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  1. benlanz

    Exacter Inc

    I am sure it detects EMI that is some times associated with breakdown mechanisms. The trouble is, there are no standards for what is good and bad EMI for most electrical equipment so the process leaves you guessing or relying on the vendor to decide what is good and bad. Another problem is that...
  2. benlanz

    WATER TREEING IN XLPE CABLE

    YUSNIDA83, As you my know, water treeing in power cable is a topic that has been discussed since the 1970's. Currently there is no commercially available way to pinpoint water treeing in a cable system. We have a great deal of experience performing Tangent Delta (TD) tests in the field with...
  3. benlanz

    AC vs DC Hipot Test

    Hello to all, I am coming to the discussion late too. I have thoroughly enjoyed reading all of your posts. I am glad to see such a lively discussion about this often misunderstood subject. It is exciting to hear so many writing in with fairly accurate, up-to-date information. The word is...
  4. benlanz

    cable passing through duct banK

    Zaza123, I recommend a strong word of caution how much faith you put in a DC HIPOT/ insulation resistance test. In order for a typical DC HIPOT test to detect a cable insulation problem you basically need to cut all the way through the insulation (an insulation failure). This is one of the...
  5. benlanz

    Cable bending radius

    a10jp, You are absolutely correct. An insulation resistance test will not detect even extreme bending radius issues. In order for an insulation resistance test to detect a problem you basically need to cut all the way through the insulation (an insulation failure). This is one of the reasons...
  6. benlanz

    69 kV Buried Cable

    Most 69kV cable is not armored. A concentric wire design is plenty good enough for the typical utility application. I recommend that you contact one of the major manufacturer's. If you need high level application engineering contacts, I would be glad to help. Benjamin Lanz Past Chair of IEEE...
  7. benlanz

    Old Cables

    VTpower is right that injection can help with water trees in HMWPE and XLPE cable insulation which do not have strand-filled or solid conductors. However, injection does nothing for defective splices, terminations, cable insulation voids or electrical trees. The industry best practice is to...
  8. benlanz

    Cable spacing

    There are hugh derating factors for adjacent AC cables. I recommend that you contact your manufacturer, ask for applicaiton engineering. They typically have models which they can use to give you a conservative estimate. Benjamin Lanz Past Chair of IEEE 400 Sr. Application Engineer IMCORP-...
  9. benlanz

    Medium Voltage Underground Cable / Smallest Available Size

    Ask Okonite about their line of X-ray cable. I am not sure that it is up to the NEC but the cable is 220mil EPR with tiny conductors. However, the conductors may be too small for your application. You will also have trouble finding a termination for this cable. If you need more help let me...
  10. benlanz

    Old Cables

    Hello and greetings to all again. I haven’t posted to this site in a while but, with all the confusion I hear in the above discussion, it appears that we need to open up this topic again. We have had this discussion several times on this forum but perhaps many of you don’t remember our previous...
  11. benlanz

    AC Hi-pot Sizing

    The only trouble with VLF is that the PD results can not be compared to IEEE standards. You need power frequency to use the standards. Benjamin Lanz Vice Chair of IEEE 400 Sr. Application Engineer IMCORP- Power Cable Reliability Consultants
  12. benlanz

    VLF AC Testing Waveshape

    Sorry. I am not an expert in the area of PD measurements on rotating machines. I recommend talking to Eaton or IRIS. If you have other cable questions I would be happy to help. Benjamin Lanz Vice Chair of IEEE 400 Sr. Application Engineer IMCORP- Power Cable Reliability Consultants
  13. benlanz

    VLF AC Testing Waveshape

    Truthfully, there isn't much difference. Large scale studies show similar results. Both wave shapes can be used for an IEEE type 1 destructive withstand test. Both low frequency AC waveforms are capable of aggressively failing insulation defects much faster than DC. The two companies you...
  14. benlanz

    VLF test of MV/HV cables

    Slava, You are welcome for the explanations. The ultrasound technique is typically an on-line technique. Ultrasound is only likely to detect PD activity when the probe is nearly in contact with the source. This creates a very high potential for false negatives and positives. Generally this...
  15. benlanz

    Partial discharge Testing online

    Generally speaking on-line PD testing of switch gear is useful if performed by an expert but, on-line PD monitoring is much more effective. I would check out eaton.com Benjamin Lanz Vice Chair of IEEE 400 Sr. Application Engineer IMCORP- Power Cable Reliability Consultants
  16. benlanz

    Does Partial Discharge Test Make Hi-Pot Unneccesary?

    Zogzog, I believe I understand your question much better now. Your question is a good one. No test can predict if a cable is going to be mistreated and over heated. However, some conduction types of defects can produce localized heating. This is a very low probability event in extruded...
  17. benlanz

    Does Partial Discharge Test Make Hi-Pot Unneccesary?

    Zogzog, My definition of a thermally driven mechanism is: a means of dielectric failure which is created by elevating the cable insulation temperature beyond its rated thermal limits. For example, ~>80C for PILC, ~>90C for XLPE and some EPRs, and ~>110C for new specially designed EPRs. I am...
  18. benlanz

    Partial discharge error?

    I would recommend an off-line test so that you can test each electrical component separately. This may not always work for rotating machinery because some PD activity is only active during specific loading conditions. However, our experience with cable diagnostics shows that it is necessary to...
  19. benlanz

    Does Partial Discharge Test Make Hi-Pot Unneccesary?

    Olicq, We use the IMCORP DSD Technology. Benjamin Lanz Vice Chair of IEEE 400 Sr. Application Engineer IMCORP- Power Cable Reliability Consultants
  20. benlanz

    Does Partial Discharge Test Make Hi-Pot Unneccesary?

    You are welcome Olicg. I agree with you. Separating noise and signal is very difficult while testing on-line. I know of several case studies where external signals were mistaken for PD activity in the cable. Petamn. I am glad you find my comments interesting. I hope you find them useful...

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