DGA Interpretation Example DGA Start-Up Program Completed and Routine DGA Program Started

Transcription

1 1

2 2 DGA Start-Up Program Completed and Routine DGA Program Started DGA Performed Compute Delta Value Update Rate Evaluation All Gases < Table 1 All Deltas < Table 3 All Rates < Table 4 DGA Status 1 Continue Routine DGA and rmal Transformer Operation Any Gas > Table 2 OR Any Rates > Table 4 DGA Status 2 IncreasedT ransformer Surveillance and DGA Frequency DGA Status 3 Perform Fault Identification and Transformer assesment Take appropriate Action based on Transformer assessment results and company policy

3 3 DGA Sample Results for High Resistance DETC Contact Gas Concentration (ppm) Data Point Sample Date H 2 CH 4 C 2 H 6 C 2 H 4 C 2 H 2 CO CO 2 N 2 O 2 1 Day ,603 76,587 6,085 2 Day ,002 76,256 6,423 3 Day ,951 78,592 7,188 4 Day ,531 45,599 1,431 O2 / N2 < Years in Service

4 4

5 5 DGA Start-Up Program Completed and Routine DGA Program Started DGA Performed Compute Delta Value Update Rate Evaluation All Gases < Table 1 All Deltas < Table 3 All Rates < Table 4 DGA Status 1 Continue Routine DGA and rmal Transformer Operation Any Gas > Table 2 OR Any Rates > Table 4 DGA Status 2 IncreasedT ransformer Surveillance and DGA Frequency DGA Status 3 Perform Fault Identification and Transformer assesment Take appropriate Action based on Transformer assessment results and company policy

6 6 O 2 /N O 2 /N 2 > 0.2 Transformer Age in Years Transformer Age in Years Gas (ppm) Unknown >30 Unknown >30 H CH C 2 H C 2 H C 2 H CO CO

7 7

8 8 Maximum ppm Variation between Consecutive DGA Samples Gas (ppm) O 2 /N O 2 /N 2 > 0.2 H CH C 2 H C 2 H 4 20 C 2 H 2 Any Increase CO CO

9 9

10 10 DGA Start-Up Program Completed and Routine DGA Program Started DGA Performed Compute Delta Value Update Rate Evaluation All Gases < Table 1 All Deltas < Table 3 All Rates < Table 4 DGA Status 1 Continue Routine DGA and rmal Transformer Operation Any Gas > Table 2 OR Any Rates > Table 4 DGA Status 2 IncreasedT ransformer Surveillance and DGA Frequency DGA Status 3 Perform Fault Identification and Transformer assesment Take appropriate Action based on Transformer assessment results and company policy

11 11 O 2 Ratio: O 2 /N O 2 /N 2 > 0.2 Transformer Age in Years Transformer Age in Years Gas/Age H 2 CH 4 C 2 H 6 C 2 H 4 C 2 H 2 CO CO 2 Unknown >30 Unknown >

12 12

13 13 DGA Start-Up Program Completed and Routine DGA Program Started DGA Performed Compute Delta Value Update Rate Evaluation All Gases < Table 1 All Deltas < Table 3 All Rates < Table 4 DGA Status 1 Continue Routine DGA and rmal Transformer Operation Any Gas > Table 2 OR Any Rates > Table 4 DGA Status 2 IncreasedT ransformer Surveillance and DGA Frequency DGA Status 3 Perform Fault Identification and Transformer assesment Take appropriate Action based on Transformer assessment results and company policy

14 14 DGA Start-Up Program Completed and Routine DGA Program Started DGA Performed Compute Delta Value Update Rate Evaluation All Gases < Table 1 All Deltas < Table 3 All Rates < Table 4 DGA Status 1 Continue Routine DGA and rmal Transformer Operation Any Gas > Table 2 OR Any Rates > Table 4 DGA Status 2 IncreasedT ransformer Surveillance and DGA Frequency DGA Status 3 Perform Fault Identification and Transformer assesment Take appropriate Action based on Transformer assessment results and company policy

15 15 Future DGA samples will remain in Status 3 due to the high concentration of C2H4. Future DGA samples are taken to monitor the gassing rate and track any change in fault type. Let s move on to the 4 th sample

16 16

17 17 Gas Maximum µl/l (ppm) variation between consecutive DGA Time Period between First and Last Point of the DGA Series samples Gas Rate O O 2 /N 2 /N O 2 O 2 /N /N O O 2 /N 2 /N 2 > 0.2 O 2 > /N 2 > 0.2 (ppm/year) 4-9 Months 9-24 Months 4-9 Months 9-24 Months ratio / Gas H 2 H CH 4 CH C 2 H 6 C 2 H C 2 H 4 C 2 H C 2 H 2 C 2 H 2 Any increase Any Increase Any increase CO CO CO 2 CO

18 18

19 19 DGA Start-Up Program Completed and Routine DGA Program Started DGA Performed Compute Delta Value Update Rate Evaluation All Gases < Table 1 All Deltas < Table 3 All Rates < Table 4 DGA Status 1 Continue Routine DGA and rmal Transformer Operation Any Gas > Table 2 OR Any Rates > Table 4 DGA Status 2 IncreasedT ransformer Surveillance and DGA Frequency DGA Status 3 Perform Fault Identification and Transformer assesment Take appropriate Action based on Transformer assessment results and company policy

20 20 Duval Triangle Ratios % CH 4 % C 2 H 4 % C 2 H 2 Day Day % 64 % 0 % Day % 65 % 0 % Day % 79 % 0 %

21 21 ACTIONS: Internal inspection revealed coking on the DETC contacts, resulting in high contact temperature. Repaired and put back in service.

22 22 New Business Any New Business?

23 23 Adjourn Thank you everyone