By Lorenzo Spisni and Massimo Tassinari Technical advisors for cathodic protection at InRete Distribuzione Energia From the presentation at SMART GRID DAYS 2025, October 8 – 9, 2025.
In the past, we all started from the EON potential data. Then, about ten years ago, we had access to a potential probe that could provide us with additional information. Over time, we discovered that the potential probe could detect the Esonda potential value, coupon current values (Icoupon), and, as we approached the goal of reducing ohmic drops on the potential value, the probe allowed us to obtain EOFF to reach the so-called “free of ohmic drop potential”.
The experience we have carried out on an electrical system is one that gathers a lot of information: we will obtain EOFF measurements on the pipeline and the values of EOFF on coupon. In summary, I would say measurements “with two faces”, as comparing the EOFF measurements obtained with the two techniques proposed by the standards, the data will be conflicting: some data will be compliant and others that probably no one will ‘like’.
Contradictory or ambiguous EOFF values point the way towards more in-depth investigations: these non-compliant data are not due to the reliability of the potential probe product, but we must find the causes in the pipeline – probe – coupon – ground circuit, not forgetting the presence of oxygen.
We will demonstrate that, despite the collected values being conflicting, there are many other basic conditions that completely exclude the possible corrosion of these pipelines.
The regulations and EOFF
We have definitions both in the standard UNI EN ISO 15589-1 and in the standard UNI 11094. In the latter, two methods for acquiring the EOFF potential are mentioned: directly on the structure with interruption of the cathodic current with a typical delay acquisition of 300 milliseconds or on a plate or probe after opening the electrical connection plate-structure within a maximum time of 100 ms. These techniques are valid for the detailed assessment of the effectiveness of the protection condition.
The technique and utility for testing the electrical system and periodic checks are defined in the standard UNI EN ISO 15589-1 (Appendix A.2.3 – A.2.5 and Art. 7.3 – 12.4.2 and Art. 13.3). Therefore, this information on EOFF is valid both in technical scope (how to do it) and in testing (commissioning or testing the protection condition of a system) and regarding the scheduled maintenance of a system (UNI 11094 Appendix A1, A2, A3).
Thus, the experience we bring transfers the cited regulations within a field context, to obtainEOFFinformation that comes from buried structures.
Below are the techniques adopted for the acquisition of EOFF potential:
directly on the structure (delay of about 300 ms) EOFF-pipe
use of potential probe (within a maximum time of 100 ms) EOFF-coupon
acquisition time of EOFF potential within 2 ms (overprotection),
acquisition time of EOFF potential within 21 ms,
acquisition time of EOFF potential within 100 ms (protection criteria).
We have identified a suitable electrical system, not subject to interference or with a sufficient non-interference period for data monitoring, where the characteristic measurement points were equipped with potential probes.
The system was identified in a small urban area.
The peculiarity of this system is the presence of a different ground resistivity: in fact, there are areas where, following the reclamation of marshy and lagoon areas, the resistivity is around 7-8 Ω·m, while others, formed on fluvial deposits, present a resistivity in the order of 100 Ω·m.
To explore in detail, it is possible to download the complete case study.
Massimo Tassinari is the technical contact for cathodic protection at INRETE Distribuzione, where he is involved in commissioning and supervising the testing of cathodic protection systems, updating monitoring systems and coordinating ARERA data reporting.
By Ivano Magnifico, Product Manager AUTOMA From the presentation “Back to the future: when the past is already the future” SMART GRID DAYS 2025, 8 – 9 October 2025.
Are we using the data we receive from the monitoring systems of cathodic protection as we should? To understand this, let’s summarise the history, the current situation and the future of pipeline monitoring, particularly focusing on what we take for granted and what seems normal because we see it every day.
In this article and the previous one, we talk about monitoring methods and how to optimise data transmission, showing you some concrete examples.
With this content, we are mainly addressing foreign readers, who have different management practices than those we have in Italy. However, in any case, the recap can also be useful for us Italians to see if we are working to the best of our abilities.
Remote monitoring for cathodic protection
For a definition of remote monitoring, please click here.
Let’s now see how the information collected can help us carry out our daily business. In order to have effective and efficient cathodic protection, the first thing to do is to check that the devices we use (e.g. power supplies, decoupling devices, mitigation devices, etc.) are working properly. ISO 15589-1 gives us an indication of the devices that must be checked for cathodic protection:
Cathodic protection rectifiers
Unidirectional drainage station
Connections to third-party structures (resistive or direct)
AC/DC decoupling devices
Galvanic anodes
Measurement points
Rectifier: monitoring parameters
Below are theparameters to be monitored in the rectifier to make sure it is working properly.
DC output current
DC output voltage
AC output voltage: alarm if average value > defined threshold
Presence/absence of main power supply (real-time alarm)
DC potential structure and AC voltage
OFF potential on structure
Instant-off on coupons to measure IR-free potential
DC and AC current density on coupon
When we talk about gas distribution networks within cities, one of the most critical aspects is the life time of the ICCP anode: as long as the ICCP anode is operational, we are able to supply power, but when it wears out, it becomes a problem because it can take up to one or two years to obtain the permits to carry out the work. Therefore, it would be convenient if, in addition to the other information that comes to us, we could also know if and when the ICCP anode is reaching the end of its service life.
