Scenario
Primary substation with 3 Grid transformer and 2 shunt reactors
Nameplate data of the transformer:
Manufact: xxx
Year: 1998
Power [MVA]: 250
Voltage [KV]: 345
Oil mass [Kg]: 118.000
Oil type: naphthenic
Analitical and diagnostic results
The analysis and subsequent diagnosis performed by Sea Marconi on the machines of the customer showed a clear presence of DBDS
Solution
Solution: Selective depolarization treatment (Chedcos) by Sea Marconi performed on-site and both with transformer in service and fully load (on-load) and with the transformer out of service (off-load).
The treatments guaranteed DBDS < 10 mg/kg
Before treatment |
After treatment |
|
| DBDS [mg/Kg] | 144 | < 10 |
| H2O [mg/Kg] | 16 | 5 |
| TAN [mg KOH/g] | < 0,01 | < 0,01 |
| DF | 0,0026 | 0,0015 |
