PROTECTION SYSTEM FOR PIPELINES

Description

The invention relates to a protection system for pipes and to the use of such a protection system for protecting a pipe.

During their period of use or service life, laid pipes are exposed to various environmental influences which may result in corrosion of the pipe. Particularly in the case of buried metallic pipes, protection measures are therefore necessary to reduce the extent of corrosion or to prevent corrosion from occurring.

Such pipes are therefore usually provided with a coating of an insulating material. The problem here is that the coating can be damaged, for example, when laying the pipe and/or during necessary assembly or maintenance work. In this case, a particularly high local corrosion current is generated at the point of damage to the coating, also referred to as defective spot, which leads to rapid corrosion of the pipe.

To prevent this, it is known to provide a cathodic corrosion protection system (also referred to as “CCP system”). The corrosion protection system applies a negative direct current (DC) potential to the pipe to be protected by electrically conductively connecting the pipe to a rectifier of the cathodic corrosion protection system, which in turn is electrically connected to an anode located near the pipe. This allows a so-called CCP protection current to flow between the anode and the pipe, especially the defective spot of the pipe, which counteracts the corrosion current and thus prevents corrosion from occurring. In other words, a cathodic protection potential is generated by the cathodic corrosion protection system.

To ensure that the planned cathodic corrosion protection works reliably, the CCP system must be monitored and evaluated regularly. Evaluation criteria include, for example, the value of the unaffected pipe potential, which can be determined by measuring the voltage between the pipe and a reference electrode, usually a Cu/CuSO₄ electrode. This potential is also referred to as the “IR-free potential”. According to DIN EN 12954, the IR-free potential should be less than or equal to a minimum protection potential of about −850 mV.

The problem with this measurement is that the potential measured between the reference electrode of the voltage measurement system and the pipe can be distorted by various influences, the sum of all these influences being also referred to as “IR drop”. The relevant influences on the voltage measurement may be caused by currents from the protection current system itself, nearby external protection current systems, equalizing currents, element currents, currents from DC-operated industrial and railway systems and/or earth currents.

In practice, however, the measurement between the reference electrode and the pipe can only determine the sum of the IR-free potential and the IR drop. It is therefore basically provided to eliminate as many sources of interference as possible which contribute to the IR drop. For this reason, it is known to disconnect the rectifier of the cathodic corrosion protection system from the pipe for a few seconds, for example about 3 seconds, to measure the IR free potential. The potential thus measured is also known as switch-off potential. This procedure is known as the “switch-off technique”. As long as there are no further sources of interference, the switch-off potential is equal to the IR-free potential.

In addition to the corrosion mechanism described above, further adverse effects on pipes must be taken into account. In particular, buried pipes are often laid near high-voltage line systems. As a result, the electromagnetic field of the high-voltage lines of such high-voltage line systems induces an AC voltage in the pipe, the magnitude of which depends, among other things, on the relative position of the pipe to the respective high-voltage line. If this induced AC voltage exceeds certain limit values, for example an effective AC voltage of 60 V, it is necessary to take measures to reduce the AC voltage, as otherwise, for example, alternating current corrosion or dangerously high touch voltages may occur.

For this purpose, so-called decouplers are known which dissipate an occurring AC voltage to an grounding device, but at the same time do not negatively affect the DC potential generated by the cathodic corrosion protection system. To this end, common decouplers have a capacitor which is conductive for AC voltages but has a high impedance for DC voltages. The greater the capacitance of the capacitor, the lower the AC resistance, so that the dissipation of occurring alternating currents is improved.

However, the problem with such a combination of a decoupler and a cathodic corrosion protection system is that the measurement of the IR-free potential is distorted by the decoupler. This is due to the fact that, due to the high capacitance of the decoupler, necessary for the best possible dissipation of alternating currents, a current still flows to the pipe even after the rectifier of the cathodic corrosion protection system has been disconnected for the voltage measurement, as the charged capacitor of the decoupler acts as a DC voltage source. In other words, a stray current is generated which continues to flow until the capacitor of the decoupler is fully discharged.

To avoid this problem, it is known to disconnect the decoupler from the pipe at the same time as the rectifier of the cathodic corrosion protection system, so that no more equalizing currents can flow. However, this has the consequence that the AC voltage generated on the pipe is no longer limited for the duration of the measurement, which may lead to dangerously high touch voltages in the pipe and thus complicates the work and handling of the pipe.

