Monday May 18, 2009, 9:15 a.m. to 10:15 a.m. at the Rosen Center, Orlando.

Scope: This guide describes very low frequency (VLF) withstand and diagnostic tests and the measurements that are performed in the field on service-aged shielded medium voltage cables with extruded and laminated dielectric insulation. VLF test methods utilize ac signals at frequencies less than 1 Hz. The most commonly used, commerically available, VLF test frequency is 0.1 Hz. Whenever possible, cable systems are treated in a similar manner to individual cables. Tables are included of the recommended test voltage levels for installation, acceptance and maintenance tests.

Purpose: This guide is intended to provide troubleshooting and testing personnel with information to test shielded medium oltage cable systems using very low frequency techniques.

The attendance was 72. As the vice-chair was not able to attend the meeting, F. Koch took notes of the meeting.

The Chair announced that a PAR has been approved for the revision of IEEE 400.2 and that a Working Group now has to be established. The Chair reviewed the IEEE information on patents as required at each WG meeting.

The following persons indicated on the attendance list that they wanted to be members of the Working Group.

Name IEEE No, e-mail address

Densley, John j.densley@ieee.org

Abdolall, Kal kal.abdolall@powertechlabs.com

Baur, Martin m.baur@baur.at

Bernstein, Bruce b.s.bernstein@ieee.org

Brown, Kent kwbrown@tva.gov

Cote, Jacques cote.jacques.3@hydro.qc.ca

Fenger, Mark mark.fenger@kinectrics.com

Goodwin, Craig craig@hvdiagnostics.com

Gulski, Ed e.gulski@tudelft.nl

Hans, John John.hans@comed.com

Hong Leeman hongl@coned.com

Jiang, Grace gjiang@mmm.com

Lanz, Ben ben.lanz@imcorptech.com

Makowski, Leo makowski@hvtechnologies.com

Oetjen, Henning hoetjen@hdwelectronics.com

Patterson, Ralph ralphpatterson@powerproducts.biz

Petzold, Frank petzold.f@sebakind.com

Reed-Harmel, Brieana Brieana.reed-harmel@pacificorp.com

Vencus, Richard vencusr@nu.com

Von Herrmann, Martin mvh@voncorp.com

Walton, Mark mwalton@generalcable.com

Wen, Yingli y.wen@ieee.org

Zenger, Walter Wxz2@pge.com

Zhao, Dawn dzhao@aetnawire.com

The Chair indicated that the working group members will receive a copy of a draft with all changes discussed in previous meetings incorporated. He stressed that it is important to make all comments on the forms that will be provided to avoid confusion in trying to put together many different “marked-up” copies. He hopes to have the draft available around the end of June and will provide a date when comments are due back at that time.

There was a discussion of the extension of the standard to cover cables up to 69 kV and the background and methodology for the test values indicated in 400.2 were presented. There seemed to be general agreement and no-one voiced a negative opinion on the additions. Later in the meeting it was decided to include additional voltages of interest to Canadian, Asian and European users. As a result, 10 kV, 20 kV, 28 kV and 30 kV voltage systems will be included in the chart. It was pointed out that the curves for the installation and acceptance test levels used in the discussion were incorrectly labeled.

B. Lanz stated that some utilities do a test that is about equivalent to normal line voltage before re-energizing after some repairs. There was a short discussion and it is known that individual utilities often adopt their own practices internally.

K. Abdolall asked how to define Maintenance and Acceptance test values and times for circuits that have had a failure and a new section of cable installed. K. Brown said that they do an installation test on the new cable before it is spliced in and then a complete circuit test after repairs. In the nuclear field this is more of a business decision based on the procedures, crafts and times needed to do testing and repairs. L. Hong indicated that ConEd does not test a new cable being installed into an existing circuit until after the repairs have been completed. They test the entire circuit at one time which includes the new splices and new cable. Comments from the group seemed to indicate that this was the most common practice in distribution work and it does differ from some “in plant” practices.

K. Abdolall asked which test would be followed after repairs resulting from a failure that occurs during an acceptance test of a new system. Agreement was that you should do another acceptance test. N. Hampton suggested it would be good to provide some guidance in the new document to cover these various situations. H. Oetjen stated that though many people are concentrating on the new cable and splices, the bigger problem may actually be the old cable and that it should certainly be tested at some point. N. Hampton suggested these items be placed in the Testing Considerations section of the new document.

A question was raised on whether existing cables should be tested with values appropriate to their cable rating or according to the normal circuit voltage. W. Zenger and J. Cote indicated they thought the values should be based on the cable rating. L. Hong indicated this is a problem because in some situations equipment connected to the circuit, such as transformers, would have to be disconnected. This is because many utilities will install a higher rated cable on a circuit that is still energized at a lower voltage, such as 15 kV cable in a 4 kV area. This allows the ability to convert to a higher voltage later by changing the transformers but not all the cable.

