Evaluation of live-line maintenance techniques used on BPA reduced clearance 500 kV lines
Bibliographic record
Abstract
One way to increase transmission availability is to perform maintenance while the line is energized. The proposed practices for performing live-line maintenance on the Bonneville Power Administration (BPA) compact 500 kV designs have not been tested. The purpose of this project is to determine the electrical safety margin of these live-line techniques. Full-scale tower models based on BPA's compact 500 kV line design were constructed and tested at the Carey High Voltage Lab in Vancouver, Washington. Switching impulse tests were conducted to determine the critical flashover (CFO) level of each configuration. Several variables were evaluated including insulator type, number of broken units, position of broken units, and presence of tools. A team of experts from maintenance, safety, laboratories, conductor design, and structural design participated in this project from the planning stage to the review of test results. The following conclusions resulted from this collaboration: there is adequate electrical safety margin to replace as many as four broken insulators in a given V-string; the maximum degradation of the tower dielectric strength due to the presence of tools is 9%; the porcelain insulators used for these tests exhibited the same dielectric strength as the glass insulators, even when broken; and the single circuit tower window has 9% higher dielectric strength than the double circuit structure.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".