It is therefore the object of the invention to provide a protection system for pipes which ensures the dissipation of AC voltages while at the same time allowing a measurement of the cathodic protection potential which is as accurate as possible.

According to the invention, the object is achieved by a protection system for pipes, comprising a cathodic corrosion protection system which comprises a rectifier and a corrosion protection switching element which is electrically conductively connected to the rectifier, wherein the cathodic corrosion protection system is set up to switch between a corrosion protection mode and a measuring mode, wherein the rectifier is not connected in the measuring mode. The protection system also includes a decoupler which comprises a first capacitor and a second capacitor and a capacitor switching element. The capacitor switching element is electrically conductively connected to the first capacitor in a first switch position when the cathodic corrosion protection system is in the corrosion protection mode. In a second switch position, the capacitor switching element is electrically conductively connected to the second capacitor when the cathodic corrosion protection system is in the measuring mode.

According to the invention, several capacitors are therefore provided in the decoupler, between which it is switched depending on the current operating mode of the cathodic corrosion protection system. In this way, it is ensured at all times that the pipe to be protected is connected to one of the capacitors of the decoupler, i.e. the first capacitor or the second capacitor, and is thus protected against any AC voltages.

The respective capacitor of the decoupler which is not electrically conductively connected to the capacitor switching element can furthermore not cause any disruptive equalizing currents, as it is no longer in a closed electric circuit with the pipe.

At the same time, the first capacitor and the second capacitor may be charged to different potentials to eliminate or at least minimize equalizing currents in the measuring mode of the cathodic corrosion protection system.

This enables a reliable measurement of the cathodic protection potential generated by the cathodic protection system, while at the same time an AC voltage present in the pipe to be protected is limited at all times by the decoupler.

In contrast to the known “switch-off technology” of cathodic protection systems, this principle is referred to as “switchover technology”.

The first capacitor is also referred to as “main capacitor” and the second capacitor as “measuring capacitor”.

The main capacitor and the measuring capacitor may be designed differently.

In particular, the main capacitor, which in the installed position is connected to the pipe to be protected for the majority of the operating time of the decoupler, may be a capacitor with higher performance characteristics than the measuring capacitor, which in the installed position is only connected in the measuring mode of the cathodic corrosion protection system, i.e. for comparatively short periods of time. In this way, the total costs and the space required for the protection system according to the invention may be optimized.

The pipe is an electrically conductive pipe and is in particular buried, i.e. laid in the ground, so that the soil is a medium along which currents flow. However, in addition to soil, other media can generally also surround the electrically conductive pipe, which is why this may generally refer to an electrically conductive pipe which is laid in a medium, namely a medium along which currents flow.

The term “electrically conductively connected” means here and in the following that there is a connection through which an electric current flows.

In particular, the pipe is a metallic pipe having a coating of an insulating material. Such pipes have a high mechanical stability and load-carrying capacity, the service life of which is optimized by the coating. At the same time, the protection system according to the invention also provides reliable corrosion protection in the event of any damage to the coating.

The compositions of the metallic pipe and the insulating material are not further restricted, so that all materials known in the prior art can be used.

For example, the metallic pipe is made of steel or copper.

To reduce the duration of the switching process between the first switch position and the second switch position of the capacitor switching element, the capacitor switching element may be a power semiconductor switch. This further ensures that any AC voltage present on the pipe remains below a predetermined limit, even during the switching process.

To further improve the accuracy of the cathodic protection potential measurement, the protection system may be set up to charge the first capacitor to a switch-on potential and to charge the second capacitor to a switch-off potential in a training phase of the protection system, the switch-on potential corresponding to the potential of the pipe to be protected in the corrosion protection mode and the switch-off potential of the second capacitor corresponding to the potential of the pipe to be protected in the measuring mode.

The potential of the pipe to be protected in the corrosion protection mode of the cathodic corrosion protection system depends on the protection potential generated by the cathodic corrosion protection system. In other words, in the training phase, the first capacitor is charged to the switch-on potential based on the cathodic protection potential and the cathodic protection current of the cathodic corrosion protection system via a charging current flowing through the pipe. In contrast thereto, in the measuring mode, the potential of the pipe to be protected is not influenced by the cathodic protection potential, because in the measuring mode, the pipe to be protected is no longer electrically conductively connected to the rectifier of the cathodic corrosion protection element.

