Pump start instability on a low head pump turbine and testing with partial deaeration
Bibliographic record
Abstract
Abstract Since 2019 Iberdrola has had an interest in enabling pump operation of the Valparaiso hydropower plant. Iberdrola contacted Andritz, the original manufacturer of the machines, and a collaboration for that purpose was started. This powerplant was equipped with two pump turbine units in the 1980ies but pump operation has not been possible since strong vibrations occurred during pump commissioning in 1995. Therefore, the units had only been operated in turbine mode since then. In 2020 Iberdrola and Andritz performed a renewed pump start test with a fully rewatered machine. This again led to high vibrations during the initial phase of guide vane opening. Subsequently, guide vane flutter (self-excitation) was investigated as a potential cause of the vibrations but could not be established as the cause. Instead, it was found, that due to a transient effect, the machine entered the unstable part of the pump characteristic. Partial deaeration before guide vane opening during pump start was then considered as a solution and successfully tested in 2021.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".