1 / 17

CONTENT

MODERN METHODS OF INSTALLATION AND DIAGNOSTIC TESTING OF DISTRIBUTION POWER CABLES Edward GULSKI , onsite.hv.solutions, Switzerland Frank DE VRIES , Alliander, The Netherlands Piotr CICHECKI ,, onsite.hv.solutions Benelux, The Netherlands Johan J. SMIT , TU Delft, The Netherlands. CONTENT.

colby-moon
Download Presentation

CONTENT

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MODERN METHODS OF INSTALLATION AND DIAGNOSTIC TESTINGOF DISTRIBUTION POWER CABLESEdward GULSKI, onsite.hv.solutions, SwitzerlandFrank DE VRIES, Alliander, The Netherlands Piotr CICHECKI,, onsite.hv.solutions Benelux, The Netherlands Johan J. SMIT, TU Delft, The Netherlands

  2. CONTENT • Introduction • Testing with DAC (OWTS) • Standards and knowledge rules for after installation tests • Standards and knowledge rules for diagnostic tests • Practical example • Conclusions • Future steps

  3. INTRODUCTION • Biggest DSO in the Netherlands • Over 35000km MV cable circuits • MV levels: 6, 10, 20 and 50kV • 15 years experience in PD measurements on MV cables • 3 teams specialists • Over the last 10 years more than 3500 cables have been diagnosed with DAC

  4. TEST PRINCIPLE OF DAC (OWTS) C cable L HV Source Solid state switch U & PD Computer wifi

  5. PD MEASUREMENT WITH DAC (OWTS) Testvoltage PD activity

  6. IMPORTANT PARAMETERS • PD inception voltage (PDiV) • PD extinction voltage (PDeV) • PD level @ Uo • PD level vs Testvoltage • Phase resolve pattern • PD location

  7. Based on NEN3620 Voltage Withstand Test cablesheath 5kVDC-5 min Voltage Withstand Test main insulation 3xUo, 0,1Hz-15min or 50 cycles 3xUo DAC PD measurements 0,25-0,5-0,75.....2xUo Voltage withstand tests Simple rule accepted / rejected Destructive method Not monitored PD measurements Monitored test method Gives information about abnormalities Interpretation of results is complex STANDARDS FOR AFTER INSTALLATION TESTSON NEW CABLES Alliander: All new cablecircuits are tested according NEN3620 also PD measurement are performed on new cable circuits that include joints

  8. Decision process for PD testing with DAC After laying testing of new Cable circuits: XLPE insulation PDiV < 1,7xUo PDiV > 1,7xUo Rejected Accepted

  9. Decision process for PD testing with DAC After laying testing of new Cable circuits: Cable joints PDiV < 1,2xUo 1,2xUo < PDiV < 1,7xUo PDiV > 1,7xUo no PD intensity > 3 per cycle ? yes no PD magnitude > 100pC ? yes no Repetition of test possible? yes Test repetition Rejected Accepted

  10. For XLPE cable circuits Voltage Withstand Test on cable sheath 5kVDC-5 min PD measurements up to 2xUo* For PILC circuits PD measurements up to 2xUo* TanD measurements up to 2xUo* Voltage withstand test with DC 2xUo√2* 5 minutes, VLF 2xUo* 5 minutes or DAC 2xUo* 50 cycles COMPANY STANDARDS FOR DIAGNOSTIC TESTSON AGED CABLES * Or lower testvoltage in case of safety aspects Alliander: Only suspicious cablecircuits are diagnosed. * Or lower testvoltage in case of safety aspects

  11. Theoretical information Measurement data Predict Detect Evidence Test Failure information Laboratory tests DEVELOPMENT OF KNOWLEDGE RULES FOR DIAGNOSTIC TESTS -Physics of PD processes -Component properties (design and materials) -Operation parameters -Determination -Statistic boundaries Knowledge rules -Escalation (destructive tests) -Fundamental tests -Behaviour of different PD types -Statistics -Component investigations

  12. PRACTICAL EXAMPLEPD activity in a joint Cable circuit in Alkmaar area: - 10kV PILC 3x95Cu and 3x150AL - 4 joints (different types of oil joints) 1100m Joint 1: 260m Joint 2: 310m Joint 3: 650m Joint 4: 700m Interruption caused by external damage. After repairing the failure the cable sometimes broke down at 1,5Uo during the DC voltage test. Localisation of breakdown was difficult. We applied PD measurement on the cable to detect the problem.

  13. PRACTICAL EXAMPLEAdvise and taken action Failure information Measurement data Joint 1 type A: 24000pC Joint 2 type B: 6000pC Based on experiences joint 2 was replaced. However joint 1 had much higher max PD magnitude than joint 2 !!! After replacing joint 2 no problems occurred in the circuit.

  14. CONCLUSIONS • Combining PD measurements with withstand tests give much more information about the quality of the components • After installation testing and diagnoses of new and old MV cable circuits by means of DAC gives reliable results • Knowledge rules are developed for the determination of the condition of new and old cables and accessories

  15. FURTHER STEPS • Pilot project in 2011: implementation of DAC diagnoses on old 50kV XLPE cable circuits • 25 measurements • Development of knowledge rules • Condition evaluation and proposal for the future • Consider to implement DAC technology for after installation test procedure on 50kV cable circuits

  16. THANK YOU FOR YOUR ATTENTION For more information: frank.de.vries@alliander.com

More Related