DE102014100068B4 - Method and device, namely handheld network analysis device, for the rapid and simple detection of line-based interference in the lower frequency range on power supply network lines - Google Patents

Abstract

Process for the quick and easy detection of line-based interference in a lower frequency range from 500 kHz to 1 kHz or from 150 kHz to 2 kHz on power supply network lines using a network analysis handheld device, in which the voltage of the power supply network is first measured, the measurement being carried out by connecting a power plug the mains analysis handheld is carried out directly at a mains socket of the supply network; - then the basic frequency of the measured mains voltage is filtered out via a high-pass filter; - different frequencies are selected using a bandpass filter; - the various selected frequencies are amplified using an amplifier; - the amplitudes of the amplified frequencies in measured by an AD converter; - the measured amplitudes are fed to a microcontroller as digitally processed signals; - the digitally processed signals are evaluated by means of an evaluation device; and- in which the evaluated signals are output to an LCD panel of the handheld network analysis device.

Description

The present invention relates to a method and an apparatus, namely a handheld network analysis device, for the rapid and simple detection of line-based interference in the lower frequency range on power supply network lines.

To get out of the constant voltage source by fast switching processes (in the ms range) motors, drives and. Frequency converters are used to drive machines. The generating amplitudes and frequencies can be changed in single and three-phase operation and thus increase the efficiency based on the supply voltage. However, they only serve to do “work”.

In practice, frequency converters are, for example, IGBTs from neighboring or in-house industrial plants, elevators, drives, petrol pumps at petrol stations, ventilation systems), solar inverters of photovoltaic systems, thyristor circuits (drives), phase angle controls (dimmers), switching power supplies, contactors, welding systems, satellite systems, household appliances , such as vacuum cleaners, washing machines, induction cookers, energy-saving lamps, LED lamps, fluorescent lamps and switches etc. realized.

With their fast switching processes in the millisecond range, frequency converters cause a high energy content, sometimes up to 10 KV / µs, and transfer this energy into their own and into the public energy supply network. These high-energy interferers are largely responsible for influencing equipment and systems and their frequent destruction, and in some cases generate interference voltages of> 160 dBµV, which are fed into the energy supply network. This means that devices, systems and household appliances that are connected to the power supply network are subjected to peak voltage values of up to 400 VAC (230 VAC nominal voltage plus peak value of> 141 V).

In addition, there are often additional peak voltage values (dU / dt) in household networks due to defective devices, short circuits and switching operations, such as IGBTs of up to 10,000 V / µs.

The EP 1 512 207 B1 discloses a residual current circuit breaker with a unit for detecting a residual current within an electrical power supply network and a mains disconnection unit, the unit for detecting a residual current comprising a device for recording the residual current according to the signal, which can be coupled to the power supply network, and the unit for detecting a residual current Fault current analysis unit for spectral characterization of the fault current, which is connected to the mains disconnection unit, characterized in that the fault current analysis unit has at least one filter unit with, preferably low-frequency, bandpass characteristics for filtering the fault current signal, and a transformation Unit for transforming the fault current signal formed in the device for signal-accurate recording of the fault current from the time range into an image range, preferably into the frequency range.

The DE 44 30 246 A1 discloses a method and an arrangement for monitoring power supply networks used with fault recorders. Spectral values are calculated from the sample values of the mains voltage or current using the discrete Fourier transformation. Of these, only those that are greater than a predetermined threshold value are transmitted or stored. To reconstruct the sample values, the missing spectral values are assumed to be zero. In general, only those spectral values are transmitted or saved that belong to a disturbance and a pre- and post-history of a few seconds.

In principle, conventional spectrum analyzers are not able to measure interference voltages directly on 230VAC supply lines. This is always done via a decoupling unit, e.g. a LISN (Line Impedance Stabilization Network). This is specified for interference frequencies from 9 kHz to> 30 MHz. As a decoupling unit, a LISN has a high pass, which must block the fundamental frequency of the mains voltage (in Germany 50 Hz) and also the harmonics of the harmonics of this fundamental frequency, since the level of these harmonics in practice exceeds the permissible input voltage of conventional spectrum analyzers and destroys the input stage . Finally, a conventional spectrum analyzer uses an FFT (Fast Fourier Transform) to determine the spectrum, which means that all frequencies are on the measurement path at the same time. This is possible because in practice no higher amplitude values are to be expected in the frequency range 9kHz - GHz range.