After some discussion, there appeared to be agreement that it would be prudent to test according to the full cable rating at installation, assuming equipment that could be damaged is not yet connected, but according to the circuit voltage rating afterwards.

C. Goodwin raised a question about defining the ramp up and hold time; he feels it needs better definition as if the suggestion of recording failures during ramp up is accepted then it should be defined. N. Hampton mentioned that this idea came from field data which revealed many failures occurred in the very beginning of the test, often in the first 30 seconds or so. The idea was to try to capture the data for cables that were failing before the test voltage was reached rather than trying to dictate a ramp up time because that can vary based on the type of test set being used, i.e. manual vs. electronic. There was a suggestion that when recording data on failures, the data should indicate the time at the voltage where the failure occurred. C. Goodwin will provide some suggested wording to cover this topic and indicate that the test time in the table should be the time at the test voltage, meaning the time begins when the test voltage has been reached.

The Chair thanked F. Koch for taking notes of the meeting.

The attendance was 27 members and 42 guests.

The following Working group members attended the meeting: New members are indicated with a “ + “.

Densley, John Oetjen, Henning

Abdolall, Kal +Pachot, Jim

+Bader, Kraig Patterson, Ralph

Bernstein, Bruce Petzold, Frank

Brown, Kent Reed-Harmel, Brieana

Côté, Jacques Schlesinger, Rob

Fenger, Mark +Tarampi, Dexter

Goodwin, Craig Vencus, Richard

Gulski, Ed Von Herrmann, Martin

+Kasandra, Kishna Walton, Mark

+Koch, Fred +Williamson, Rick

Lanz, Ben Zenger, Walter

Makowski, Leo Zhao, Dawn

+Mathew, Roy

The IEEE-SA policy slides concerning patent issues had been presented at the Opening Session. The Chair provided an opportunity for participants to identify patent claims, patent application claims, or patent application claims of which any participant was personally aware and that may be essential for the use of this standard. No issues were identified at this time.

The basic purpose of this meeting was to discuss the current document Draft 6 which incorporates changes made to the earlier document, These changes are summarized on a table “Comments on Draft of IEEE 400.2 dated September 2009”, and was the basis for discussion, Only those subjects highlighted in red, considered of greatest importance, were discussed at the meeting due to the short duration of the meeting,

The following are those issues and their resolution,

1. Reference is made to Medium Voltage Class in the Guide, however subjects reference 69 kV cables, which are in excess of the definition of Medium Voltage

Resolution: The PAR will have to be adjusted accordingly

2. Comment on page 7 by Ed Gulski, line 5. A chart was proposed to be added for PILC cables, but questioned if this would be more appropriate to be in the 400. Document, since this document is concerned with issues of XLPE.

The question of defining a “severe” defect was raised and resolved as “A condition causing a breakdown” (not whether it results in PD since the term severe or less severe regarding PD has a different meaning when referring to XLPE vs, PILC). Another question was raised concerning adding other cable types to this document.

Kent Brown then questioned how detailed this document should be regarding the evaluation of test results.

Resolution: Kent Brown is to provide wording for this section.

3. Page 17-18 Ed suggested removing this section

Resolution: Leave this section in, Do not remove.

4. Page 22 comments by Bruce Bernstein, Should reference to Infra Red testing be removed. Recommendation is to use IR scanning but there is no guidance as to what to do with this information. It is clear there will be differing tan delta readings at different temperatures.

Resolution: Kent Brown suggested that an advisory/cautionary note be included stating that if testing causes temperatures to rise there may be different readings than at ambient temperatures.

5. Reference to Table 5, Martin Baur suggested that Table 5 be separated into multiple tables between Water Tree Retardant XLPE and XLPE.

Resolution: It was agreed after discussion that the data shown on Table 5B will be removed. The information shown is considered not accurate or reliable for the very low values indicated.

6. Question asked concerning the pass/fail criteria of the use and comparison of absolute or differential values of tan delta.

Resolution: If either absolute or differential values are not achieved then the cable is considered to have failed.

7. Use of cosine-rectangular wave for dissipation factor measurements. Is there a commercially available diagnostic device to perform this test?

Resolution: It was agreed that this section will be removed since there is not a commercially available diagnostic device to evaluate dissipation factor for the cosinerectangular wave. There was also a concern about the validity of the Hamon approximation used, for example, the approximation is valid as long as the response is not voltage dependent.

Prepared by Rob Schlesinger.