After completion of the training phase, the first capacitor and the second capacitor are thus charged to the potentials of the pipe to be protected that are to be expected in the respective mode of the cathodic corrosion protection system, so that in every switch position of the capacitor switching element, it is ensured that no equalizing currents are to be expected through the decoupler which could influence the measurement of the cathodic protection potential, apart from unavoidable fluctuations.

In particular, the switch-on potential is more negative than the switch-off potential. Accordingly, the second capacitor may be designed to be simpler than the first capacitor in terms of its performance characteristics, in particular with respect to the maximum capacitance, as a result of which the costs and the required installation space of the entire protection system according to the invention can be minimized.

The first capacitor and/or the second capacitor may have a capacitance in the range of 0.1 to 1.0 F. At a capacitance lower than 0.1 F, the ability of the capacitors to dissipate alternating currents may be insufficient, while the costs and space requirements increase excessively at a capacitance of more than 1.0 F.

In particular, the decoupler has a grounding device which is electrically conductively connected to the first capacitor and the second capacitor.

In other words, only one common grounding device is used, which allows alternating currents to be dissipated. This further reduces the complexity and cost of the protection system.

In one variant, a clipping diode is connected in parallel with the second capacitor.

The clipping diode serves to limit the potential to which the second capacitor is charged when the protection system is used, in particular the switch-off potential, to a limit value predetermined by the choice of diode. This is particularly advantageous if the pipe to be protected has such a high propagation resistance that, despite switching to the second capacitor in the measuring mode, it takes so long for the potential of the second capacitor to equalize with the potential of the pipe to be protected that the measurement of the cathodic protection potential could still to be affected.

Furthermore, the second capacitor in this variant may be selected such that the maximum voltage sustaining capability thereof is only slightly above the limit value predetermined by the diode, even if the pipe to be protected would have a higher potential in the measuring mode.

The limit value predetermined by the choice of diode is, for example, in the range of 0.5 to 0.7 V.

If the protection system in this variant passes through the training phase described above, the expression that the switch-off potential of the second capacitor corresponds to the potential of the pipe to be protected in the measuring mode means that the switch-off potential of the second capacitor corresponds to the potential of the pipe to be protected in the measuring mode to the extent permitted by the clipping diode.

To synchronize the switching processes of the corrosion protection switching element and the capacitor switching element even better, the cathodic corrosion protection system and the decoupler may have switching control elements which are time-synchronized.

The switching control element of the cathodic corrosion protection system is set up to control the corrosion protection switching element and thus trigger the changeover of the cathodic corrosion protection system between the corrosion protection mode and the measuring mode.

The switching control element of the decoupler is set up to control the capacitor switching element and thus cause the changeover between the first switch position and the second switch position.

In other words, the switching control element minimizes the latency between the switching processes.

The time synchronization can be carried out taking the spatial distance between the cathodic corrosion protection system and the decoupler into account. For this purpose, both the cathodic corrosion protection system and the decoupler may have a respectively associated GPS module or, in general, a respectively associated GNSS module, which enables the cathodic corrosion protection system or the decoupler to be located.

The switching control elements may also each have a communication module for data exchange, the switching control elements being set up to exchange data with each other by means of the respective communication modules.

Furthermore, the switching control elements may be set up to send data to and/or receive data from a control center by means of the communication modules, for example diagnostic data, protocol data and/or control signals.

The data exchange may be effected in a wired or wireless manner, for example via Ethernet, a WLAN connection and/or a mobile radio connection.

The object of the invention is further achieved by using the protection system as previously described to protect a pipe, the corrosion protection switching element and the capacitor switching element being electrically conductively connected to the pipe.

The features and characteristics of the protection system for pipes described above apply accordingly to the use of the protection system for protecting a pipe and vice versa.

The pipe is in particular buried and for example a pipeline, in particular a gas pipeline.

Further features and characteristics of the invention will become apparent from the description below of exemplary embodiments, which are not to be understood in a restrictive sense, and from the drawings, in which:

FIG. 1 shows a first embodiment of a protection system for pipes according to the invention in a first operating mode,

FIG. 2 shows the protection system of FIG. 1 in a second operating mode,

FIG. 3 shows the protection system of FIG. 1 in a first step of a training phase,

FIG. 4 shows the protection system of FIG. 1 in a second step of a training phase,

FIG. 5 shows a second embodiment of the protection system for pipes according to the invention in the second operating mode, and

FIG. 6 shows a third embodiment of the protection system for pipes according to the invention in the first operating mode.

FIG. 1 schematically shows a protection system 10 according to the invention for a pipe 12.