However, conventional spectrum analyzers are unable to detect interference voltages in the lower frequency range on power supply network lines, in particular in the interval from 2 kHz to 10 kHz. Among other things, this is because the component sizes for frequencies below 10 kHz increase significantly.

In addition, the maximum input voltage of all commercially available and current analyzer measuring devices is reduced to a maximum of 5 V (input voltage). Voltages that lie above destroy the input boards (diodes) of each analyzer. It is therefore always necessary for conventional analyzers to be supplied with the input signal via a line simulation (Line Impedance Stabilization Network; abbreviated: LISN) or a suitable decoupling adapter.

Proceeding from this, the present invention is based on the object of providing a method and a device, namely a handheld network analysis device, for the rapid and simple detection of line-based interference in the lower frequency range on power supply network lines. In particular, it should be possible to measure conducted interference voltages in the lower frequency range from approximately 500 kHz to 1 kHz. In the interval 150 kHz to 2 kHz interference voltages should particularly preferably be detectable. In addition, the operation of the device should be simple and manageable even for people who do not have special electrical engineering knowledge. After all, as a device developed for private end users, it should be as small and handy as possible.

This object is achieved by means of a method and a device, namely a handheld network analysis device, for the rapid and simple detection of line-related interference in the lower frequency range on power supply network lines, with the features of the independent claims.

• - zunächst die Spannung des Energieversorgungsnetzes gemessen wird, wobei die Messung durch Aufschalten eines Netzsteckers des Netzanalysehandgerätes mittels direkt an einer Netzsteckdose des Versorgungsnetzes durchgeführt wird;
• - sodann zumindest die Grundfrequenz der gemessenen Netzspannung (z.B. 50 Hz) über einen Hochpassfilter ausgefiltert wird;
• - mittels Bandpassfilter verschiedene Frequenzen selektiert werden;
• - die verschiedenen selektierten Frequenzen mittels eines Verstärkers verstärkt werden;
• - die Amplituden der verstärkten Frequenzen in einem AD-Wandler gemessen;
• - die gemessenen Amplituden als digital aufbereite Signale einem Mikrokontroller zugeführt werden;
• - die digital aufbereiteten Signale mittels einer Auswerteinrichtung ausgewertet werden; und
• - bei dem die ausgewerteten Signale an einen LCD-Panel des Netzanalysehandgerätes ausgegeben werden.

The method according to the invention for the quick and easy detection of line-based interference in the lower frequency range, in particular between 500 kHz and 1 kHz or 150 kHz and 2 kHz, on power supply network lines by means of a network analysis handheld device is characterized in that

• - The voltage of the energy supply network is first measured, the measurement being carried out by connecting a mains plug of the mains analysis handheld device directly to a mains socket of the supply network;
• - Then at least the fundamental frequency of the measured mains voltage (eg 50 Hz) is filtered out via a high-pass filter;
• - Different frequencies are selected using a bandpass filter;
• - The various selected frequencies are amplified by means of an amplifier;
• - The amplitudes of the amplified frequencies measured in an AD converter;
• - The measured amplitudes are supplied to a microcontroller as digitally prepared signals;
• - The digitally processed signals are evaluated by means of an evaluation device; and
• - in which the evaluated signals are output to an LCD panel of the network analysis handheld device.

In order to measure the results According to the invention, keeping it accessible to end users is provided for the digitally processed signals to be evaluated by means of an evaluation device.

Furthermore, according to the invention, the evaluated signals are output to an LCD (liquid crystal display) panel of the handheld network analysis device.

While commercial applications have so far hardly been feasible with decreasing frequency accuracy, the present invention for the first time creates a method for the quick and easy detection of line-based interference in the lower range by using several bandpass filters for the purpose of selectively selecting several different frequencies, their respective amplification and conversion into digital signals To provide a frequency range of less than 500 kHz to almost 1 kHz on power supply lines using a handheld network analysis device.

Advantageous developments and further developments of the invention, which can be used individually or in combination with one another, are specified in the dependent claims.

In one embodiment of the invention, the different frequencies can be measured in a selectable measurement mode (in particular peak, max hold, min hold or average).

The measurement in peak, max hold, min hold, or average mode is preferably carried out automatically, for example, after entering the time and date and the desired measurement mode, with “peak” measurement value acquisition being preferred as the preset start mode.

