SI20767A - Procedure for automatic measuring of parameters of electrical wiring in houses - Google Patents

Abstract

The procedure for automatic measuring of parameters of electrical wiring in houses automatically measures the line (RLINE) resistivity, the loop breakdown resistivity (RLOOP), the tactile voltage (Uc), tests the operation of the disconnector against differential current and can be expanded by measuring the resistivity of terminals. The procedure can also be enhanced by corresponding voltage tests on inputs and the identification of the direction of the driving field. It compares the measurement results with the defined values and displays the results on a display as acceptable - false or by digits. It can also include the storage of results in a memory location and the transfer of data to external PCs. The required (reference) values are entered into the memory by the producer of the device for the practical application of the procedure or the user itself by using a computer.

Description

Technical problem

The invention solves the technical problem of developing a process for automatically changing the parameters of electrical house wiring such as insulation resistance between phase and protective conductor, insulation resistance between neutral and protective conductor, contact voltage between the reference "ground" and accessible part on the potential of the protective conductor, etc.

The state of the art

Electrical installations in buildings must be tested for safety. In this connection, it is necessary to measure: the insulation resistance between the phase and neutral conductors, the insulation resistance between the phase and the protective conductor, the contact voltage between the reference 'ground' and the accessible part on the potential of the protective conductor, the resistance (impedance) of the loop loop, the resistance (impedance) lines etc. In addition, the circuit breaker must be tested for differential current, if installed.

These measurements and tests take a lot of time because of each meter setting. Care should also be taken in the order of tests or measurements. In addition, there is the possibility of errors and misjudgments of results if measurements are not made by appropriately qualified personnel. Of the automatic test procedures, only auto-test of the differential current protection circuit breakers is known to the auto.

Description of the new solution

The essence of the new solution according to the invention is an automatic procedure, which includes the testing of all parameters of electrical house wiring, their evaluation and display.

In the following, the invention will be described and explained in more detail.

Individual symbols mean:

Role impedance of the line

R-loop impedance impinges on loops

U _{c the} contact voltage at the protective conductor

Ιδν is the nominal value of the differential current

-3-3ί _Δ time of tripping of the protection switch on the differential current

Depending on the type of home electrical installation, the process for automatically measuring the parameters of electrical domestic installation has three basic variants, namely:

1. to test electrical house wiring without a differential current protection switch;

2. to test the electrical wiring with a residual current-proof circuit breaker without triggering it;

3. to test the electrical wiring with a differential current-proof circuit-breaker and trigger it.

If the electrical installation does not have a residual current circuit breaker, we generally measure the Rloop resistance with a higher current than if the line has a circuit breaker. In this case, this current is the flow of the measurement of R _L ine · If the measurement of D _L ine indicates a resistance value greater than defined limits, the display shows the corresponding words, a process that may be completed or continued. If the measured Rline value corresponds, the process is continued by measuring the Rloop value.

The procedure described above is triggered by the person testing the house wiring with a special command, after which it is performed independently, either until the first negative result or until the end of the measurements included in the procedure.

If the house wiring has a differential current protection switch but we do not want to initiate it, we use the procedure according to version 2. Here we need to use a smaller current to measure the Rloop than to measure the Rline in order not to trigger the protection switch. In this procedure, the contact voltage U _{c is} also measured. As a rule, the flow is the same size as for the Rloop changes. · The process is automatically measured by type: Rline, Rloop and U _c . The negative outcome of any measurement can mean the end of the process and the corresponding display on the display. If there are no negative results, the display will show the appropriate caption (eg appropriate or OK). In both procedures above, the order of measurements is arbitrary.

*

If the house wiring is equipped with a differential current protection switch and is not disturbed by its initiation, the procedure according to version 3 is used. This procedure contains all the tests as in the version 2 procedure, and also the test of the differential current protection switch activation. The latter

-4-4The test according to the reported procedure is performed by means of a tripping current from the set of rated tripping currents of the differential current protection switches.

An important parameter is the insulation resistance. For this measurement, the test piece must not be connected to the mains voltage. In the case of the procedure described above, it is advantageous that this measurement is added to the successfully passed test of tripping the protective switch on the differential current, otherwise it is necessary to switch off the circuit tests for this purpose.

The process of the invention can be further extended by other measurements such as e.g. a test of the resistance of the connection between the sockets of the socket or between the two sockets or of the connection of accessible conductors with a protective conductor.

The results of the test results are also wide, as they can be presented in the simplest form as appropriate - inappropriate, and numerically and alternatively by transferring to other devices (eg a computer). The obtained data can also be stored in the memory of the device for performing the procedure and used for various purposes. The simplest form of the procedure has inserted values, which are compared with the results of measurements, and the result is displayed on the device display in the form appropriate - inappropriate. Reference values are usually obtained based on requirements and experience and are either built into the process by the manufacturer of the process device or by a user using a computer.

In order to perform measurements correctly according to the declared procedure, the input terminals of the device must have adequate voltage. Due to the possibility that the voltages at the input terminals of the device do not correspond, the described procedure can be extended by estimating and displaying the voltages at the inputs. An example of inadequate tensions is, for example. incorrectly connected socket where the phase and neutral conductors are replaced. The process can be further extended by determining the phase sequence or direction of rotation field in a three-phase line.