Rectifier: assessing the status of the ICCP anode
In the graph below, we are not measuring impedance (the ratio between voltage and current) to evaluate the total resistance of the circuit, but we are only measuring the output voltage on a rectifier that has always operated at constant current; therefore, the voltage trend follows the trend of the total impedance seen by the rectifier.
The reference period is 2012-2020. Looking at the graph, we clearly recognise the seasonal trend, i.e. the change in soil resistance between the summer and winter periods. However, it is also possible to detect a certain linearity, which is given by the trend of the volume loss of the ICCP anode over time. As we approach the end of service life, we lose this linear trend that tends to become exponential and this can help us predict even a couple of years in advance the moment when a new ICCP anode will be needed.
Unidirectional drainage
In the vicinity of a railway line, at the point where the interference creates an anode zone of current on our pipe that returns to the original circuit, we will need a drainage, if there are no other ways to solve the problem.
The purpose of drainage is to allow the current, which we absorb in the cathodic area from the railway line, to return via an electrical path to the rail and the substation to which it belongs. Clearly, we only want this current to flow back to the substation and not vice versa.
Another interesting parameter is the potential difference between the structure and the rail: when the structure is more positive than the rail, we expect current to drain, returning to the original circuit; whereas, when the polarisation is reversed, we do not expect current through the diode, because it is reverse polarised.
The monitoring parameters are:
DC drain current
Normal condition: Ir ≥ 0
Alarm if Ir < 0 (damaged diode)
Pipe-to-rail potential (Erail)
Normal condition: -V < Erail < 0.7 V + Ir (Rb+Rpr) (Rpr = parasitic resistance of the diode)
DC potential structure and AC voltage
OFF potential on structure
Instant-off on coupons to measure IR-free potential
DC and AC current density on coupon
Real cases
Unidirectional drainage: diode failure detection
Let’s look at some practical examples. Below you see the diode current trend over a series of days; the current flows in one direction only until 22 May. As shown, after the fault, our pipeline is receiving 55A, 134A, 68A from the rail through an electrical connection: this current, however, must return to its original circuit. Generally, corrosion is not a rapid phenomenon, but in this case it can become so. Therefore, it is essential to receive an alarm so that prompt action can be taken.
With reference to the Remote Datalogger Unit, it is interesting to point out that we can occasionally ask the device to download the measurement second by second in order to analyse in detail what happened; and that is what we did in this example. We downloaded the intensive measurement per second on the day the diode broke. Below we can see the drained current, the On potential and the tube-rail potential.
AC mitigation device: monitoring parameters
The AC decoupler is a large capacitor between the pipe and the grounding system, which allows the AC current to be discharged to the grounding system while remaining an open circuit for the DC current.
What do we monitor?
AC current discharged;
DC current:
Normal condition: average IDC= 0
Alarm if average IDC ≠ 0 (damaged decoupler, presence of resistive path)
Grounding potential (Egnd):
Alarm if Egnd drops to more negative values;
DC potential on structure and AC voltage;
OFF potential on structure;
Instant-off on coupon to measure IR-free potential;
DC and AC current density on coupon.
AC mitigation device: fault detection
The daily report shows the direct current recorded over several days, until the day when the average value becomes different from zero.
Taking the potential of the grounding system into consideration, we see that the variation is slight; this is because the ground network is very extensive and a lot of current is needed to generate a significant variation in potential. Instead, looking at the graph on the right, one can see that the potential varies greatly, going from -1.7 V to -1 V. In this case, we are far enough away from the rectifier that it does not realise that something is drawing current.Therefore, the rectifier continues to operate, losing 600-700 mV on the ON potential.
Therefore, we can identify the day and detect the presence of the fault, also analysing the temporal trend. This is important because if I have to do a historical analysis of the data – not only on this measurement point but on the other points of the system – having a signal that allows me to understand when the alternating current discharge device was not working properly also allows me to correlate the other values.
Effective cathodic protection
To ensure that cathodic protection is effective, ISO 15589-1 defines two steps:
General assessment
ON potential measurements performed on all measurement points or at least on selected ones.
Detailed and comprehensive evaluation
OFF potential measurements preferably carried out at all measurement points.
When an OFF potential measurement on the pipe is not possible, OFF potential measurements are required using probes or coupons at significant time intervals.
The NACE SP0169 standard, which is equivalent to 15589-1, establishes the following criteria:
A minimum of 100 mV cathodic polarisation.
Structure-electrolyte potential equal to or more negative than -850 mV relative to a copper/copper sulphate saturated electrode (CSE).
This potential can be a direct measurement of the polarised potential or an ON potential.
Use of cathodic protection coupons to establish current density levels, corrosion potential, polarisation levels.
Evaluation of ON potential
The graph below shows that we are protected during the year. There is, however, a period when the daily maximum is out of protection. This does not mean that we are in a serious risk of corrosion, because we must also evaluate the other information provided by the daily report (e.g. time out of protection).
