection in the connected state as well.

According to an advantageous embodiment of the invention, the control device is provided for automatically switching the electrical switching device between the switching state, i.e. the connected state and the disconnected state, at predetermined regular and/or irregular time intervals by means of a control signal generated by the control device. In this way, the manual ground check up to now can be performed completely automatically. The inspection frequency can be increased particularly significantly as a result of the automatic execution, for example to a number of ground inspections per minute. The control device can in particular generate an on signal and an off signal as control signals and send them to the electrical switching device. The on-signal and off-signal thus subsequently result in a pulse width modulated signal (PWM signal), by means of which the electrical switching device is actuated.

According to an advantageous embodiment of the invention, the connection state is triggered more frequently than the interruption state on time average. This has the advantage that only short test pulses, in which an interruption state exists, are required for the evaluation of the electrical signal at the earth conductor connection. Otherwise there is always a connection state that is desired by itself. Since the connection state is present on average more frequently than the disconnection state, it is also possible to ensure that the safety device is triggered as intended in the event of a fault, i.e. when grounding occurs. In this way, the relevant regulations can be met.

This makes it possible, for example, to switch the pulse width modulated signal with a duty cycle of 95% on-duration and 5% off-duration. Accordingly, the connection state is present for 95% of the time. Generally, the duty cycle may be in the range of 90% to 99%, for example. The switch-off duration, i.e. the duration of the interrupt state, may be less than 500ms, or less than 100ms or less than 10 ms. The period duration of the pulse width modulated signal may be, for example, 10 seconds. It is generally also possible to achieve significantly shorter cycle times. In order to satisfy the relevant specification, it is advantageous if the on-time of the pulse-width-modulated signal is at least five seconds.

According to an advantageous embodiment of the invention, the evaluation of the electrical signal at the earth conductor connection is carried out without measuring the current in the earth conductor. This has the advantage that no costly components, such as shunts, are required for the ground check. Furthermore, the risk that may arise from a break in the earth conductor can be minimized.

According to an advantageous embodiment of the invention, the ground conductor monitoring device is provided for detecting, on the basis of the evaluated electrical signal at the ground conductor connection: whether the ground conductor is connected to a first potential and/or whether the ground conductor is connected to a second potential. In this way, at least the same fault situation at the earth conductor as in the previous manual test can be detected by means of the earth conductor monitoring device according to the invention.

According to an advantageous embodiment of the invention, the ground conductor monitoring device has an optical signaling device via which an optical signal can be emitted automatically when the ground conductor is connected to the first potential and/or the ground conductor is connected to the second potential, as detected by the ground conductor monitoring device. The optical signaling device may have one or more light sources. In this way the presence of a ground can be communicated for the user with an optical signal. For example, the warning signal may be issued via one or more light sources, such as via a Light Emitting Diode (LED) or a glow lamp.

According to an advantageous embodiment of the invention, the ground conductor monitoring device has an output interface via which a warning signal can be emitted when the ground conductor is connected to the first potential and/or the ground conductor is connected to the second potential, as detected by the ground conductor monitoring device. In this way, devices connected to the ground lead monitoring device, for example a system master (SPS), can be controlled by means of the ground lead monitoring device.

According to an advantageous embodiment of the invention, the output interface has a potential-free output connection. This has the advantage that further components can be connected to the output connection in a simple manner. The output terminals can be designed, for example, as ISO-OK contacts. Alternatively or additionally, the output connector can also be a data bus connector, so that a warning signal can be transmitted via the data bus.

According to an advantageous embodiment of the invention, it is provided that the ground conductor monitoring device has an evaluation circuit, via which the electrical signal at the ground conductor connection can be evaluated by means of the control device at least in the interruption state. This has the advantage that the monitoring is carried out by circuitry, so that rapid monitoring can be carried out with little effort and no software-dependent delays or other disadvantages occur.

The remaining components of the earth conductor monitoring device, in particular the control unit, can in this case form a unit for running a computer program, for example in the form of a logic circuit, completely without the aid of a computer or other means. For generating the control signal, the control device may have, for example, a hardware timer.

