Insulator Application in Insulator Application in Distribution Distribution Research & Standardization in Eskom Distribution
Welcome to the year 2 000 000 BC!
CUSTOMER REQUIREMENTS • 500 kVA mobile point of supply for diamond fields in the Kimberley area; • Turn around time = 4 HOURS; • Primary voltage = 11 kV / 22 kV; • Secondary voltage = 400 V; • The solution …………?????
MOBILE TRANSFORMER
A Definition • Technology can be ? described as the integration of people, knowledge, tools and systems with the objective to improve people’s lives.
The Technology Management Process Research
The Technology Management Process Technology selection and standardisation
The Technology Management Process Project design
The Technology Management Process Operate and maintain
The Technology Management Process Feedback
The Technology Management Process Centre of expertise
Distribution Technology Web • 25 Parts –Technology categories • Document types – Specifications – Standards – Guidelines – Technical Bulletins – Technical Instructions – Buyers guides and accepted products
Insulator Research • Done internally and externally (manufacturer input/ international stds) • A 5 year plan of most pressing needs • Insulator working groups priorities items from 5 year plan. • Research completed by insulator research specialists in conjunction with field services and manufacturers. • A research report is produced at the end of the research.
Research Questions Visual, IR and UV observation techniques for inservice insulators Inservice test towers as an aid for obtaining field performance data Brittle fracture test methodology, what should be specified? Does the new hydrophobic cyclo aliphatic material work and if so what will be the benefits to the Distribution business? Does the new hydrophobic porcelain material work? Find a coating that can be applied to fieldaged cycloaliphatic in a workshop environment. Find the criteria, which will enable an insulators remaining life and flashover performance to be predicted. Cost benefit analysis based on performance at what stage does it become viable to replace? Can defects in porcelain/cyclo aliphatic insulator products be detected by means of nondestructive laboratory tests? What is the effect on pollution performance as a result of orientation of the insulator (22 kV line post)? What protection time grading is required to ensure that damage to end fittings during arc conditions are limited as not to affect the mechanical integrity and further should arcing horns be used?
Pollution map
Koeberg Insulator Testing • Research of insulators in the field suggested that IEC 61109 test insulators adequately for SA conditions. • Particularly the accelerated aging of composite insulators (IEC 61109 Annex C). • Insulators that passed Annex C were failing in the field. • KIPTS Natural ageing and Pollution performance testing is born.
Insulation performance • Insulation is tested based on design and material • Relative performance is gauged • Pass/Fail criteria were setup to ensure service life and good performance of the insulator. • New design methodologies for insulation are found through the research and collaboration with manufacturers.
What is achieved • Good decisions on application of insulation materials and designs. • These decisions are incorporated into insulator specifications and standards. • Feedback mechanisms are setup to ensure designs are optimised. • More comprehensive realistic testing. • A set of accepted products can be put together on a listing. • Education of field staff, suppliers etc.
Feedback • Failures are feedback • Failures database • Investigation of failure modes • Expertise continually being improved.
