DE1020410B - Arrangement to protect against longer lasting disturbances and errors in high-voltage apparatus and devices accompanied by high-frequency vibrations - Google Patents

Description

GERMAN

Those involved in the manufacture of high-voltage apparatus and devices, such as converters, transformers, Capacitors, faults arising, or malfunctions occurring later have been time-consuming and costly Repairs result, especially if the fault or malfunction is not recognized in time will. The apparatus or the device can then possibly be destroyed by fire, which can even be transferred to the entire system and destroy it.

It has been found that it is possible in a simple manner to deal with the described, often very serious ones Preventing damage through immediate consideration in the bud and also a number of special ones To gain advantages, namely through a small inductance between the one to be connected to earth End of the high-voltage circuit and earth at which the low-frequency operating current is only a small one Voltage drop, while the one caused by an internal fault or an internal malfunction high-frequency oscillations at this inductance produce such a large voltage drop that it an error display or protective device is activated.

The invention primarily solves the problem of internal insulation damage in high-voltage equipment and devices to determine the damage caused by such damage, typically Long-lasting or continuously occurring high-frequency vibrations for display and for Protection of the apparatus in question can be used.

Although it has already been proposed that of electric arcs in the event of damage or faults to electrical Apparatus occur due to high frequency oscillations to indicate the disturbance use. In this case, however, the high frequency was used via an antenna and a Capacitor to operate the display device.

However, detecting damage via a high voltage capacitor and antenna is Compared to the device according to the invention, much more expensive and cumbersome, especially there an additional auxiliary network is required to generate the bias voltage for the glow relay, while the device according to the invention directly without any modification of the apparatus to be protected can be installed in the earth line.

In other known devices, the voltage drop across an inductance between the end of the high-voltage circuit to be connected to earth and the earth is used to display the operating faults, although the high-level arrangement that arises in the event of such faults and errors is used to protect against
High-frequency vibrations accompanied long-lasting malfunctions and errors in high-voltage apparatus and devices

Applicant:

Messwandler-Bau GmbH,
Bamberg, Nürnberger Str. 225

Dipl.-Phys. Erwin Schühlein, Bamberg,
has been named as the inventor

frequent vibrations is not intended. A

ao suggestion here refers to the shift of the zero converter that occurs in the event of short circuits To measure the star point in relation to the earth potential. This facility is therefore based on a very specific one Area of application, namely to a selective protection system for three-phase power distribution networks. According to another suggestion, in a network the steep rise in the star point potential at the moment of the earth fault is exploited with the help of frequency-dependent resistances in the voltage coil of the earth fault relay to generate an increased current surge. So it will be different from the new one Invention, the high-frequency pulses for display caused by interference in apparatus to be protected of the damage that has occurred, as the earth fault indicator relates to an incident that is practically always occurs in the overhead line network, i.e. outside the apparatus to be protected.

With the help of the invention, even small and very small errors and malfunctions can be eliminated if necessary simple, e.g. B. 1: 1000 translating amplifier reliably and in time, z. B. with the help of a Perceive the alarm device and, for example by means of a disconnection device, render it ineffective, so that it not to the dreaded major or total losses comes.

When using the invention, it is also advantageous that no auxiliary voltages and amplifications at most are only required for very weak high frequencies, for example to detect very small errors or malfunctions that do not necessarily cause damage. That's why they too can open the arrangement or device based on the invention and the associated devices and means subsequently to any existing high-voltage apparatus

709 808/11) 8

or device can be individually attached or built in, e.g. B. between primary winding and earth. Also mistakes and Faults that do not exist or occur in the high-voltage circuit itself can, if the Fault or malfunction is not too far away, detected and used for the protective device even if the accumulating error or disturbance values are one or more orders of magnitude are smaller.

It is also advantageous that the invention can also be used to test the high-voltage apparatus or device before it is installed in the system, d. H. thus · primarily in the test field. The apparatus and Devices such as converters, transformers, capacitors, but also the insulating materials themselves, in the case of capacitive Coupling also the surfaces of all these objects, can be checked for discharges, glow, Check and measure sliding sparks or other existing errors and subsequent malfunctions, namely without further ado, even with ongoing registration, provided the errors and disruptions of high-frequency Vibrations are accompanied.

For the practical implementation of the invention, it is useful in the high-voltage circuit, ζ. B. of the apparatus or device to provide a first, relatively small inductance, to which on the one hand by the low frequency a very small voltage drop and on the other hand due to the error or disturbance-related High frequency a much larger voltage is generated, the voltage generated by the low frequency, e.g. B. Operating frequency, small current resulting almost entirely through the first inductance to earth is derived. The rest of this current and the much larger high frequency current will be before the first Inductance expediently first fed to a small capacitor, which the remainder of the Low-frequency current blocked and the high-frequency current passed on to a second inductor. This is connected to earth and, on the one hand, conducts any remnants of the low-frequency current that may still be present to earth and on the other hand is dampened mainly by the high frequency that occurs Natural vibrations are stimulated, of which the variables for possibly measuring and registering display and'or for protection, e.g. B. to switch off at least the relevant high-voltage apparatus or device. With the help of these derived quantities z. B. Measuring instruments such as Tube voltmeter, measuring devices with rectifier, thermal cross instruments, furthermore recording devices such as strip recorders, oscilloscopes, further amplifiers, Relays, such as a magnetic relay after rectification, thermal relay, controlled which the faulty or disturbed apparatus or device or the relevant part of the system directly or via a special one Switch off the protective device.