According to an advantageous embodiment of the invention, it is provided that the evaluation circuit has at least one first voltage detection device connected between the ground line connection and the first potential connection and/or at least one second voltage detection device connected between the ground line connection and the second potential connection. This allows a simple detection and evaluation of the electrical signal at the earth conductor connection. The first voltage detection device and/or the second voltage detection device may have a trigger threshold value, for example, such that the voltage detection device emits a trigger signal as an output signal when the voltage monitored by the voltage detection device reaches, exceeds or falls below the trigger threshold value. This enables a simple subsequent signal processing of the trigger signal, which can be designed as a binary signal. Further evaluation of the trigger signal can then take place, for example, by evaluation logic, for example, by means of a trigger memory.

The first voltage detection means may be arranged to detect an insulation resistance between the earth conductor connection and the first potential connection. The second voltage detection means may be arranged to detect an insulation resistance between the earth conductor connection and the second potential connection. The mentioned trigger signal may be generated, for example, when the insulation resistance is below a predetermined resistance value, for example a value of 1k omega.

According to an advantageous embodiment of the invention, it is provided that the first and/or the second voltage detection device is/are designed as an optocoupler or as an optocoupler. This allows a simple and low-cost and long-life implementation of the first and/or second voltage detection means. The optocoupler can be switched in particular such that, when no ground connection is present, the respective light-emitting diode of the optocoupler is switched off. Only in the case of a fault, when there is a ground connection, the light emitting diode is switched on. In this way, the light-emitting diodes of the optocoupler can be protected.

According to an advantageous embodiment of the invention, it is provided that the earth conductor monitoring device has a power supply device, which is provided to supply at least the control unit and the electrical switching device with electrical energy required for operation, wherein the power supply device draws electrical energy from the first and second potential connections and outputs the electrical energy in a buffered manner by means of a buffer circuit. The buffer circuit can be designed in particular such that the electrical switching device and the control unit can thus be continuously supplied with electrical energy via the power supply device over a period of time during which a connection state exists, i.e. also in the connection state. The buffer circuit may in particular have a buffer capacitor. In this way it is possible to avoid: the function of the earth conductor monitoring device fails when the earth conductor has a relatively low-ohmic short to the second potential connection.

According to an advantageous embodiment of the invention, the ground conductor monitoring device is designed as a track-mounted terminal or is arranged in or on a track-mounted terminal. The earth conductor monitoring device can be structurally integrated into the housing of the rail-mounted terminal, for example. The rail-mounted terminal is an object used in electrical installation technology, which is provided for fastening to a support rail and can be arranged alongside one another on the support rail with the other rail-mounted terminals. The rail-mounted terminal has a plurality of conductor connections, for example in the form of spring-loaded clamping connections, so that a plurality of electrical conductors can be connected to the rail-mounted terminal.

The object mentioned at the outset is also achieved by a method for monitoring a ground line of an electrical device which is grounded by means of the ground line, the electrical device being supplied with electrical energy and/or being supplied with electrical energy by means of a first potential which is different from the potential of the ground line and a second potential which is different from the first potential and the potential of the ground line, the method having the following features:

a) automatically switching, by means of at least one electrical switching device, at predetermined regular and/or irregular time intervals between a switching state, i.e. a connection state in which an electrical connection between the first potential and the ground conductor is established by means of the electrical switching device, and an interruption state in which the electrical connection between the first potential and the ground conductor is interrupted by means of the electrical switching device;

b) detecting and evaluating an electrical signal at the earth conductor at least in the interruption state;

c) identifying from the evaluated electrical signal at the earth conductor: whether the ground conductor is connected to a first potential and/or whether the ground conductor is connected to a second potential.

Thereby, the advantages set forth above are also achieved.

According to one advantageous embodiment of the method, a warning signal is emitted when it is detected that the ground line is connected to the first potential and/or when the ground line is connected to the second potential. In this way the presence of ground can be signaled for the user. For example, the warning signal may be emitted via one or more light sources, for example via a Light Emitting Diode (LED) or a glow lamp, or via an output interface.

According to one advantageous embodiment, it is provided that the method is carried out with the aid of a ground conductor monitoring device of the type described above.

The object mentioned at the outset is also achieved by a computer program with program code means which are provided for carrying out a method of the type set forth above when said computer program is executed on a computer. The advantages set forth above are also achieved thereby.

The indefinite article "a" or "an" is not to be understood as a quantity word in the sense of the present invention. That is, when for example a component is referred to, this is interpreted as "at least one component". As long as the angular specification is given in degrees, the angular specification relates to a circle size of 360 degrees (360 °). Whenever reference is made to a computer, the computer may be arranged to execute a computer program, e.g. software. The computer can be designed as a commercially available standard computer, for example as a PC, laptop, notebook, tablet PC or smartphone, or as a microprocessor, microcontroller or FPGA, or as a combination of these components.

