Earthing system and method for conducting alternating current from a steel structure

Description

[0001] The invention relates to an earthing system for discharging alternating current from a steel structure, wherein the earthing system has an earthing electrode that is electrically connected to the steel structure. Furthermore, the invention relates to a method for discharging alternating current from a steel structure by means of at least one earthing system, wherein the earthing system has an earthing electrode that is electrically connected to the steel structure, wherein the steel structure is designed as a buried, cathodically protected pipeline subjected to alternating current.

[0002] CN 106 707 098 A discloses an online monitoring device used for the online monitoring and positioning of overhead line discharges, i.e., for fault location in overhead lines. The online monitoring device includes a transformer component for monitoring the current of the grounding wire of a steel structure. For monitoring purposes, the grounding wire or electrode of the steel structure passes through a magnetic ring of the transformer component.

[0003] CN 106 597 113 A describes an online tester for the earth resistance of a power pole. This online tester is designed to simplify earth resistance measurement, particularly enabling measurements without having to disconnect the grounding conductor. Two parallel grounding conductors are each equipped with a sensing head. An auxiliary electrode is also located in the ground. An upper coil, a lower coil, and the auxiliary electrode are connected to a signal processing module for control and data processing. The grounding conductors run through the center of each coil.

[0004] German patent DE 25 46 694 A1 discloses a measuring transmitter for high-voltage power lines. A conversion-digitization unit assigns digital values ​​to the operating potential of the high-voltage line conductor. One or more electrical or non-electrical quantities of the high-voltage line, which are fed to a high-frequency transmitter unit, are converted into a high-frequency signal. This signal is then transmitted directionally or omnidirectionally, or along the high-voltage line, using a suitable antenna. The energy required for operation is supplied to the conversion-digitization unit and the high-frequency transmitter unit with its suitable antenna by a power supply unit, which is powered by current in the conductor of the high-voltage line.The power supply includes a ring transformer, so that the conductor of the high-voltage line acts as the primary winding, and the voltage induced in the secondary winding is converted into DC voltage with the operating potential of the high-voltage conductor as the zero potential by suitable rectifier circuits. A battery maintains a constant voltage and is charged whenever the current in the high-voltage line is sufficiently high.

[0005] High-voltage overhead power lines couple alternating voltages into steel structures through their electromagnetic fields. This can result in high contact voltages between the steel structure and the ground. During peak load times, earth faults, or in cases of asymmetry between parallel high-voltage overhead power lines, the voltages coupled into a steel structure can reach high values. Therefore, grounding systems are used to protect people and animals.

[0006] In pipelines, grounding is used to limit the permanently present touch voltage to certain values. < 60V is required for the protection of personnel.

[0007] To limit the touch voltage in the case of continuous exposure, i.e., electromagnetically coupled touch voltages, earthing systems can be used that are directly connected to the steel structure.

[0008] An earthing system has at least one earthing electrode, i.e., an electrically conductive element that is in electrical contact with the earth in order to dissipate the alternating current and to achieve an alternating voltage limitation, for example, of a pipeline.

[0009] In practice, earthing systems are manually checked on site at regular intervals to ensure they are functioning correctly, i.e., to verify that the essential components of the earthing system are functioning as intended.

[0010] Each grounding system must be inspected on-site by qualified personnel to verify its functionality. Because individual grounding systems can be located far apart, this on-site inspection is very labor-intensive.

[0011] In practice, to test the earthing system on-site, a resistance measuring device is connected to its circuits. This requires intervention in the electrical circuits. Consequently, the effort required for on-site testing is relatively high.

[0012] Due to the increasing generation of renewable energy and the monitoring of high-voltage transmission lines, the factors that determine the high-voltage influence on steel structures, especially pipelines, are highly variable. Therefore, there is a need to be able to check the current level of AC influence on a steel structure at any time to ensure that the grounding systems are functioning correctly.

[0013] For on-site measurements, a power supply for a measuring device is required. Continuous or periodic measurements require a relatively high current. For example, to obtain several readings per minute, standard measuring devices or data acquisition units require approximately 20 mA / h at a 3.3 Vdc supply voltage. Low-voltage power (230 Vac) is generally not available at the locations of the grounding systems.