Instant-off potential on coupon
Measurement Technique
We perform the instant-off measurement with the coupon and manage to eliminate the IR drop. This is a measurement that we can do simply by taking the instant-off values: it is done over a few milliseconds and we can repeat it once per second. Therefore, we have a 1-1 ratio between instant-off potential on coupons and ON potential.
Daily report
In the report below we see the measurement points, the out-of-protection maximums, and the out-of-protection times. In this case, the time out of protection of the ON potential is between two and five hours. So I might be induced to go into the field to find out what is going on.
As I mentioned earlier, here we are assessing whether we are cathodic or not;we are unable to know what the IR-free potential is to compare with the criterion we apply. Coupons help us: if we take into consideration those same days and the instant-off measure on the coupon where we eliminated the IR, we see that the real time out of protection is negligible.
In a set of measurements where I may have several points where the ON potential is unprotected, the coupon measurement allows me to filter out all those points where there is actually only an ohmic drop in the ground and analyse where there is a real need.
100 mV shift
Having the coupon and being able to control it remotely, we can also evaluate the 100 mV shift criterion: I can download the measurement second by second and make the evaluation.
DC interference
The graph below is interesting because we have the 24-hour ON potential and the instant-off potential on coupon. Having both measures allows us to assess the effect of interference. Looking at the night phase, the two lines are practically parallel. During the passage of trains, however, the ON potential chases all the currents circulating in the ground – these currents do not necessarily enter our structure. Therefore, the possibility of evaluating the two curves in parallel allows us to understand when the interference generates currents only towards the ground and when it also generates them towards the structure, resulting in cathodic and anodic conditions.
ON potential vs. instant-off on coupon
In the image below we report an example that is very interesting. In an interference condition, I download the measurement second by second. We have 30 seconds of measurement in which there are the ON potential and the current in the coupon. The current in the coupon when cathodic is positive and when anodic is negative. Thus, here we have the effect of an anodic interference that lasts approximately 15 seconds, with a maximum peak of 4 A/m2. Therefore, we have: anodic interference, 4 A/m2 current density, and positive ON potential (+ 0,65V CSE).
The first action one is tempted to take to eliminate a positive potential is to increase the current. However, in this case, by analysing the average daily values, we are heavily overprotected (-1.3 V CSE), so going to increase the current would make the situation even worse.
This is where the point we were making earlier comes into play: the importance of being able to assess the time out of protection. This is because if over the course of 24 hours the structure is protected, 30 seconds of anodic interference is not enough to generate a risk of corrosion. If we were instead to evaluate the instant-off potential during this interference, the most positive maximum value we would reach is -1.1 V. Therefore, it would be harmful to increase the current. If the rest of the cathodic protection system allowed it, we could even consider reducing the current slightly and attempting to exit the overprotection condition.
Therefore, depending on the quality and type of information I receive, I may even be led to make completely opposite choices, but at the risk of making the wrong ones. The more information I can obtain, the more convinced I will be of my actions because they are supported by data –reducing the probability of error.
AC interference
Alternating interference is rather insidious, as it is highly dependent on ground conditions. Soil conditions can vary throughout the year: a compliant measurement at a certain time of the year does not guarantee – unless I have continuous monitoring – that it will be equally compliant at another time of year.
If, in this case, the technician were to take a measurement, he would find 1.5 V of AC voltage. However, the graph below shows that there are times of the year when even 15 V is exceeded. With continuous monitoring I can get this information.
The graph below shows what can happen in industrial areas. Shown below is a 24-hour intensive measurement in an industrial area where there is probably a company with machinery with poor ground insulation. Therefore, we can count the machine cycles they are performing within 24 hours, and this may help us identify the source and request a solution to the problem.
The AC density is very sensitive to changes in ground resistivity. So – given the same external conditions – I can have periods of the year when the density is above 30 A/m2, others when perhaps, with a higher resistivity (summer period), the density drops dramatically and then goes back up again.
The monitoring configuration in the presence of alternating interference becomes quite critical. What we can measure is:
DC ON potential on structure and AC voltage;
Instant off potential on DC coupon (10 cm2 or other size, for evaluation of the protection criterion)
DC coupon current density
DC and AC current density on AC coupon (1 cm2)
With this setup I can check the following criteria:
-1.2V CSE < Instant off potential on coupon < -0.850V (according to ISO 15589-1 and SP0169)
Average daily AC voltage < 15 Vac (according to ISO 18086 and SP0177)
Daily average of Jac < 30 A/m2 (or Jac < 100 A/m2 if daily average Jdc < 1 A/m2) (according to ISO 18086 and SP21424)
In this article and in the previous one we have seen something that for Italy it has been history for 25 years. The ability to integrate remote monitoring features with high-frequency measurement monitoring, typical of data loggers, allows – in the presence of local intelligence capable of processing such data – intelligent reporting, evaluation, and simple detection of conditions that are normally difficult to detect.
The technician does not disappear in this activity, but he stops being a driver: he can spend more time in the office, analysing concrete data and dealing with abnormal conditions – having consistent data. At a time when human resources tend to be increasingly scarce in various cathodic protection groups, this type of assistance becomes essential for optimising all our activities.