The described procedure can be realized by means of a device which, by means of a microprocessor and semiconductor switches, switches the measuring circuit in series in order to perform the appropriate measurement, performs a comparison of the results and performs the results or their evaluation on the display.

In the following, the feasibility of the process will be demonstrated by a case in point.

In an embodiment, a device having a microprocessor, semiconductor switches, an external computer connection module, memory, a display, and a power supply is used to perform the process of the invention. The display is in the form of a table with associated illuminants

-5-5diodami. The user is assigned a field with a button for selecting a procedure and a button for triggering the selected procedure.

The device must be connected to a single-phase or three-phase socket, depending on the type of installation. When the process is initiated, the selected measurement sequence starts at the correct voltage state at the inputs. The process may also include determining the direction of the rotating field (three-phase socket). In this case, the display will show the direction (right or left) by successively switching on and off the LEDs. The work program performs a measurement for each part of the process and compares the result with the stored value in memory. If the result is appropriate, the process proceeds to the next measurement. In this case, the LED in the field of the measurement just taken (test) goes off and the LED in the next measurement field lights up. When the entire process is successfully completed, the LED next to "OK" lights up.

If the microprocessor detects an incorrect result in a measurement, the LED of the measurement in question flashes and the process may be stopped due to an identified hazard.

The device may also have a sub-assembly for contact testing. This one is also controlled by a microprocessor. However, a special LED indicates the measured contact. When the resistance is too high or even the terminals are open, the LED does not illuminate, only illuminates when in good contact, e.g. if the resistance is less than 1 Ω. However, flashing the LED means that a voltage is present at the input of the measuring circuit.

If we also test the tripping of the circuit breaker on the differential current, the microprocessor starts the process only after it is found that the inputs are only supplying voltage at the phase conductor connector (against the neutral and protective conductors). If this condition is found, all three LEDs are lit.

After initiation of the process, the semiconductor switches set the measuring circuit to a line resistance measurement and the corresponding LED indicating this measurement is lit. The microprocessor performs a measurement with a sufficiently high current that guarantees a quality measurement and compares the result with the value in memory. If the measurement did not give a satisfactory result, the LED indicating the measurement flashes and the microprocessor may interrupt the process. The LED of the loop is then lit to measure the resistance of the loop. When measuring the resistance of a circuit breaker, the measuring current is low, as it must not trigger the differential switch. In this measurement, the microprocessor calculates the resistance and measures the voltage drop across the rated line at the rated current and compares with the prescribed values.

-6-6If the measured contact voltage or resistance of the loop fault is too high, the corresponding LED starts to flash and the LED at the differential current protection switch also flashes. The test of the protection switch contains both a test with a rated differential current I ^ n as well as a switching time ί _Δ

After switching off the safety switch, the process performs an isolation test, for which a high voltage source is included. The result will be displayed again with the LED.

The process of automatic measurement of home installation parameters can also be integrated into devices that display the result numerically and in which the integration of measuring sub-assemblies for individual measurements is performed by means of electronic relays. With these variants, it is also possible to numerically display the results, store the results, be able to select parameters, and even control using an external computer.

The advantages of the notified procedure are in particular: simple and safe operation, quick training of personnel, elimination of human errors as much as possible, rapid inspection of electrical wiring.

Claims (12)

- Patent claims 1. A method for automatically measuring the parameters of electrical domestic wiring, characterized in that it automatically measures the line resistance (Rline) and the resistance of the loop loop (Rloop) to compare the results with the prescribed values and to display the result on the display, the sequence of measurements being arbitrary and the current of equal strength is used for both measurements. A method according to claim 1, characterized in that it measures the resistance of the loop loop (Rloop) ' ⁿ contact voltage (Uc) with a lower current than that used in the measurement of line resistance (Rline), and the order of measurement is arbitrary. Method according to claim 2, characterized in that it also includes a differential current protection switch test, comprising both a test with a rated differential current (Ian) and a measurement of the tripping time of the differential current protection switch (ί _Δ ) the isolation switch is added to the test for the tripping of the circuit breaker and the results of both tests are shown in the display. The method of claim 1 or 2, further comprising measuring the insulation. Method according to claim 1, 2, 3, or 4, characterized in that the reference values are entered by the manufacturer of the device for performing the process. Method according to claim 1, 2, 3 or 4, characterized in that the reference values are entered by the user by means of a computer. Method according to claim 1, 2, 3, or 4, characterized in that it contains a test of the suitability of the voltage at the input terminals before starting the process, which is not performed at all if the voltages at the input terminals are inadequate. The method of claim 7, further comprising determining the direction of the rotating field and showing its direction. A method according to claim 1, 2, 3 or 4, characterized in that it further comprises measuring the resistance of the contacts and displaying the result on the display. -8-διό. The method according to claim 1, 2, 3, 4, 8 or 9, characterized in that the presentation of the results in the form is appropriately - inappropriate. A method according to claim 1, 2, 3, 4, 8 or 9, characterized in that the results are presented numerically. A method according to claim 1, 2, 3, 4, 8 or 9, characterized in that it further stores the results in memory. A method according to claim 1, 2, 3, 4, 8 or 9, characterized in that it further transmits the results to an external computer.