[0014] Standard lithium batteries have a capacity of approximately 19Ah. Such batteries would no longer be able to power a data acquisition unit in less than 40 days, necessitating frequent battery changes.

[0015] A solar panel could be used as an alternative power supply for a data acquisition unit, but these are susceptible to vandalism. Furthermore, many locations do not receive sufficient sunlight for a certain duration.

[0016] Therefore, the task is to further develop an earthing system for dissipating alternating current from a steel structure in such a way that monitoring of the steel structure with regard to the level of the alternating current load and / or monitoring of the earthing system with regard to functionality is possible independently of the grid using a measurement acquisition unit.

[0017] This problem is solved by an earthing system with the features of claim 1 and a method according to claim 11. Advantageous embodiments are the subject of dependent claims.

[0018] The steel component is designed as a buried, cathodically protected pipeline subjected to alternating current, with a separation unit electrically connected to the pipeline and the grounding electrode, thus providing DC isolation of the pipeline from the grounding electrode. The pipeline could, for example, be a long-distance gas pipeline.

[0019] According to the invention, the earthing system comprises a transformer component with a primary winding and a secondary winding, wherein the alternating current derived from the pipeline can be fed into the primary winding, wherein the primary winding is connected in series in the current path of the earthing system, wherein the secondary winding provides the charging voltage for a battery, and wherein a measurement acquisition unit is arranged to continuously or periodically acquire current and voltage values ​​of the boundary unit and to continuously or periodically store them.

[0020] The alternating current derived from the steel structure powers a battery that can supply at least one measurement acquisition unit on site, thus enabling continuous measurements regarding the level of alternating current influence and / or monitoring of the earthing system's functionality, independent of the mains power supply.

[0021] According to the invention, the primary winding is connected in series with the current path of the grounding system. In other words, the current path of the grounding electrode acts as the primary winding of the transformer component. On the secondary side, the turns ratio can be automatically adjusted according to the current value of the grounding system.

[0022] An advantageous embodiment is characterized in that the secondary winding of the transformer component is electrically connected to charging electronics which are configured to set and / or adjust the operating voltage of the accumulator and / or that the transformer component is adaptable to different AC current ranges.

[0023] Preferably, the secondary winding is electrically connected to charging electronics that are configured to set and / or adjust the operating voltage of the accumulator.

[0024] Advantageously, the transformer component can be adapted to different AC current ranges. The transformer component is preferably manually adjusted once to the expected leakage current of the earthing system.

[0025] Preferably, a voltage converter, which is preferably adjustable, is connected to the battery. The voltage converter can, for example, provide a supply voltage of 3.3Vdc to 3.8Vdc.

[0026] According to the invention, a measurement acquisition unit, which is supplied with power by the accumulator, is designed to continuously or periodically measure and store current and voltage values ​​of the earthing system.

[0027] A preferred further education system is characterized by the fact that a communication unit is in communication connection with the measurement acquisition unit and a remote monitoring unit.

[0028] A communication unit is understood to be a unit that wirelessly transmits data using common interfaces and data transmission standards (WLAN, GSM, UMTS, USB, LAN, etc.). A remote monitoring unit is understood to be an external data processing unit that can receive data and preferably process and / or display it. Examples include a server, a computer system, or a tablet computer.

[0029] According to the invention, the measurement acquisition unit or the remote monitoring unit is configured to display the derived alternating current and / or to calculate and display, from the measured current and voltage measurements, those resistance values ​​that are characteristic for the functionality of the earthing system and / or to compare them with target values.

[0030] According to the invention, the resistance values ​​that characterize the functionality of the earthing system can be calculated and displayed in the measurement acquisition unit from the measured current and voltage values. Optionally, the calculated values ​​can be compared with target values. If the calculated values ​​deviate from the target values, a signal can be sent to the remote monitoring device via the communication unit, depending on the magnitude of the deviation, in order to initiate measures for checking the earthing system on site.

[0031] Alternatively, the measured current and voltage values ​​can be sent via the communication unit to the remote monitoring unit, which may be located in a control center. The resistance values ​​characteristic of the earthing system's functionality are calculated and displayed centrally from the locally measured current and voltage values. Optionally, the calculated values ​​can be compared centrally with target values. If the calculated values ​​deviate, measures can be taken, depending on the extent of the deviation, to check and restore the earthing system's functionality on-site.

