7. Summary of IMPROVEMENTS
BY PROBLEM SOLVING + FMEA
LOWEST RPN ON SEALING
- ALL JOINTS – UNDEROIL
LOWEST RPN ON CONDUCTOR
- CASTINGS – WELDING
RISK REDUCED AT TOP CONNECTION
- 3 NOS TAPPED HOLES
HEAT SINK FOR HOTSPOT
- SOILD TOP TERMINAL
CURRENT SHARE EQUALLY
- PLANETARY + SINGLE PIECE
ELCTROPLATING DEFECTS
- ELECTROLESS
We understand and We care
8. SOME CASE STUDIES
NO WELDING –better
conductance
INTEGRAL terminal –
thermal performance
Electroless
Nickel
11. AGEING of BUSHING
High ambient temperatures & temperature changes
High & frequent load cycles (e.g. pump storage power plants)
Overvoltage/transients (switching, lightning, harmonics)
Leakage à moisture ingress
Oil leakage (OIP only) à loss of insulation/dielectric properties
Corrosive contaminants in oil (for OIP only)
Capillary cracks (RBP types)
Partial discharges
12. SMART PLANS
Step 1: Identify & Clustering Bushing Fleet
• Voltage level
• Current level
• Technology
• Age
• Type of transformer
• Importance of substation
13. SMART PLANS
Step 2: Risk Assessment of Installed Bushing Fleet
• Based on Age
• Site Measurements
- Tandelta + Capacitance
- thermography
- Dissolved Gas Analysis-oil sampling
- Partial Discharge limited by background noice
< 1% OK
1`2%..??
>2%..ICU
14. Step 3: Definition of Bushing Style to Replace
Installed Fleet
Step 4: Set Up Risk-Based Replacement Schedule
Step 5: Execution of Bushing Fleet Replacement
Strategy
16. OIL + PAPER INSULATION
Oil Impregnated Paper (OIP)
Century Old Proven need Long Process time
Need Monitoring of oil level + Quality
Moisture settles down at most stressed part
Failure may lead to a devastating fire
18. RESIN + PAPERRESIN + PAPERRESIN + PAPERRESIN + PAPER
Dry type Resin Impregnated Paper (RIP)
A big relief against the nuance of oil
But RESIN do not marry PAPER well
Long Process time to remove water from paper
SLOW Impregnation of RESIN to Paper
PAPER absorb moisture STORAGE in store
RIP is BETTER than OIP but not the BEST
being fully dry and pressure-free;
• featuring a higher temperature class;
• being partial-discharge free;
• having low dielectric losses;
• being fire resistant, and;
• having outstanding mechanical properties
20. RESIN INFUSED GLASS
Most proven FRP system Resin Infused Glass widely
accepted from Boat to Aircraft
Superb Electrical and Mechanical properties
Popular for Polymer INSULATORS, Wind Mill etc..
Factory tested values retain life Long
P.Keith Ellis ..IEEE ex.chairman…
“….seen many failures of RIP leading fire…if you need a
safer bushing for transformer…look in to fiberglass
impregnated Glass.
21. RESIN +GLASS
Safer, no risk of fire and explosion.
Totally maintenance-free, low cost of ownership.
Superior resistance to mechanical and thermal stresses.
Environmentally friendly – no risk of toxic leakage.
Sealed and impervious to water and pollution.
Real time tracking for unmatched peace of mind.