DE202012001729U1 - Arrangement for plant and personnel protection in the low voltage area - Google Patents

Abstract

Arrangement for system and personal protection in the low-voltage range by generating a short circuit by means of a short-circuiting device with a switching element, which is triggered by an arc fault detection, the short-circuiting device comprises two relatively movable contacts or electrodes, which are held by a sacrificial element at a distance, wherein further with Help the switching element, the sacrificial element is influenced such that the mutually movable contacts or electrodes in a short circuit state, characterized in that the electrical energy for triggering the switching element exclusively results from the energy of the arc occurring.

Description

The invention relates to an arrangement for system and personal protection in the low voltage range by generating a short circuit by means of a short-circuiting device with a switching element, which is triggered by an arc fault detection, wherein the short-circuiting device comprises two relatively movable contacts, which are held by a sacrificial element at a distance, wherein Furthermore, with the aid of the switching element, the sacrificial element can be influenced in such a way that the mutually movable contacts transition into a short-circuit state, according to claim 1.

Systems for short-circuiting low-voltage systems to reduce the damage due to arcing faults are state-of-the-art. In systems of this kind, system protection, system availability and short periods for recommissioning are superficial. Previously known systems are usually permanently installed in the system.

In addition to system protection, known systems also assume functions relating to personal protection during normal operation. The function of the systems is usually coupled directly or indirectly to the mains voltage of the systems. The time to operational readiness of the systems is sometimes quite high.

Also, mobile systems are known, which are geared in particular to the interests of personal protection when working under tension. Such systems usually operate independently. In this regard, the shows DE 10 2008 038 248 A1 an arc fault protection device for electrical power distribution systems, comprising at least one short-circuiter, a control and a sensor for arc fault detection. Short circuiters, control and arc fault detection sensor are not stationary, but portable. The aforementioned means are connected on site to the live equipment and removed after completion of the work. Preferably, the previously known arc fault protection device has a separate power supply, so that an independence from the respective power grid or the respective energy supply system is given.

Known short-circuiting devices are controlled in many cases by arc detection systems, which control mostly parallel devices connected to the plant separation. The short-circuiting device is used to quickly extinguish the arc, since conventional switches have delay times of several 10 to 100 ms. An effective system protection is usually not possible only at high short-circuit currents with an arc fault protection system consisting only of detection system with control of the circuit breaker without additional short-circuiting device.

In addition, arc fault detection systems for controlling circuit breakers are known. By adding a short circuiter, many such systems can effectively protect equipment with high short circuit currents.

The addition of a detection device within existing low-voltage systems is essential if the short-circuit power of the system, z. B. increased by interconnection in ring operation or the system is extended or an improved system availability is necessary.

The commissioning of systems with permanently installed systems and also during maintenance may result in inadequate protection of the system or of persons.

When a system is first or restarted, a short circuit can occur, for example as a result of forgotten tools, damaged or bridged insulators, directly at the time of connection, without a mains voltage being built up. The voltage at the phases in this case corresponds only to the voltage drop in the case of a short-circuit current or the arc fault voltage after overloading of the short-circuiting bridge. Especially in these situations, people are directly endangered by the arc fault.

In some known detection systems, moreover, without passivation of the triggering function, the systems can not be maintained or even opened for the purpose of optical sighting, as this may lead to misdetection.

The installation of an additional mobile protection device and in particular a short-circuiting device to protect the working people accordingly DE 10 2008 038 248 A1 is therefore often not made or considered unjustified.

The prior art further includes short-circuiting devices for use in low and medium voltage systems for property and personal protection, comprising a switching element which can be actuated by the trigger signal of an error detection device.

Such a short-circuiting device according to DE 10 2005 048 003 B4 has two opposing contact electrodes with means for supplying power, these electrodes being connected to one Circuit can be contacted with terminals of different potential. Furthermore, the contact electrodes are under mechanical prestressing and, in the event of a short circuit, can perform a relative movement with respect to one another in a spring-assisted manner.