[0032] Preferably, the earthing system is characterized in that the measurement acquisition unit, which is powered by the accumulator, is configured to continuously or periodically measure and store current and voltage values ​​of the earthing system, that a communication unit for transmitting the measured values ​​is in communication connection with the measurement acquisition unit and a remote monitoring unit, that the remote monitoring unit is configured to display the derived alternating voltage or the derived alternating current and / or to calculate and display from the transmitted current and voltage measurement values ​​those resistance values ​​that are characteristic for the functionality of the earthing system and / or to compare them with target values.

[0033] The measured values ​​are preferably transmitted continuously or periodically to the remote monitoring unit. The current level of AC interference affecting a steel structure can be checked centrally at any time. Furthermore, multiple earthing systems for protection against impermissible touch voltages due to AC interference can be monitored centrally and simultaneously at any time to determine whether they are operational.

[0034] Central remote monitoring allows for continuous or periodic checks at selected times or intervals, without requiring personnel, to verify that the relevant components of the grounding system are functioning correctly for their intended purpose. Safety deficiencies that could endanger people or animals are detected promptly.

[0035] The communication unit can be a modem or a similar component. It can be a separate component. Preferably, the communication unit is integrated into the measurement acquisition unit and forms a single unit with it.

[0036] According to the invention, the measurement acquisition unit is designed to calculate at least the earth propagation resistance of the earthing system.

[0037] Alternatively, the remote monitoring unit is advantageously configured to calculate at least the earth resistance of the earthing system, wherein an auxiliary earth electrode is connected in parallel to the earthing system, wherein the earthing system has a first current measuring resistor at which the total alternating current flowing through the earthing system can be measured, wherein the measurement acquisition unit is configured to measure the alternating voltage between the earthing electrode and the pipeline and the alternating voltage between the earthing electrode and the auxiliary earth electrode, and wherein the remote monitoring unit is configured to calculate the earth resistance of the earthing system from the difference of the measured alternating voltages divided by the measured total alternating current.

[0038] The earth resistance should be as low as possible. Continuous remote monitoring ensures that the earthing system is functioning correctly.

[0039] According to the invention, instead of the remote monitoring unit, the measurement acquisition unit is configured to calculate the earth resistance of the earthing system from the difference of the measured alternating voltages divided by the measured total alternating current.

[0040] According to the invention, the earthing system is characterized in that the measurement acquisition unit is configured to measure and store current and voltage values ​​of the boundary unit, and that the measurement acquisition unit or the remote monitoring unit is configured to calculate and display, and / or compare with target values, those resistance values ​​that are characteristic of the functionality of the boundary unit from the measured current and voltage measurement values.

[0041] The calculated values, which characterize the functionality of the boundary unit, are displayed either on-site in the measurement acquisition unit or in a remote monitoring unit, which may be located in a monitoring center. Optionally, the calculated values ​​can be compared with target values, and appropriate measures can be derived from this comparison.

[0042] Within the scope of the invention, the measurement acquisition unit is configured to continuously or periodically measure and store current and voltage values ​​of the boundary unit, wherein the communication unit is in communication connection with the measurement acquisition unit and the remote monitoring unit for transmitting the measured values, wherein the remote monitoring unit is configured to calculate and display, and / or compare with target values, those resistance values ​​that are characteristic for the functionality of the boundary unit from the transmitted current and voltage measurement values.

[0043] An advantageous embodiment of the invention consists in the fact that the boundary unit comprises a first boundary module and a second boundary module connected in parallel thereto, that the first boundary module is designed as a series resonant circuit, that the second boundary module has a switch which closes when an alternating voltage induced in the pipeline exceeds a set alternating voltage threshold, that a second current measuring resistor is located in the first boundary module designed as a series resonant circuit, and that the measured value acquisition unit is configured to measure the alternating voltage across the earthing system, the total alternating current flowing across the earthing system at the first current measuring resistor, and the partial alternating current flowing across the first boundary module at the second current measuring resistor, and that the remote monitoring unit is configured toto calculate the internal resistance of the first boundary module from the AC voltage of the earthing system divided by the partial AC current, and to calculate the internal resistance of the second boundary module from the AC voltage divided by the total AC current of the earthing system.

