Oil_Analysis_T62_20260105.pdf

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Attached to
Life Extension for Deerhaven Unit 1 Transformers
Solicitation number
2026-093
Issued by
Alachua County, Graceville City, Florida

About this file

This is an Oil Analysis Report for transformer DHT62, a 138 kV, OA/FA-model transformer owned by Gainesville Regional Utilities (GRU) located at the Deerhaven substation in Gainesville, Florida. The report, generated on January 27, 2026, documents comprehensive testing and analysis of the transformer's oil condition based on samples collected on January 5, 2026, and previous samples dating back to 2023. The transformer, manufactured by Westinghouse (ABB) in 1970 and rated at 138,000 volts with a fluid volume of 4,440 gallons, has been in service continuously. The analysis includes dissolved gas analysis (DGA) from 87 total samples, with 61 DGA samples reviewed, revealing 10 gassing events since 2002. Current gassing status indicates no recent production of fault gas, with a cumulative liquid severity of 1.07 percent and an accumulated hydrocarbon gas failure rate (NEI-HC) of 1.07 kJ/kL. The most recent analysis shows decreased concentrations of combustible gases and an acceptable moisture level of 10 mg/kg with 26 percent relative saturation.

The transformer's reliability assessment indicates moderate overheating of insulating paper outside the windings rather than hotspot faulting, based on a CO/CO2 ratio showing general aging characteristics. All fluid quality parameters remain acceptable, including dielectric breakdown strength of 47.0 kV, acid number of 0.012 mg KOH/g, interfacial tension of 31.6 mN/m, and non-corrosive sulfur classification. Furan levels are within acceptable limits at zero µg/L for 2-furfural, and PCB contamination testing shows 7.0 mg/kg, classified as non-contaminated. The breathing analysis indicates an N2-blanket preservation system with positive pressure and low oxygen levels. The equipment is scheduled for DGA retest on January 5, 2027, with a 365-day interval. This analysis directly supports GRU's life extension initiative for Deerhaven Unit 1 transformers, which includes radiator replacement, wiring replacement, component refurbishment, and comprehensive testing for transformers T-61 and T-62, with T-65 limited to testing only.

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Life_Extension_for_Deerhaven_Unit_1_Transformers.pdf PDF
T61.JPEG JPEG file
T61_.JPEG JPEG file
T61___.JPEG JPEG file
T62.JPEG JPEG file
T62_Nameplate.JPG JPG image
T62_.JPEG JPEG file
T61_Nameplate.JPG JPG image
T62___.JPEG JPEG file
T65_.JPEG JPEG file
T65_Nameplate.JPEG JPEG file
T65.JPEG JPEG file
T61_T62_Outline_Drawing.pdf PDF
T61_T62_Cabinet_Wiring_Diagram_(1).pdf PDF
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Power_Transformer_Maintenance_Checklist_Unit_1_(2).pdf PDF
Oil_Analysis_T62_20260105_(1).pdf PDF
Oil_Analysis_T61_20260105.pdf PDF
DH_Unit_1_Transformers_Life_Extension_Specification_2026-093.docx DOCX document
Power_Transformer_Maintenance_Checklist_Unit_1.pdf PDF
T61_T62_Cabinet_Wiring_Diagram.pdf PDF
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Text version

TOA™ Analysis Report TRN DHT62

1 Report generated from GRU at 20260127T020114Z

Equipment DHT62 MVAR Actual 52.267

Serial No. 7001633 In service True

Apparatus type TRN Spare False

Owner GAINESVILLE Tank MAIN

Region GAINESVILLE Norms used TRN_IEEE_INC_69_288KV

Substation Deerhaven Gassing status 2

Norms TRN_IEEE_INC_69_288KV DGA result 1→1

Fluid type OIL Breathing result 2→2

Description Transformer Moisture result 2↘1

Manufacturer Westinghouse (ABB) FQ result 1→1

Year manufactured 1970 Trace elements result 0→0

Model OA/FA Particle analysis result 0→0 kV ratings 138 PCB result 1→1

Max rated voltage 138000 Furan result 1→1

Fluid volume 4440 Oil test status UNREVIEWED

Last Analysis Done On 2026-01-26

Last sample date 2026-01-05

Tank last modified date 2026-01-26

Equipment last modified date 2020-07-17

Norms last modified date 2021-06-05

Last analysis date 2026-01-26

Read-only samples 5

Excluded samples 0

Total samples 87

Sample Remarks

Sampled Container Lab remarks

2026-01-05 EX092 A50 Concentrations of combustible gases have decreased

2025-07-02 GA164 A50 Concentrations of combustible gases not increasing

2024-12-10 AT314 A50 Concentrations of combustible gases not increasing

2024-04-10 ER379 A50 Concentrations of combustible gases not increasing

2023-09-18 FZ914 A50 Concentrations of combustible gases not increasing significantly