Insulator Audit Insulator Audit Gareth Stanford Pr Eng. Gareth Stanford Pr Eng. Insulator Working Group Insulator Working Group IARC IARC Acknowledgements: Acknowledgements: Dr W Vosloo, Mr R Macey Dr W Vosloo, Mr R Macey
Insulator Audits Sheet Insulator Audits Sheet INSULATOR FIELD INSPECTION SHEET Line/Substation Equipment Voltage, Um (kV) Phase Tower / Pole No / Bay Insulator Description Defects Insulator Body Metalware Interfaces Function Cat. Fault Qty Cat. Fault Qty Cat. Fault Qty Strain Shattered Broken Sulphur Cement Melted 1 Suspension Cracked Bent Housing to Rod Failure Support >25% Sheds Broken Pin/Clip Missing Housing Punctured Pin/Clip Not Inserted Cement Cracking Type Core Exposed Loose Bolts Seal Damaged 2 1 1 Disc, No in string Housing Split Loose Arcing Horns Sealant Peeling Long Rod, No of sheds Core Fractured Loose Corona Ring Sealant Puncture Pin Burnt Arcing Horns Melted Line Post, No of sheds Tracking Corona Rings Melted Other Apparatus, No of sheds Erosion > 0.5mm Deep Power Arc Damage Cat. Fault Qty Material Insulator Skew Glass Grease Leakage Cap Corrosion Mounting Incorrect 2 Porcelain Flashover Mark Disc Pin Corrosion Bonding Wire Broken Composite Handling Damage Flashover Mark 1 Bonding Wire Missing 2 Resin Moulding Defect Tie Incorrect Coated Erosion < 0.5mm Deep 3 General Corrosion Tie Loose Greased Embrittlement Coating/Grease Layer Tie Damaged Cat. Fault Qty Condition Polluted Chipped Eroded Conductor Damage Pollution type Sheds Broken <25% Tracked 2 Pole Top Burning Surface Conductivity (µS) Discolouration Peeled Oil Leak 3 1 Hydrophobicity Class (17) Chalking Oxidised (whitened) Profile Crocodile Skin Removed Comments Alternating sheds Rodent Damage Sheds Bridged Electrical Activity/Conductivity Plain sheds Ribbed sheds Cat. Fault Qty Crocodile Skin Shed clearance (mm) Discharges >25% 2 Hydrophobicity Loss 1 Shed spacing (mm) Conductivity >60µS Uneven Layer Shed projection (mm) Creepage distance (mm) Discharges <25% Discoloured 3 2 Arcing distance (mm) Conductivity >30<60µS Chalking Corona Category 1 Replace or Correct 2 Requires Further Investigation 3 Monitor Condition Name: …………………………………… Sign: ……………………………… Date: …………………………..
Shattered disc
Cracked Porcelain Post Cracked Porcelain Post
Broken Porcelain Sheds Broken Porcelain Sheds
Core Exposure Core Exposure
Burnt Burnt
Puncture Disc Puncture Disc
Puncture Shed Puncture Shed
Puncture Sheath Puncture Sheath
Core Fracture (brittle fracture) Core Fracture (brittle fracture)
Core Fracture (handling damage) Core Fracture (handling damage)
Core Fracture (handling damage) Core Fracture (handling damage)
Core Fracture (bullet damage) Core Fracture (bullet damage)
Tracking Tracking
Flashover Mark Flashover Mark
Flashover Mark Flashover Mark
Erosion Erosion
Erosion Erosion
Sheath Split (handling damage) Sheath Split (handling damage)
Sheath Abrasion (rope damage) Sheath Abrasion (rope damage)
Shed torn (handling damage) Shed torn (handling damage)
Moulding defect Moulding defect
Moulding defect Moulding defect
Chalking and Discolouration Chalking and Discolouration
Chalking and Discolouration Chalking and Discolouration
Chalking and Discolouration Chalking and Discolouration
Rodent Damage Rodent Damage
Embrittlement Embrittlement
W Clip not Inserted Clip not Inserted W
Loose Bolts Loose Bolts
Power Arc Damage (end fitting melted) fitting melted) Power Arc Damage (end
Power Arc Damage (corona ring melted) Power Arc Damage (corona ring melted)
Missing Arcing Horn Missing Arcing Horn
Loose Arcing Horn Loose Arcing Horn
Arcing Horn Melted Arcing Horn Melted
Loose Corona Ring Loose Corona Ring
Corrosion Corrosion
Corroded Pin Corroded Pin
Bent Pin Bent Pin
Interface Failure (rod/housing) Interface Failure (rod/housing)
Sealant Peeling Sealant Peeling
Mounting Incorrect (restricted movement) Mounting Incorrect (restricted movement)
Mounting Incorrect (restricted movement and split pin) Mounting Incorrect (restricted movement and split pin)
Partial Discharge Activity Partial Discharge Activity
Corona Activity Corona Activity
Tracking of Grease Layer Tracking of Grease Layer
Uneven Grease Layer Uneven Grease Layer
Peeling, Chalking and Discoloured coating Peeling, Chalking and Discoloured coating
Coating with tracking and loss of hydrophobicity Coating with tracking and loss of hydrophobicity
Questions?
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