1. Frankfurt (Germany), 6-9 June 2011 E. Fred Steennis on behalf of E.Fred Steennis – Netherlands – Session 1 – Paper 0875 THE INTRIGUING BEHAVIOUR OVER TIME OF PD'S FROM DEFECTS IN MV CABLES AND ACCESSORIES LESSONS LEARNED WITH SCG, an on-line monitoring system

2. 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

3. 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

4. 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

5. 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 access to their PD plots KEMA experts recom- mend on action if needed

6. 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

7. Frankfurt (Germany), 6-9 June 2011 Some results 4 days PILC of 666 m with water at 396 m

8. Frankfurt (Germany), 6-9 June 2011 Some results 3 weeks XLPE cable of 4.3 km with joint at 1678 m

9. Frankfurt (Germany), 6-9 June 2011 Some results > 4 weeks XLPE cable of 7 km with various weak spots

10. Frankfurt (Germany), 6-9 June 2011 Some results 3 months PILC of 2.2 km with liquid filled joint at 1794 m top view

11. 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

12. 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

13. Frankfurt (Germany), 6-9 June 2011 Lessons learned – PD’s are intruiging  SCG.... how much time for repair?

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. Frankfurt (Germany), 6-9 June 2011 THANK YOU FOR YOU ATTENTION