Method and arrangement for testing an earthing system
By dividing earthing system measurements into partial voltages and utilizing phase relationships, the method simplifies and flexibly determines descriptive parameters with shorter measuring wires, addressing the challenges of complex and cumbersome traditional methods.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- OMICRON ELECTRONICS GMBH
- Filing Date
- 2025-11-28
- Publication Date
- 2026-06-11
Smart Images
Figure EP2025084668_11062026_PF_FP_ABST
Abstract
Description
[0001] Procedure and arrangement for testing an earthing system
[0002] The present invention relates to a method and an arrangement for determining a value of a descriptive parameter for describing an earthing system arranged at least partially in an earthing area of the physical earth.
[0003] State of the art
[0004] For electrical installations of all kinds, whether in residential, industrial, or commercial settings, proper grounding is a crucial prerequisite for safe and reliable operation. An improperly grounded electrical installation poses significant risks to users as well as to technical equipment in the immediate vicinity. This is especially true for electrical installations used for power transmission, such as power plants, transformer stations, or overhead line pylons, as the higher electrical power levels involved in a grounded electrical installation carry a greater potential for damage. Depending on the network type (IT, TT, TN), the type of electrical installation (residential / industrial, urban / rural), and the type of safety shutdown device, various methods exist to verify that the grounding is properly and correctly installed.
[0005] In many earthing testing procedures, measuring earth resistance and / or earth impedance is the core of the inspection. Generally speaking, this involves measuring a value for a descriptive parameter used to describe the earthing system, such as earth resistance or earth impedance, and checking whether the measured value falls within a permissible range. Earth resistance and earth impedance measurements are performed, for example, on transformer earth electrodes, high- and medium-voltage pylons, railway tracks, foundation earthing systems, and lightning protection systems.
[0006] To measure earth resistance or earth impedance, the typical procedure is as follows. First, an electrical source is provided, which is electrically connected to the earthing system on one side. On the other side, the source is electrically connected via a source electrode to an earthing area in which the earthing system is at least partially located. An electrical test current is thus introduced into the earthing system via the electrical source. Based on this, and in known solutions particularly using the same device that also contains the electrical source, an electrical voltage drop across the earthing system is measured. In known solutions, the voltage measuring device is connected on one side to the earthing system itself and on the other side to the earthing area via an earth rod at a sufficient distance from the earthing system, as is the case, for example, with...This is known from publications AT 005 503 U1 or EP 2 325 661 A1. To measure the entire voltage drop at once, large distances often need to be maintained between the connection point on the grounding system and the ground rod. Distances on the order of kilometers are not uncommon.
[0007] Achieving such large distances with known solutions requires the use of long measuring wire, i.e., wire several hundred meters, but especially several kilometers long, such as 1 km, 2 km, or more. The cable drums used for transporting and storing this measuring wire are often quite heavy, making transport difficult. Furthermore, the long measuring wire must be wound and unwound at the beginning and end of a measurement, which often proves to be a laborious and time-consuming task. In addition, the terrain of the grounding area where the measurements are taken is usually unknown beforehand. If obstacles and / or impediments must be circumvented in the grounding area, the long measuring wire often presents a hindrance.
[0008] Description of the invention
[0009] The object of the invention is therefore to provide a more flexible and easier-to-use method for testing an earthing system. In particular, it should enable the use of shorter measuring wires.
[0010] This problem is solved by the invention. According to the invention, in the aforementioned method, a test alternating current is introduced into the earthing system, preferably by means of an earthing test main unit, and an initial electrical voltage is measured between the earthing system and an initial measurement position in the earthing area, as well as an electrical section voltage between a first section measurement position in the earthing area and a second section measurement position in the earthing area, preferably by means of an earthing test remote unit. Based on these voltage measurements, an initial phase relationship between the initial voltage and the test alternating current and a section phase relationship between the at least one section voltage and the test alternating current are established, preferably in an evaluation unit.A value of the description parameter, which is preferably a value of an electrical impedance of the earthing system, is determined from the test alternating current, the initial voltage, the at least one section voltage, the initial phase relationship and the section phase relationship, preferably also in the evaluation unit.
