Frankfurt (Germany), 6-9 June 2011

E. Fred Steennison behalf of

E.Fred Steennis – Netherlands – Session 1 – Paper 0875

THE INTRIGUING BEHAVIOUR OVER TIME OF PD'S FROM DEFECTS IN MV

CABLES AND ACCESSORIESLESSONS LEARNED WITH SCG,

an on-line monitoring system

Frankfurt (Germany), 6-9 June 2011

Content

how to measure PD’s on-line in MV cables some results lessons learned – the intruiging behaviour

of PD’s conclusions

Frankfurt (Germany), 6-9 June 2011

Content

how to measure PD’s on-line in MV cables some results lessons learned – the intruiging behaviour

of PD’s conclusions

Frankfurt (Germany), 6-9 June 2011

How to measure PD’s on-line

applied method = SCG SCG means: Smart Cable Guard

CU SIU

up to 8 km

Frankfurt (Germany), 6-9 June 2011

How to measure PD’s on-line

with SCG diagnose cables (≤ 8 km)

data via internet to KEMA server, 1 h updates

customers have accessto their PD plots

KEMA experts recom-mend on action if needed

Frankfurt (Germany), 6-9 June 2011

Content

how to measure PD’s on-line in MV cables some results lessons learned – the intruiging behaviour

of PD’s conclusions

Frankfurt (Germany), 6-9 June 2011

Some results

4 days

PILC of 666 m with water at 396 m

Frankfurt (Germany), 6-9 June 2011

Some results

3 weeks

XLPE cable of 4.3 km with joint at 1678 m

Frankfurt (Germany), 6-9 June 2011

Some results

> 4 weeks

XLPE cable of 7 km with various weak spots

Frankfurt (Germany), 6-9 June 2011

Some results

3 months

PILC of 2.2 km with liquid filled joint at 1794 m

top view

Frankfurt (Germany), 6-9 June 2011

Content

how to measure PD’s on-line in MV cables some results lessons learned – the intruiging behaviour

of PD’s conclusions

Frankfurt (Germany), 6-9 June 2011

Lessons learned – PD’s are intruiging

How effective is SCG?

4 years SCG 158 km cable monitored

41 defects found in 7 cases (17 %) : no PD at all in 34 cases (83 %) : clear PD activity and

time to act

SCG is effective in warning for upcoming failures

Frankfurt (Germany), 6-9 June 2011

Lessons learned – PD’s are intruiging

SCG . . . . how much time for repair?

Frankfurt (Germany), 6-9 June 2011

Lessons learned – PD’s are intruiging

SCG . . . . how much time for repair?

water in PILC joints with hot conductor screen interruption in XLPE liquid filled joints in PILC

Frankfurt (Germany), 6-9 June 2011

Lessons learned – PD’s are intruiging

SCG . . . . how much time for repair?

water in PILC: days *)

joints with hot conductor screen interruption in XLPE liquid filled joints in PILC

*) between start of heavy PD activity and failure

Frankfurt (Germany), 6-9 June 2011

Lessons learned – PD’s are intruiging

SCG . . . . how much time for repair?

water in PILC: days *)

joints with hot conductor: days *)

screen interruption in XLPE liquid filled joints in PILC

*) between start of heavy PD activity and failure

Frankfurt (Germany), 6-9 June 2011

Lessons learned – PD’s are intruiging

SCG . . . . how much time for repair?

water in PILC: days *)

joints with hot conductor: days *)

screen interruption in XLPE: weeks *)

liquid filled joints in PILC

*) between start of heavy PD activity and failure

Frankfurt (Germany), 6-9 June 2011

Lessons learned – PD’s are intruiging

SCG . . . . how much time for repair?

water in PILC: days *)

joints with hot conductor: days *)

screen interruption in XLPE: weeks *)

liquid filled joints in PILC: months - years *)

*) between start of heavy PD activity and failure

Frankfurt (Germany), 6-9 June 2011

Content

how to measure PD’s on-line in MV cables some results lessons learned – the intruiging behaviour

of PD’s conclusions

Frankfurt (Germany), 6-9 June 2011

Conclusions

SCG can diagnose PILC, XLPE or mix up to 8 km, with 1 % length accuracy exp. so far: 4 years; 158 km monitored effective to see defects on time: 83 % ! PD’s from many types of defects only visible

for a few days before the failure, in others cases there is (much) more time SCG most effective if monitoring over longer time

Frankfurt (Germany), 6-9 June 2011

THANK YOU FOR YOU ATTENTION