Attendance

Joe Zimnoch Consultant

John Ainscough Xcel Energy

Hemming Oetjen HDW Electronics

Brian Marz HV Technologies, Inc.

Craig Goodwin HV Technologies, Inc.

Luigi Testa TechImp

Ben Lanz IMCORP

Mohammand Eyad Al-Sibai High Voltage Inc.

Bruce Olson High Voltage Inc.

John Hans Commonwealth Edison

Vern Buchholz Consultant

Seysd Hajassadollah FPL

Jacques Coté Hydro Quebec

Ray Awad Hydro Quebec

Jean-Francois Drapeau Hydro-Quebec (IREQ)

Jon Mosteller MLGW

Phil Wharton Horizon Wind Energy

Randy Fredericksen Brugg Cables

Ralph Patterson NETA

Phil Vinal Exxon Mobil

Ed Gulski Delft Univ.

Eric Bulington Anixter

Jerry Landers The Von Corp.

Martin von Herrmann The Von Corp.

John Densley ArborLec

Frank Petzold SEBA KMT

Frank de Vries Alliander

Rich Vencus Northeast Utilities

Robert Segura Lumznant Power

Timothy Hayden National Grid

Steffen Fuchs Highvolt

Jade Wang ConEdison

Ben Sielski NIPSCO

Alex Cervantes NIPSCO

Dennis Wozniak Retired

Michael Wallace Progress Energy

Wayne Chatterton Utilx Corp

Nigel Hampton NEETRAC

Kal Abdolall Powertech Labs Inc.

Robert Gorman RSCC Wire & Cable

Steve Thomas Padoma Wind

Grace Jiang 3M

Harry Orton OCEI

Minutes

The group met on March 22, 2010 from 11:15 to 12:30 with 43 members and guests attending.

The Chair Harry Orton welcomed the attendees and briefly introduced each presenter. There were three presentations.

The first presentation, see Appendix F15, was “Assuring Critical Cable System Reliability with Effective Diagnostics”, Ben Lanz, IMCORP

Discussion

Hemming Oetjen: What is 2Uo?

Reply: Two times of operating voltage. It is an IEEE standard.

Hemming Oetjen: It is not high enough. It (the defect) will fail at 3Uo.

Reply: IEEE standard is 2Uo.

Frank Petzold: This kind of discussion (tests other than PD are not very effective in finding defects in the system) can continue over long time. But it depends on the technology, what you have and the situation you have. You can’t have a closed view of that.

Reply: Well. Let’s present the case for you.

The second presentation, see Appendix F16, was “Web Database for Results of PD Measurements and Visual Inspection of PD Faults in MV Cable Systems”, Frank Petzold, SEBA KMT

Harry Orton: We introduced this database to you at last meeting. Please give some thought to a standardized approach of such a practice.

Discussion

Craig Goodwin: I have a question related to my concerns about this database. Did you maintain or consult with anyone to create this database? Or is it done by one or specific groups?

Reply: No. A working group was established last year. We had one meeting and in March this year we had second meeting. Now it is running at full speed. It is supported by a small utility who maintains the database from their server. It is mutual level, not from one or two groups. It is group activity. It is not a SEBA KMT database. It is a database for users, manufacturers and research facilities.

Nigel Hampton: Did you test PILC cable systems?

Harry Orton: Would you please show slide 44, the XLPE joint? For this one, PD is decreasing, at 1670 meters. This is the one that failed.

Reply: If you look here it is increasing. But if you look at it alone it is decreasing.

Harry Orton: I tried to introduce such a database many years ago. But the problem was that utilities did not want to submit any data due to deregulation.

Reply: This is also a good question. Be very careful, not to give any indications of the sources of the data. There is no location, no utility mentioned. You have to be very careful when you input such pictures. No company logo.

Frank De Vries: You mentioned that the cable connection will be included. I think it is important how you make the reference. Since one company compressed the connector and the other company might have done it differently. You will get inconsistent data for more difficult situations.

Reply: This is a big issue. Which information should be included, which information should be there for searching, selection and viewing. We will set up filter for users. This is the subject we will discuss during establishing the database. You cannot include a lot of information. One type of information will be failure data. Someone is doing PD measurement. They waited till it failed. You found a failure in one phase of a three core cable and took pictures. But the same thing might be in the other two phases. So you can select the time and see how long the other will survive. The field for connected cable is very important information.

