Performance Evaluation of Overcurrent and Directional Overcurrent Relays Under Harmonic and Imbalance Conditions: A Case Study of a 132/20 kV Substation
Bibliographic record
Abstract
This paper investigates the impact of harmonics and imbalance on the performance of overcurrent relays (OCRs) and directional overcurrent relays (DOCRs) used in electricity transmission companies. For this purpose, one of the typical substation posts of 132/20 kV in Mashhad, Iran was simulated in EMTP software. This system was simulated under heavy harmonic loads, and then various types of faults in different locations of the substation and load feeder were placed to capture voltage and current waveforms. To investigate the relays' performance, first, simplified models of OCR and DOCR were implemented in MATLAB software. Next, by using the recorded fault, it was observed that the simulated relays performed correctly. Finally, the recorded data was used by the BER 3-protection relay test set to evaluate digital OCRs' and DOCRs' performance. The evaluation was done by examining Siemens SIPROTEC 7SJ62 and GE Multilin F650. The results show that both relays performed acceptably with respect to harmonics, but unlike the SIPROTEC 7SJ62, the Multilin F650 could not detect the direction of nearby three-phase faults in an unbalanced voltage scenario. Moreover, the SIPROTEC 7SJ62 records voltage and current samples after passing through a filter and therefore cannot provide insightful information about pre-fault power quality status.
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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 | 0.001 | 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".