Digital Steel

Pow­er out­ages are a steel manufacturer’s worst night­mare. Accaierie Bertoli Safau relies on dig­i­tized trans­form­ers to keep the elec­trons and, hence, the steel flow­ing with­out any inter­rup­tions.

Daniele Giro would love it if his trans­form­ers could talk to him. They could tell him on their own when they are break ing down or need main­te­nance. Any out­age wears on his nerves and costs his employ­er a for­tune. With­out pow­er, the pro­duc­tion of Accaierie Bertoli Safau (ABS) is at a stand­still. The loss­es are gigan­tic in this case: Every hour, the two elec­tric arc fur­naces in the steel­works near the north­ern Ital­ian city of Udine melt around 200 tons of scrap met­al down into valu­able spe­cial steel for the auto­mo­tive indus­try, the rail­way or for gas pipelines.

Daniele Giro, head of high and medi­um volt­age dis­tri­b­u­tion, can check the sta­tus of the trans­former direct­ly from his con­trol room.

A total of nine trans­form­ers keep the volt­age sta­ble at the ABS plant.

Mea­sured by aver­age price per ton, this means that sev­er­al tens of thou­sands of euros per hour would quick­ly go down the drain for the com­pa­ny. “If you con­sid­er that it some­times takes sev­er­al days for a defec­tive trans­former to get up and run­ning again, you can image how great the loss is,” says Giro. As the head of high and medi­um volt­age divi­sion, he is respon­si­ble for keep­ing the plant grid, with nine big oil trans­form­ers and around 30 MV elec­tri­cal rooms, sta­ble and fail­ure-free.

This is no easy task—ABS alone con­sumes approx­i­mate­ly the same amount of ener­gy as the ein­tre city of Udine with its 100,000 inhab­i­tants. This is pri­mar­i­ly due to the two elec­tric arc fur­naces, the core of the steel­works. They func­tion like an over­sized weld­ing unit. Inside the melt­ing pot, there are elec­trodes made of graphite through which thou­sands of amperes pass. This caus­es elec­tric arcs between the elec­trodes that increase the tem­per­a­ture to more than 2,000 degrees Cel­sius. This makes it pos­si­ble to melt hun­dreds of tons of scrap steel in one filling every hour. “We basi­cal­ly recy­cle the mate­r­i­al and give the scrap met­al new life,” says Giro.


The com­pa­ny was found­ed in 1988 from the fusion of the two steel­works “Officine Bertoli”, found­ed in 1813, and “SAFAU”, found­ed in 1934. The com­pa­ny is part of the Danieli Group and today employs around 1,000 work­ers at the two pro­duc­tion loca­tions in Car­gnac­co in Udine province and Sisak in Croa­t­ia. It also has its own research cen­ter in Metz, France.

The plant gets the ener­gy need­ed for this over a high-volt­age line. Two step down trans for­m­ers first reg­u­late the volt­age from 230 kilo­volts to 21 kilo­volts, which reach the pro­duc­tion sys­tems via the plant’s inter­nal grid. Four pow­er trans­form­ers are used for the elec­tric arc fur­naces alone. They have the tough est job. With around 200,000 tap-change oper­a­tions per year, the on-load tap-chang­ers switch more fre­quent­ly than many sim­i­lar units in a typ­i­cal pri­ma­ry sub­sta­tion do in their entire ser­vice lives. Three addi­tion­al trans­form­ers are respon­si­ble for the sup­ply of the remain­ing sys­tems, such as the rolling mills.


Giro and his two co-work­ers have their hands full with keep­ing the tech­nol­o­gy run­ning in this harsh envi­ron­ment. “It would be best if we could make a sys­tem where inter­rup­tions nev­er hap­pen. While that is just a dream, we are doing what we can to get close to this ide­al.” Since Giro start­ed at ABS six years ago, he has con­stant­ly been look­ing for solu­tions to bet­ter mon­i­tor his trans­former fleet. Cur­rent­ly, he has only had two peri­ods for year in which he is able to thor­ough­ly check the trans­form­ers and per form main­te­nance work: dur­ing three weeks of sum­mer down­time in August and two dur­ing win­ter down­time over the Christ­mas hol­i­days.

“I would like to have a sys­tem that allows me to check the con­di­tion of my trans­form­ers at any time through­out the year.” Daniele Giro,Head of high and medi­um volt­age divi­sion, ABS

But what hap­pens between these two peri­ods? Giro has only been able to hope that the main­te­nance work has been enough and every­thing runs well. Actu­al­ly, that wasn’t enough for him. “ I would like to have a sys­tem that allows me to check the con­di­tion of my trans­form­ers at any time through­out the year.” The vis­it two years ago by Ste­fano Vig­nali, Area Sales Man­ag­er at Rein­hausen Italia, was oppor­tune. The two com­pa­nies have had a long­stand­ing relationship—on-load tap-chang­ers from Maschi­nen­fab­rik Rein­hausen are in- stalled in all trans­form­ers at ABS, and the reg­u­lar ser­vice work by MR-tech­ni­cians leads to active dis­course. Vig­nali had come to intro­duce the ETOS® automa­tion solu­tion (see box).

The elec­tric arc fur­naces in the steel­works con­sume as much elec­tric­i­ty as an entire city.