[0044] Alternatively, instead of the remote monitoring unit, the measured value monitoring unit can be configured to calculate the internal resistance of the first boundary module from the AC voltage of the earthing system divided by the partial AC current, and to calculate the internal resistance of the second boundary module from the AC voltage divided by the total AC current of the earthing system.

[0045] The second isolation module can be configured in any way. It can be a capacitive isolation unit consisting of electrolytic capacitors with protective circuitry. Alternatively, a thyristor isolation unit can be used. Finally, the second isolation module can be a purely capacitive isolation unit.

[0046] According to a further advantageous feature of the invention, the system is characterized in that the measurement acquisition unit is additionally configured to measure the total direct current flowing through the earthing system at the first current measuring resistor and / or the partial direct current flowing through the first boundary module at the second current measuring resistor, and that the remote monitoring unit is configured to display the measured direct current values ​​for the detection of direct current leakage currents.

[0047] Remote monitoring of potential DC leakage currents that may arise due to cathodic protection is very important in practice because the protective current used to protect the pipeline must not be diverted, as this would increase the protective current requirement.

[0048] The problem is further solved by the following method: A method for discharging alternating current from a steel structure by means of at least one earthing system, wherein the earthing system has an earthing electrode that is electrically connected to the steel structure, wherein the steel structure is designed as an underground, cathodically protected pipeline subjected to alternating current and has a boundary unit that is electrically connected to the steel structure and the earthing electrode and causes a DC separation of the steel structure from the earthing electrode, wherein the earthing system is electrically connected to a transformer component with a primary winding and a secondary winding, wherein the primary winding is connected in series in the current path of the earthing system.wherein the alternating current derived from the earthing system is fed into the primary winding of the transformer component and wherein the secondary winding provides the charging voltage for a battery and wherein current and voltage values ​​of the boundary unit are continuously or periodically recorded and continuously or periodically stored by means of a measurement acquisition unit.

[0049] Preferably, the secondary winding of the transformer component is electrically connected to charging electronics with which the operating voltage of the battery is set and / or changed and / or the transformer component can be adapted to different AC current ranges.

[0050] Preferably, a voltage converter, which is preferably adjustable, is connected to the accumulator.

[0051] The accumulator can supply power to a measurement acquisition unit independently of the mains, enabling continuous measurements and remote monitoring of the earthing system.

[0052] Further development of the process is characterized by the following steps: Continuous recording and storage of current and voltage values ​​of the earthing system on site using at least one measurement acquisition unit powered by the accumulator, transmission of the measured values ​​to a remote monitoring unit via a communication unit, display of the alternating voltage or alternating current affecting the steel structure and / or calculation of resistance values ​​characteristic of the functionality of the earthing system from the transmitted current and voltage measurements and display and / or comparison of the calculated resistance values ​​with target values ​​using the remote monitoring unit.

[0053] The measured values ​​from the data acquisition unit are preferably transmitted continuously or periodically to the remote monitoring unit. The alternating current is primarily diverted from the steel structure to protect against impermissible touch voltages. This remote monitoring method ensures at all times that the safety of people or animals is not compromised.

[0054] Remote monitoring is cost-effective because it eliminates the need for personnel to inspect the grounding system on-site. Furthermore, it increases the safety and reliability of grounding systems by enabling continuous or regular monitoring at short intervals.

[0055] A preferred embodiment is characterized in that the total alternating current flowing through the earthing system is measured by means of a current measuring resistor using the measurement acquisition unit, and the alternating voltage between the earthing system and the pipeline and the alternating voltage between the earthing electrode and an auxiliary earth electrode are measured, that the measured values ​​are transmitted to the remote monitoring unit via the communication unit, and that the earth resistance of the earthing system is calculated by means of the remote transmission unit from the alternating voltage difference between the earthing electrode and the auxiliary earth electrode divided by the total alternating current.