Like Marty McFly in 1955,the rest of the world is finally reaching a future that for us has already been present for a quarter of a century. Italian technology has been the DeLorean, bringing innovation where it seemed impossible.
AUTOMA designs and produces innovative, Made in Italy hardware and software solutions for remote monitoring and control in the Oil, Gas and Water sectors.
We were born in 1987 in Italy, and today over 50,000 Automa devices are installed in more than 40 countries around the world.
Do you want to know the benefits for the security of your networks that you could have with the AUTOMA monitoring system for cathodic protection?
Contact our team without obligation and we will tell you what we can do to optimise your infrastructure control.
Electronics engineer, he is certified as a Senior Technician in cathodic protection and specialises in market analysis and industry standards. With more than 15 years of experience in remote cathodic protection monitoring and a patent on an intelligent reference electrode, Ivano is a member of the Board of Directors of Ceocor (European Committee for the Study of Corrosion and Protection of Piping Systems) and Delegate of AMPP Italy Chapter, as well as an active member of the ISO and AMPP standard working groups for cathodic protection.
By Ivano Magnifico, Product Manager AUTOMA From the presentation “Back to the future: when the past is already the future” SMART GRID DAYS 2025, 8 – 9 October 2025.
Are we using the data we receive from the monitoring systems of cathodic protection as we should? To understand this, let’s summarise the history, the current situation and the future of pipeline monitoring, particularly focusing on what we take for granted and what seems normal because we see it every day.
In this article and the next, we will talk about the monitoring methods and how it is possible to optimise data transmission.
With this content, we are mainly addressing foreign readers, who have different management practices than those we have in Italy. However, in any case, the recap can also be useful for us Italians to see if we are working to the best of our abilities.
Definition of Remote Monitoring
UNI EN ISO 15589-1:2017 proposes this definition of remote monitoring: “At a minimum, remote monitoring must provide the same level of information obtained by cathodic protection operators in the field”.
What does this mean? The “minimum” is a precise measurement taken at the same frequency with which a technician can go out into the field to carry out checks. Relying solely on this standard means taking things a bit too literally: you can imagine what it means to take a precise measurement every six months, considering everything that can happen in the meantime.
There is no definition of remote monitoring in the NACE standards. However, there is a working group that has the task of drafting the MR21551 standard on remote monitoring. When this standard is drafted, you will find that there is some reference to what we do in Italy.
RMU vs Datalogger
When we limit ourselves to what the standard requires, we are faced with a contrast between what a remote monitoring unit (RMU) does, which takes measurements from time to time, and what a data logger does, which analyses the effects of interferences with high-frequency measurements. Normally, one faces a dilemma: which one to choose?
If we choose a remote monitoring unit, we limit ourselves toperiodic measurements withlow transmission requirements, but we forego high-frequency sampling. If we choose adata logger, we will have high sampling frequencies and an assessment of transienteffects, but data retrieval will be difficult and usually done manually, as the device does not have remote access.
ON potential trend on structure
This graph shows four potential trends at four measurement points over six months (one measurement per week).
These measurements appear to belong to different cathodic protection systems, but in reality these curves derive from the exact same measurement point but relate to different times: we have the curve for 10:00, 13:00, 20:00 and 21:00 (in the figure below on the left). Therefore, this is what I get when I make a precise measurement with a certain periodicity. I lose track of everything that happens in the meantime: I cannot get clear information on the actual trend, which is what can be seen in the graph on the right.
Remote Data Logger Unit and Edge Computing
To overcome this problem, we need a tool that combines the features of a Remote Monitoring Unit (RMU) and a data logger: a Remote Data Logger Unit. This is a device that not only allows us to combine remote communication with high-frequency monitoring, but is also intelligent, highlighting only the key aspects of the information (indeed, there are constraints in terms of the amount of data that can be sent). The goal is to optimise transmission.
This goal can be achieved through edge computing: a computing model that processes information locally and sends only essential data to the Cloud (daily report). It is therefore a device that, like a data logger, can take one measurement per second at the site where it is placed. With this measurement frequency, at the end of the day, 86,400 measurements will be obtained: being a very high quantity, it is unthinkable to send them all, especially since the device runs on battery.
Therefore, the device processes this information and provides a summary, indicating:
Daily minimum, average, maximum: where the average value is a consistent value derived from one measurement per second over the course of the day, making it possible to understand the actual trend (not as in the previous graph on the left).
Statistical information:trend, i.e. the most frequent value measured within the 86,400 samples; standard deviation; and variability, to get an idea of how much the measurement varies throughout the day.
Total time (seconds) below the minimum threshold and above the maximum threshold during the day: to have a range in which to consider the signal valid or invalid; in the latter case, there will be a series of alarms or conditions to pay attention to.
Total number of exceedances of the minimum threshold during the day.
Total number of exceedances of the maximum threshold during the day.
All this information, which is summarised in sets of numbers (see figure below), is contained in few kilobytes of data per day but tells the story of everything that happened over the 24 hours, and it will do so as long as the device is installed.
Read the daily report
Edge Computing
In the figure, we see in detail some values.
Min, avg, max
How can we transform the recording of 24 hours of data into a daily report?