The pipe 12 is a metallic pipe made of stainless steel and having a coating 14 made of an insulating material.

It is understood that the pipe 12 may also be made of other materials, in particular other metals, as known from the prior art.

The pipe 12 is buried, for example, i.e. it is laid in the ground below the surface of the earth (not shown) and is thus in contact with the surrounding soil.

In the embodiment shown, the coating 14 has a defective spot 16, i.e. a damage. At the defective spot 16, the metal surface of the pipe 12 is in direct contact with the surrounding soil, so that the pipe 12 has an increased tendency to corrode at this point.

In addition, the pipe 12 is located near a high-voltage line system (not shown), which causes an AC voltage in the pipe 12.

The protection system 10 has a cathodic corrosion protection system 18 and a decoupler 20, the functions of which will be described in more detail below.

The corrosion protection system 18 includes a rectifier 22, a corrosion protection switching element 24, which in FIG. 1 connects the pipe 12 in an electrically conductive manner to the rectifier 22, and an anode 26 electrically conductively connected to the rectifier 22.

The rectifier 22 is connected to a voltage source (not shown) which supplies the rectifier 22 with energy.

The decoupler 20 has a first capacitor 28, also referred to as “main capacitor”, and a second capacitor 30, also referred to as “measuring capacitor”.

The first capacitor 28 and/or the second capacitor 30 has/have a capacitance in the range of 0.1 to 1.0 F, the capacitance of the first capacitor 28 being in particular higher than the capacitance of the second capacitor 30.

In addition, the decoupler 20 has a capacitor switching element 32 which is electrically conductively connected to the pipe 12.

In FIG. 1, the capacitor switching element 32 is shown in a first switch position, in which the capacitor switching element 32 is electrically conductively connected to the first capacitor 28.

The decoupler 20 also includes a grounding device 34.

The grounding device 34 is electrically conductively connected both to the first capacitor 28 and to the second capacitor 30.

The pipe 12 is also electrically conductively connected to a voltage measuring system 36.

The voltage measuring system 36 includes a voltmeter 38 and a reference electrode 40.

The voltage measuring system 36 can be a component of the protection system 10 according to the invention or can form a separate component. Basically, it is also conceivable that the voltage measuring system 36 is integrated into the cathodic corrosion protection system 18 or the decoupler 20.

FIG. 1 shows the protection system 10 according to the invention in a first operating mode, in which the corrosion protection switching element 24 is electrically conductively connected to the rectifier 22, i.e. the cathodic corrosion protection system 18 is in a so-called “corrosion protection mode” and the capacitor switching element 32 is in a first switch position in which the capacitor switching element 32 is electrically conductively connected to the first capacitor 28.

FIG. 2 shows the protection system 10 according to the invention in a second operating mode, in which the corrosion protection switching element 24 is not connected to the rectifier 22, so that the cathodic corrosion protection system 18 is in a so-called “measuring mode” and the capacitor switching element 32 is in a second switch position in which the capacitor switching element 32 is electrically conductively connected to the second capacitor 30.

The corrosion protection switching element 24 and the capacitor switching element 32 are synchronized or coupled to each other, as indicated by the dashed line 42 in FIG. 1 and FIG. 2. For example, the corrosion protection switching element 24 and the capacitor switching element 32 are designed as change-over switches. This means that the capacitor switching element 32 is in the first switch position when the corrosion protection switching element 24 connects the rectifier 22 in an electrically conductive manner to the pipe 12, and the capacitor switching element 32 is in the second switch position when the corrosion protection switching element 24 does not switch on the rectifier 22, i.e. does not connect it to the pipe 12.

However, the corrosion protection switching element 24 and the capacitor switching element 32 are preferably separate switches which are synchronized or coupled to each other.

The capacitor switching element 32 is in particular a power semiconductor switch to achieve the shortest possible switching time.

In the following, the mode of operation of the protection system 10 according to the invention is described in more detail, i.e. the use of the protection system 10 for protecting the pipe 12 and a method of protecting the pipe 12.

First, the cathodic corrosion protection system 18 and the decoupler 20 are coupled to the pipe 12 to be protected by connecting the corrosion protection switching element 24 and the capacitor switching element 32 in an electrically conductive manner to the pipe 12.

During its period of use or service life, the pipe 12 is exposed to various influences which can lead to corrosion and thus to damage to the pipe 12. In particular, at the defective spot 16, where the coating 14 is damaged and the metal surface of the pipe 12 comes into direct contact with the surrounding soil, there is a high tendency to corrosion, resulting in a so-called corrosion current.