[0056] The method according to the invention is further characterized in that the measurement acquisition unit is configured to continuously or periodically measure and store current and voltage values ​​of the boundary unit, that the communication unit transmits the measurement values ​​to a remote monitoring unit, and that the remote monitoring unit is configured to calculate and display, and / or compare with target values, those resistance values ​​that are characteristic of the functionality of the boundary unit from the transmitted current and voltage measurement values.

[0057] In the case where the boundary unit comprises a first boundary module and a second boundary module connected in parallel to the first boundary module, and the first boundary module is configured as a series resonant circuit, a further development of the method is characterized by the fact that the partial alternating current flowing through the first boundary module is measured by means of a second current-measuring resistor, and that the internal resistance of the first boundary module is calculated by means of the remote monitoring unit from the AC voltage of the earthing system divided by the partial alternating current of the first boundary module, and the internal resistance of the second boundary module is calculated from the AC voltage across the earthing system divided by the total AC current of the earthing system. The AC voltage of the earthing system is understood to be the voltage between the earthing electrode and the pipeline.

[0058] In a preferred embodiment, the total direct current flowing through the earthing system is measured at the first current measuring resistor, preferably continuously or at intervals, using the measurement acquisition unit. Alternatively or additionally, the partial direct current flowing through the first isolation module is measured at a second current measuring resistor located in the first isolation module, which is configured as a series resonant circuit. The measured direct current values ​​are then displayed by the remote monitoring unit to detect direct current leakage currents.

[0059] The invention, further advantages, and the technical context are explained in more detail below using a preferred embodiment as an example with reference to the accompanying drawings. The invention is not intended to be limited by the illustrated embodiments. It is also possible to combine partial aspects of the features described in the figures with other features from other figures and / or the description.

[0060] They show, in schematic representation: Figure 1: an earthing system for dissipating alternating current from a steel structure.

[0061] In Figure 1Figure 1 shows an earthing system for dissipating alternating current from a steel structure in the form of a buried, cathodically protected pipeline 2, which is affected by alternating current from an adjacent high-voltage overhead line 3. For the sake of simplicity, the general term "steel structure" will be replaced by "pipeline" in the following. The pipeline 2 is cathodically protected by a protective current device 4, which is electrically connected on its secondary side to the pipeline 2 on one side and to at least one buried anode 5 on the other. The pipeline 2 and the anode 5 are buried in the ground, which is known to have an electrolytic effect. The protective current serves to apply a negative voltage to the pipeline 2 in order to prevent corrosion.

[0062] The earthing system for protecting the pipeline against impermissible touch voltage has a connecting cable 6 and a grounding electrode 7. The alternating voltage acting on the pipeline 2 is reduced to a non-critical value via the current path of the earthing system 1. The alternating voltages coupled into the pipeline 2 are thus limited to a touch voltage level that is critical for persons. The earthing system 1 preferably has a single grounding electrode 1. An auxiliary earth electrode 8, which serves for measurement purposes, is connected in parallel to the earthing system 1.

[0063] There is no low-voltage power supply (230 Vac) at the location of the grounding system, so according to the invention, the diverted alternating current is fed into the primary winding of a transformer component 9. The secondary winding provides the charging voltage for a battery 10, which supplies at least one measurement acquisition unit 11 with power independently of the mains supply. The transformer component 9 can, for example, be designed as a toroidal transformer.

[0064] The secondary winding of the transformer component 9 is electrically connected (not shown) to charging electronics (not shown) which allow the operating voltage of the accumulator 10 to be set and / or adjusted. The transformer component 9 is adaptable to different AC current ranges.

[0065] A voltage converter (not shown) is connected to the accumulator 10, which is preferably adjustable.

[0066] A DC separation of the pipeline 2 from the earthing electrode 7 is effected by means of a boundary unit 12, which is electrically connected on one side to the pipeline 2 and on the other side to the earthing electrode 8.

[0067] The boundary unit 12 has a first boundary module 12a, which is designed as a series resonant circuit, consisting of a non-polarized film capacitor 12a' in series with a choke coil 12a".