[0011] The inventive method achieves and combines a multitude of advantageous effects. Specifically, it allows the complex measurement of a single, large voltage to be divided into the measurement of at least two partial voltages: the initial voltage and at least one section voltage. The initial voltage and the at least one section voltage are then both used to determine the value of the descriptive parameter; preferably, they are added in phase. It is immediately apparent that dividing a large measuring section, over which a single, large voltage is measured in the prior art, into at least two comparatively smaller partial measuring sections, over which correspondingly smaller partial voltages are measured, results in shorter measuring sections. A remote voltage measurement unit, i.e., a mobile voltage measuring device, must be connected to the ends of these shorter sections using measuring wire.The invention thus allows the use of a shorter measuring wire.
[0012] During the determination of a descriptive parameter value, the test AC current preferably exhibits a single, constant frequency, or a single, dominant, constant frequency. A dominant frequency is defined as a frequency whose corresponding frequency component is, for example, 5, 10, or 50 times higher than all other frequency components of the test AC current. The initial voltage and the section voltage can then be measured at the same frequency to determine the value of the descriptive parameter—that is, at the single frequency occurring in the test AC current or at the dominant frequency of the test AC current. In this way, the initial and section voltages used to determine the value of the descriptive parameter have the same frequency as the test AC current.As is well known in complex AC circuit analysis, combining, i.e., in particular adding, frequency components with different frequencies to determine a single impedance value is typically not practical, or even impossible when using complex phasors. In the case of noisy measurement signals or in the case of multiple frequency components, the currents and voltages occurring within the scope of the invention can be suitably filtered, e.g., by means of a low-pass filter or a band-pass filter, etc., in order to isolate frequency components with the same frequency from the aforementioned currents and voltages and subsequently use them for determining a value of the descriptive parameter.However, it should be noted that, using the method according to the invention, it is of course also possible to determine several values of the description parameter for different frequencies in succession. To determine a first value at a first frequency, the test alternating current can be specified at the first frequency, and to determine a second value at a second frequency, the test alternating current can be specified at the second frequency in a corresponding manner. In this case, even when using only a single frequency to determine each individual value of the description parameter, several frequencies can occur when applying the invention.
[0013] In a particularly preferred method, the initial voltage and at least one electrical section voltage are added to obtain a total voltage, taking into account the initial and section phase relationships. This total voltage is then used to determine the value of the descriptive parameter. As will be explained in detail later, the phase relationship can, in particular, describe a phase angle between the test AC current and the aforementioned voltages. Specific methods for determining the values of the descriptive parameter from a total voltage and the test AC current will be explained in detail later.In a well-known manner, for example, the value of an absolute value can be determined by division, where the amplitude of the total voltage at a specific frequency is divided by the amplitude of the test AC current at the same frequency. If impedance is sought as a descriptive parameter, a phase shift caused by the grounding system must be taken into account in addition to the amplitude division, in a similarly well-known manner. If the currents and voltages, and consequently the total voltage, are represented by complex phasors, and if an angle is known for each phasor orienting it in the complex plane, the phase shift caused by the grounding system can be determined by subtracting the phase angle of the test AC current phasor from the phase angle of the total voltage phasor.These methods are well known to anyone skilled in the field of electrical engineering, as are a number of other methods for determining the value of a resistance or impedance. Within the scope of the invention, it is also conceivable to use only a phase shift as a descriptive parameter, particularly when determining the corresponding phase information is easy, but determining the corresponding amplitudes is more difficult. A key insight of the invention is that electrical voltages, especially alternating voltages, that were not measured at the same time can only be correctly added to a correct total voltage if their phase relationship is known and if this phase relationship is taken into account accordingly, in particular their phase relationship to a common reference quantity, such as the test alternating current, or their phase relationship to each other.The invention is based on the insight that by correctly using accurate phase information about the current and the measured voltages, it becomes possible to use easier-to-handle partial measurements instead of an otherwise complex overall measurement.