First of all, we have the following information:
Minimum value: the most negative value measured over 24 hours;
Average value: given by the arithmetic mean of the samples taken over 24 hours;
Maximum value: the most positive value measured over 24 hours.
Moda
Arithmetically, trend is the most frequent value within a set of samples (86,400 seconds). Usually, mean and trend have similar values, but when we are faced with a non-stationary interference, such as at a railway crossing (see fig. below), the trend takes on a very particular meaning: during the night hours, we find a slightly more stable measurement range and, almost always, the trend value coincides exactly with the value during the night when the system is not interfered with. Indeed, it is more likely that a value will appear consistently multiple times within that range.
So, even in a condition where there is considerable variability, it is possible, from these few numbers, also extract information about what the potential is – in the absence of interference – relative to that measurement point.
Standard deviation and variability
Looking at the type of graph in the figure below on the left, we would expect the standard deviation (or Mean Square Deviation, MSD) to be quite high. I could have measurements with similar minimum and maximum values, but perhaps due to a single interference that lasted only a few seconds.
This can be seen from the standard deviation value; indeed, this value indicates how stable my sample population was over the course of 24 hours. Therefore, even if I have rather wide minimum and maximum values as a range, if I realise that I have a low standard deviation (below 0.05), I know that in reality, throughout most of the day, my value has been close to the average value.
Time and number of alarms
The daily report also allows us to know how long we have been outside the limit conditions we have set.
The minimum out-of-threshold time and the minimum out-of-threshold number provide an overview of how many times you went below that value: in the case shown in the image below, the minimum out-of-threshold was reached once for 1 second. On the other hand, the maximum out-of-threshold time and the maximum out-of-threshold number show how many times one wentabove that value: in the case below, a total maximum out-of-threshold time of less than 2 minutes was reached in forty-five intervals. This, by the way, gives us an idea of the average time out of protection; in this case, we are around 2.5 seconds.
Why is it crucial? Because by takingcontinuous measurements, I canfind out everything that is happening, and I only need to look at this value to check whether the structure is at risk of corrosion. It is clear that in a condition of continuous cathodic protection, small intervals outside the protection levels do not entail an immediate risk of corrosion: it is up to the technician to decide and set the interval above which it is necessary to be alerted. In any case, in Italy, the regulation has established a maximum value of 3,600 non-continuous seconds.
According to ChatGPT, the term “Edge Computing” started to be known from 2014, but became commonly used around 2017. It is important to note this for a simple reason: everything we have seen so far is what has been done in Italy since 2001 as required by the UNI 10950 standard published that year.
In the chart below is the first daily report found in our database, which dates back to 1999, proving that we have been doing Edge Computing “without knowing it” for more than 25 years.
AUTOMA designs and produces innovative, Made in Italy hardware and software solutions for remote monitoring and control in the Oil, Gas and Water sectors.
We were born in 1987 in Italy, and today over 50,000 Automa devices are installed in more than 40 countries around the world.
Do you want to know the benefits for the security of your networks that you could have with the AUTOMA monitoring system for cathodic protection?
Contact our team without obligation and we will tell you what we can do to optimise your infrastructure control.
Electronics engineer, he is certified as a Senior Technician in cathodic protection and specialises in market analysis and industry standards. With more than 15 years of experience in remote cathodic protection monitoring and a patent on an intelligent reference electrode, Ivano is a member of the Board of Directors of Ceocor (European Committee for the Study of Corrosion and Protection of Piping Systems) and Delegate of AMPP Italy Chapter, as well as an active member of the ISO and AMPP standard working groups for cathodic protection.
From the speech “The evolution of the distribution network” SMART GRID DAYS 2024, 18 — 19 September 2024.
Centria is a city distributor that operates in 16 mainly Tuscan provinces (Italy), but with some excursions to Puglia and Umbria, and has collaborations with other companies in the Grosseto area (Lazio region). It has about 6,000 km of gas pipelines, managed mainly at medium and low pressure, and more than 400,000 customers.
Centria has always wondered if it is possible to make a contribution to decarbonization. Today, cathodic protection also asks itself this question. The distributor would like to make his work more efficient and advanced, despite offering an energy-intensive service.
In this case, technology comes to the aid: the case studies thatwe present are two examples of interventions carried out on the cathodic protection of two city distribution systems using impressed current. In both cases, an AUTOMA G-POWER device was installed to replace the rectifier previously inoperation: in the first case, G-POWER replaced the only rectifier in the system, while in the second it replaced one of the two rectifiers.
Case 1: The starting situation and the AUTOMA solution
The system is located in the town of Montale, in the province of Pistoia. It is equipped with 13 km of pipes, of which about 50% mediumpressure and 50% low pressure, and a single cathodic protection rectifier, operating at constant potential, with base current.
The adjustment was made with the Eon potential because it was the only way that that rectifier could work, that is, with a potential of -2.8 V corresponding to about an Eoff of -1.1 V. The base current was 1.30 A that had to be constantly supplied even in conditions of potential lower than that required. The current supplied varied a lot because it is a veryinterferedsystem. The variation ranged from 7 A to 12 A, with an average value of about 10.5 A.
