Implementation of a Blackstart cranking path sequence operation through PMU
Bibliographic record
Abstract
The complexity of the interactions due to the integration of inverter-based resources and changes in generation mix is forcing utilities to focus on identifying blackstart cranking path sequences to restore the power system in the shortest period of time. This requires the use of an on-site generation unit or blackstart resources to start up and produce power without the need for an external (off-site) power source when recovering from a blackout event that involves the loss of many generation units.This paper presents a blackstart approach by Southern California Edison (SCE) using a subregional island methodology that is comprised of a self-starting unit used to start a larger generating unit(s) through energization of few generator step-up transformers, transmission line(s), and starting of motors and other auxiliary loads needed to restart non-blackstart generating units. Energization of the unloaded transmission line(s) during a blackstart is a critical step, as the charging current causes a voltage rise along the transmission line. The charging current could be significantly high that the blackstart generation unit will absorb reactive power. Regular studies are performed to verify that the proposed blackstart restoration plans are compliant with voltage and frequency operation limits, as well as to ensure that the blackstart generating unit is capable of absorbing reactive power within its limits under the lightly-loaded blackstart condition. Also, it is important to ensure that the magnitude, duration, and harmonic content of the transformer inrush current will not cause resonance issues. Also, a key concern is ensuring that abnormal system conditions and faults are detected during transmission line energization, and other steps of power system restoration. This is especially true for transmission lines that transverse through wildfire prone areas. Energization of a downed conductor could ignite a wildfire and is a concern for public safety. During the broken conductor condition and lightly-loaded line conditions, the expected performance of the protection system may be compromised, as the current magnitude may be below the relay set threshold or a pickup current.In order to facilitate the restoration process, a synchrophasor-based wide area scheme is used to guide the operator during the blackstart cranking path sequence, using the line protection relays to send the real-time current and voltage measurements to a central controller for monitoring the line health, as well as any failing conductor conditions. Additional relays in critical locations are also used to obtain node voltage and current measurement points required to avoid any switching error. The architecture of the restoration system used is presented in this paper, including the topology, sequence logic and steps followed, as well as the HMI for the blackstart restoration process.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".