Vern Buchholz: How you input PD magnitude in the database? There is big discussion of calibration for PD, etc. How did you implement that?

Reply: One mistake we try to avoid is that we do not want to compare different measuring systems. I am pretty sure we cannot compare PD levels from VLF with PD levels from 50 Hz or Damped AC. You could compare your own measurements with the system voltage. We try to compare things which are comparable.

Vern Buchholz: You have PD initiation and extinction voltages. But you put in the name of people who did the measurements. So how could you do the comparison?

Reply: We have to trust people who are doing their jobs

The third presentation, see Appendix F17, was “Modeling and Practical Verification of PD Occurrence in Installation Defects of 150kV Joints”, Ed Gulski, Delft Univ. of Technology

Discussion

John Hans: Can you talk more about the internal and external sensors? Is it the actual position of the sensors? When you put internal sensors, how much was the PD affected by the sensors?

Reply: Of course if you put sensors which make PD, it is not good. It is obvious that if you insert sensors that make PD, you will always have PD issues. The sensor were put there, they will not interference with PD. There are ways to do it. But it could also be a manufacturing concern for the long-term performance because of the sensors. But you know exactly the location of the sensor, you can do a sensitivity check. For this case, you know you can detect 5 pC PD. For external sensors, when you look in the publications, most PD detected is in terminations. I did not see much evidence of systematic results of PD in joints.

Harry Orton: We do not have time to discuss the standardization about the database. We will send out the web link of the database to you all. And you can have a chance to use them and give a check. Maybe at the next meeting we can talk about the standardization.

Nigel Hampton: One thought. I think we should stay away from the word of “standard”.

Harry Orton: We are thinking of a guide rather than a standard.

Nigel Hampton: No. I think the first part is the discussion from people’s experience on the user side and on the producer side. What will be the minimum information to report?

Harry Orton: Would you please give a presentation on this subject for next meeting?

Nigel Hampton: Probably.

Harry Orton: Thank you. Thank you all for attending.

Minutes prepared by Grace Jiang.

Attendance

Ainscough, John Xcel Energy

Bobb, Lawrence Ptomac Electric Power

Brown, Kent W. TVA

Campbell, Tom ComEd

Comar, Badrinath Hydro One Networks Inc.

Côté, Jauques Hydro Quebec

De Vries, Frank Alliander

Densley, John ArborLec

Dixon, Deb WCNOC

Drapeau, Jean-Francois Hydro-Quebec (IREQ)

Graham, Steven Duke Energy

Grodzinski, Chris EHV Power ULC

Hinchn, Konrud LIDS Technology

Jepriest, Douglas S TVA

Jiang, Grace 3M

Jovanovic, Ivan G&W Electric

Kraetge, Alexander OMICRON

Lanz, Ben IMCORP

Oh, Gcoanghoon UJIN Electric Co. Ltd.

Orton, Harry OCEI

Pasha, Mohammad The United Illumination Co.

Petzold, Frank SEBA KMT

Reynaud, Lionel Hydro Quebec

Spalding, Matthew Tyco Electronis

Thomas, Denise Exelon Nuclear

Uzelac, Milan G&W Electric

Von Herrmann, Martin The Von Corporation

Wallace, Michael Progress Energy

Wong, Jade ConEdison

Warton, Steve G&W Electric

Williams, Jay Power Delivery Consultants

Winter, Paul OMICRON

Minutes

The group met on October 20, 2010 from 10:15 AM to 12:00 PM with 32 members and guests attending.

The Chair Harry Orton welcomed the attendees and briefly introduced the four presentations.

The first presentation, see Appendix F-9, given by Frank Petzold, HDW, Germany, was “Web Database Results of PD Measurements and Visual Inspection of PD Faults in MV Cables”.

Discussion

Harry Orton: A question arises of how confidential the information will be when added to the database.

Frank Petzold: Normally, a utility does not want to identify their data because of deregulation. So the database administrator will ensure that only politically correct data is published.

Harry Orton: Let me add that ten years ago we tried to set up a similar on-line system, but found it to be very difficult due to disinterest, due to the fact that deregulation was just about to come in. Utilities in the US and Canada did not want to make this kind of information available to public, because of the obvious reason that Frank mentioned. So that is why it is very important to maintain confidentiality.