The influence of the first inductance in the high-voltage circuit on the accuracy of the device, z. B. a voltage converter is negligibly small.

In the case of two-pole and multi-pole, ungrounded converters, the arrangement according to the invention can be capacitive, z. B. on the always existing partial capacities between high-voltage parts and the housing the earthed secondary winding or a metallization of the transducer to which one pole the grounded arrangement is conductively connected, be coupled.

Reinforcements can be used, especially in the case of major disruptions, such as those that lead to permanent damage do not apply, since the high-frequency voltage is sufficient to control the high-frequency measuring devices, such as tube voltmeters etc. to operate and control. Auxiliary voltages can always be dispensed with here.

Advantageously, the arrangement according to the invention is given selectivity with respect to errors or interference occurring high frequencies, z. B. by designing the second inductance as a band filter and / or by adding a corresponding, possibly adjustable, small parallel capacitor is assigned.

The arrangement according to the invention can easily be designed and dimensioned so that certain disturbances, eg. B. one-time impacts, a display and / or shutdown of the affected apparatus, device or part of the system. Advantageously, for this purpose, for. B. at the output of the arrangement a special, optionally changeable RC element is provided, by means of which the display and / or shutdown or some other protective measure can be delayed as desired. In addition to or instead of such time delay elements, z. B. also clockworks, time relays or the like.

In the case of three- or multi-phase devices, devices, systems, etc. or several such devices, etc. A single display and / or protection device may be sufficient, e.g. B. in the joint Return line, such as earth line, is installed.

Further features of the invention can be found in the drawing and the following description.

The high voltage connected to 1 leads to the primary or high voltage side 2 of the to be monitored Apparatus or device, e.g. B. a single-pole isolated voltage converter, on the secondary side 3 the burden, e.g. B. a counter is located. The first is between the high voltage side 2 and earth 4 Inductance 5, at the corresponding to the complex resistance except for the relatively small voltage drop the operating frequency of e.g. B. 50 Hz in the event of an error or a malfunction also the proportionate higher voltage arises due to the high frequency occurring during the fault or disturbance.

In order to screen out the operating frequency, at 6, i. H. between high voltage side 2 of the converter and the inductance 5, a relatively small coupling capacitance 7 connected to the other Covering the second inductance 8, the inductance value of which is approximately equal to that of the first inductance is. The other pole of the second inductance is also connected to earth 4, so that it does not have the first inductance derived to earth, the remainder of the operating frequency is also derived to earth.

Because of the high frequency, something like that of a spark discharge «! occurs, the second inductance is excited to natural oscillations or resonance, the frequency of which can be determined with the capacitance 9 connected in parallel to the inductance and optionally controllable. At the inductance 8 and possibly the parallel capacitance 9, the display and / or protection device is amplified ^{at 10 and 11, if necessary via \ T.} connected.

Claims (5)

Patent claims: 1. Arrangement to protect against long-lasting, accompanied by high-frequency vibrations or permanent malfunctions and errors in high-voltage apparatus and devices by a small inductance between the end of the high voltage crisis and earth to be laid on earth. what inductance the small low-frequency operating current only causes a small voltage drop, while the high-frequency vibrations caused by an internal fault or an internal disturbance at this inductance produce such a large voltage drop that a fault display or protective device is actuated. 2. Arrangement according to claim 1, characterized in that between the high voltage circuit and inductance, suitably over any remainder of the low frequency current blocking capacitance, a second grounded inductance is connected to the one hand dissipates the small remainder of the low-frequency current that is still present behind the capacitance to earth and on the other hand by the at the first inductance ehigh-frequency voltage is excited to natural oscillations that are necessary for operation and controlling the display and / or protection devices. 3. Arrangement according to claims 1 and 2, characterized in that at least one inductance, preferably the second, is designed as a band filter, for example by adding a further, optionally tunable capacitance is connected in parallel. 4. Arrangement according to claims 1 to 3 for two- or multi-pole, ungrounded transducers or the like., characterized in that the arrangement kapa, -zitiv, z. B. on the always available partial capacities between high voltage parts ίο and the housing, the secondary winding or a metallization of the transducer or the like, to which one pole of the grounded arrangement is conductive is connected, is coupled. 5. Arrangement according to claims 1 to 4, characterized is characterized in that the generated high frequency currents rectified and then a DC-sensitive device, e.g. B. a moving coil device or a magnetic relay. Considered publications:
German patent application S 3228VIIIb / 21c (published November 13, 1952); German patent specifications No. 592 378, 649 615. 1 sheet of drawings