[0014] As mentioned, the inventive method reduces the length of the measuring wire required to electrically connect a remote unit, particularly a voltmeter, to the points between which voltages are measured. Consequently, less measuring wire needs to be wound and unwound. The invention also ensures that sufficient measuring wire is always available. If the grounding system to be measured is unknown beforehand, it may turn out that there is insufficient measuring wire to determine the entire required voltage with a single measurement. Therefore, prior art requires planning in advance how much measuring wire will be needed. This necessity is eliminated by applying the invention, which represents a significant practical advantage.
[0015] In a further, particularly preferred embodiment of the invention, it becomes possible to measure a plurality of section voltages, each dropping between pairs of section measurement positions in the grounding area, and to use these to determine the value of the descriptive parameter, preferably by adding the plurality of section voltages to a total voltage, taking into account their respective phase relationships to the test alternating current. In this preferred embodiment, the voltage measurement is not divided into just two partial measurements, but into a plurality of partial measurements, which further enhances the advantageous effects of the invention (even shorter wire, even simpler measurement procedure).
[0016] To advantageously arrange the measurement of the initial voltage and the at least one measurement of the section voltage, and also to enable a particularly efficient execution of the method according to the invention, the initial measurement position and the first section measurement position can be selected to be less than a predetermined measurement position distance apart. The predetermined measurement position distance can preferably correspond to one meter, more preferably to 0.5 meters, most preferably to 0.1 meters, or it can be provided that the initial measurement position corresponds to the first section measurement position, and / or that, in the case of a plurality of section measurements, each section measurement position, except for a final section measurement position, is used to measure two voltages each.In this way, adding the measured voltages becomes particularly efficient, and the practical execution of the measurements is also simplified. If ground rods are used to electrically connect a mobile remote unit, such as a mobile voltage measuring device, to the points in the grounding area between which the respective voltages are measured, a ground rod can simply be left in place if a measurement position always falls into two segments, as is the case in the aforementioned preferred embodiment where the initial measurement position corresponds to the first segment measurement position. Here, one and the same ground rod can be used for measuring both the initial voltage and the voltage of at least one of the first segments.
[0017] As explained at the outset, the consideration of phase relationships or phase information plays a crucial role in the invention. The invention offers considerable flexibility in providing this phase information, allowing for the selection of a different, most suitable method depending on the specific requirements of an application. Specifically, the invention enables the test alternating current to be synchronized to a predetermined time standard for establishing the initial and intermediate phase relationships, and this time standard to be taken into account when measuring the initial voltage and at least one intermediate voltage. This time standard could, for example, be a GPS-defined time standard, a clock signal, an atomic clock signal, or a predetermined point in time.Since the test alternating current is alternating current, synchronization can be achieved, for example, by specifying or defining a time position of a minimum (if the test alternating current has an offset) or a zero crossing (if the test alternating current has no offset) of the test alternating current.
[0018] As a further option for providing phase information, a reference signal can be transmitted and received, for example via radio, Wi-Fi, or other wireless technology. The reference signal could be, for instance, a pulse that describes a zero crossing of the test AC current or a point in time at which the test AC current reaches a maximum or minimum. Using such information, the phase angle of a measured voltage, such as an initial voltage or a section voltage, can be determined in order to subsequently take it into account correctly and, in particular, without phase discrepancies. As is well known, a phase angle that is 180° incorrect would turn a necessary addition into a subtraction, or vice versa, ultimately leading to completely incorrect measurement results.
[0019] The reference signal can preferably be emitted from a source for supplying the test AC current and received by a mobile remote unit for measuring the initial and section voltage, or the reference signal can be emitted from a mobile remote unit for measuring the initial and section voltage and received by a source for supplying the test AC current.
[0020] To carry out the method described above, an arrangement according to the invention can be provided, comprising a main earthing test unit, a remote earthing test unit, and an evaluation unit. The main earthing test unit can be configured to feed the test alternating current into the earthing system, and the remote earthing test unit can be configured to measure the initial electrical voltage between the earthing system and the initial measurement position, as well as to measure at least one electrical section voltage between a first section measurement position in the earthing area and a second section measurement position in the earthing area.The evaluation unit can further be designed to determine the value of the description parameter from the test AC current, the initial voltage, the at least one electrical section voltage, an initial phase relationship between the initial voltage and the test AC current, and a section phase relationship between the at least one section voltage and the test AC current.