[0068] The containment unit 12 has a second containment module 12b, which is connected in parallel to the first containment module 12a and which, in the exemplary embodiment, is designed as a so-called thyristor containment unit and which includes an electronic power switch 12b' and a polarized electrolytic capacitor 12b". The power switch 12b' closes when an alternating current induced in the pipeline 2 exceeds a set AC voltage threshold and serves as protection for the first containment module 12a, which has a higher resistance than the second containment module 12b. Other embodiments of the second containment module 12b are possible. For example, the polarized electrolytic capacitor 12b" could be omitted.

[0069] The switching threshold of the circuit breaker 12b' is set via a control unit (not shown). The current AC voltage, which is compared with the threshold value or switching threshold, can be easily measured using the auxiliary earth electrode 9.

[0070] Instead of the thyristor-based isolation unit, an isolation module operating on a different principle could also be used. Instead of the power switch, a mechanical switch that can be electrically controlled could also be used.

[0071] The measurement acquisition unit 11 has an integrated communication unit 13 which is in communication connection with a remote monitoring unit 14 and transmits the measured data via common interfaces and data transmission standards (WLAN, GSM, UMTS, USB, LAN, etc.).

[0072] The current and voltage values ​​of the earthing system 6 and / or the boundary unit 13 are continuously or periodically, preferably every five minutes, recorded by the measurement acquisition unit 11 and stored continuously or periodically, preferably every second. The communication unit 13 serves to transmit the measured values ​​to the remote monitoring unit 14, which is located remotely from the measurement location in the remote monitoring center of the pipeline operator or a data center. The stored measured values ​​are continuously or periodically transmitted from the communication unit 13 to the remote monitoring unit 14.

[0073] The remote monitoring unit 14 continuously displays the level of the alternating current affecting the pipeline, thus enabling simple remote monitoring of the respective alternating current influence on a steel structure.

[0074] Furthermore, resistance values ​​are calculated in real time from the transmitted current / voltage values, which are characteristic of the functionality of the earthing system 1 and / or the boundary unit 12.

[0075] The earthing system has a first current measuring resistor 15 in the form of a shunt, i.e., a low-resistance resistor, across which the total alternating current flowing through the earthing system 1 is continuously measured. The measured value acquisition unit 11 continuously acquires the alternating voltage between the earthing electrode 7 and the pipe 2, as well as the alternating voltage between the earthing electrode 7 and an auxiliary earth electrode 8.

[0076] In the remote monitoring unit 14, the earth resistance of the earthing system 1 is calculated continuously or at intervals by dividing the difference between the measured AC voltages by the total AC current flowing through the earthing system 1. The earth resistance must be as low as possible to reliably dissipate the AC current. If the calculation of the earth resistance shows that it is too high, repair measures can be initiated.

[0077] In addition, the partial alternating current flowing through the series resonant circuit is measured continuously or periodically, for example every five minutes, at a second current measuring resistor 16 in the form of a shunt, which is located in the series resonant circuit that forms the first boundary module 12a.

[0078] The remote monitoring unit 14 calculates centrally, preferably in real time, from the alternating voltage across the earthing system 1, i.e., from the alternating voltage between the earthing electrode 7 and the pipeline 2, divided by the measured partial alternating current, measured at the second current measuring resistor 16, the internal resistance of the series resonant circuit that forms the first boundary module 12a.

[0079] The remote monitoring unit 14 further calculates the internal resistance of the second boundary module 12b of the boundary unit 13 from the alternating voltage across the earthing system 1, divided by the total alternating current flowing across the earthing system 1.

[0080] The calculated internal resistance values ​​are displayed centrally to monitor the functionality of the boundary unit and / or to detect changes.

[0081] The calculated resistance values ​​can be compared with target values. If the calculated values ​​deviate from the target values ​​in an unacceptable manner, immediate action, in particular repair measures, can be taken to restore the operational condition of the earthing system and / or the boundary unit.

[0082] By means of the measurement acquisition unit 11, the total direct current flowing through the earthing system and / or the partial direct current flowing through the first boundary module 12a are additionally measured at the first current measuring resistor 15 and transmitted to the remote monitoring unit.

[0083] No direct current may flow during the operation of the earthing system, as the cathodic protection current should not be dissipated. If direct currents do flow, these are undesirable leakage currents that can be easily detected remotely using the measured values ​​displayed continuously or periodically by the remote monitoring unit 14.

