### Comments on the Navigant Engineering Analysis

1. Although it is fully understood that this committee is working to a very tight time line, it is suggested that we spend as much of the time prior to and if necessary during the Oct 12 and Oct 13 meetings, ensuring that the Navigant analyses are correct. The committee cannot propose revised standards if the data that we are utilizing is flawed. It appears that many questions have been raised concerning the validity of the Navigant analysis since the initial report was issued in March of 2011. Until the committee’s transformer design specialists and utility engineering experts sign-off on the analysis (basis on which the committee will make our recommendation) it is difficult to propose or debate new efficiency standards. 2. Most of the below items have been or most likely will be brought forward by the transformer design engineers and utility engineers on the committee, but some of the concerns related to the validity of the Navigant analysis are; a. Is the 50% load assumption correct? b. What was the basis for selecting the design lines? Do the Navigant selected design lines adequately represent of each of the actual market segments? c. Is 20 years a more realistic life expectancy for pole-type transformers? d. Does the OPS model include stray losses? e. Does the OPS model restrict material selections to only commercially available materials (for example-based on thicknesses and widths that are commercially available for insulating paper)? f. How did Navigant factor in transformer size restrictions in their analysis (pole-type weights, foot print limitations for network transformers, etc) 3. Despite the comments in items #1 and #2 concerning the validity of the Navigant Engineering Analysis, the committee does need to travel along parallel paths (as we consider corrections to the Navigant analysis) due to the current deadlines. Therefore, using the Navigant data from their March 2011 report the attached table was constructed. This table is an effort to summarize the data as well as meet the objective established by the rule making committee at the Sept 15 and 16 meeting that any proposed transformer efficiency standard must be able to be cost effectively manufactured by utilizing multiple core steel materials. The attached table highlights the maximum CSL for each design line based on the Navigant analysis and the ability to produce the transformer core from conventional grain-oriented, domain-refined High B, or amorphous. The table suggests that there is not much room for efficiency tightening for the liquid-filled units, but some efficiency improvement may be possible for the medium voltage dry-type (and possibly the low voltage dry-type which is being handled by a separate committee).4. D esign CSL - 0 (current) CSL - 1 CSL - 2 CSL - 3 CSL - 4 CSL - 5 CSL - 6 CSL - 7 1 50 kVA 1 phase liquid pad Best option M - 3 M - 3 SA1 SA1 SA1 SA1 SA1

Alternatives ZDMH

M - 2 M - 5 ZDMH

M - 2 ZDMH

M - 2 M - 3 2 25 kVA 1 phase liquid pole Best option ZDMH ZDMH SA1 SA1 SA1 SA1

Alternatives M - 3

M - 2 M - 4 M - 5 M - 2

M - 3 M - 4 ZDMH

3 500 kVA 1 phase liquid Best option ZDMH M - 2 M - 3 ZDMH

M - 2 SA1

ZDMH SA1 SA1 SA1 SA1 SA1

Alternatives SA1

M - 4 M - 5 M - 3

SA1 M - 4 M - 2

M - 3

4 150 kVA 3 phase liquid Best option ZDMH M - 2 M - 3 ZDMH

M - 2 M - 3 SA1 SA1 SA1 SA1 SA1

Alternatives M - 5

5 1,500 kVA 3 phase liquid Best option ZDMH M - 3 M - 2 ZDMH SA1 SA1 SA1 SA1 SA1

Alternatives SA1

M - 2 M - 4 SA1

M - 2 M - 3 ZDMHDesign CSL - 0 (current) CSL - 1 CSL - 2 CSL - 3 CSL - 4 CSL - 5 CSL - 6 CSL - 7

6 25 kVA 1 phase dry 10kV BIL Best option M - 3 M - 4 M - 6 M - 4 M - 4 SA1 M - 4 SA1

M - 4 SA1 SA1

Alternatives M - 6 M - 0H laser M - 3 SA1

M - 0H laser M - 3 M - 0H

laser M - 3 M - 0H

laser

7 75 kVA 3 phase dry 10kV BIL Best option M - 6 M - 6 M - 6 M - 6 M - 3 M - 6 M - 0H laser M - 4 M - 0H

laser SA1 M - 3 SA1 SA1

Alternatives M - 12 M - 12 M - 3 M - 4 M - 3

M - 4 M - 4

8 300 kVA 3 phase dry 10kV BIL Best option M - 6 M - 5 M - 5 M - 5 M - 0H laser SA1 SA1

Alternatives M - 6 M - 3 M - 4 M - 3

M - 0H laser M - 3

M - 4

9 300 kVA 3 phase dry 45kV BIL Best option M - 5 M - 5 M - 0H laser SA1 SA1 SA1

Alternatives M - 3

M - 6 M - 3

M - 0H laser M - 6 M - 3

M - 5 SA1 M - 0H

laser

10 1,500 kVA 3 phase dry 45kV BIL Best option M - 5 M - 5 SA1 SA1 SA1 SA1

Alternatives M - 5 M - 0H laser M - 0H

laser M - 3

11 300 kVA 3 phase dry 45kV BIL Best option M - 3 M - 4 M - 0H laser M - 0H

laser M - 3 M - 4 SA1

M - 0H laser SA1 SA1 SA1

Alternatives SA1 M - 3 M - 4 12 1,500 kVA 3 phase dry 95kV BIL Best option M - 5 M - 5 M - 4 M - 0H laser M - 0H

laser SA1 SA1 SA1 SA1 SA1

Alternatives M - 4

M - 0H M - 3 M - 4 M - 3 M - 0H

laserlaser M - 3 SA1 M - 5

13 2,000 kVA 3 phase dry 125kV BIL Best option M - 5 M - 5 M - 0H laser SA1 SA1 SA1

Alternatives M - 4 M - 4 M - 3 M - 0H laser M - 3

SA1 M - 4 M - 0H

laser



### 4. The committee needs to determine the availability of permanently domain-refined high B material as a viable core steel selection for the wound core units.