The kilometer extension of the system is quite large, so you start from a fairly flat area and arrive at the first hills. As can be seen from the first image, the pipes are fairly distributed. While in the second image you can see the dislocations of the characteristic and remotely monitored measurement points.
From the remote control databefore replacing the rectifier, you can actually see that the current has values between 7 and 12 A, with an average value around 10 A.
We removed the rectifier that was previously in operation and replaced it with AUTOMA’s G-POWER. After turning it on, we reset the parameters that were used with the previous rectifier, namely constant potential regulation with an Eon value of -2.8 V. We chose to use G-POWER with the same setting as the previous rectifier to check if there were any operating differences under the same conditions. In the table you can see the new data returned.
So we haven’t changed either the adjustment system or the system or its surrounding elements. Right from the first ignition we had a fairly unexpectedsurprise: the current was reduced by almost 25%, going from an average value of 8 A to just over 6 A.
We asked ourselves why and with AUTOMA we did a bit of analysis on these measures. Let me start by saying that the amount of time we had for analysis was short: the rectifiers were put into operation in the month of July-August 2024, and what you see are preliminary data about two months after the start of the system, in September 2024. But these checks give us hope that we have at least taken the right path.
Why was there this reduction in power? Going to see the measurements, we noticed that the only thing that has really changed in the data coming from the remote control is the average square deviation from the adjusted value. The difference is important: we went from 0.2 to 0.02. This variation indicates that the regulation is much more stable over time, which translates into a smaller variation in the current supplied and therefore in a more stable and lower current than it was initially.
Case 2: The starting situation and the AUTOMA solution
The second system we are talking about is in the town of Sesto Fiorentino (Florence), where Centria has tworectifiers. Of these, only one was replaced during this test because we wanted to see the interaction of G-POWER with other rectifiers.
Both starting rectifiers operated at constant potential and were both adjusted to -2 V of Eon potential, corresponding to about -1.1 V of Eoff potential. The total current was 13 A, divided more or less equally on the two rectifiers.
We have about 11 km of mainly medium-pressure network, so we had networks in the fourth species andnetworks in the sixth species (0.5 bar and 5 bar) in the city center of Sesto Fiorentino, which is a very interfered area with the presence of a railway.
Only the rectifier that has been replaced has been set to make the adjustment work on the Eoff potential. We did several tests and then decided to adjust the Eoff potential no longer to -1.1 V (as it was set on previous rectifiers) but to -0.95 V.
At this point, the second rectifier was turned off because G-POWER was more than enough to protect the entire connected structure. First, the two rectifiers shared the current load (about 6 A/6.5 A each), but with the introduction of AUTOMA’s G-POWER one of the two was completely stopped, while the other supplied about half of the current that was previously supplied in total by two rectifiers.
The reduction in current in this case was significant, by 50%, both for the adjustment stability of the rectifier and for the lowering of the Eoff potential. Achieving these results is an important goal for a company with environmental certification.
Let’s mention the ease of installation of the AUTOMA device. G-POWER has also incorporated the data logger, and therefore all its functions: cyclic switch, remote controls, transmission system. It is enough to bring it on site and attach some cables to make it immediately operational, while for the previous rectifiers it was necessary to do a wiring that perhaps in some cases required half a day to connect all the devices. Even a quick installation translates into better efficiency for the company.
In conclusion, with AUTOMA’s G-POWER we have a product that has better regulation and stability in its operation, which is certainly also due to the fact that it has very new electronics. Clearly, being a new product, its potential is still to be explored. But for the moment we can say that, in addition to a significant simplicity of installation, it also offers a great advantage in the possibility of adjusting on the local Eoff potential.
AUTOMA designs and produces innovative and Made in Italy hardware and software solutions for remote monitoring and control in the Oil, Gas and Water fields.
We were founded in 1987 in Italy, and today more than 50,000 Automa devices are installed in more than 40 countries around the world.
Do you want to knowthe cathodic protection advantages you could have with the AUTOMAmonitoring system?
Contact our team without obligation and we’ll tell you what we can do to optimize your infrastructure control.
Head of Cathodic Protection and Electrical Systems Management and Development for Centria Srl (a company of the Estra SpA Group)
Leonardo Ferri is a cathodic protection technician involved in the management of cathodic protection for companies in the Estra SpA Group (both subsidiaries and directly controlled companies), designer of new cathodic protection systems, research and development of new plant solutions, commissioning and supervision of cathodic protection systems.
From the intervention “Cathodic protection. Commissioning of an impressed current system in the presence of non-stationary interference” SMART GRID DAYS 2024, 18 – 19 September 2024.
The INRETE distribution group, part of the Hera Group, is involved in the distribution of gas and electricity in Emilia-Romagna and Tuscany.
The case study we present concerns the commissioning of a cathodic protection system with impressed current for a distribution structure in the presence of non-stationary interference. Due to the morphology of the structures, this type of setup is extremely dynamic. We will see how the use of AUTOMA technologies, applied to regulation (with a G-POWER installed as the rectifier closest to the interference) and measurement techniques (a G4C-PRO device installed on the second power supply and a G4C-PRO with SOLAR BOX installed at the remote measurement point) can contribute to the efficiency of our plants, regulating them in a more effective way.