[0084] Using the remote monitoring unit 14, additional information about the functionality of other components of the isolation unit 12 can be derived centrally from the measured values: If a lower alternating current flows in the current path of the first isolation module 12a in the form of a series resonant circuit than in the main current path of the earthing system, the second isolation module 12b has been switched on via the control unit. The switching points of the control unit are set and recorded once during commissioning. These switching points can be centrally checked based on the measured alternating voltage between the pipe 2 and the auxiliary earth electrode 9 and the asymmetry in the current path of the first and second isolation modules 12a, 12b.

[0085] Remote monitoring takes place, which refers to measures taken by a central location remote from the pipeline and / or the earthing system / boundary, to determine and assess the current state of the monitored unit at any time.

[0086] The embodiments described above are to be understood as examples. Features or process steps described with reference to one of the above embodiments can also be used in combination with other features or process steps of other described embodiments without leaving the scope of the patent claims.

[0087] The features described together with other features define, regardless of whether they are disclosed in the description, the claims, the figures or otherwise, also individually essential components of the invention.

[0088] Modifications to the invention are readily possible. Other devices could also be powered locally using the accumulator supplied with derived alternating current.

[0089] Finally, it is pointed out that the term "featuring" does not exclude any components or elements, that reference numerals in the claims do not constitute a limitation, and that "a" or "an" includes a plurality. Reference symbol list

[0090] 1 Earthing system 2 Steel structure / pipeline 3 High-voltage overhead line 4 Protective current device 5 Anode 6 Connecting cable 7 Earthing electrode 8 Auxiliary earth electrode 9 Transformer component 10 Accumulator 11 Measurement unit 12 Limiting unit 12a First limiting module 12a Film capacitor 12a Choke 12b Second limiting module 12b Switch 12b Polarized electrolytic capacitor 13 Communication unit 14 Remote monitoring unit 15 First current measuring resistor 16 Second current measuring resistor

Claims

1. Earthing installation for dissipating alternating current from a steel structure (2), wherein the earthing installation (1) has an earthing electrode (7) which is electrically connected to the steel construction (2), wherein the steel construction (2) is in the form of an underground cathodically protected pipeline which is influenced with alternating current, wherein a delimitation unit (12) is electrically connected to the steel construction (2) and the earthing electrode (7) and brings about a direct-current separation of the steel construction (2) from the earthing electrode (7), wherein the earthing installation has a transformer component (9) with a primary coil and a secondary coil, wherein the dissipated alternating current can be fed into the primary coil, wherein the primary coil is connected in series in the current path of the earthing installation, wherein the secondary winding provides the charging voltage for an accumulator (10) and wherein a measurement value detection unit (11) is configured to continuously or periodically detect and continuously or periodically store current and voltage values of the delimitation unit (12).

2. Earthing installation according to claim 1, characterized in that the secondary winding of the transformer component (9) is electrically connected to an electronic charging unit which is configured to set and / or adjust the operating voltage of the accumulator and / or in that the transformer component (9) can be adapted to different alternating-current ranges.

3. Earthing installation according to at least one of the preceding claims, characterized in that a voltage transformer which is preferably adjustable is connected to the accumulator (10).

4. Earthing installation according to any one of the preceding claims, characterized in that the measurement value detection unit (11) which is supplied with power by the accumulator (10) is configured to continuously or periodically measure and store current and voltage values of the earthing installation.

5. Earthing installation according to claim 4, characterized in that a communication unit (13) is in communicating connection with the measurement value detection unit (11) and a remote monitoring unit (14).

6. Earthing installation according to claim 4 or 5, characterized in that the measurement value detection unit (11) or the remote monitoring unit (14) is configured to display the dissipated alternating-current voltage and / or to calculate and display the resistance values which are characterizing for the functionality of the earthing installation from the measured voltage and current measurement values and / or to compare them with desired values.

