Identification of Sub-Synchronous Interaction in MMC Systems using Frequency Scanning
Bibliographic record
Abstract
The interaction between the Modular Multi-level Converter (MMC) and the ac system can result in oscillation, even instability in the sub-synchronous frequency range. Rather than using an analytical model of the MMC which is complicated and often ignores details of commercial proprietary controllers, this paper proposes the application of frequency scanning of the MMC modelled on a real-time digital simulator (RTDS). The frequency response of the MMC looking from the Point of Common Coupling (PCC) bus can be extracted from the scan in either the dq0 domain or the modified PNO domain, which would be discussed in detail. The system behavior can be studied using the Generalized Nyquist stability Criterion (GNC) or equivalently, the Bode plot. The approach can predict the Critical Short Circuit Ratio (CSCR) of the ac system resulting in marginal stability, as well as the oscillation frequency. The result is then validated by real-time simulation on RTDS.
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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 | 0.000 | 0.001 |
| 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) | 0.001 | 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".