Harry Orton: Are there any comments or suggestions for Frank? Kent, you said earlier that you looked at the database, are there any comments?

Kent Brown: As mentioned before, the pictures will tell the story about the failure characteristics. It is good to have a quick access to so much failure information.

Frank Petzold: There are two targets for this database. The first is to convince your management that there is benefit of this interaction, i.e., there is really a fault and you can locate with PD and hence we can prevent this service failure. This is the first intention. The second is that if you use your PD equipment and you find a certain type of cable and accessory having a certain PD level and pattern, and you can locate similar cases in the database, then you could probably find similar causes for your PD problems.

Ben Lanz: It is very powerful to give pictures as well as information online. One thing I suggest is that will you provide information within the database about sensitivity.

Frank Petzold: This is the question. When you have a long paper insulated cable, and you have a 1000 pC PD, and you cannot calibrate, then you know the sensitivity is not so good. But you see a typical example of the PD data in the database that has 1000s or 100s pC of PD level. It will be quite easy to locate PD in similar lengths of cables. We are stressing the scientific side, but more towards the application side.

Ivan Jovanovic: Are there any plans to go to the higher voltages?

Frank Petzold: Not really. In HV cables, there are seldom failures, seldom PD, also you will have a commissioning test. We have some data at 110 kV, but there is not sufficient data to add to the database. More often, failures are in the medium voltages at distribution levels.

Harry Orton: I think it is a good point. Yes, there are not many failures in high voltage cables. But they do occur, so it is worth looking at.

The second presentation, see Appendix F-10, given by Ed Gulski, onsite.hv.solutions AG, Switzerland, was “Different Aspects of Application Unconventional PD Detection to Power Cable Accessories”.

Discussion

Ben Lanz: I think this is a great presentation and excellent template. I think you have done quite a good job to bring lot clarity of this area. Thank you.

Reply: Thank you.

The third presentation, see Appendix F-11, given by Luigi Testa, TechImp, Italy, was “Application of UWB Approach to Partial Discharge Testing of Power Cable Systems”.

Discussion

Steve Warton: Did you mention that the results could be on both accessories and cable insulation materials. How could you separate them?

Reply: This is related to a point that I really did not explain in this presentation. The question is that how we identify the PD. Let us look at this chart. The operator might be able to identify the PD source of internal PD or corner PD. But we use other technologies to identify them. These phenomena have the same or mixed characteristics. Like these charts, they are not purely internal PD, or surface PD. They are both.

Ben Lanz: Interesting presentation. My question is about these charts. You draw circles around these dots. Is it just for illustration?

Reply: Yes. The circles are just for illustration. How it was done is that you did the PD measurement and you got the pattern of the rectangle. Then you do your analysis.

Ben Lanz: Did you ignore the dots outside the rectangle you drew, or do you think it is useful?

Reply: I looked at them all and then I performed the separation. I drew the rectangle here and then I looked at the pattern here.

Alexander Kraetge: How do you identify which dots belong to which group? Here you have B and D. Some dots are overlapping. How do you identify which belongs to B, which belongs to D? Do you have two set of data? How are you doing that?

Reply: We implied an automatic separation tool algorithm. In the end, the human operator has to draw the rectangle in this way. We also have these data to show these are related to B, and these are related to D. So you see they are different, then you make the separation.

The fourth presentation, see Appendix F-12, given by Jean-Francois Drapeau and Jacque Côté, IREQ, Quebec, was “Influence of Performing VLF Withstand Tests on Degraded Joints (Preliminary Results)”.

Discussion

Question: Are you considering doing the measurements on the whole system?

Reply: We do not have information to make this decision. What you see here is not something about connector heating, there is really something wrong with the bulk of the insulation. What we do in practice is to replace the splice right away if it has a problem. The next question is, what causes it? We are not there yet.

Ed Gulski: I have a comment. We could see something similar to this when it has PD. I wonder how PD is related to this?

Reply: That is what we will do in the future. For a case like this with temperature increasing in joints, we did not see PD. Of course, for this one we did not do it. But we plan to do it in the future.

Paul Winter: What frequency range did you use to perform TDS?

Reply: TDS is in time domain. I did not go in details here. Basically, what we applied is a dc step of low voltage, and we collected information with dielectric spectra. The frequency range was 0.01Hz to 10-4Hz, we centered on 1 mHz.