The open oper­at­ing sys­tem makes it pos­si­ble to mon­i­tor, con­trol and reg­u­late pow­er trans­form­ers. “The sys­tem has a mod­u­lar struc­ture, so the users can decide for them­selves which com­po­nents of the trans­former they want to mon­i­tor. Sub­se­quent instal­la­tions are also pos­si­ble,” explains the Rein­hausen expert. For exam­ple, this can include mon­i­tor­ing the bush­ings and the transformer’s oil or the intel­li­gent con­trol of cool­ing sys­tems. For Vig­nali, it is clear that ETOS® cre­ates more secu­ri­ty. “In steel­works, cement plants or any fac­to­ries that have a pow­er trans­former, mon­i­tor­ing is extreme­ly impor­tant. I know of com­pa­nies that just have one trans­former — when it fails, all pro­duc­tion goes down.”


Giro was primed to accept this sug­ges­tion. The ABS phi­los­o­phy is to always invest in new tech­nolo­gies. As a mem­ber of the Danieli Group, a lead­ing plant man­u­fac­tur­er for the met­al­lur­gi­cal indus­try, ABS has the option to try out tech­nol­o­gy that is not yet on the mar­ket. “Exper­i­ment­ing is impor­tant,” says Giro. He did not shy away from exper­i­ment­ing, even with his most impor­tant pieces of equip­ment. Still, he played it safe at first. To learn more about ETOS®, Giro decid­ed to use it ini­tial­ly on two trans-for­m­ers and with all avail­able modules—because if it’s worth doing, then it’s worth doing right. One was a trans­former that has already been in oper­a­tion for sev­er­al years; the oth­er was a brand new one which ABS com­mis­sioned from an Ital­ian trans­former man­u­fac­tur­er.

“The infor­ma­tion col­lect­ed by the sys­tem is huge­ly impor­tant for us. For the first time, we have the option of track­ing the con­di­tion in real time and are also learn­ing more about the trans­former.” Daniele Giro, Head of high and medi­um volt­age divi­sion, ABS

The retrofit on the exist­ing trans­former was per­formed dur­ing the down­time in August 2020. In mug­gy heat with tem­per­a­tures of 39 degrees Cel­sius, the Rein­hausen tech­ni­cians worked, attach­ing the pre­configured ETOS® con­trol cab­i­net to the trans­former, wiring the sen­sors and final­ly check­ing every­thing for func­tion. The work began on a Mon­day and was finished on Fri­day.


Since then, Giro has tak­en a sig­nifi­cant step toward his wish for a talk­ing trans­former. He can trace what is occur­ring with­in the trans­former in detail on his screen in the con­trol room. In prin­ci­ple, Giro could even access the con­di­tion data from any com­put­er in the plant. This is made pos­si­ble by the inte­grat­ed web serv­er in the cen­tral pro­cess­ing unit in the ETOS® con­trol cab­i­net. Giro can read the tem­per­a­ture in the wind­ings, learn more about the qual­i­ty of the oil and, of course, con­trol the on-load tap-chang­er from any­where. In addi­tion to the options for mon­i­tor­ing, ETOS® also makes intel­li­gent con­trol of the trans­form­ers possible—such as the on-load tap- chang­er or the cool­ing fans.

Daniele Giro plans to dig­i­tize all of the trans­form­ers on a grad­ual basis.

This enables more effi­cient oper­a­tion, and thus ener­gy sav­ings. “The infor­ma­tion col­lect­ed by the sys­tem is huge­ly impor­tant for us. For the first time, we have the option of track­ing the con­di­tion in real time and are also learn­ing more about the trans­former. Now, we know how it responds to cer­tain events in oper­a­tion. We are still at the begin­ning, but I sus­pect that the sig­nifi­cant­ly improved data sit­u­a­tion gives us a much bet­ter basis for deci­sion-mak­ing and we will be able to plan bet­ter. We have tak­en the first step.” He does not want to lose too much time on the next steps. In the next three years, the automa­tion of the oth­er trans­form­ers is set to progress rapid­ly.


ETOS ® – the Embed­ded Trans­former Oper­at­ing Sys­tem – is an open, mod­u­lar sys­tem solu­tion for mon­i­tor­ing, con­trol­ling and reg­u­lat­ing pow­er trans­form­ers. There are six func­tion pack­ages to choose from depend­ing on the mon­i­tor­ing require­ments.

  • Trans­former mon­i­tor­ing: Mon­i­tor­ing of motor-dri­ve unit sig­nals, oil tem­per­a­ture and tap-change oper­a­tion sta­tis­tics.
  • On-load tap-chang­er mon­i­tor­ing: Sta­tus reports regard­ing tem­per­a­tures, pro­tec­tive devices, cur­rents, and volt­ages. Cal­cu­la­tion of the aging rate and loss-of-life.
  • Online DGA mon­i­tor­ing: Eval­u­a­tion of the gas con cen­tra­tion and mois­ture in the insu­lat­ing oil.
  • Con­trol and mon­i­tor­ing of the cool­ing sys­tem: Mon­i­tor­ing of the start of cool­ing and cool­ing effi­cien­cy as well as intel­li­gent con­trol based on load con­di­tions and ther­mal con­di­tions.
  • Bush­ing mon­i­tor­ing:Con­tin­u­ous mon­i­tor­ing of the bush­ings using the dou­ble ref­er­ence method.
  • Auto­mat­ic volt­age reg­u­la­tion: From sim­ple volt­age reg­u­la­tion to a wide range of par­al­lel oper­a­tion meth­ods for trans­form­ers and right up to com­plex reg­u­la­tion tasks.

ETOS® can be inte­grat­ed or retro­fit­ted seam­less­ly in any envi­ron­ment and forms the inter­face between the process and con­trol lev­els in the field lev­el area.


Do you have ques­tions about ETOS® and the project at ABS?
Ste­fano Vig­nali is here to help:

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