The solution after DE 10 2005 048 003 B4 Also includes a sacrificial element as a spacer between the contact electrodes and an electrical connection between the sacrificial element and the switching element on the one hand and one of the contact electrodes on the other hand to bring about a flow-induced thermal destruction of the sacrificial element targeted. According to one embodiment, the sacrificial element may be a thin-walled hollow cylinder with a ratio between diameter and wall thickness of the hollow cylinder greater than 10: 1, consisting of a refractory metallic material.

For the passive or active short-circuiting device for use in low and medium voltage systems for property and personal protection DE 20 2006 020 737 U1 are also two opposing contact electrodes with means for supplying power, which are contactable to a circuit with terminals of different potential. Furthermore, the contact electrodes are under mechanical prestressing and, in the event of a short circuit, can perform a relative movement with respect to one another in a spring-assisted manner.

In one embodiment for the operation with auxiliary energy, a double-sided executed sacrificial element is present, which by auxiliary power, for. B. from an emergency supply, regardless of the conditions on the main contacts can be placed in the short circuit.

In summary, the realization of an electrical short circuit in low-voltage systems for reducing the effects of an arc fault for system and personal protection state of the art. Both permanently installed and mobile short-circuiting devices are known. These short-circuiting devices generally consist of an arc detection unit and the actual short circuiter. Usually, the aforementioned units need a common or a separate power supply. In the case of an internal arc in the system, the mains voltage breaks down to the generally low value of the arc voltage. Therefore, the supply voltage for the above-mentioned units by uninterruptible power supplies, separate auxiliary voltages, buffer memory, batteries or a mains voltage tap, which takes place before the upstream operating switch of the system, guaranteed. In addition to this increased effort to realize a power supply, there are also restrictions on the reliability.

The storage and buffering operation inevitably leads to delay times with regard to operational readiness. The detection devices also often have a routine for self-examination, which can take several seconds to minutes, especially in complex systems.

The operation of known detection devices is based exclusively on the evaluation of the light emission, which additional safety measures or even a decommissioning of the protective device is required when opening the equipment or during maintenance.

From the foregoing, it is therefore an object of the invention to provide a further developed arrangement for plant and personal protection in the low voltage range by generating a short circuit by means of a short-circuiting, which ensures the necessary safety already at the first start-up and maintenance activities, especially when working under tension, namely without having to use batteries, buffers or uninterruptible external power supplies.

It is therefore an object of the invention to provide an arrangement with short-circuiting device, which is functional without additional auxiliary power and capable of, in the formation of an arc fault z. B. from the overload of a voltage applied during working jumper to respond in a timely manner.

Furthermore, the short-circuiting device should also be subsequently adaptable to any known detection systems and allow parallel operation of various detection devices. Furthermore, the short-circuiting device should be alternatively or only temporarily controllable, especially for work under tension with an additional mobile and self-sufficient detection unit, wherein the protective function of the short-circuiting device is always maintained by and during attachment.

The object of the invention is achieved by the feature combination according to claim 1, wherein the dependent claims include at least expedient refinements and developments.

The short-circuiting device according to the invention requires no additional power supply. The energy required to trip the short-circuiter is obtained from a power source which is supplied from the voltage of the fault arc itself.

In this case, this electronic current source is preferably regulated via an insulated gate bipolar transistor (IGBT).

The short-circuiting device including the electronic power source meets the requirements for use in low-voltage power supply systems.

The function of the short-circuiting device is ensured at arc voltages from 30 V with a delay time of a few microseconds after signal output by the detection device. The short-circuiting device has a control which can be actuated independently of the type of arc detection unit present in each case.

During commissioning or maintenance work on systems, the short-circuiting device can be connected in parallel or exclusively by an additional, z. B. mobile detection system, which can detect, for example, strong external illumination or independent of the short-circuit current arcs, are activated.

The short-circuiting device can also be permanently installed in the system or additionally introduced.