[0021] The earth test remote unit, the earth test main unit, and / or the evaluation unit can all be configured to determine the initial phase relationship and the section phase relationship. Furthermore, the evaluation unit can be integrated as part of the earth test remote unit or as part of the earth test main unit. If the evaluation unit is located in the remote unit, the value of the descriptive parameter is determined at a measurement position for voltage measurement. This is often advantageous because initial results are generated during the measurement itself, which can then be used to plan further measurements of additional section voltages. If the evaluation unit is located in the main unit, the value of the descriptive parameter is determined at a feed-in position for the test alternating current.Furthermore, it is conceivable that the evaluation unit is arranged in a computing unit, for example as part of a desktop PC or as part of a laptop or other computing unit that is independent of the earth test remote unit and / or the earth test main unit, so that flexibility exists in this area of the invention to best adapt the invention to the requirements of specific applications. A particularly advantageous further embodiment of the earth test remote unit can be realized by providing a graphic display element or screen on the earth test remote unit, by means of which one or more values determined by the invention are graphically displayed, particularly preferably during the measurement.
[0022] Brief description of the characters
[0023] The present invention is explained in more detail below with reference to Figures 1 to 4, which show exemplary, schematic, and non-limiting advantageous embodiments of the invention.
[0024] Fig. 1 shows an earthing system with a determination of a descriptive parameter according to the invention.
[0025] Figs. 2a-c show possible configurations of an arrangement according to the invention.
[0026] Fig. 3a-b shows possible current and voltage indicators when applying the invention.
[0027] Fig. 4 shows a possible course of a descriptive parameter when applying the invention.
[0028] Implementation of the invention
[0029] Fig. 1 shows an earthing system 1, such as can be used in particular for earthing an overhead line mast, a high-voltage transformer, a high-voltage generator, or other high-voltage switching device, and in which the determination of a descriptive parameter according to the invention can be applied in a particularly advantageous manner. The earthing system 1 can, for example, comprise an earthing network or a meshed earth electrode. The earthing system 1 shown in Fig. 1 is connected to the physical earth via an earthing impedance ZE in order to ensure, in a known manner, the dissipation of electrical currents into the earth in the event of a fault. In order to verify the correct design and operation of the earthing system 1, a variety of test methods are used to determine an earthing resistance, a grounding resistance, or an earthing impedance as precisely as possible and to compare these values with standardized values.General information on earthing systems and their testing can be found in a large number of scientific publications and printed materials, which is why the basic functionality and testing of an earthing system 1 will not be discussed in more detail here.
[0030] Fig. 1 further shows the components of an arrangement 100 according to the invention for determining the value of a descriptive parameter ZE for describing an earthing system 1 that is at least partially located in an earthing zone EB of the physical ground. The arrangement 100 comprises an earthing test main unit H, an earthing test remote unit F, and an evaluation unit A. To implement the invention, the earthing test main unit H is configured, in this case by means of an electrical source Q, to inject a test alternating current IAC into the earthing system 1. The test alternating current IAC is typically predetermined for this purpose and is therefore usually known a priori. However, within the scope of the invention, it is also conceivable to measure the test alternating current IAC, for example, using a suitable current measuring device.The source Q is designed to generate the test alternating current IAC at a predetermined frequency that remains constant during the determination of a value of the description parameter ZE, preferably at a single, constant frequency. The predetermined frequency can, for example, be in a range from 10 Hz to several hundred Hz, or from 20 Hz to 100 Hz. The current of the test alternating current iAc can be, for example, several amperes, in the range of 1 A to 50 A. Depending on the conditions, however, a lower current, for example on the order of 100–200 mA, may also be sufficient. These relationships are well known to anyone skilled in the field of AC technology.