To counteract this corrosion current, the cathodic corrosion protection system 18 generates a cathodic protection potential in the corrosion protection mode, which results in a protection current between the anode 26 and the pipe 12, indicated in FIG. 1 by a dotted arrow 44.

As long as the cathodic protection potential is sufficiently high, for example, a minimum protection potential of −850 mV or less is generated, corrosion of the pipe 12 at the defective spot 16 is reliably prevented.

As can be seen in FIG. 1, the capacitor switching element 32 is connected to the first capacitor 28 in the corrosion protection mode of the cathodic corrosion protection system 18.

In this way, AC voltages induced in the pipe 12, for example due to the nearby (not shown) high-current line system, are dissipated via the first capacitor 28 to the grounding device 34, thus reducing the effective AC voltage on the pipe 12.

Due to the fact that at the same time the cathodic corrosion protection system 18 generates a protection current, a charging current also flows from the pipe 12 to the first capacitor 28 in the first operating mode of the protection system 10, in which the capacitor switching element 32 is in its first switch position, as indicated by a dotted arrow 46 in FIG. 1, until the first capacitor 28 has charged to the same potential as the pipe 12.

In addition, a switch-on potential, indicated by a double arrow 48 in FIG. 1, occurs between the grounding device 34 and the pipe 12.

To ensure that the minimum protection potential is guaranteed, i.e. that the cathodic protection potential is sufficiently high to prevent corrosion of the pipe 12, the potential of the pipe 12 to be protected is measured by means of the voltage measuring system 36.

In particular, the measurement of the potential of the pipe 12 to be protected is repeated at regular intervals by means of the voltage measuring system 36.

In FIG. 1, a double arrow 50 indicates that the voltage measuring system 36 can only determine the potential respectively present between the pipe 12, in particular at the relevant defective spot 16, and the reference electrode 40.

However, this value is influenced by the cathodic protection potential of the cathodic corrosion protection system 18 and possible further sources of error such as nearby external protection current systems, equalizing currents, element currents, currents from DC-operated industrial and railway systems and/or earth currents.

To nevertheless enable a reliable measurement of the potential of the pipe 12 to be protected, the measurement is carried out by the voltage measuring system 36 as a measurement pair, the measurement pair comprising a first measurement which is carried out with the rectifier 22 connected, i.e. while the cathodic corrosion protection system 18 is in the corrosion protection mode (as shown in FIG. 1) and a second measurement, which is carried out with the rectifier 22 not connected, i.e. while the cathodic corrosion protection system 18 is in the measuring mode (as shown in FIG. 2).

The actual potential of the pipe 12 to be protected is then determined, for example, as the difference between the first measurement and the second measurement, the respective signs of the measured voltage value being taken into account accordingly when calculating the difference.

If it can be assumed that no further sources of interference are present, it is then possible, as an alternative to determining the cathodic protection potential, to carry out a single measurement with the rectifier 22 not connected, similar to the second measurement.

To prevent the second measurement from being distorted by the first capacitor 28 discharging, which was previously charged due to the charging current in the first operating mode of the protection system 10, thus to prevent a direct current from being generated between the reference electrode 34 and the pipe 12, the capacitor switching element 32 switches to the second switch position, in which the second capacitor 30 is electrically conductively connected to the pipe 12 instead of the first capacitor 28, in synchronism with the change of the cathodic corrosion protection system 18 to the measuring mode (see FIG. 2).

Thus, a charging current flows between the pipe 12 and the second capacitor 30 (indicated by a dotted arrow 52 in FIG. 2) only until the second capacitor 30 is charged to the potential of the pipe 12 with the cathodic corrosion protection system 18 deactivated.

This results in a switch-off potential between the grounding device 34 and the pipe 12, which is indicated by a double arrow 54 in FIG. 1.

The switch-off potential is usually more positive than the switch-on potential, or the switch-on potential is usually more negative than the switch-off potential, so that the switch-off potential is reached very quickly and after that there is no longer any risk of the protection system 10 influencing the voltage measurement of the voltage measurement system 36.

At the same time, one of the capacitors of the decoupler 20, i.e. the first capacitor 28 or the second capacitor 30, remains connected to the pipe 12 at all times to discharge any AC voltages induced in the pipe 12 to the grounding electrode 34 and thus limit them.