The short circuiters can according to the solutions according to DE 103 13 045 B3 . DE 10 2005 048 003 B4 . DE 10 2008 038 248 A1 or DE 20 2006 020 737 U1 be built or realized.

The short-circuiting device according to the invention has one or more optical inputs for driving by one or more detection systems.

To use different detection systems, which, for example, have no optical signal output, an adapter can be provided which converts conventional signal outputs of the detection devices into an optical signal.

Such outputs are, for example, potential-free normally open or z. B. capacities that can be discharged using the energy.

The connection of another, z. B. mobile detection device can also be done to the adapter or optical signal output directly to the short-circuiting device. The attachment can be realized without interrupting the reliability.

For a remote triggering of the adapter or the electronic power source of the short-circuiting device can be controlled directly via a radio signal or by means of a modulated on the phases of the low-voltage system signal.

By using the proposed solution, the function of the short-circuiter of the system can therefore be ensured at any time of an arc fault during commissioning or maintenance.

On the disclosure side, therefore, an arrangement for system and personal protection in the low-voltage range is assumed by generating a short circuit by means of a short-circuiting device with a switching element which can be triggered by an arc fault detection, wherein the short-circuiting device comprises two relatively movable contacts which are kept at a distance by a sacrificial element are, further using the switching element, the sacrificial element can be influenced such that the mutually movable contacts pass into a short-circuit state.

According to the invention results in the electrical energy for triggering the switching element exclusively from the energy of the arc occurring.

Furthermore, according to the invention an electronic trip module is provided which includes a bipolar transistor with an insulated gate electrode whose collector and emitter are connected between two phases L1 and L2 and which is in communication with a switching transistor which becomes conductive upon the occurrence of an arc fault and its output the switching element actuated. In this case, the bipolar transistor with insulated gate electrode in conjunction with the switching transistor and the arc fault voltage acts as quasi-internal power source.

Furthermore, as already mentioned above, an adapter can be provided which converts signals of known arc detectors into an optical signal and feeds it via an optical fiber connection of the electronic triggering assembly.

The switching element can be designed as a thyristor.

The electronic trip module is activated by an AND operation of an optical signal and the arc fault voltage, so that then the switching element is actuated.

For this purpose, the electronic triggering assembly has a photodiode, a phototransistor, a photoresistor or the like, with the aid of which the switching transistor can be put into a conducting state.

According to the invention, it is also possible to use directly optically controllable thyristors as switching elements.

The arrangement according to the invention can be installed under voltage, so that a system interruption is not necessary.

The inventively used short-circuiting device is, for example, according to the DE 103 13 045 B3 or the DE 10 2005 048 033 B4 realized. The relevant disclosure of the cited documents is expressly designated as belonging to the present description.

The energy for driving the switching elements, as mentioned, for. B. are executable as thyristors, according to the invention obtained by a current source from the voltage of the arc fault, wherein the current source is controlled by the IGBT.

The current source is switched by the aforementioned AND operation of light signals and arc fault greater than 20 V low impedance, whereby the control of the thyristors and thus the short-circuiting device takes place.

In the high-impedance state, the power loss of the control electronics is negligible and the circuit meets the requirements for permanent use in transformer-near feed of low-voltage networks.

The control with light has the advantage that a change of overvoltage protection category between the permanently installed arc detection devices and the short-circuiting device is easily possible even at longer distances.

If the detection device does not have a directly optical signal output, the mentioned adapter can be used, which converts very different signal outputs of detection devices almost without delay into a corresponding light signal.

As a signal for this purpose are those common potential-free normally open, potentialed NO, capacitance discharge and the wiring with conventional supply voltages, which are used to control undervoltage tripping of circuit breakers, suitable.

The adapter has for this purpose several specified inputs, which can be used alternatively alternatively or also in parallel to the signal generation. In one embodiment of the invention, the adapter may have a receiver for radio triggering or, if correspondingly connected, also cable-bound signal variables for remote triggering.

