Tertiary Voltage Unbalance Compensation for 500kV Single Phase Autotransformer Banks
Bibliographic record
Abstract
In an ungrounded transformer tertiary system, most often the phase-to-ground voltages are slightly unbalanced. Therefore all equipment supplied by the tertiary must have extra insulation to withstand the expected phase-to-ground overvoltages that arise from such unbalance. However, in a recent 3 × 250MV A single phase transformer bank replacement project, it was found that the tertiary phase-to-ground overvoltages were abnormally high therefore the transformer bank could not be put back into service. After extensive investigation, it was found that the transformer inter-winding capacitances and tertiary phase-to-ground capacitances were unbalanced, resulting in excessive unbalance in the tertiary phase-to-ground voltages, which was directly responsible for the overvoltage. A mitigation plan was developed. The plan was to modify the tertiary phase-to-ground capacitances in such a way that the voltage unbalance due to the asymmetry in the inter-winding capacitances cancels the voltage unbalance due to the asymmetry in the phase-to-ground capacitances. Based on theoretical derivation and EMTP simulation, two CVTs (Capacitive Voltage Transformer) were selected from the warehouse and installed on the transformer tertiary. The voltage unbalance was successfully mitigated and the transformer bank was put back into service. The mitigation methodology developed in the project achieved significant cost saving and will have great value in future project development.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| 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".