The starting situation
The system we are examining is a portion of a distribution plant in an urban neighbourhood where there is an interference caused by the nearby electrical substation of a direct current traction system.
The network, laid in predominantly sandy soil, is protected by two impressed current systems and served by a unidirectional drainage system. The architecture of the grid (qui credo ci vada grid) is mainly meshed, with an extension of about 24 km, and a surface area of slightly over 10,000 m².
Everything begins with the decommissioning of the unidirectional drainage system.
The new setup started in 2019 with: determination of the electrical state; assessment of the variability of the electric field; regulation and thus balancing of the electrical system. The new morphology places the two rectifiers (the two diamonds you see in the image – next page) in positions that are very off-center with respect to the detected interference.
This means that the urban area closest to the interference registers very evident potential attenuations. We therefore decide to design an impressed current system, determining the variability of the electric field and analysing the most anodic areas, therefore the most suitable for this implementation.
The impressed current system
In October 2022 we realised the new impressed current system. Consequently, we also moved on to the implementation across the entire network of new measurement points with polarisation probes. In November 2022, we realised the new electrical setup which, indeed, places the newly designed rectifiers closer to interference.
Following the new commissioning and the variation of monitored electrical parameters – in compliance with UNI11094 – we reclassified all measurement points. We consequently decided to redo a new commissioning of the entire system, adhering to UNI EN ISO15589-1, starting from a preliminary investigation:
Verification of the integrity of the disconnection.
Verification of all wiring.
Variability of the electric field.
Start-up of the system with a checklist of all installations and related safety devices.
Start-up of the installations with electrical state settings.
Verification of electrical continuity.
Rebalancing both the installations and the resistors on our network.
Measurements of currents on the joints.
Consequently, we proceeded to the complete mapping of the entire system.
Me moved on with the reclassification of measurement points, cartography update, and – a frequently forgotten step – the collection of all these data in a commissioning report, where we recorded the reference values of the electrical state of our system, in accordance with the ISO standard, for comparison with future measurements.
Our remote monitoring system provides us with the opportunity to report for each individual measurement point its set point following calibration, directing it towards the balancing of the system. As can be seen in the image, this means that, in case of exceeding the set point, the monitoring system creates an anomaly line, from which an intervention order can be generated.
A current impressed system is particularly dynamic and the initial interventions, in addition to the aforementioned decommissioning of the drainage system, have provided the opportunity to improve the system, reducing the current density from 2.7 mA/m² obtained with the first setup in 2017 to about 1.0 mA/m² in 2023.
The AUTOMA solution to the interference problem
All these activities have certainly mitigated the issues present in the system, but without resolving the interferences that interact with the rectifier control system.
Fortunately, technologies are on our side and the adoption of the technique of measuring the Eoff potential (Instant-off) on the most interfered rectifier will prove to be a wise choice.
The new rectifier, the G-POWER by AUTOMA, has given us the ability to control the system directly based on the Eoff Value, which is the value corrected for the IR component, allowing its PID controller to be less sensitive to potential fluctuations.
This is particularly noticeable in the standard deviation of the current output from the rectifier. In this first setup, where both rectifiers operated at variable current, it is possible to see how variable the standard deviation was throughout the day.
In the subsequent testing phase, we linked the control of the rectifier closest to the interference to a remote E-probe even closer to the interference itself, while the other impressed current system was set to constant current (the visible spikes in the image are due to maintenance activities).
In the final setup, where the interfered rectifier was set to a local Eoff potential, a flattening of the root mean square deviation can be observed. With this configuration we have effectively halved the standard deviation of the current, a factor that, although less evident but equally interesting, is also noticeable in the root mean square deviation of the DDP E-probe detected at the most characteristic point of our system. Even in this case, there is an almost halving of the value in the phase of controlling the rectifier via local Eoff, which manages to operate at less electro-negative E-probe potentials.
AUTOMA designs and produces innovative hardware and software solutions made in Italy for monitoring and remote control in the Oil, Gas and Water sectors.
We were born in 1987 in Italy, and today over 50,000 Automa devices are installed in more than 40 countries around the world.
Do you want to know the advantages for the safety of your networks that you could have with the AUTOMA cathodic protection monitoring system?
Contact our team without obligation and we will tell you what we can do to optimize your infrastructure control.
Massimo Tassinari is the technical contact for cathodic protection at INRETE Distribuzione, where he is involved in commissioning and supervising the testing of cathodic protection systems, updating monitoring systems and coordinating ARERA data reporting.
Cathodic protection has always been one of the fundamental strategies to slow down the corrosion of underground metal structures, such as pipelines. However, until recently, the techniques adopted to verify its effectiveness were often limited to manual, punctual measurements and not adequately representative of the entire system, especially in the presence of interference.
Today, thanks to the introduction of advanced technologies, big data and artificial intelligence, cathodic protection monitoring is undergoing a real revolution.