The possibility of remote triggering can be realized alternatively, but also directly on the short-circuiting device. The adapter and the short-circuiting device can both have an input for driving by a separate, z. B. mobile arc detection system, which allows the parallel or the alternative operation of the short-circuiting device.

The short-circuiting device can already be installed during commissioning and be firmly connected to the system or even be installed during maintenance work under voltage. For this purpose, in particular to an embodiment according to DE 20 2006 020 737 U1 directed.

Thus, the short-circuiting device can be used to supplement systems with any detection devices, which previously served only to control switching devices, whereby the scope of protection is greatly expanded at Störlichtbögen. The short-circuiting device can also be used for personal protection when working under tension even with unsuitable permanently installed detection device by the temporary use of a z. B. mobile detection unit application.

The presented teaching consists in summary of a known short-circuiter together with adapter for driving and the signal output via an optical fiber connection. In this case, the short-circuiting device is characterized in that no additional energy is needed and the assembly can be done under tension if necessary.

The optical fiber connection between the adapter and the short-circuiter provides electrical isolation, which allows the devices to be arranged in areas with different overvoltage protection categories and in almost arbitrary distances.

The above allows a flexible installation and a low probability of tripping due to the EMC-friendly installation. The separate connection possibility of a mobile detection device results in a better protection during maintenance work under voltage and during commissioning regardless of the design of an existing fixed detection unit.

The presented adapter allows the coupling of the short-circuiting device with all known arc fault detection devices, which in a simple manner existing arc fault protection devices can be complemented without short circuiter with such, whereby the efficiency in the protection of facilities and facilities can be significantly increased. The installation of the adapter is easily possible due to the fiber optic signaling and the unnecessary connection to a supply voltage.

The invention will be explained below with reference to an embodiment and with the aid of figures.

Hereby show:

1 an exemplary system version with short-circuiter, adapter and mobile detector;

2 an exemplary construction of a short-circuiter or a short-circuiting device as a principle-sectional view with switching device and electronic trip module and

3 a circuit diagram of the electronic trip module for activating the designed as a thyristor switching element.

The arc detection device 1 to 1 with an optical detector 2 captures the symbolically with 3 designated arc LB.

The arc detection device 1 activates an upstream circuit breaker 4 , Which after an actuation time of several 10 to 100 ms, the system affected by the fault arc disconnects from the mains voltage.

In addition, from the arc detection device 1 a short-circuiter can be activated to shorten the arc fault time.

The retrofitting of a short-circuiting to existing detection systems, however, has only been possible to a limited extent, since the signaling, the detection device and the short-circuiter must be coordinated.

So far, therefore, only short-circuiters can be retrofitted to detection devices, which are already provided in principle for this function, for which, however, the system must be disabled.

The installation of a short-circuiting device 5 can also be done later under tension according to embodiment.

The short circuiter (s) 5 have switching devices which can be controlled via an electronic triggering on the basis of a power source.

The signal to the triggering device 6 of the short circuiter concerned 5 Preferably takes place via an optical fiber connection or radio or other line-bound signals on the phases.

During installation, the short-circuiting device can be directly controlled by a mobile detection system with special suitability for live work.

If required, it is also possible to control the circuit breaker 4 alternatively or parallel to the permanently installed system of the arc detector 1 respectively.

The connection of the installed short-circuiter with the arc detection device 1 done with the help of an adapter 7 ,

The adapter 7 enables the connection of conventional signal outputs of known detection systems. The adapter 7 can with free channels of the arc detection device 1 or in parallel, z. B. to the control of the circuit breaker 4 be connected. The adapter 7 itself also has at least one separate input for connection of the mobile detection system 8th , which is suitable for working under tension.

For a purely optical output of the detection system 8th can the adapter 7 also be used for the passage or division of the light signal.

Furthermore, there is the possibility of the adapter 7 remote control via a radio signal or similar.

The phases of the low-voltage system are designated according to the figures with L1, L2 and L3.

