Condition Monitoring of Oil Condition Monitoring of Oil Filled Ring Main Units Filled Ring Main Units
FACTS FACTS FACTS FACTS Oil Filled Ring Main Units are a critical part Oil Filled Ring Main Units are a critical part Oil Filled Ring Main Units are a critical part Oil Filled Ring Main Units are a critical part of networks of networks Maintenance is infrequent (every 5 Maintenance is infrequent (every 5 Maintenance is infrequent (every 5 10 Maintenance is infrequent (every 5-10 10 10 years) years) Details of operations and wear activity is D t il D t il Details of operations and wear activity is f f ti ti d d ti it i ti it i unknown unknown
BACKGROUND (UK) BACKGROUND (UK) BACKGROUND (UK) BACKGROUND (UK) 1998: EA Technology in co 1998: EA Technology, in co 1998: EA Technology in co-operation with 1998: EA Technology, in co operation with operation with operation with several Utilities, undertook extensive several Utilities, undertook extensive investigation to: investigation to: investigation to: investigation to: Determine how long oil can be left in equipment Determine how long oil can be left in equipment Detect unacceptable electrical /mechanical wear Detect unacceptable electrical /mechanical wear Detect unacceptable electrical /mechanical wear Detect unacceptable electrical /mechanical wear Oil samples were analysed and physical Oil samples were analysed and physical examination of hundreds of 30-40 year old examination of hundreds of 30 i i ti ti f h f h d d d d f 30 40 f 30 40 year old 40 ld ld units from thirty different makes and models units from thirty different makes and models were performed were performed ere performed ere performed
KEY FINDINGS KEY FINDINGS KEY FINDINGS KEY FINDINGS The most important factor in The most important factor in The most important factor in The most important factor in preventing material degradation and preventing material degradation and ensuring long service is the condition ensuring long service is the condition i i l l i i i th i th diti diti of the insulating oil of the insulating oil Invasive maintenance is only required Invasive maintenance is only required when significant degradation of the oil when significant degradation of the oil when significant degradation of the oil when significant degradation of the oil has occurred has occurred
Deterioration of Insulation Properties of Oil In Tank Physical Properties (Condition) Contaminants Increasing Chemical Changes Decreasing A B C Maintain Maintain Time
Deterioration of Insulation Properties of Oil In Tank Physical Properties (Condition) Contaminants Increasing Chemical Changes Decreasing Weeks A B C Maintain Maintain Time
Deterioration of Insulation Properties of Oil In Tank- Stage Two Physical Properties (Condition) Contaminants Increasing Chemical Changes Decreasing Years A B C Maintain Maintain Time
Deterioration of Insulation Properties of Oil In Tank – Stage Three Physical Properties (Condition) Contaminants Increasing Chemical Changes Decreasing 4-5 years A B C Maintain Time
STAGE C STAGE C MAINTAIN STAGE C - MAINTAIN STAGE C MAINTAIN MAINTAIN Relatively rapid aging process Relatively rapid aging process Relatively rapid aging process Relatively rapid aging process Moisture and acidity increase rapidly Moisture and acidity increase rapidly Breakdown strength decreases significantly Breakdown strength decreases significantly Breakdown strength decreases significantly Breakdown strength decreases significantly Maintenance Maintenance Should be completed before rapid Should be completed before rapid S S f f degradation occurs degradation occurs UK experience suggests within an 8 UK UK experience suggests within an 8-10 year UK i i t t ithi ithi 8 8 10 10 10 year period (typical maintenance cycle), failure can period (typical maintenance cycle), failure can occur occur occur occur