In order to be able to take into account not only rigidly predetermined but also variable frequencies that can be adapted to particularly interesting and / or encountered boundary conditions, an embodiment is preferred in which the individual bandpass filters can be controlled to predetermined frequencies.

In particular, it is preferred if the individual bandpass filters are activated via the microcontroller.

It is preferred, for example, if the microcontroller displays the maximum values of the individual bandpass filters, in particular logarithmically.

In a further preferred embodiment it is provided that the different selected frequencies are amplified by means of a logarithmic amplifier. This has the advantage that low voltage values (e.g. 1 µV to 10 Volt) can be represented more precisely.

Finally, the present invention also relates to a device, namely a network analysis handheld device, set up to carry out a method as described above.

In particular, a network analysis handheld device according to the present invention is not bound to the limitations encountered in the prior art, in particular to the 50 ohms. Rather, it can be connected directly to the 230VAC supply network using the supplied mains plug.

The use of a method or a device, namely a handheld network analysis device, is possible in many areas, particularly wherever line-bound interference voltages have to be determined, such as in the areas of building biology, power line communication (PLC), electrical installation companies, fitters, energy suppliers or where electrical and electronic devices are disturbed.

The invention is described in more detail below with reference to the accompanying drawing using a preferred exemplary embodiment of a handheld network analysis device:

• 1 ein Netzanalysehandgerät als ein bevorzugtes Ausführungsbeispiel nach der Erfindung;
• 2 das LCD-Panel eines mittels des Netzanalysehandgerätes gemäß 1 beispielhaft erhaltenes erstes Messergebnis;
• 3 das LCD-Panel eines mittels des Netzanalysehandgerätes gemäß 1 beispielhaft erhaltenes zweites Messergebnis mit eingeblendeten Grenzwertkurven; und
• 4 die in einem Diagramm dargestellten Daten einer Störspannungsmessung.

It shows schematically:

• 1 a network analysis handset as a preferred embodiment according to the invention;
• 2nd the LCD panel according to a using the network analysis handheld 1 first measurement result obtained by way of example;
• 3rd the LCD panel according to a using the network analysis handheld 1 second measurement result obtained by way of example with superimposed limit value curves; and
• 4th the data of an interference voltage measurement shown in a diagram.

This in 1 The handheld network analyzer shown measures the input signal, in the case focused in the context of the present invention the mains voltage, and filters away the basic frequency of 50 Hz, which is common in the German power distribution network, via a high-pass filter. Additional bandpass filters select the different frequencies. The handheld network analyzer measures one frequency and disregards the other frequencies. The level measurement can be adjusted.

The individual frequencies are amplified via a preferably extremely broadband, preferably logarithmic, amplifier. In particular, however, the selected interference signal is processed via the amplifier for an AD converter and fed to the microcontroller. A preferred microcontroller also controls the individual bandpass filters, calculates the maximum values and transfers the evaluated signal to an LCD panel of the network analysis handheld device.

2nd shows the LCD panel according to a by means of the network analysis handheld device 1 first measurement result obtained by way of example. In addition to the display - as shown - the LCD (liquid crystal display) panel can include a membrane keyboard with keys such as " 7 ";"Record","Peak","Enter" or "Menu".

• - Mittelwert (Average)
• - Spitzenwert (Peak)
• - Maximalwert gehalten (Max. hold)
• - Minimalwert gehalten (Min. hold)

For network analysis, the mains connection cable of the mains analysis handheld device is plugged into a functional Schuko or mains connection socket. There is no need to pay attention to any phase position. The rocker switch on the mains analysis handheld can then be switched to "ON = I". The mains analysis handheld then automatically scans the frequency range from 1 kHz to 500 kHz in "peak mode" as soon as the on / off switch (0 / I) has been switched on. A data recording is preferably only carried out when actions indicated with the displayed key membrane number are started; in the example shown, if the " 7 “On the membrane keyboard, date and time have been entered and a measuring mode has been defined! The following measurement methods can be carried out with the handheld network analysis device:

• - Average
• - peak value
• - Maximum value held (Max. Hold)
• - Minimum value held (min. Hold)

Appropriate limit value curves can be shown for this purpose.

The mode of operation of a preferred handheld network analysis device is illustrated below using various practical examples:

Example: Peak measurement

In this mode (measurement setting), each measured peak value is preferably displayed on the screen and saved as a value for later evaluation on the SD card. The screen can be overwritten with the next scan and a new, determined value (bar) can be displayed.

