Estimation of health index for power transformers based on offline and online diagnostic methods

Kontinuiranim starenjem visokonaponske opreme podiže se svijest o stanju i raspoloživosti transformatora. Skupe odluke o obnovi i zamjeni moraju se bazirati na pouzdanoj procjeni stanja pojedinih transformatora. Dostupno je nekoliko izvora podataka, od periodičkih offline ispitivanja do sustava za monitoring, ali je potrebno uzeti u obzir njihove različite važnosti kako bi se prikazala realna vjerojatnost kvara komponenti transformatora. Napretkom tehnologije omogućeni su kontinuirani monitoring i kontrola podsustava transformatora, te se gubi potreba za isključivanjem transformatora iz pogona u svrhu obavljanja periodičkih ispitivanja, osim u slučaju problema otkrivenog motrenjem i potrebe za daljnjom analizom. Opisana je metoda utvrđivanja pouzdanog indeksa pouzdanosti uzevši u obzir nove podatke dostupne iz sustava za monitoring.With the progressive aging of transmission equipment, awareness of transformer's health condition and reliability is growing. Costly decisions regarding transformers refurbishment or replacement must rely on dependable assessment of individual transformer conditions. Several sources of data are available, from periodic off-line tests to continuous on-line monitoring, but they should be compounded with different weightings to reflect the actual failure probability of transformers components. Technology today can monitor and control all operating characteristics of power transformer and has evolved to the state where it is not necessary to take an outage and perform periodic testing unless a problem is indicated. A method is presented to establish a dependable global health index as new data become available through monitoring system