RESULTS CLASSIFICATION RESULTS CLASSIFICATION RESULTS CLASSIFICATION RESULTS CLASSIFICATION Pass = Satisfactory Condition Pass Satisfactory Condition Pass = Satisfactory Condition Pass Satisfactory Condition Retest at the next maintenance interval or 5 years Retest at the next maintenance interval or 5 years (whichever is the shorter) (whichever is the shorter) Retest = Indication of Some Degradation Retest = Indication of Some Degradation Unit should be maintained at 50% of maintenance interval or Unit should be maintained at 50% of maintenance interval or 3 years (whichever is the shorter) 3 years (whichever is the shorter) 3 3 ( hi h ( hi h i th i th h h t t ) ) Maintain = Advanced Degradation Maintain = Advanced Degradation Plan for Maintenance Within 6 Plan for Maintenance Within 6 Plan for Maintenance Within 6 Months Plan for Maintenance Within 6 Months Months Months Immediate Action Immediate Action Plan for Urgent Attention, recommended no live switching Plan for Urgent Attention recommended no live switching Plan for Urgent Attention recommended no live switching Plan for Urgent Attention, recommended no live switching
SAMPLING SAMPLING SAMPLING SAMPLING Access is through the top of the tank using Access is through the top of the tank using Access is through the top of the tank using Access is through the top of the tank using a specially designed cover plate for test a specially designed cover plate for test probe access probe access probe access probe access Sampling can be performed live Sampling can be performed live Sampling must be performed strictly in S Sampling must be performed strictly in S li li t b t b f f d t i tl i d t i tl i accordance to established procedures and accordance to established procedures and guidelines using the correct materials guidelines using the correct materials id li id li i i th th t t t t i l i l The procedure is safe The procedure is safe
LIVE TANK OIL SAMPLING LIVE TANK OIL SAMPLING (LTOS) (LTOS) (LTOS) (LTOS)
STATISTICS (NEDL STATISTICS (NEDL - UK) STATISTICS (NEDL STATISTICS (NEDL UK) UK) UK) BASED ON 437 UNITS BASED ON 437 UNITS Pass Pass Retest Retest Maintain Maintain No Units No Units 382 382 37 37 8 8 % % 89.5 89.5 8.7 8.7 1.9 1.9
LTOS RESULTS LTOS RESULTS LTOS RESULTS LTOS RESULTS NEDL (UK) : 437 units 2% 9% Pass R etest Maintain 89%
New Zealand Experience New Zealand Experience New Zealand Experience New Zealand Experience Used by more then 6 Utilities ( Vector Used by more then 6 Utilities ( Vector Used by more then 6 Utilities ( Vector Used by more then 6 Utilities ( Vector Powerco Powerco etc) etc) Close to 700 Units Tested Close to 700 Units Tested Close to 700 Units Tested Close to 700 Units Tested Training and Retesting of plates by MHL Training and Retesting of plates by MHL Approved Safety Procedures Approved Safety Procedures Approved Safety Procedures Approved Safety Procedures Results available in soft copy Results available in soft copy L&C , L&C L&C L&C , Reyrolle R R Reyrolle, ll ll , Statter Statter, St tt St tt , Andelect A d l Andelect, A d l t ABB SD t , ABB SD ABB SD ABB SD
LTOS RESULTS LTOS RESULTS LTOS RESULTS LTOS RESULTS New Zealand :686 units Pass 582 5% Retest 29 6% 6% M i t i Maintain 43 43 4% Immediate 32 85% 85%
$$ SAVINGS $$ SAVINGS $$ SAVINGS $$ SAVINGS Time based maintenance vs LTOS (less Time based maintenance vs LTOS (less Time based maintenance vs LTOS (less Time based maintenance vs LTOS (less units, less time) units, less time) Repair versus replacement Repair versus replacement Repair versus replacement Repair versus replacement Downtime Downtime Collateral Damage and Repair Collateral Damage and Repair Collateral Damage and Repair Collateral Damage and Repair Environmental Costs Environmental Costs R Regulator Fines R Regulator Fines l t l t Fi Fi Lost Revenue Lost Revenue
THANK THANK-YOU THANK THANK YOU YOU YOU EA Technology EA Technology gy gy
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