[0031] The earthing test remote unit F is designed within the scope of the invention to measure electrical voltages, in particular an initial electrical voltage U.e , which drops between the earthing system 1 itself and an initial measuring position A-1 in the earthing area EB, and an electrical section voltage U a ,i between a first section measurement position A-1 in the earthing area EB and a second section measurement position A-2 in the earthing area EB. As noted earlier, the earthing test remote unit F can have a display for outputting results and other components, such as operating elements. In a further step, to determine the value of the description parameter ZE ZU required for earthing testing from the measured voltages, which can be, for example, in the range of a few millivolts, a few volts, or several volts, the evaluation unit A is designed to determine the value of the description parameter ZE ZU from the test alternating current i. A c, the initial voltage Ue, which is at least one electrical section voltage U a,i, an initial phase relationship between the initial voltage U e and the examination alternating current i A c, a section-phase relationship between the at least one section voltage U a ,i and the examination alternating current i AC .
[0032] It should be noted that the illustrated arrangement of the evaluation unit A in the earth test remote unit F is purely exemplary. Within the scope of the invention, it is equally possible to provide the evaluation unit A as part of the earth test remote unit F or as part of the earth test main unit H. Possible embodiments of the arrangement 100 according to the invention, which differ in the placement of the evaluation unit A, are shown in Figures 2a-c. The components earth test remote unit F, earth test main unit H, and evaluation unit A can preferably communicate via a wireless data connection, such as radio or WLAN, etc. If the evaluation unit A is provided as part of one of the other units (main unit H, remote unit F), conventional cabling can, of course, also be used.In principle, the earth test remote unit F, the earth test main unit H and the evaluation unit A can be implemented in the form of microprocessor-based hardware, a microcontroller, or an integrated circuit (ASIC, FPGA).
[0033] To determine the initial voltage and at least one electrical section voltage U a To measure i, the depicted earth test remote unit F has a first measuring probe X and a second measuring probe Y, which are connected to the measuring positions and wired to the earth test remote unit F by means of measuring wire. The earth test remote unit F therefore comprises or is designed as a voltage measuring device capable of measuring the aforementioned voltages, i.e., at least of detecting that frequency component of the initial voltage and the section voltage that corresponds to the frequency of the test alternating current i. Ac corresponds to. As is known, two connections of the source Q are required for introducing the test alternating current. In this invention, a source electrode QE is provided to connect the source Q to the grounding area EB, and an electrically conductive connection is provided directly from the source Q to the grounding system 1. This ensures that the test alternating current circulates via the grounding system 1, allowing the determination of the value of the descriptive parameter ZE by measuring the current and voltage. As explained earlier, an arrangement according to the invention, as shown in Fig. 1, makes it possible to divide the complex measurement of a single, large voltage into the measurement of at least two partial voltages.It is immediately apparent that dividing a large measuring section, over which a single, large voltage is measured according to the prior art, into at least two comparatively smaller partial measuring sections, over which correspondingly smaller partial voltages are measured, results in shorter measuring sections. A remote unit, i.e., a mobile voltage measuring device, must be connected to the ends of these shorter sections using measuring wire. The invention thus allows the use of shorter measuring wire. As mentioned, the inventive method reduces the length of the required measuring wire that electrically connects a remote unit to the points between which the corresponding voltages are measured. Consequently, less measuring wire needs to be wound and unwound.
[0034] As can also be seen from Fig. 1, in the scenario shown not only a section voltage U a,i measured, which would already be sufficient for carrying out the invention, but a multitude of section stresses U are measured. a ,i , U a ,2, U a ,3, U a ,4, which each drop between pairs of section measurement positions A-1, A-2, A-3, A-4, ... in the earthing area EB, are measured and used to determine the value of the description parameter ZE. A distance between the section voltages U a ,i , U a ,2, U a ,3, U a ,4, can be a few meters, for example 10 m or 50 m or up to 100 m, but is advantageously chosen to be smaller than the distances of one kilometer or more that are otherwise customary in the prior art.