Traditionally, it was based on surveys carried out at certain points in the network: operators collected periodic readings of the ON potential and, based on these measurements, adjusted the setpoints of the rectifiers. This method, however, showed significant limitations: the values detected represented only an instantaneous measure and did not take into account fluctuations during the day or external interferences, such as stray currents generated by nearby infrastructures.
With the evolution of networks and the increase in interference, it was understood how necessary a paradigm shift was. This is how AUTOMA created the idea of an intelligent management of the cathodic protection system (Smart CP System): an ecosystem capable of monitoring every point of the network in real time, automatically regulating the current supplied by the cathodic protection rectifiers and predicting critical issues before they turn into concrete problems.
AUTOMA’s Smart CP System is an innovative approach that combines digital technology, data analysis and artificial intelligence to optimize the operation of the entire cathodic protection system in real time.
From analog to digital: the Smart CP System, the AUTOMA revolution
In the past, as we said just above, operators performed spot surveys on specific ‘points’ of the network, manually measuring the ON potential. This data was used to configure rectifiers, often with a high safety margin to compensate for measurement uncertainty and fluctuations over time. The result? Often more current was supplied than necessary, with consequent energy waste and, above all, the risk of overprotection and damage to the coatings.
In addition, the increase in ground interferences — due to stray currents, electric railway lines, industrial plants or power lines — has made the ON potential less and less reliable as the only reference parameter, or at least considerably more complicated to interpret.
The Smart CP System was created to overcome these limits. It is a centralized and intelligent management platform that continuously and dynamically controls all components of the cathodic protection system: rectifiers, measuring points, electrodes, and remote control devices. Its objective is twofold: to keep the IR-free protection potential stable and to optimize the output current of the rectifiers, avoiding waste and malfunctions.
Among the system’s key technologies:
RDU (Remote Datalogger Unit) installed at every critical point of the network, able both to function as a remote datalogger and to transmit measurements of the On and IR-free potential in real time.
Smart rectifiers, capable of working in a new automatic mode based on IR-free potential.
Remote control of the rectifiers, with the possibility of modifying the operating parameters from a central platform.
Adaptive algorithms that analyze historical data, seasonality, environmental conditions, and network status to anticipate and solve problems before they occur.
The heart of the Smart CP System is the new generation of smart rectifiers developed by AUTOMA, capable not only of operating in traditional modes, but also of working on the basis of IR-free potential. Connected to a coupon, these rectifiers constantly measure the real potential of the structure and adapt the current supplied to keep it stable.
All this is made possible thanks to a digital platform that integrates data analysis, predictive algorithms and remote control.
Not only that: currently, rectifiers in automatic operating mode base their adjustment on local feedback, but they must guarantee effective protection over the entire extension of the protected structure. For this reason, the possibility of identifying the most critical point (or points) of the network, equipping it with an RDU that allows more frequent communication during the day and connecting this point to the rectifier so that it works and varies its current supply based on the measurements taken by the critical point, opens up a completely new and much smarter opportunity to manage cathodic protection: the possibility of guaranteeing in every moment an effective protection of the entire structure to be protected, while at the same time delivering the minimum current necessary to achieve this purpose.
Scalable configurations and intelligent algorithms
The Smart CP system is extremely flexible and can be configured in different ways, depending on the complexity of the infrastructure (number of rectifiers and critical reference points identified):
One to one: a rectifier controlled by a remote measuring point.
One to many: a rectifier controlled by multiple critical points, with an algorithm that identifies the dominant point for regulation.
Many to many: multiple rectifiers interact with a network of measurement points, with an intelligent balancing of the currents.
There are two main approaches to control algorithms:
Time-based: the platform interrogates devices at regular intervals and adjusts rectifiers based on predefined thresholds.
Event-driven: each measurement point actively communicates to the platform when it detects a significant deviation, triggering immediate action.
Concrete benefits
The introduction of the Smart CP system brings tangible advantages:
Reduction of energy consumption, thanks to a more precise regulation of the current.
Longer anode life, avoiding overprotective conditions, and generally delivering more current than necessary.
Proactive corrosion prevention, thanks to the real-time view of the network status.
Lower maintenance costs, with targeted and data-based interventions.
Greater sustainability of the entire infrastructure system.
The first field applications confirm the effectiveness of the approach. The Smart CP system is not only a natural technological evolution, but a real paradigm shift: from static and reactive protection to intelligent, predictive and adaptive management of critical infrastructures.
AUTOMA designs and produces innovative and Made in Italy hardware and software solutions for remote monitoring and control in the Oil, Gas and Water fields.
We were founded in 1987 in Italy, and today more than 50,000 Automa devices are installed in more than 40 countries around the world.
Do you want to knowthe security advantages of your networks that you could have with the AUTOMA cathodic protection monitoring system?
Contact our team without obligation and we’ll tell you what we can do to optimize your infrastructure control.
Nicolas Rossi is an Electronic Technician and certified Level 2 Cathodic Protection Technician with experience in remote monitoring and control for cathodic protection and pressure-network systems. At AUTOMA S.r.l. he works together with hardware, firmware and software teams to deliver cutting-edge industrial solutions.
Core competencies:
Level 2 Cathodic Protection Technician – Underground Metal
Structures (EN ISO 15257)
Technical Coordinator at INRETE 
