The Protection of Transmission Lines Connected to DFIG-Based WTGs
Notice bibliographique
Résumé
Recently, many countries have proposed various plans to address the issue of climate change, and increasing the capacity of renewables is one of the major common components of such plans. The uncertainty and variability of generation, introduced by renewable energy sources (RESs), pose significant protection challenges to the power systems. Although many studies have identified the challenges associated with the protection of power systems with RESs and have proposed various algorithms to address these challenges, only a few of them comprehensively discuss all the protection challenges within one system. To begin with, a single test system is developed and used to illustrate the protection challenges and to provide a review of the existing protection schemes, which have been proposed in the literature to tackle the protection challenges associated with power systems with RESs. \nAfter introducing the protection challenges associated with the integration of RESs in the power system, this thesis focuses on the protection of transmission lines connected to doubly-fed induction generator (DFIG)-based wind turbine generators (WTGs). DFIG-based WTGs, or namely Type III WTGs, which connect to the power systems via reduced-size converters, raise additional protection challenges such as the maloperation of distance relays due to the frequency deviation of the current measurement caused by the short-circuit characteristics of the DFIGs, and the impact of the fault resistance on the calculated impedance. The protection challenge associated with the frequency deviation caused by the short-circuit characteristics of DFIG is further discussed in detail, and a modified permissive underreaching transfer trip (PUTT) scheme is presented to address the challenge. With the addition of a frequency tracking element, the modified scheme correctly prevents the maloperation of the distance elements during external faults and enables the trip of the relay during internal faults. Besides, the protection challenges associated with conventional distance relays at the terminal of DFIG-based WTGs that are caused by the fault resistance and the frequency deviation associated with the short-circuit characteristics of the DFIG, are addressed and investigated. A modified distance protection scheme is presented to address these protection challenges by using an averaging filter to correct the current phasors and removing the error term caused by the fault resistance in the measured impedance. Pure-fault circuits are used to calculate the pure-impedance of the WTG and pure-fault sequence networks are used to estimate the fault current flowing through the fault resistance. Simulation results show that, for various fault scenarios with different fault resistances, the developed modified distance protection scheme is able to accurately estimate the positive-sequence impedance between the fault and relay location, with fast operations.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».