2 Report generated from GRU at 20260127T020114Z

Reliability-based DGA Summary

DGA last date 2026-01-05 Cumulative sev liquid % 1.07

DGA samples 61 Cumulative sev paper % 0.00

Gassing events 10 Gassing status 2

Event fault type N/A Normalized HF ratio 0.00

HF %/yr combined 0.00

Accumulated NEI-HC

Fa ilu re r at e

1.07 % Grey area represents cumulative gassing event severity.

Red arrow represents event severity growth rate.

Reliability-based DGA Diagnosis

No recent production of fault gas (gassing status 2). A moderate increase in CO/CO2 suggests general overheating of insulating paper outside the windings, rather than the hotspot.

Dissolved Gas Analysis

Lab report number 250565-002 247423-004 244280-019 240105-002 237213-002

Sample date 2026-01-05 2025-07-02 2024-12-10 2024-04-10 2023-09-18

Sample temp 12 27 19 22 27 °C

Hydrogen (H2) 52 98! 26 19 17! µL/L

Methane (CH4) 5.0 10.0 14.0 36.0 45.0! µL/L

Ethane (C2H6) 38.0 63.0 110.0* 180.0* 209.0* µL/L

Ethylene (C2H4) 2.0 3.0 5.0 7.0 9.0 µL/L

Acetylene (C2H2) 0.0 0.0 0.0 0.0 0.0 µL/L

Carbon Monoxide (CO) 77 143 69 59 54 µL/L

Carbon Dioxide (CO2) 755 881 599 447 360 µL/L

Oxygen (O2) 3006 1731 2538 1208 1716 µL/L

Nitrogen (N2) 80036 81381 77652 81536 78580 µL/L

Total heat gas 45 76 129 223 263 µL/L

TDCG 174 317 224 301 334 µL/L

Equivalent TCG 0.184 0.336 0.129 0.110 0.110 %

Total partial press 98.6 92.2 91.9 94.1 88.8 % atm

3 Report generated from GRU at 20260127T020114Z

Lab report number 250565-002 247423-004 244280-019 240105-002 237213-002

Est. safe handling limit 5.3 5.4 5.9 5.8 5.7 %

Predicted composite fault gas 66 124 38 30 27 µL/L

Acetylene/Hydrogen (C2H2/H2) 0.0 0.0 0.0 0.0 0.0

CO2/CO 9.805 6.161 8.681 7.576 6.667

CO/CO2 0.102 0.162 0.115 0.132 0.150

Oxygen/Nitrogen (O2/N2) 0.038 0.021 0.033 0.015 0.022

ETCG/ESHL 0.035 0.063 0.022 0.019 0.019

NEI-HC 0.19 0.31 0.53 0.91 1.07 kJ/kL

NEI-CO 1.37 1.83 1.12 0.87 0.73 kJ/kL

DGA retest days 365 365 90 90 90 days

DGA retest date 2027-01-05 2026-07-02 2025-03-10 2024-07-09 2023-12-17

DGA reference days 187.0 204.0 244.0 205.0 221.0 days

DGA result 1 1 2 2 2

DGA diagnosis T2 T1 T1

Gassing status 2 2 2 3 3

HF %/yr combined 0.00 0.00 0.00 0.04 0.08

Symbol legend: !: sharp jump, *: abnormal level

Dissolved Gas Analysis Remarks

No anomalies.

Gassing Events

Date

NE

I-H

C [k

J/k L]

3: T1 6: T1

8: T1|PD

Accumulated Hydrocarbon Gas NEI

NEI-HC

Cumulative NEI-HC Gassing Event

4 Report generated from GRU at 20260127T020114Z

Date

NE

I-C

O [k

J/k L]

