Increasing Transformer Reliability by SMART Bushing

OVERVIEW TECHNOLOGIES

Types RBP OIP RIP RIS RIF

Insulation Srbp Paper+Oil Paper+Epoxy Synth+Epoxy Glass+Epoxy

Tan 0.7 0.4 0.4 0.35 0.3

Pressure Nil Yes Nil Nil Nil

Life 25 40 40 50 50

Population 8 % 80 % 10 % 1 1

PD high

FAILURE ANALYSISEUROPE

45%

7%

1%

17%

3%

26%

1%

Windings

Lead exit

Insulation

Bushing

Core

Tapchanger

Others

50% >400kV

RD2

Slide 3

RD2 Ramachandran Damodaran, 05-08-2016

ROOT CAUSE ANALYSIS

80% leakage (OIP Bushings )

13% deterioration of insulation

7% mechanical damage (mainly

porcelain insulators)

WEAK LINKS

Water accumu

late

High RPN

Summary of IMPROVEMENTSBY 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

SOME CASE STUDIES

NO WELDING better conductance

INTEGRAL terminal thermal performance

ElectrolessNickel

SOME CASE STUDIES

JOINTS ABV OIL LVL

SOME CASE STUDIES

JOINTS ABV OIL LVL

AGEING of BUSHING

High ambient temperatures & temperature changes

High & frequent load cycles (e.g. pump storage power plants)

Overvoltage/transients (switching, lightning, harmonics)

Leakage moisture ingress

Oil leakage (OIP only) loss of insulation/dielectric properties

Corrosive contaminants in oil (for OIP only)

Capillary cracks (RBP types)

Partial discharges

SMART PLANS

Step 1: Identify & Clustering Bushing Fleet

Voltage level

Current level

Technology

Age

Type of transformer

Importance of substation

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% OK1`2%..??>2%..ICU

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

THANK YOU

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

RIP IS POPULARMANY

APPLICATIONS

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

SEARCH FOR Alternative to RIP..

ABBMICAFIL

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 fireif you need a safer bushing for transformerlook in to fiberglass impregnated Glass.

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.

MGCPCORE

TRENCH

BETTER with POLYMER HOUSING

TRANSFORMER BUSHINGSTRANSFORMER BUSHINGSTRANSFORMER BUSHINGSTRANSFORMER BUSHINGS

No Grading

with Grading