[0035] As also shown in Fig. 1, the section stresses U a ,i , U a ,2, U a ,3, U a,4 between pairs of section measurement positions (A-1, A-2), (A-2, A-3), (A-3, A-4), etc., wherein the section measurement positions (except for the first and last section measurement positions) always occur in two pairs. As explained earlier, this is advantageous. In this way, means for connecting the earth test remote unit F to the section measurement positions A-2, A-3 can remain at a section measurement position for at least two measurements, so that the arrangement according to the invention has to be rearranged less often. The aforementioned means for connecting the earth test remote unit F to the section measurement positions A-1, A-2, A-3, A-4 are usually constructions consisting of measuring wire and a measuring electrode X,Y; the measuring electrode X,Y can, in this context, be designed in particular as an earth rod.More detailed descriptions of corresponding ground rods can be found, among other places, in documents AT 005 503 U1 or EP 1 736 786 B1. In the situation shown, the initial measuring position A-1 also corresponds to the first section measuring position A-1. However, it is also conceivable to arrange the initial measuring position A-1 and the first section measuring position A-1 within a predetermined measuring position distance of each other, wherein the predetermined measuring position distance preferably corresponds to one meter, particularly preferably 0.5 meters, most preferably 0.1 meters, in order to be able to take the measured stresses into account unchanged when calculating the value of the descriptive parameter. If the distances become too large, however, measurement errors can occur, since the sum of the measured initial stress and the measured section stresses, i.e., the sum of the partial stresses, may then no longer correspond to a total stress U. ges corresponds to the value that, in the case shown in Fig. 1, would drop, for example, between the initial measuring position A-1 and the fourth section measuring position A-4.
[0036] The currents and voltages that can occur when applying the invention are further illustrated in Figures 3a-b, using the complex phasor method commonly used in AC circuit analysis. As is customary in complex AC circuit analysis, the quantities involved are represented with capital letters and underlined in the following explanations. Figure 3a represents a situation in which only an initial voltage U is present. a and a first section voltage U e ,i can be measured. Both the initial voltage U a and the first section voltage U e The two values are of course measured at the same frequency; otherwise, no meaningful combination / addition would be possible, especially to achieve a total voltage U. ges, but also no representation as complex phasors in the same, common complex plane. In the case of using a representation of the occurring currents and voltages by means of complex phasors, the phase relationship according to the invention can, for example, be expressed in the form of a phase angle. In order to determine a value of the descriptive parameter ZE ZU, the initial voltage Ue and the at least one electrical section voltage U can be a ,i taking into account the initial phase relationship and the section phase relationship to a total voltage U ges to be added, i.e., U ges = U e + U a ,i can be set, and the total voltage U can be determined. ges to determine the value of the description parameter ZE.
[0037] Fig. 3b, in contrast, shows a situation in which an initial voltage U e and a variety of section stresses U a ,i, U a ,2, Ua ,3, U a ,4, U a ,s, specifically five section voltages, measured and taking into account a respective phase relationship to the test alternating current IAC TO a total voltage U ges The phase relationship is taken into account in this case by considering the orientation of the phasors in the complex plane during the addition. Even in the situation shown in Fig. 3b, the resulting total voltage U is ultimately calculated. ges used to determine the value of the description parameter ZE. In the case of using multiple stresses, as in the situation shown in Fig. 3b, there is also the often particularly advantageous possibility of not first determining a total stress U. geInstead of determining the value of the description parameter from the total voltage Uges, a value of a section description parameter is determined for each individual section voltage, and then this multitude of section description parameters is combined to obtain the desired value of the description parameter. For example, if a total earthing impedance is sought, a series of partial impedances can be determined in this way, which are then summed in phase. Alternatively, all partial voltages available at any given time can be continuously added to obtain preliminary total voltages, and partial values of the description parameter can be continuously determined from these preliminary total voltages. In this way, the temporal development of the description parameter can be monitored during the process. Fig.Figure 4 shows a possible progression of such partial values of a descriptive parameter. In the following discussion of Figure 4, a further, particularly advantageous embodiment of the invention will be addressed.
[0038] To provide the information central to the invention regarding the phase relationship between the test AC current and the measured voltages, various options exist, as explained earlier. In the situation shown in Fig. 1, the test AC current IAC can be synchronized to a predetermined time standard, preferably a GPS-defined time standard, to establish the initial and intermediate phase relationship. Alternatively, a reference signal can be transmitted, e.g., from the main earth test unit H, particularly from a source Q in the main earth test unit H, and received, e.g., from the remote earth test unit F, or vice versa, preferably via radio, Wi-Fi, or Wi-Fi.It should be noted that in an advantageous embodiment of the invention, in which the test alternating current IAC has only one frequency, or only one dominant frequency, the phase angle at that single frequency is already sufficient to carry out the invention.