Drawings

The present invention will be explained in detail below by using the drawings according to embodiments. The figures show:

FIG. 1 shows a rail-mounted terminal with earth conductor monitoring, and

FIG. 2 shows a schematic diagram of a ground lead monitoring device, an

Fig. 3 shows an evaluation circuit of the earth conductor monitoring device.

Detailed Description

Fig. 1 shows a rail-mounted terminal 1, which is provided for fastening to a support rail 5. The rail-mounted terminal 1 has a support rail fastening element 4 on the housing side oriented toward the support rail 5. The rail-mounted terminal 1 can be locked on the carrier rail 5, for example, by means of the carrier rail fastening element 4. The carrier rail 5 may have a ground conductor potential PE.

The rail-mounted terminal 1 has a plurality of conductor insertion openings 2 which lead to corresponding conductor connections 3. The line connection 3 can advantageously be designed as a spring-loaded clamping connection. The electrical line inserted into the line insertion opening 2 can be electrically connected to the rail-mounted terminal 1 via the line connection 3.

The rail-mounted terminal 1 also has a ground conductor monitoring device 7. On the side of the housing facing away from the carrier rail fastening element 4, there is an optical signal unit 6, which is part of the earth conductor monitoring device 7. The optical signal unit 6 can be used, for example, to transmit an optical signal to a ground fault detected by the ground conductor monitoring device 7.

Fig. 2 shows the configuration of the earth conductor monitoring device 7. The earth conductor monitoring device 7 has an earth conductor connection 13 to which an earth conductor potential PE can be connected. The ground line monitoring device 7 has a first potential connection 12, at which a first potential 0V can be connected. The earth conductor monitoring device 7 has a second potential connection 11 to which a second potential U can be connected_b。

The earth conductor monitoring device 7 also has an electrical switching device 14, an evaluation circuit with a first voltage detection device 17 and a second voltage detection device 16, a control unit 8 with a timer 9, an optical signal unit 6, an output interface 20 and a power supply device 10. The power supply device 10 is used to supply the components of the earth conductor monitoring device 7 to be powered with electrical energy. The electrical energy required for the supply is obtained from the voltage difference between the first potential connection 12 and the second potential connection 11.

The control unit 8, in this case via its timer 9, is connected via a signal line 15 to a control input of an electrical switching device 14. Via the signal line 15, the timer 9 can send an electrical control signal to the electrical switching device 14 in order to actuate it, so that an electrical connection between the first potential connection 12 and the earth conductor connection 13 is established or interrupted.

The first voltage detection device 17 is connected to the first potential connection 12 and the ground line connection 13. The first voltage detection means 17 can thus evaluate the voltage between these two connections. When a specific voltage is recognized between these connections, which indicates a lower than specific insulation resistance, the first voltage detection device 17 sends a signal to the control unit 8 via the signal line 19. Said signal then indicates the grounding of the second potential connection 11.

The second voltage detection device 16 is connected to the second potential connection 11 and the ground line connection 13. The second voltage detection means 16 can thus evaluate the voltage between these two connections. When a specific voltage is recognized between these connections, which indicates a lower than specific insulation resistance, the second voltage detection device 16 sends a signal to the control unit 8 via the signal line 18. The signal then indicates the grounding of the first potential connection 12.

The signals received via the signal lines 18, 19 are evaluated in the control unit 8 and the optical signaling device 6 is actuated with ground. Alternatively or additionally, the warning signal can be sent to the output connector 21 via the output interface 20. Thus, for example, SPS can be controlled.

Fig. 3 shows an advantageous embodiment of the first voltage detection device 17 and the second voltage detection device 16. The first voltage detection device 17 has a series circuit composed of a zener diode 33, a resistor 34, and a light emitting diode of a photocoupler 35. The optocoupler 35 has an output connection which is connected to the signal line 19, so that when the light-emitting diode of the optocoupler 35 is switched on, a corresponding signal can be sent to the control unit 8.

The second voltage detection device 16 has a series circuit composed of a zener diode 30, a resistor 31, and a light emitting diode of a photocoupler 32. The optocoupler 32 has an output connection which is connected to the signal line 18, so that when the light-emitting diode of the optocoupler 32 is switched on, a corresponding signal can be sent to the control unit 8.