CAVLAR®

Ilse Pieterse-Quirijns

400 mm NGIJ400

mm

NG

IJ

Valve failure III

500 mm GGIJValve failure II

300 mm GGIJ

Known valve failure

Mains replacement

• Failure of valves:– I (known): 2 extra valves, no

extra customers– II: 4 extra valves plus extra

customers– III: 5 extra valves plus extra

customers

Valves can fail

CAVLAR®

• Quantifying the contribution of valves (or the fialure of valves) to the supply of drinking water

CAVLAR®

CAVLAR® :

Criticality Analysis Valve Locations And Reliability

Location valves: section analysis of distribution network

Reliability of valves: calculate performance distribution net

critical sections

critical valves

Effect of valve maintenance: improvement valve reliability

improvement of performance distribution net

1

2

3

CAVLAR®: required input

Required information:

• LIS data:

• Failure data:

• Maintenance data:

Volendam

number of connections, length, diameter

failure probability

supply interruption durance

valve reliability

Insight in existing distribution net

0

50

100

150

200

0 1 2 3 4 5 6 7 8 9 10

Num

ber

of

sect

ions

Number of valves per section

0

1000

2000

3000

4000

0 100 200 300 400 500 600

Leng

th p

er

sect

ion (

m)

Number of sections

0

50

100

150

200

0 100 200 300 400 500 600

Connect

ions

per

sect

ion

Number of sections

0.001

0.01

0.1

1

10

100

1000

0 100 200 300 400 500 600

Volu

me p

er

sect

ion (

m3

)

Number of sections

Location of valves

Section:

number of connections

diameter

length

failure probability

Valve:

Reliability

Section diagram

Adjust valve configuration

Adjust valve configuration (2)

New valve locations: comparison of configurations

number of valves per section

020406080

100120140160180200

0 1 2 3 4 5 6 7 8 9 10

number of valves

nu

mb

er o

f se

ctio

ns

Original configuration

New configuration

number of connections in a section

0

50

100

150

200

250

300

350

400

0-20

21-4

0

41-6

0

61-8

0

81-1

00

101-

120

121-

140

141-

160

161-

180

181-

200

number of connections in a sectionn

um

ber

of

sect

ion

s

less dependent sectionsnew config.:

less valves in a section

50% of valvesmore connections in a sectionnorm Groningen:< 200

33% of sections

Reliability of valves: critical sections (1)

• For each section CAVLAR® calculates performance indicators at a certain valve

reliability:

• Impact : number of connections

• Ratio : impact/number of connections in section

• CML (min/section/year) : minutes that costumer does not have water

• CI (1/year) : customer interruptions

highest CML critical sections

Performance indicator:ImpactRatio

CICML

critical sectioncritical valves

Reliability of valves: critical sections (2)

159 conn.3 valves

I = 181Ratio = 1.138CML = 06:54:08CI = 0.042vave rel.=0.90

Critical

section 1:

A_123Y

Reliability of valves: critical sections (3)

Reliability of valves: critical sections (4)

First 10 (5%) sections: 24% of total CML

First 22 (10%) sections: 40 % of total CML

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

0 50 100 150 200 250

number of sections

per

cen

tag

e o

f C

ML

Reliability of valves: critical sections (5) Judge new valve configuration based on CML

number of valves reliability number of sections CML [min]

original configuration 712 0.90 555 5:01

new configuration 333 0.90 183 11:56

new configuration + maintenance

333 0.95 183 9:42

x 0.5 x 0.33 x 2.3

CML improvement: 18.7%

weight reduction operational costs and CML increase

optimalisation valve configuration

Influence of increased valve reliability

0:00:00

0:07:12

0:14:24

0:21:36

0:28:48

0:36:00

0:43:12

0:50:24

0.7 0.8 0.85 0.9 0.95 0.98 1

valve reliability [-]

CM

L [

min

/co

nn

./ye

ar]

original configuration

new configuration

Effect of valve maintenance: Judge maintenance scenarios

Maintenance of valves:

• increase of valve reliability 0.90 0.95 effect maintenance for Winschoten: improvement CML with 18.7%

• CAVLAR® determines prioritization of valves

(ranking valves with diminishing effect on performance of distribution net)

input for maintenance scenarios

Effect of maintenance on CML maintain 50% of

most critical valves

75% of max.

possible result

same effect with

maintenance of

22% of most

critical valves to

higher reliability

btbh 0.95

btbh 0.98

willekeurig naar 0.95

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

0% 20% 40% 60% 80% 100%

percentage valves

imp

rove

men

t C

ML

vs

0.90

Conclusion

Roll of CAVLAR®: tool for optimisation of distribution network tool for prioritisation of sections and valves tool for advise in maintenance plans

1

2

3

Smart maintenance: good maintenance of critical valves results in

same performance

Smart configuration: judgement and optimisation of valve configuration