January 29, 2014 MWG Meeting Topics for Discussion

January 29, 2014 MWG Meeting Topics for Discussion

Topics for discussion:

• 9:00 am – 9:05 am 1.) ERCOT Anti-Trust Admonition (D. DiSanto)

• 9:05 am – 9:15 am 2.) Attendance roll-call and introduction (D. DiSanto)

• 9:15 am – 9:30 am 3.) Nomination & selection of new MWG Chairperson & Vice-chairperson (D. Tucker/H. Perez)

• 9:30 am – 10:30 am 4.) Discussion of SMOGRR relating to NPRR-570 (D. Tucker/P. Vinton)

• 10:30 am – 10:45 am 5.) Break

• 10:45 am – 11:45 am 6.) Discussion of data estimation using telemetry points measuring the same energy flows as an EPS metering point (D. Tucker/P. Vinton)


• 11:45 am – 1:00 pm 7.) Lunch Break

• 1:00 pm – 1:15 pm 8.) Follow-up discussion on CCVT 5-year re-certification (H. Perez)

• 1:15 pm – 1:45 pm 9.) Presentation of revised wordings in

SMOG 1.3.7 regarding Parallel CT (H. Perez)

• 1:45 pm – 2:15 pm 10.) Presentation of revised wordings in SMOG 1.4.7 regarding Loss of Potential (H. Perez)

• 2:15 pm – 2:30 pm 11.) Break


• 2:30 pm – 2:45 pm 12.) Presentation of revised wordings in SMOG regarding TDSP’s submission of nameplate photos of newly-installed instrument transformer (CTs & VTs) as part of the Site Certification Documents (H. Perez)

• 2:45 am – 3:55 pm 13.) New or other business items (D. DiSanto)

• 3:55 am – 4:00 pm 14.) Meeting Wrap-up (D. DiSanto)

• 4:00 pm 15.) End of Meeting

1.) Legal Disclaimers and Admonitions

Antitrust Admonition

ERCOT strictly prohibits market participants and their employees who are participating in ERCOT activities from using their participation in ERCOT activities as a forum for engaging in practices or communications that violate antitrust laws. The ERCOT Board has approved guidelines for Members of ERCOT Committees, subcommittees and working groups to be reviewed and followed by each market participant attending ERCOT meetings. For details, please review the guidelines in the attachments tab of this presentation (if available).

2. Attendance roll-call and introduction (D. DiSanto)

If you are planning to attend in person, please e-mail me at [email protected] so we can provide your name to our Security Department and that you will be given access to the meeting venue on that day of the meeting.

mailto:[email protected]

3) Nomination and selection of new MWG Chairperson and Vice-chairperson (D. Tucker/H. Perez)

Nominations are now open.

4. Discussion of SMOGRR relating to NPRR-570 (D. Tucker/P. Vinton)

5. Break

6) Discussion of data estimation using telemetry points measuring the same energy flows as an EPS metering point (D. Tucker/P. Vinton)

- EPS Meter Mapping to Telemetry Point for Estimation during communications failures

- Initial Proof-of-Concept with subset of TDSPs/Sites

- Initial Setup Process prior to May 1, 2014

- On-Going Maintenance Process after May 1, 2014

6) Con’t – EPS Meter Mapping to Telemetry Point for Estimation Purposes

7. Lunch Break

8) Follow-up discussion on CCVT 5-year re-certification (H. Perez)

* Out of 207 units of CCVTs used as EPS metering PTs in the ERCOT region, only 6 units (2.8% of total) had the original test report when it first came out of the factory and had the “as-found accuracy” and “as-left accuracy” test data from the re-certification test provided to ERCOT.

* This is a small sample and may not be useful to arrive at a conclusion on whether the CCVTs retain its metering accuracy over time or not.

* Ideally, a more reasonable sample rate would be 36% of the total number of CCVTs

* Status of the proposed field testing?

9. Presentation of revised wordings in SMOG 1.3.7 regarding Parallel CT (H. Perez)

SMOG 1.3.7 (e) Paralleling of Current Transformers – Connected burden

Paralleling of current transformers is not recommended. However, when it is necessary, the following requirements apply.

(e) Each current transformer must be capable of supporting n times the total common connected burden on all CTs in parallel plus its own burden within the accuracy class of the transformers, where n = number of current transformers in parallel.

Note: We can re-word the above statement using the concepts illustrated on the attached documents (Current Transformer Burden Sheet Draft V2.1.xls & CPS parallel CTs.pptx)

Open item questions with answers regarding paralleling of CTs:

i. How to verify individual impedance on each conductor and common impedance? Answer: By calculation or measurement.

ii. Is common burden shared equally between all parallel CTs?Answer: Per CPS study, the total common burden will be shared equally by each CT when flow is distributed equally on paralleled CT’s. For further discussion.

iii. Should maximum current (at rating factor) be utilized in calculating total burden on each CT in case of flow thru scenarios (eg. Breaker-and-half scheme)? Answer: Yes.

iv. What is the impact if CT primary is shorted? Answer: The burden increases.

v. What was the result of the lab test conducted by CPS regarding paralleling of CTs? Answer: CPS study is posted in the key documents.

10. Presentation of revised wordings in SMOG 1.4.7 regarding Loss of Potential (H. Perez)

1.4.7 Loss of Potential

The secondary circuit shall be monitored for loss of potential on each phase whenever meter input voltage falls below 75% of the nominal value for 1 second or more.

Note: We can add in the language a statement such as: “This event logging will take effect starting MM/DD/YYYY”.

11. Break

12. Presentation of revised wordings in SMOG regarding TDSP’s submission of nameplate photos of newly-installed instrument transformers (CTs & VTs) as part of the Site Certification Documents (H. Perez)

3.2.3 Site Approval Request Package

The Site Approval Request Package should be provided within 60 days after the site has been certified and must include:(a) Site Certification Form;.. (i) Readable photos of the nameplates of newly-installed or replaced instruments transformers;

(j) Other information as required

Nameplate photos of newly-installed instrument transformers



13. New or other business items (D. DiSanto)

14. Meeting Wrap-up (D. DiSanto)

15. End of meeting

Questions?