Accumulated Carbon Oxide Gas NEI

NEI-CO

Cumulative NEI-CO

Date

0.00

0.05

0.10

0.15

CO

/C

O2

1 2 4 5

Carbon Monoxide to Carbon Dioxide Ratio

CO/CO2

Smoothed CO/CO2 Gassing Event

ID Event Event start Start value Inc Days Samples FT RCOR % Sev % HF %/yr

1 R 2002-10-29 0.012 0.025 890 6 199

2 R 2005-10-12 0.024 0.018 201 2 73

3 HC 2003-04-15 0.510 0.447 1112 7 T1 0.21 0.14

4 R 2007-10-15 0.012 0.006 1661 10 47

5 R 2016-01-19 0.019 0.009 359 4 50

6 HC 2011-05-31 0.990 0.267 2260 15 T1 0.13 0.01

7 R 2018-09-19 0.022 0.109 1142 12 498

8 HC 2020-12-07 1.273 1.112 1015 13 T1|PD 0.55 0.04

9 R 2021-11-29 0.059 0.091 658 5 155

10 R 2024-12-10 0.115 0.047 204 2 41

Breathing Status Analysis

Sample date 2026-01-05 2025-07-02 2024-12-10 2024-04-10 2023-09-18

Oxygen (O2) 3006 1731 2538 1208 1716 µL/L

Nitrogen (N2) 80036 81381 77652 81536 78580 µL/L

Total partial press 98.6 92.2 91.9 94.1 88.8 % atm

Median O2 1731 1731 1907 1907 1907

Median N2 80036 81381 81536 81536 86654

Max deviation O2 1330 1330 2406 2406 2406

Max deviation N2 3884 8735 8735 8735 8735

5 Report generated from GRU at 20260127T020114Z

Sample date 2026-01-05 2025-07-02 2024-12-10 2024-04-10 2023-09-18

Predicted preservation class

N2-BLANKET N2-BLANKET N2-BLANKET N2-BLANKET N2-BLANKET

Breathing status result 2 2 2 2 2

Breathing Status Remarks

Oil preservation type is not defined on the equipment properties. A value is required to check if it is consistent with the data. Appears to be an N2-blanketed system with positive pressure and low O2.

O2 & N2 Diagram

O2/N2 = 0.5

Supersaturated

0 5000 10000 15000 20000 25000 30000 35000 Oxygen (O2) [µL/L]

20000

40000

60000

80000

100000

Ni to rg en

(N 2)

[µ L/

L]

Oil Preservation System as a Function of O2 and N2

Air

Cons-Sealed

N2-blanket Sealed

Super-atmospheric (Pressurized) Atmospheric (Air) Sub-atmospheric (Sealed) Illogical Previous sample(s) Latest sample Time Progression

Moisture Analysis

Lab report number 250565-002 247423-004 244280-019 240105-002 237213-002

Sample date 2026-01-05 2025-07-02 2024-12-10 2024-04-10 2023-09-18

Sample temp 12 27 19 22 27 °C

Moisture (H2O) 10 22 19 14 13 mg/kg

Relative saturation 26 30* 36* 23 18 %

Dew point -14 0 -2 -8 -10 °C

Moisture result 1 2 2 1 1

Moisture diagnosis HUMID-OIL HUMID-OIL

Symbol legend: *: abnormal level

6 Report generated from GRU at 20260127T020114Z

Moisture Remarks

The water content of the oil is acceptable.

Fluid Quality

Lab report number 237213-002 224586-001 224426-001 220686-002 219034-002

Sample date 2023-09-18 2021-08-04 2021-07-26 2020-12-07 2020-08-26

Sample temp 27 27 13 34 °C

Diel breakdown D877 47.0 55.0 47.0 52.0 kV

PF at 25°C 0.000 0.000 %

PF at 100°C 1.180 1.450 %

Acid number 0.012 0.012 0.012 0.010 mg KOH/g

Interfacial tension 31.6 33.0 31.4 34.1 mN/m

Specific Gravity 0.8820 0.8800 0.8800 0.8800

Color 2.0 2.0 2.0 2.0

Oil quality index 0.4 0.4 0.4 0.3

Visual CLEAR CLEAR CLEAR CLEAR

Corrosive Sulfur D1275B Noncorrosive

Fluid quality retest days 365 365 365 365 days

Fluid quality retest date 2024-09-17 2022-08-04 2022-07-26 2021-12-07

FQ result 1 1 1 1

Fluid Quality Analysis Remarks

No oil quality problems were detected.

Furans / Alcohols

Lab report number 224586-001 224426-001 150203-017 136966-006

Sample date 2021-08-04 2021-07-26 2008-10-29 2006-05-01

Sample temp 27 35 40 °C

2-furfural (2FAL) 0 0 0 0 µg/L

Furan result 1 1 1 1

Furan Analysis Remarks

Furan levels are within acceptable limits.

