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From:
"Conto, Jose" <[log in to unmask]>
Reply To:
Planning Geomagnetic Disturbance Task Force <[log in to unmask]>
Date:
Thu, 21 Feb 2019 15:16:58 +0000
Content-Type:
multipart/mixed
Parts/Attachments:
***** EXTERNAL email. Please be cautious and evaluate before you click on links, open attachments, or provide credentials. *****

It appears EPRI has a tool to evaluate harmonics impact due to a GMD event.   The tools is released as "open source".  For more information contact EPRI.

Thanks,

Josť

From: Planning Geomagnetic Disturbance Task Force [mailto:[log in to unmask]] On Behalf Of Rake, Stewart
Sent: Thursday, February 21, 2019 9:08 AM
To: [log in to unmask]
Subject: Re: Harmonics (was PGDTF Agenda for the February 26th meeting)


***** EXTERNAL email. Please be cautious and evaluate before you click on links, open attachments, or provide credentials. *****
Thanks Andrew.  This is helpful information.

Stewart Rake
Luminant Compliance
Office:  (214)875-8091
Cell:  (903)436-0134

From: Planning Geomagnetic Disturbance Task Force <[log in to unmask]<mailto:[log in to unmask]>> On Behalf Of Andrew Mattei
Sent: Thursday, February 21, 2019 8:57 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: Harmonics (was PGDTF Agenda for the February 26th meeting)

EXTERNAL EMAIL


I don't think a determination of the actual harmonic content from the ERCOT Benchmark data is feasible at the moment. However, the approach I took was to look at the GIC magnitudes for our equipment in the case data and see where there might be elevated DC. Some of our transformers had only a couple of amps DC flowing through them; these areas will not be an issue. As DC current increases, harmonics will increase. From a protection perspective, I know that microprocessor based relays only operate on the fundamental frequency and not the harmonic content, so in most cases* microprocessor-based protection systems will be fine.

Electromechanical relays may or may not be OK. Most EM differential relays (ABB HU, GE STD, GE BDD for example) have harmonic blocking built into them, and since the dominant harmonic of a GIC event is the second, these relays probably* won't misoperate. Unfiltered EM relays (such as the time-overcurrent CO9) do include the harmonic content and will "measure" higher than the actual fundamental and would be more likely to mis-operate. I'd like to get my hands on a negative sequence relay, as I anticipate issues with those also because of the phase-shift construction that won't work correctly at non-fundamental frequencies.

What I'd suggest would be to first look at the DC current magnitudes, and then look at the generator protection system to see what type of relaying is in use, and whether or not that relaying incorporates filtering. I can't give a "rule of thumb" other than what I found from the IEEE K-11 Working Group ("The Effects of GIC on Protective Relaying", IEEE Transactions on Power Delivery, Vol. 11, No. 2, April 1996): "GIC levels below 30 A have no noticeable effect on the power system." Better safe than sorry, though.

Best regards,

Andrew

*In protection there are exceptions to everything. For example, a neutral conductor with heavy harmonics can have 70A with only 15A fundamental and may not be protected properly by a filtered relay.

Andrew K. Mattei, P.E.
Supervisor, Electrical Engineering Design
Brazos Electric Power Cooperative
254-750-6767

ATTENTION:  This message may contain confidential or privileged information. DO NOT FORWARD. If you are not the addressee, please notify its sender and delete it from your files.  Report compliance and ethics concerns here www.lighthouse-services.com/brazoselectric<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.lighthouse-2Dservices.com_brazoselectric&d=DwMFAg&c=trp9rTvIdyEWh1VWB5x8_2JiPaB5oGZOtWPDws2_VoY&r=HpsU9WKxDO7QBdY6V17BEIeyR-iphxJHvPBZPu7svRc&m=0mdtHFHd_1bi53I4egbwT9_axlrFdo2Xx7gevQMugmA&s=7ELazGoFPazzw-_nsrBhK3UDDQe3AMmiPQ5-KSedvVQ&e=>



From: Planning Geomagnetic Disturbance Task Force <[log in to unmask]<mailto:[log in to unmask]>> On Behalf Of Rake, Stewart
Sent: Thursday, February 21, 2019 8:34 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: PGDTF Agenda for the February 26th meeting

Aster,

Will the determination of harmonics from the benchmark GMD event will be discussed at the February 26th meeting?  Several of the generators I have been in contact with concerning the attached market notice are unclear how to determine what ERCOT is requesting.
This may have been covered in a previous meeting.  If so, any information you could share would be appreciated.

Stewart Rake
Luminant Compliance
Office:  (214)875-8091
Cell:  (903)436-0134

From: Planning Geomagnetic Disturbance Task Force <[log in to unmask]<mailto:[log in to unmask]>> On Behalf Of Aster Amahatsion
Sent: Wednesday, February 20, 2019 2:16 PM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: PGDTF Agenda for the February 26th meeting

EXTERNAL EMAIL


PGDTF members,
Attached is the agenda for February 26th PGDTF meeting updated based on comments received.

Thanks,
Aster Amahatsion
2019 PGDTF Chair


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