Keeping an Eye On Voltage

Slove­nia has been pro­vid­ing its neigh­bor, Italy, with pow­er since 2010. The MSENSE® BM online mon­i­tor­ing sys­tem from MR makes sure that the ener­gy flows reli­ably.

In August 2020, Bas­t­ian Nie­der­meier, Sales Engi­neer Ser­vice at MR, and his col­leagues from MR Ser­vice had a par­tic­u­lar­ly excit­ing two weeks. Dur­ing this time, they car­ried out their annu­al main­te­nance on Sloven­ian net­work oper­a­tor ELES’s phase shift­ing trans­form­ers (PSTs). At the same time, they were tasked with per­form­ing an unusu­al retro­fitting job: Employ­ees from a local ser­vice provider replaced the pre­vi­ous mon­i­tor­ing sys­tem for two of the PSTs with the new MSENSE® BM bush­ing mon­i­tor­ing sys­tem from MR.

With the help of a sim­ple instruc­tion book­let, the local team installed the MSENSE® BM sen­sors on all 12 oil-impreg­nat­ed paper bush­ings (OIP bush­ings) of the two PSTs on their own. After­wards, MR com­mis­sion­ing spe­cial­ist Peter Schel­ter showed the team how to indi­vid­u­al­ly adjust the para­me­ters that were already stored in the system—that was all it took for the elec­tric­i­ty to flow between Slove­nia and Italy more reli­ably than ever.


Although it may sound sim­ple, in real­i­ty it was of course much more com­pli­cat­ed, as Alek­sander Pola­jn­er, Head of the High-Volt­age Device Depart­ment at ELES, describes with a smile: “Revi­sion of phase-shifter trans­form­ers is chal­leng­ing and needs to be planned care­ful­ly. These devices con­trol the flow of pow­er­ful elec­tri­cal loads between two coun­tries, and there­fore guar­an­tee the safe, reli­able, inter­rup­tion-free trans­fer or exchange of elec­tric­i­ty. In the event of an unplanned fail­ure, in the worst-case sce­nario, a net­work out­age due to over­load could occur.”

MSENSE® BM sen­sors are suit­able for mon­i­tor­ing resin-impreg­nat­ed (RIP) bush­ings, oil-impreg­nat­ed (OIP) bush­ings, or resin-impreg­nat­ed syn­thet­ic (RIS) bush­ings with volt­age lev­els between 10 kV and 800 kV.

MR designed the MSENSE® BM mon­i­tor­ing sys­tem for reli­able mon­i­tor­ing of high-volt­age bush­ings. An inno­v­a­tive algo­rithm mon­i­tors their capac­i­tance as well as the dis­si­pa­tion fac­tor, and com­pares any devi­a­tions with pre­de­ter­mined lim­it val­ues. The sys­tem imme­di­ate­ly noti­fies high­er-lev­el sys­tems if the lim­it val­ues are exceed­ed before the trans­former sus­tains any dam­age. MR Sales Engi­neer Ser­vice Bas­t­ian Nie­der­meier explains: “Around 17 per­cent of all trans­former fail­ures are caused by defec­tive bush­ings. For this rea­son, it is cru­cial to mon­i­tor them in order to ensure the reli­a­bil­i­ty of the sys­tem as a whole.”


MSENSE® BM fea­tures an inno­v­a­tive con­cept that uses what is referred to as a dou­ble-ref­er­ence method that mon­i­tors the con­di­tion of the bush­ing insu­la­tion based on a change in capac­i­tance and the dis­si­pa­tion fac­tor in a three-phase sys­tem. Nie­der­meier: “Since the algo­rithm per­ma­nent­ly mon­i­tors all three bush­ings and com­pares them with one anoth­er, the tem­per­a­ture depen­den­cy of oth­er process­es, which only mea­sure the volt­age at one bush­ing, is also deter­mined and linked to oth­er mea­sure­ments, for exam­ple the tem­per­a­ture.”

“Our expe­ri­ence in recent years has demon­strat­ed that MR offers excel­lent sup­port as well as Alek­sander Pola­jn­er, Head of High Volt­age Device Depart­ment at ELES

The MR sys­tem for detec­tion of sym­me­try of the three-phase net­work uses the sig­nals of the respec­tive volt­age trans­form­ers as a ref­er­ence and checks whether the mea­sure­ments are valid and whether asym­me­tries in the net­work are effec­tive­ly com­pen­sat­ed and elim­i­nat­ed. MR filed a patent for this con­cept in 2017.


In addi­tion to trans­fer­ring elec­tric­i­ty to Italy and vice ver­sa, ELES also oper­ates trans­mis­sion grids that are con­nect­ed with Aus­tria and Croa­t­ia and they are cur­rent­ly plan­ning a con­nec­tion to Hun­gary. This makes ELES part of the Europe-wide mul­ti-region­al cou­pling (MRC) project.

Alek­sander Pola­jn­er explains: “Our part­ners count on the reli­a­bil­i­ty of our sys­tems. That is why we are so care­ful when it comes to choos­ing the com­pa­nies we work with. Our cur­rent trans­form­ers are already equipped with MR sys­tem solu­tions. Our expe­ri­ence in recent years has demon­strat­ed that MR offers excel­lent sup­port as well as inno­v­a­tive, reli­able, safe solu­tions. By decid­ing to imple­ment the MSENSE® BM mon­i­tor­ing sys­tem going for­ward, we are already ben­e­fit­ing today from ser­vice from a sin­gle source.”


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