[0039] Finally, Fig. 4 shows a possible course of a description parameter ZE as it can be set when applying the invention if, as described above, an initial voltage U is applied. e as well as a variety of section stresses U a ,i , U a ,2, U a ,3, U a ,4 is measured and immediately after measuring a section voltage U a ,i , U a ,2, U a ,3, U a,4 a new value of the description parameter ZE is determined, always using all available information about the measured voltages, i.e., all partial voltages available at a given time are added to a preliminary total voltage, and this preliminary total voltage is used to determine a preliminary value of the description parameter. It should be noted that the values shown are determined at the same frequency. As is well known, the impedance of a system can change with the frequency of the applied voltage / current, so comparing or summing impedances at different frequencies would not yield meaningful results.
[0040] The indices on the abscissa symbolize the voltage measured immediately before the corresponding value was determined. As the number of available measurements increases, the value of the descriptive parameter ZE converges to a final value Z. E1 A key reason for this is that voltages measured further away from the earthing system 1 decrease, so that voltages measured further away contribute correspondingly less to any total voltage U that may be determined. ge s deliver. The insight that values of the description parameter Z E Since the values converge with an increasing number of measurements, this can now be used for a further advantageous embodiment of the invention. Specifically, values of the descriptive parameter Z can be used. EThey can be compared, and further section voltages can be measured as long as, for example, two consecutive values of the description parameter Z are found. E , such as Z E ,2 and Z E "3, to differentiate at least one predefined deviation. The predefined deviation can be specified, for example, as a relative value, such as 10%, 5%, 1%, or 0.5%. If the deviation of two consecutive values of the description parameter Z is less than..." E The deviation suggests a converged state, meaning that further measurement of a section stress will not result in any significant change to the determined value. Small deviations between successive values of the descriptive parameter Z EThis corresponds to decreasing section voltages, which is equivalent to a flattening of the electrical potential profile in the earthing area EB. The absence of significant changes in the potential profile can therefore be considered evidence that one is outside the influence of the earthing system being measured, where further measurements would yield no or only negligible additional information. In such a case, a termination signal can be issued, e.g., a graphic signal displayed on the earthing test remote unit F, which can advise a user or operator not to perform any further measurements. However, the final decision as to when the section voltage measurement is actually terminated should preferably be made by a qualified operator, even in this case.
Claims
Patent claims 1. Method for determining a value of a description parameter (ZE) for describing an earthing system (1) located at least partially in an earthing area (EB) of the physical soil, comprising the steps: - Injecting a test alternating current (i A c) into the earthing system (1); - Measuring an initial electrical voltage (U e ) between the earthing system (1) and an initial measuring position (A-1) in the earthing area (EB); - Measuring at least one electrical section voltage (U) a ,i) between a first section measurement position (A-1) in the earthing area (EB) and a second section measurement position (A-2) in the earthing area (EB); - Establishing an initial phase relationship between the initial voltage (U e ) and the examination alternating current (i A c); - Establishing a section-phase relationship between at least one section voltage (U) a ,i) and the examination alternating current (i AC ); - Determining the value of the description parameter (ZE) from the test alternating current (i AC ), the initial voltage (U e ), which at least one section voltage (U a ,i), the initial phase relationship and the section phase relationship.
2. Method according to claim 1, characterized in that the initial measuring position (A-1) and the first section measuring position (A-1) are separated by less than a predetermined measuring position distance, wherein the predetermined measuring position distance preferably corresponds to one meter, particularly preferably to 0.5 meters, most preferably to 0.1 meters, or that the initial measuring position (A-1) corresponds to the first section measuring position (A-1).
