Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 1

Power Transmission and Distribution

Transformers

Ageing of Solid Transformer InsulationAgeing of Solid Transformer Insulation

THE INFLUENCE OF MOISTURE,

AIR AND OIL-TYPE

ON THE AGEING OF SOLID

INSULATION IN TRANSFORMERS

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 2

Power Transmission and Distribution

Transformers

Ageing of Solid Transformer InsulationAgeing of Solid Transformer InsulationAgeing Factors & Ageing MechanismsAgeing Factors & Ageing Mechanisms

Primary Ageing Factors

• Air

• Moisture

• Temperature

• Electrical Stress

• Contamination

Oil + Paper

Ageing ProductsAcids +

Sludge +

Moisture

Ageing

Feedback

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 3

Power Transmission and Distribution

TransformersDP = 800

DP = 200

Ageing of Solid Transformer InsulationAgeing of Solid Transformer InsulationAgeing of PaperAgeing of Paper

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 4

Power Transmission and Distribution

Transformers

GSU Transformer

Manufacturing Year 1996, Picture 2002

Oxidation processes lead to sludge formation with non-inhibited oils at normal operating service temperatures

Ageing of OilAgeing of Oil

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 5

Power Transmission and Distribution

Transformers

ROLE OF CHEMICAL ENVIRONMENT ROLE OF CHEMICAL ENVIRONMENT

ON THE AGEING PROCESSES AT TRANSFORMERON THE AGEING PROCESSES AT TRANSFORMER

SERVICE TEMPERATURESSERVICE TEMPERATURES

ROLE OF MOISTURE ROLE OF MOISTURE

WHAT DO WE KNOW NOW?

Ageing of Solid Transformer InsulationAgeing of Solid Transformer Insulation

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 6

0

0,2

0,4

0,6

0,8

1

1,2

0 2 4 6 8 10

Time (months)

DP/

DPo

Power Transmission and Distribution

Transformers

1% moisture

4% moisture

10% moisture Additional moisture

ingress

Development of DP with time at different starting moisture contents at 95°C.

Ageing of Solid Transformer InsulationAgeing of Solid Transformer InsulationRole of Moisture Role of Moisture

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 7

Power Transmission and Distribution

Transformers

ROLE OF CHEMICAL ENVIRONMENT ROLE OF CHEMICAL ENVIRONMENT

ON THE AGEING PROCESSES AT TRANSFORMERON THE AGEING PROCESSES AT TRANSFORMER

SERVICE TEMPERATURESSERVICE TEMPERATURES

ROLE OF MOISTURE & AIRROLE OF MOISTURE & AIR

WHAT DO WE KNOW NOW?

Ageing of Solid Transformer InsulationAgeing of Solid Transformer Insulation

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 8

Power Transmission and Distribution

Ageing of Solid Transformer InsulationAgeing of Solid Transformer InsulationAgeing of Kraft Paper Ageing of Kraft Paper ––Influence of Air or/and Moisture Influence of Air or/and Moisture

Thermal Behaviour of Kraft Paper under the Influence of Air and Moisture at 115°C

0

200

400

600

800

1000

1200

1 2 3

Time (Months)

DP

Moisture + Air

Air, no Moisture

Moisture, no Air

no Moisture, no Air

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 9

Power Transmission and Distribution

AgeingAgeing of Paperof PaperAgeing of Solid Transformer InsulationAgeing of Solid Transformer InsulationComparison Thermally Stabilized Paper & Kraft Paper Comparison Thermally Stabilized Paper & Kraft Paper

Thermal Behaviour of Kraft and Thermostabilized Paper under the Influence of Air and Moisture at 115°C

0

200

400

600

800

1000

1200

1 2 3

Time (Months)

DP

Moisture + Air

Air, no Moisture

Moisture, no Air

no Moisture, no Air

Moisture + Air

Air, no Moisture

Moisture, no Air

no Moisture, no Air

Kraft Paper

Thermally Stabilized Paper

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 10

Power Transmission and Distribution

Transformers

Ageing of Solid Transformer InsulationAgeing of Solid Transformer InsulationInfluence of the Insulation Fluid Influence of the Insulation Fluid

Development of DP with time at 115°C in Midel 7131

0

200

400

600

800

1000

1200

1 2 3

Time (months)

DP

Moisture + Air

Air, no Moisture

Moisture + Air

Air, no Moisture

Kraft Paper

Thermally Stabilized Paper

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 11

0

0,0005

0,001

0,0015

0,002

0,0025

0,003

0 1 2 3 4 5 6

Time (Months)

1/DP

Power Transmission and Distribution

Transformers

Non inhibited oil, air

Inhibited oil, air

Non inhibited oil, absence of air

Progress of Ageing (DP), Effect of Air, Inhibitor (85°C, 4% moisture in pressboard)

Ageing of Solid Transformer InsulationAgeing of Solid Transformer InsulationInfluence of the Insulation Fluid Influence of the Insulation Fluid

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 12

Power Transmission and Distribution

Transformers

Ageing of Solid Transformer InsulationAgeing of Solid Transformer Insulation

Summary• Humidity in the solid material and contact of Oil to the Air accelerate the ageing process

• The primary moisture content determines the slope of aging especially in the first time

• Thermally Stabilized Paper shows a better aging behavior than Kraft Paper under the influence of Humidity and/or Air

• The influence of primary Humidity inside Paper is lower in Ester-Fluids than in Mineral oil due to the better moisture absorbing behavior of the Ester-Fluid

• Inhibited Oil shows lower ageing of the solid insulation under the influence of air than non-inhibited oil

Further information see report of

CIGRE Task-Force TF D1.01.10 - Paper Ageing Paris Session 2004

Convener: Lars Lundgaard

Siemens AG, PTD T Höhlein / Heinzig IEEE Transformers Committee Meeting, Jackson (MS) March 2005 - Foil 13

Power Transmission and Distribution

Transformers

Ageing of Solid Transformer InsulationAgeing of Solid Transformer Insulation

Thank You For Your Attention