The 2 shows the exemplary construction of a short-circuiting device 9 with switching device 10 and the electronic trip module or electronic control 11 via an optical fiber signal 3 respectively. 8th ,

The short circuiter 9 consists of two main electrodes 12 and 13 which through a sacrificial element 14 kept at a distance.

The sacrificial element 14 is electrically conductive with the main electrode 12 and a separate auxiliary electrode 15 contacted. Between the auxiliary electrode 15 and the main electrode 13 There is a switching element, for example, designed as a thyristor.

When controlling the electronic triggering via an optical fiber signal 3 from the arc detection device 1 (please refer 1 ) or a signal from the mobile detector 8th becomes the thyristor 10 controlled and connects the main electrode 13 with the auxiliary electrode 15 ,

Due to the resulting flow of current through the sacrificial element 14 this is destroyed and it moves the electrode 12 under the action of the spring force 16 to the electrode 13 , causing a metallic short circuit of the electrodes 12 and 13 arises.

The 3 shows a basic structure of the electronic trip module 11 with a thyristor as a switching element 10 ,

The trigger assembly does not require any additional power supply. The switching function of the thyristor 10 is at a voltage of about 20 V, for example, between the phases L1 and L2 and the input of the optical fiber signal 3 or 8th given almost distortion free.

The arc voltages in low-voltage systems typically reach values> 70 V. The current source, which is preferably based on an IGBT 17 is realized by the optical fiber signal 3 respectively. 8th briefly displaceable from the high-impedance to a low-impedance state. As a result, the control of the thyristor takes place 10 and the current over the sacrificial element begins 14 (see explanation to 2 ) to flow.

LIST OF REFERENCE NUMBERS

1

Arc detection device

2

optical sensors

3

arc

4

breakers

5

Earthing

6

Tripping device of the short circuiter

7

adapter

8th

mobile detection system

9

mechanical structure of the short-circuiter

10

Switching element or thyristor

11

electronic trigger assembly

12, 13

main electrodes

14

sacrificial element

15

auxiliary electrode

16

feather

17

IGBT

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008038248 A1 [0004, 0011, 0030]
• DE 102005048003 B4 [0013, 0014, 0030]
• DE 202006020737 U1 [0015, 0030, 0055]
• DE 10313045 B3 [0030, 0046]
• DE 102005048033 B4 [0046]

Claims (9)

Arrangement for system and personal protection in the low-voltage range by generating a short circuit by means of a short-circuiting device with a switching element, which is triggered by an arc fault detection, the short-circuiting device comprises two relatively movable contacts or electrodes, which are held by a sacrificial element at a distance, wherein further with Help the switching element, the sacrificial element is influenced such that the mutually movable contacts or electrodes in a short circuit state, characterized in that the electrical energy for triggering the switching element exclusively results from the energy of the arc occurring. Arrangement according to claim 1, characterized in that an electronic trip unit is provided, which comprises an insulated gate bipolar transistor (IGBT) whose collector and emitter is connected between two phases (L1 and L2) and which is in communication with a switching transistor which becomes conductive upon occurrence of an arc fault and actuates the switching element via its output. Arrangement according to claim 2, characterized in that an adapter is provided which converts signals of known arc detectors into an optical signal and this via a, preferably optical fiber connection, the electronic trigger assembly zuleitet. Arrangement according to claim 3, characterized in that the adapter has a remote trigger input or remote trigger connection. Arrangement according to one of the preceding claims, characterized in that the switching element is designed as a thyristor. Arrangement according to one of claims 2 to 5, characterized in that the electronic trip module is activated by ANDing an optical signal and an arc fault voltage and actuates the switching element. Arrangement according to claim 6, characterized in that the electronic triggering assembly comprises a photodiode, a phototransistor, a photoresistor or the like component, by means of which the switching transistor can be set in a conductive state. Arrangement according to claim 5, characterized in that directly optically controllable thyristors are used as switching elements. Arrangement according to one of the preceding claims, characterized in that it can be installed under voltage.

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