Example: Max Hold

In this mode (measurement setting), each measured maximum value is preferably recorded on the screen and updated with further maximum values in the respective frequency range. As a result, the absolute maximum value that has occurred can be displayed for each frequency range over the period of the measurement.

Example: Min Hold

In this mode (measurement setting), each measured minimum value is preferably recorded on the screen and updated with further minimum values in the respective frequency range. As a result, the absolute minimum value that has occurred can be displayed for each frequency range over the period of the measurement.

Example: Average

In this mode (measurement setting) are preferred for each frequency 6 Measured values are recorded and the mean value is formed from them.

Example: Showing limit value curves

3rd shows the LCD panel according to a using the network analysis handheld device 1 second measurement result obtained by way of example with displayed limit value curves.

In accordance with the currently valid EN standard "EN 55011", the limit value in NA 02-13 from 150 kHz to 500 kHz is binding for every manufacturer and system operator (in 3rd shown with a solid line). The EN 55011 standard itself regulates the maximum interference limit of 150 KHz to 30 MHz. The 1 kHz - 150 kHz range is currently not regulated by any standard or law.

Therefore, the specified in 3rd Limit values in the range from 1 kHz to 150 kHz shown with a dashed line are only a recommendation. However, this recommended limit value ensures that there are no EMC influences in the power supply network and that devices and systems can be operated in an EMC-safe manner. This limit recommendation in the range of 1 kHz - 150 kHz is also supported by specialist circles.

In the event of a standard adjustment, or a change in the law on the electromagnetic compatibility (EMC) of equipment (EMC law for short), an update for the network analysis handheld device can be installed.

The limit value recommended as a practical value in the range of 1 kHz - 150 kHz is stored in measurement mode EN 55011 - B and can be switched on or off using the menu option "Limit values". The recommended limit curve is in 3rd shown with a dashed line

To summarize: The display with the limit value from 1 kHz is only stored in the "Limit values" menu EN 55011-B. The in 3rd frequency range shown with a broken line is a recommended value. In the 3rd Limit curve shown with a solid line is binding for all manufacturers and system operators!

Example: Proposal for determining sources of interference in the supply network (house / building)

This possibility of fault detection is only recommended if no important control, work or production process is interrupted by switching off the fuses.

The distance of the interference source in a house / building has a significant influence on the interference voltage value (dBµV), which is shown on the display depending on the frequency.

The closer the interference source is to the handheld network analyzer, the higher the interference level (losses due to long cable lines also dampen the displayed level of the original interferer in the house / building).

If the source of interference cannot be determined by a large number of interference sources, there is the option of inserting the handheld network analyzer as close as possible to a socket in the immediate vicinity of the fuse box.

Then switch all circuit breakers "OFF"

Please note that all devices on the network are switched off and can lose their basic settings and memory functions.

Switching off all fuses can trigger a "reset" on various devices and systems including computers and clock radios, so that new settings and synchronization settings are required after the fuses have been commissioned.

Then switch on each fuse in the fuse box individually and observe the measurement result of the handheld power analyzer.

Wait for a reasonable time after each individual activation (approx. 10-15 seconds), because some consumers need a start-up and Initialization time until you work with the maximum power.

By switching on fuses individually, you can determine one or more sources of interference in a house in the respective backup path and then select the relevant interfering device or system in this fuse branch.

With the determined test result, you can contact the Federal Network Agency, consumer protection centers, or building biologists and experts. Depending on the test result and the current legal and normative situation, you may need help in solving the problem.

Example: long-term measurements

The long-term measurement must be carried out with the charger supplied and operated on the mains. A long-term measurement, which is only carried out via the built-in device battery, could lead to data loss if the charge capacity of the battery is insufficient for the duration of the measurement.

The single, short, and long-term measurement can be carried out with any measurement mode (peak, max hold, min hold, average). The subsequent evaluation and documentation can be presented in the same way (Excel file).

The bar graph of the handheld network analyzer - for reasons of storage space, the screen can only be captured with an external photo.

The maximum long-term measurement depends on the use of the SD card (not included in the scope of delivery).

Example: Evaluation and display of measurement results

All measurement data of the handheld network analyzer are saved on the SD card in a txt file.

This txt file is transferred to the Excel table (PC) and each value in the frequency range, the respective measuring mode, date and time is shown.

