E.R.S. Groot, The Netherlands, Session 1, Block 1.1: SWITCHGEAR Barcelona 12-15 May 2003 1 Successful implemented Condition Based Maintenance for switchgear

1E.R.S. Groot, The Netherlands, Session 1, Block 1.1: SWITCHGEAR

Barcelona 12-15 May 2003

Successful implemented Condition Based Maintenance for switchgear

Presenter: E.R.S. Groot

Session No 1, Paper No 14

Edwin R.S. GROOTNuon InfraCore

Edward GULSKIDelft University

Abe van DAMEneco Netbeheer

Frank J. WESTER Nuon InfraCore

The Netherlands



A guided tour through the implementation process of CBM

(step by step)

based on questions and problems we dealed with



Where did we start?? (more then 60 different type of switchgear)

Based on the selection criteria:

• Current maintenance costs

• Current outage time for maintenance

• Risk for maintenance induced failures

• Population size

• Age and expected lifetime

• Current failure behaviour and frequency

…….we started with a minimum oil breaker



What are critical components of this switchgear ??

We applied an FMECA approach and weighted each component

• Failure frequency (score 0,1,2)

• Impact of failure on energy supply (score 1,2,3)

• Corrective costs (score 1,2,3)

• Environmental impact (score 1,2)



FMECA register (screen dump)



The outcome of the FMECA exercise resulted in a new

optimised maintenance program …..

A mixture of maintenance, inspections and measurement activities were focused on critical components only

This optimised maintenance program resulted in the first cost reduction of 29%



How do we:- control and update the new maintenance program in the field- support the electrician with actual normsand instructions- guaranty the continuation of feed back of field experience



Therefore we developed the Inspector software tool:



Field support with actual norms and instructions



How do we handle the increased amount of data like:

• Measurement results

• Inspection results

• Maintenance information

• Failure information



We developed the I-Core database

typetime

analysis



The I-Core database for:

• storage of data (measurement and inspection results, failure information etc)

• optimising norms and criteria

• research of aging mechanisms

• improvement and optimisation of the condition based maintenance program



Example: correlation between moisture level in oil and aging of coqolite

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25 30 35

Moisture level (ppm)

Tang

ensD

elta

(%)

Coqolite is good

Coqolite has to be dried

Coqolite is irreparable



Example: norm and criteria optimisationSwitch of velocity

1,5 2,0 2,5 3,0 3,5 4,0 4,5

Velocity (m/s)

Ch

anc

e d

en

sit

y

Probability density curve of switching velocity

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

0,0 5,0 10,0 15,0 20,0 25,0

Contactpressure (kg)

Velo

cit

y (

m/s

)

Correlation between contact pressure and velocity

Norm definition for velocity based on large population measured data

Define a maximum norm for contactpressure based on influence on velocity



The outcome of the data analyses resulted in a further

optimised maintenance program …..

The optimisation of both the mixture of maintenance and measurement

activities and frequency resulted in a total cost reduction of 35%



Conclusion

• Good experiences with CBM

• Still implemented it succesfully for other type of switchgear

• Growing importance for condition data (not only as a foundation for CBM)

Documents

E.R.S. Groot, The Netherlands, Session 1, Block 1.1: SWITCHGEAR Barcelona 12-15 May 2003 1 Successful implemented Condition Based Maintenance for switchgear