Page 55 - Energize August 2022

TECHNICAL

Figure 6: End of life criteria (Degree of polymersiation DP <200): 75% tensile strength loss

removes furan compounds). Findings
The maintenance history of the transformer revealed that oil The transformer was removed to a works facility and inspected.
replacement and purification took place on 12 March 2000. The The paper insulation clearly was at End of life criteria.
Furan production rate was 160 ppb (parts per billion) per month
(ppb/month). The Morgan Schafer Company reports that a Furan Risk assessment to plan remedial actions:
production rate of 25 ppb/month is cause for concern. A transformer with a low DP can continue to operate normally
The transformer oil analysis indicated a case of advanced paper providing it does not experience any external events.
insulation deterioration. (See Table 3) In a situation where the load is suddenly changed, or the

SampleDate H2 02 N2 CH4 CO CO2 C2H4 C2H6 C2H2 %Gas H20 kV Acidity Temp Furan SampleType
13-Dec-2004 434 2340 64873 16 355 5863 15 0 0 8,63 64 20 0,10 40 8,97
7-Sep-2004 0 0 0 0 0 0 0 0 0 0 10 87 0,09 60 Purification
9-Jul-2004 167 2500 55983 15 324 6322 0 0 0 8,01 52 34 0,09 56
15-Feb-2004 0 0 0 0 0 0 0 0 0 0 10 83 0,09 50 Purification
19-Nov-2003 40 8547 70970 9 351 4259 17 19 0 8,38 65 23 0,09 61
28-Aug-2003 0 0 0 0 0 0 0 0 0 0 16 72 0,07 65 Purification
23-Jun-2003 21 19370 65345 5 114 2116 0 0 0 8,53 43 35 0,07 52
31-Mar-2003 0 0 0 0 0 0 0 0 0 0 12 82 0,08 60 Purification
3-Feb-2003 0 0 0 0 0 0 0 0 0 0 13 69 0,08 60 Purification
9-Dec-2002 120 21162 73130 7 124 2601 0 10 0 8,63 45 25 0,08 49
23-Oct-2002 23 20525 56656 0 55 1189 0 0 0 8,01 38 35 0,09 45
11-Oct-2002 24 5878 46760 1 63 4297 0 0 0 6,22 10 70 0,09 40 Purification
2-Oct-2002 45 9531 61661 11 237 4833 15 17 0 8,74 78 17 0,08 63 Suspect Fault
27-Dec-2001 0 0 0 0 0 0 0 0 0 0 10 82 0,07 67 Purification
6-Nov-2001 102 11165 53340 10 236 3729 11 11 0 7,03 52 19 0,07 54
28-Nov-2000 0 24042 59971 9 207 2281 19 0 0 8,58 52 22 0,05 55
12-Mar-2000 0 0 0 0 0 0 0 0 0 0 11 14 0,05 60 Oil rep/pur
9-Dec-1999 53 13284 59226 7 159 3754 18 19 0 8,8 78 18 0,05 66
23-Feb-1999 0 0 0 0 0 0 0 0 0 0 34 48 0,18 70 Purification
8-Dec-1998 50 8079 69484 5 429 4872 10 0 0 8,49 65 26 0,18 60
26-Feb-1998 0 0 0 0 0 0 0 0 0 0 14 71 0,17 46 Purification
30-Jan-1998 19 18445 68637 7 359 6250 9 0 0 10,97 100 24 0,17 60
9-Dec-1996 58 15222 72938 17 425 9269 18 15 0 9,71 94 46 0,15 64
4-Jul-1996 19 19031 67861 10 244 6588 5 0 0 9,5 68 43 0,13 57
14-Nov-1995 16 4377 44646 6 351 6777 8 2 0 5,99 68 40 0,13 40
Table 3: Spreadsheet of transformer oil analysis and maintenance history

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