7. Earthing installation according to any one of claims 4 to 6, characterized in that the measurement value detection unit or the remote monitoring unit (14) is configured to calculate at least the earthing propagation resistance of the earthing installation (1), in that an auxiliary earthing (8) is connected in parallel to the earthing installation (1), in that the earthing installation (1) has a first current measurement resistor (15) on which the overall alternating current flowing over the earthing installation (1) can be measured, in that the measurement value detection unit (11) is configured to measure the alternating-current voltage between the earthing electrode (7) and the steel construction (2) and the alternating-current voltage between the earthing electrode (7) and the auxiliary earthing (8) and in that the measurement value detection unit or the remote monitoring unit (14) is configured to calculate the earthing propagation resistance of the earthing installation (19) from the difference of the measured alternating-current voltages divided by the measured overall alternating current.

8. Earthing installation according to claim 1, characterized in that the measurement value detection unit (11) is configured to measure and store current and voltage values of the delimitation unit (12), in that the measurement value detection unit or the remote monitoring unit (14) is configured to calculate and display the resistance values which are characterizing for the functionality of the delimitation unit (12) from the measured voltage and current measurement values and / or to compare them with desired values.

9. Earthing installation according to claim 1, characterized in that the delimitation unit (12) has a first delimitation module (12a) and a second delimitation module (12b) connected parallel thereto, in that the first delimitation module (12a) is in the form of a series resonant circuit, in that the second delimitation module (12b) has a switch (12b') which closes when an alternating-current voltage which is induced in the pipeline exceeds a set alternating-current voltage threshold value, in that a second current measurement resistor (16) is located in the first delimitation module (12a) which is in the form of a series resonant circuit, and in that the measurement value detection unit (11) is configured to measure the alternating-current voltage across the earthing installation, the overall alternating current flowing over the earthing installation (1) on the first current measurement resistor (15) and the partial alternating current flowing over the first delimitation module (12a) on the second current measurement resistor (16), and in that the measurement value detection unit (11) or the remote monitoring unit (14) is configured to calculate the internal resistance of the first delimitation module (12a) from the alternating-current voltage of the earthing installation (1) divided by the partial alternating current and to calculate the internal resistance of the second delimitation module (12b) from the alternating-current voltage divided by the overall alternating current of the earthing installation (1).

10. Earthing installation according to any one of claims 1 or 9, characterized in that the measurement value detection unit (11) is additionally configured at the first current measurement resistor (15) to measure the overall direct current flowing over the earthing installation (1) and / or at the second current measurement resistor (16) to measure the partial direct current flowing over the first delimitation module (12a) and in that the remote monitoring unit (14) is configured to display the measured direct current values for identifying direct current leakage currents.

11. Method for dissipating alternating current from a steel construction by means of at least one earthing installation, wherein the earthing installation (1) has an earthing electrode (7) which is electrically connected to the steel construction (2), wherein the steel construction (2) is in the form of an underground cathodically protected pipeline which is influenced with alternating current and has a delimitation unit (12) which is electrically connected to the steel construction (2) and the earthing electrode (7) and brings about a direct-current separation of the steel construction (2) from the earthing electrode (7), wherein the earthing installation (1) is electrically connected to a transformer component (9) having a primary winding and a secondary winding, wherein the primary winding is connected in series in the current path of the earthing installation, wherein the alternating current which is dissipated from the earthing installation (1) is fed into the primary winding of the transformer component (9) and wherein the secondary winding provides the charging voltage for an accumulator (10) and wherein by means of a measurement value detection unit (11) current and voltage values of the delimitation unit (12) are continuously or periodically detected and continuously or periodically stored.

12. Method according to claim 11, characterized by the following steps, - continuously detecting and storing current and voltage values of the earthing installation (1) in situ by means of at least the measurement value detection unit (11) which is supplied with power by means of the accumulator (10), - transmitting the measurement values to a remote monitoring unit (14) by means of a communication unit (13), - displaying the alternating-current voltage which influences the steel construction (2) or displaying the dissipated alternating current and / or - calculating resistance values which are characterizing for the functionality of the earthing installation (1) from the transmitted current and voltage measurement values and displaying the calculated resistance values and / or comparing the calculated resistance values with desired values by means of the remote monitoring unit.

13. Method according to claim 12, characterized in that the communication unit transmits the measurement values of the measurement value detection unit (11) to the remote monitoring unit (14) and in that the remote monitoring unit (14) is configured to calculate and display the resistance values which are characterizing for the functionality of the delimitation unit (12) from the measured voltage and current measurement values and / or to compare them with desired values.