With the individual values recorded and taken over in tabular form, various and individual graphics can be created, displayed and further processed in Excel.

An Excel template is available on the CD

step 1 )

• Unterschiedliche Messungen auf einer SD - Karte werden der Mess - Reihenfolge nach abgespeichert.
• Bei diesen Messungen wurde keine Zeit und Datum eingegeben!

Messung: PEAK in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 400kHz 500kHz Zeit Datum 077 070 070 072 074 067 051 040 041 040 00:22:44 00/00/13 Messung: MIN-HOLD in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 400kHz 500kHz Zeit Datum 086 079 065 060 059 055 041 040 040 040 01:58:43 00/00/13 090 076 066 060 060 068 042 040 040 040 01:58:47 00/00/13 Messung: MAX-HOLD in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 4000kHz 500kHz Zeit Datum 098 085 082 072 077 069 046 041 041 043 01:59:13 00/00/13 098 085 082 072 077 071 047 041 041 043 01:59:17 00/00/13 100 085 082 075 077 071 047 041 041 043 01:59:21 00/00/13 Messung: AVERAGE in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 400kHz 500kHz Zeit Datum 082 073 069 066 066 065 0415 041 041 041 02:00:00 00/00/13 Read SD card in card reader via PC:

• Different measurements on an SD card are saved in order of measurement.
• No time and date were entered for these measurements!

Measurement: PEAK in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 400kHz 500kHz time date 077 070 070 072 074 067 051 040 041 040 00:22:44 00/00/13 Measurement: MIN-HOLD in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 400kHz 500kHz time date 086 079 065 060 059 055 041 040 040 040 01:58:43 00/00/13 090 076 066 060 060 068 042 040 040 040 01:58:47 00/00/13 Measurement: MAX-HOLD in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 4000kHz 500kHz time date 098 085 082 072 077 069 046 041 041 043 01:59:13 00/00/13 098 085 082 072 077 071 047 041 041 043 01:59:17 00/00/13 100 085 082 075 077 071 047 041 041 043 01:59:21 00/00/13 Measurement: AVERAGE in dBµv 2kHz 5kHz 10kHz 20kHz 50kHz 100kHz 200kHz 300kHz 400kHz 500kHz time date 082 073 069 066 066 065 0415 041 041 041 02:00:00 00/00/13

step 2nd )

Call the Excel program on the PC, start and load the file MESSPRO.txt into the Excel program with "Open". Important: (file type: select all files). Call MESSPRO with a double click ...

step 3rd )

Text Conversion Assistant appears ...
Mark the file type "Separated" and set the file jump to "MS-DOS".
To the next step ...

step 4th )

Mark "space" for a later table display (text appearance), then "Next" or "Finish".

After the steps 1-4 the Excel table appears in this format with all measured and accepted measured values, as exemplified in 4th is shown. It can be seen how individual graphics and tables can be designed with the data listing.

In the usual practice, capacitance diodes are mainly used. However, this is out of the question for the network analysis handheld device shown here, since the effort is too high. Rather, the AD converter measures the amplitude of the vibration and passes it on as a digital signal to the microcontroller. An evaluation via Fourier transformation, as is carried out with conventional analyzers, is not necessary here and is also too complex for higher frequencies> 10 kHz.

The handheld network analysis device obtainable according to the invention is compact, user-friendly and also inexpensive. It is designed accordingly. Conventional laboratory measuring devices are usually much more complicated and often require knowledge and understanding of which settings are required for a wide variety of measurements. The present invention, on the other hand, is as simple as possible, especially when it comes to operation. Nevertheless, it was surprisingly possible to place all the required parts in a small device housing so that there was no mutual interference, so that EVM compatibility was maintained.

• • einfach zu bedienen;
• • Messwertdarstellung in dBµv grafisch und nummerisch;
• • Messung direkt an der Netzsteckdose;
• • Störspannungswerte in Anlehnung der Norm EN 55011;
• • Aufzeichnung von Messwerten für 24 Stunden auf SD-Card bis zu einem Jahr;
• • einschaltbare Grenzwertdarstellung;
• • Grenzwerte können auch festgelegt und dargestellt werden;
• • Akku- und Netzbetrieb.

Further characteristics and / or advantages of the network handheld device described above can be summarized as follows:

• • easy to handle;
• • Representation of measured values in dBµv graphically and numerically;
• • measurement directly at the mains socket;
• • interference voltage values based on the standard EN 55011;
• • Recording of measured values for 24 hours on SD card up to one year;
• • Switchable limit value display;
• • Limit values can also be set and displayed;
• • Battery and mains operation.