7 Report generated from GRU at 20260127T020114Z

PCB Analysis

Lab report number 192008-002 152796-002 150203-017 136966-006

Sample date 2016-01-19 2009-05-12 2008-10-29 2006-05-01

Sample temp 35 45 35 40 °C

Total PCB 7.0 7.0 7.0 6.0 mg/kg

PCB result 1 1 1 1

PCB Remarks

Not PCB contaminated. For a report of the last PCB sample, see the PCB in Oil Report.

History Graphs and Diagnostic Charts µL /L

Hydrocarbon gases and hydrogen

H2

CH4

C2H6 C2H4 C2H2 µL /L

Atmospheric gases and carbon monoxide

N2 O2

CO2

CO

https://www.toa4online.com/toa/redirect?page=pcb_report&db=GRU&equipnum=DHT62&serialnum=7001633&apprtype=TRN&tank=MAIN

8 Report generated from GRU at 20260127T020114Z

1999 2004 2009 2014 2019 2024 2029 0.0

0.5

1.0

NEI-HC

kJ /k

L

1999 2004 2009 2014 2019 2024 2029

NEI-CO

kJ /k

L 1999 2004 2009 2014 2019 2024 2029

Hydrogen (H2) µL /L

1999 2004 2009 2014 2019 2024 2029

Methane (CH4) µL /L

1999 2004 2009 2014 2019 2024 2029

Ethane (C2H6) µL /L

1999 2004 2009 2014 2019 2024 2029

Ethylene (C2H4) µL /L

1999 2004 2009 2014 2019 2024 2029 0.0

1.0

2.0

3.0

Acetylene (C2H2) µL /L

1999 2004 2009 2014 2019 2024 2029

Carbon Monoxide (CO) µL /L

9 Report generated from GRU at 20260127T020114Z

1999 2004 2009 2014 2019 2024 2029

Carbon Dioxide (CO2) µL /L

1999 2004 2009 2014 2019 2024 2029

Oxygen (O2) µL /L

1999 2004 2009 2014 2019 2024 2029

20000

40000

60000

80000

100000 Nitrogen (N2) µL /L

1999 2004 2009 2014 2019 2024 2029

Total heat gas µL /L

1999 2004 2009 2014 2019 2024 2029

TDCG

µL /L

1999 2004 2009 2014 2019 2024 2029 0.0

0.1

0.2

0.3

0.4 Equivalent TCG

1999 2004 2009 2014 2019 2024 2029

Total partial press a tm

1999 2004 2009 2014 2019 2024 2029

Est. safe handling limit

10 Report generated from GRU at 20260127T020114Z

1999 2004 2009 2014 2019 2024 2029

Predicted composite fault gas µL /L

1999 2004 2009 2014 2019 2024 2029 0.0

0.2

0.4

0.6

0.8

1.0 Acetylene/Hydrogen (C2H2/H2)

1999 2004 2009 2014 2019 2024 2029

CO2/CO

1999 2004 2009 2014 2019 2024 2029 0.00

0.05

0.10

0.15

0.20

CO/CO2

1999 2004 2009 2014 2019 2024 2029 0.00

0.02

0.04

0.06

0.08

Oxygen/Nitrogen (O2/N2)

1999 2004 2009 2014 2019 2024 2029 0.00

0.02

0.04

0.06

ETCG/ESHL

2006 2011 2016 2021 2026

Diel breakdown D877 kV

2006 2011 2016 2021 2026

-0.4

-0.2

0.0

0.2

0.4

PF at 25°C

11 Report generated from GRU at 20260127T020114Z

2006 2011 2016 2021 2026 0.0

0.5

1.0

1.5 PF at 100°C

2006 2011 2016 2021 2026 0.00

0.05

0.10

0.15

0.20

Acid number m g

KO

H

/g 2006 2011 2016 2021 2026

Interfacial tension m N

/m

2006 2011 2016 2021 2026 0.0

0.2

0.4

0.6

0.8

Specific Gravity

2006 2011 2016 2021 2026 0.0

0.5

1.0

1.5

2.0

2.5 Color

2006 2011 2016 2021 2026 0.00

0.10

0.20

0.30

Oil quality index

2001 2006 2011 2016 2021 2026 2031

Moisture (H2O) m g/ kg

2001 2006 2011 2016 2021 2026 2031

Relative saturation

12 Report generated from GRU at 20260127T020114Z

2006 2011 2016 2021 2026

2-furfural (2FAL) µg /L

1999 2004 2009 2014 2019 2024 2029

Sample temp

°C 2018 2020 2022 2024 2026 2028

0.0

0.5

1.0

1.5

2.0 HF %/yr combined

Raw Data Upper alert limit Lower alert limit

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