To minimize the influences of the charging currents to the first capacitor 28 and to the second capacitor 30 on the voltage measurement even further, the protection system 10 is in particular set up to pass through a training phase, which is shown schematically in FIGS. 3 and 4.

In a first step of the training phase, which is shown in FIG. 3, the first capacitor 30 is charged to the switch-on potential, which corresponds to the potential of the pipe 12 to be protected in the corrosion protection mode of the cathodic corrosion protection system 18, as indicated by the hatching in FIG. 3.

In other words, no charging current (see dotted arrow 46 in FIG. 3) flows as soon as the first capacitor 28 has reached the switch-on potential.

In a second step of the training phase, which is shown in FIG. 4, the cathodic corrosion protection system 18 switches to the measuring mode, causing the capacitor switching element 32 to switch to the second switch position and connect the second capacitor 30 in an electrically conductive manner to the pipe 12.

Thus, the second capacitor 30 is charged to the switch-off potential, which corresponds to the potential of the pipe 12 when the cathodic corrosion protection system 18 is in the measuring mode.

As indicated by the hatching in FIG. 4, the switch-on potential in the illustrated embodiment is greater than the switch-off potential.

During the second step of the training phase, the first capacitor 28 remains charged to the switch-on potential because it is not electrically conductively connected in a closed electric circuit. When the capacitor switching element 32 returns to the first switch position, the second capacitor 30 remains charged to the switch-off potential because the second capacitor 30 is then no longer electrically connected in a closed electric circuit.

Thus, at the end of the training phase, the first capacitor 28 and the second capacitor 30 have exactly those potentials which are to be expected for the pipe 12 when the cathodic corrosion protection system 18 is in the corrosion protection mode or in the measuring mode.

Therefore, no more equalizing currents, even short-term ones, are to be expected when switching between the corrosion protection mode and the measuring mode of the cathodic corrosion protection system 18 to determine the cathodic protection potential, apart from unavoidable fluctuations, so that an even more reliable determination is made possible, while at the same time protection of the pipe 12 against undesirably high AC voltages is ensured at all times.

A second embodiment of the protection system 10 according to the invention is shown in FIG. 5.

The second embodiment corresponds essentially to the first embodiment, so that only differences will be discussed in the following. Identical reference numerals denote identical or functionally identical components, and reference is made to the above explanations.

In the second embodiment, a clipping diode 56 is connected in parallel with the second capacitor 30 and between the capacitor switching element 32 and the second capacitor 30.

The clipping diode 56 serves to limit the charging of the second capacitor 30 to a maximum value predetermined by the clipping diode, for example to a potential in the range of 0.5 to 0.7 V.

In this way, the desired potential of the second capacitor 30 is reached even faster, so that in the second operating mode of the protection system 10, no equalizing currents (indicated by a dotted arrow 58 in FIG. 5) flow at all after a very short time.

FIG. 6 shows a third embodiment of the protection system 10 according to the invention.

The third embodiment corresponds essentially to the first embodiment, so that only differences will be discussed in the following. Identical reference numerals denote identical or functionally identical components, and reference is made to the above discussions.

In the third embodiment, both the cathodic corrosion protection element 18 and the decoupler 20 have a switching control element 60 or 62.

The switching control element 60 is set up to control the corrosion protection switching element 24 and thus trigger the change of the cathodic corrosion protection system 18 between the corrosion protection mode and the measuring mode.

The switching control element 62 is set up to control the capacitor switching element 32 and thus to cause the change between the first switch position and the second switch position.

In other words, the respective operating mode of the protection installation 10 is determined via the switching control elements 60 and 62.

The switching control elements 60 and 62 are time-synchronized. This means that the switching control elements 60 and 62 ensure that the switching processes of the corrosion protection switching element 24 and the capacitor switching element 32 have the lowest possible latency with respect to each other.

To further reduce latency, the switching control elements 60 and 62 include GNSS modules 64 and 66, respectively, which enable the cathodic corrosion protection system 18 and the decoupler 20 to be located, so that the spatial distance between the cathodic corrosion protection system 18 and the decoupler 20 can be taken into account in the switching process, i.e. when changing the operating mode of the protection system 10.

In addition, the switching control elements 60 and 62 have communication modules 68 and 70, respectively, which enable data exchange between the switching control elements 60 and 62, for example by means of an Ethernet, WLAN and/or mobile radio connection.

It is understood that such switching control elements 60 and 62 can also be used in the second embodiment.