3. Method according to claim 1 or 2, characterized in that the initial voltage (Ue) and the at least one electrical section voltage (U) a ,i) taking into account the initial phase relationship and the section phase relationship, are added to a total stress (Utotal) and that the total stress (Utotal) ges ) is used to determine the value of the description parameter (ZE).
4. Method according to one of the preceding claims, characterized in that a plurality of section stresses (U) a ,i, U a ,2, U a ,3, U a ,4), which each between The voltage drop between pairs of section measurement positions (A-1, A-2, A-3, A-4, ...) in the earthing area (EB) is measured and used to determine the value of the description parameter (ZE), preferably by measuring the plurality of section voltages (U). a ,i , U a ,2, U a ,3, U a4) taking into account a respective phase relationship to the test alternating current OAC) TO a total voltage (U ge s) are added, where the total voltage (U ge s) is used to determine the value of the description parameter (ZE).
5. Method according to one of the preceding claims, characterized in that a value of an electrical impedance of the earthing system (1) is determined as the value of the description parameter (ZE).
6. Method according to one of the preceding claims, characterized in that the test alternating current (IAC) for establishing the initial and section phase relationship is synchronized to a predetermined time standard, preferably a time standard determined by GPS, and that the time standard is used when measuring the initial voltage (Ue) and the at least one section voltage (U). a ,i) is taken into account.
7. Method according to one of claims 1 to 5, characterized in that a reference signal is transmitted and received to establish the initial and intermediate phase relationship.
8. Method according to claim 7, characterized in that the reference signal is emitted from a source (Q) for supplying the test alternating current (IAC) and is received by a mobile remote unit (F) for measuring the initial and section voltage, or that the reference signal is emitted from a mobile remote unit (F) for measuring the initial and section voltage and is received by a source (Q) for supplying the test alternating current (IAC).
9. Method according to claim 7 or 8, characterized in that the reference signal is transmitted and received via radio, WLAN or Wifi.
10. Method according to one of the preceding claims, characterized in that the determination of the value of the description parameter (ZE) is carried out in the area of a measuring position for voltage measurement, preferably in a mobile remote unit (F) for voltage measurement, or that the determination of the value of the description parameter (ZE) is carried out in the area of a feed-in position for feeding in the test alternating current (OAC), preferably in a stationary main unit (H) with an electrical source for feeding in the test alternating current (OAC).
11. Method according to one of the preceding claims, characterized in that determined values of the description parameter (ZE) are displayed, preferably graphically, preferably on a display of a mobile remote unit (F) for voltage measurement.
12. Arrangement (100) for determining a value of a description parameter (ZE) for describing an earthing system (1) arranged at least partially in an earthing area (EB) of the physical earth, the arrangement (100) comprising an earthing test main unit (H), an earthing test remote unit (F) and an evaluation unit (A), wherein - the earth test main unit (H) is designed to provide a test alternating current (i A c) to feed into the earthing system (1); - the earthing test remote unit (F) is designed, • an initial electrical voltage (U e ) between the earthing system (1) and a To measure the initial measurement position (A-1) in the earthing area (EB), • at least one electrical section voltage (U) a ,i) to measure between a first section measurement position (A-1) in the earthing area (EB) and a second section measurement position (A-2) in the earthing area (EB); - the evaluation unit (A) is designed to determine the value of the description parameter (ZE) ZU from the test alternating current (i A c), the initial voltage (U e ), which at least has an electrical section voltage (U) a ,i), an initial phase relationship between the initial voltage (U e ) and the examination alternating current (i AC ), a section-phase relationship between the at least one section stress (U a ,i) and the examination alternating current (i A c) 13. Arrangement according to claim 12, characterized in that the earthing test remote unit (F) and / or the earthing test main unit (H) and / or the evaluation unit (A) are configured to determine the initial phase relationship and the section phase relationship.
14. Arrangement according to claim 12 or 13, characterized in that the evaluation unit (A) is provided as part of the earth test remote unit (F) or as part of the earth test main unit (H).
15. Arrangement according to one of claims 12 to 14, characterized in that the earthing test remote unit (F) has at least a first measuring probe (X) and a second -17- measuring probe (Y) to determine the initial voltage and at least one electrical section voltage (U) a ,i) to measure.