The preferred embodiment of a handheld network analysis device can also be described by the following performance data: Max. Input voltage: 110 VAC - 250 VAC 50/60 Hz; Display: 2.8 "display; Measuring range: 1 kHz - 500 kHz; preferably 2 kHz - 150 kHz; Examination after: VDE 0100, DIN VDE 0105-100 and 0701-0702; BetriebsSichV: based on BGV A3; Climate class: HPF (25/085/21); Connection input: Plug / plug E / CEE; Working temperature: -10 ° C to +60 ° C; Housing dimensions (WxHxL): 100 x 50 x 195 mm; Weight: about 0.3 kg; Measuring intervals / measuring speed: 6 measurements / second Measurements: Hold peak, or Peak value, or Mean, or Quasi peak; The measurement in peak, max hold, min hold or average mode takes place automatically after entering the time and date and the desired measurement mode. The start mode preset at the factory is the "peak" measured value acquisition. Storage of measured values / storage capacities: The data is preferably recorded on a pre-formatted SD card, for example: SD: 8 or 256 MB to 2 GB, or SDHC: 4 GB to 32 GB, or SDXC: 48 GB up to max. 2 TB; The following SD card sizes can be used: 256 MB - recording time up to 1 month 2 GB - recording time up to 0.5 years 4 GB - recording time up to 1 year Evaluation option: from the display, and / or Excel table ; Battery operating time: 2 hours. ; Battery charging time: 3 hours. ; Recording time: Max. 24 hours, with such long-term measurements, the mains analysis handheld device must be operated continuously via the charger. In the event of a power failure, the built-in battery advantageously buffers the data already recorded.

While commercial applications have so far hardly been feasible with decreasing frequency accuracy, the present invention creates a method for the quick and easy detection of for the first time with the use of several bandpass filters for the purpose of selective selection of several different frequencies, their respective, preferably logarithmic, amplification and conversion into digital signals to provide line-based interference in the lower frequency range of less than 500 kHz to almost 1 kHz, but in particular also in the interval 150 kHz to 2 kHz, on power supply network lines.

The use of the invention as an especially inexpensive network handheld analyzer is possible in many areas, particularly wherever line-bound interference voltages have to be determined, such as in the areas of building biology, power line communication (PLC), electrical installation companies, fitters, energy suppliers or where electrical and electronic devices are disrupted.

It is suitable for measuring interference voltages from 1 kHz - 500 kHz, in particular also in the interval 2 kHz to 150 kHz, and for detecting interference sources in buildings that can generate voltage swings of up to 10,000V / µs with the clock frequencies in the kHz range and thereby influencing other devices and / or systems and threatening to partially destroy them!

Claims (8)

Method for the quick and easy detection of line-based interference in a lower frequency range from 500 kHz to 1 kHz or from 150 kHz to 2 kHz on power supply network lines by means of a network analysis handheld, in which - The voltage of the energy supply network is first measured, the measurement being carried out by connecting a mains plug of the mains analysis handheld device directly to a mains socket of the supply network; - Then the fundamental frequency of the measured mains voltage is filtered out via a high-pass filter; - Different frequencies are selected using a bandpass filter; - The various selected frequencies are amplified by means of an amplifier; - The amplitudes of the amplified frequencies measured in an AD converter; - The measured amplitudes are supplied to a microcontroller as digitally processed signals; - The digitally processed signals are evaluated by means of an evaluation device; and - in which the evaluated signals are output to an LCD panel of the network analysis handheld device. Procedure according to Claim 1 , in which the measurement of the different frequencies takes place in a selectable measurement mode (in particular peak, max hold, min hold or average). Procedure according to Claim 2 , in which the measurement takes place automatically after entering the time and date and the desired measurement mode. Procedure according to one of the Claims 1 to 3rd , in which the individual bandpass filters are set to predeterminable frequencies. Method according to one of the preceding claims, in which the individual bandpass filters are controlled via the microcontroller. Method according to one of the preceding claims, in which the microcontroller represents the maximum values of the individual bandpass filters, in particular logarithmically. Method according to one of the preceding claims, in which a logarithmic amplifier is used. Device, namely handheld network analysis device, set up to carry out a method according to one of the preceding claims.

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