Sökning: "transformers"

Visar resultat 1 - 5 av 100 avhandlingar innehållade ordet transformers.

1. 1. A calibration system for instrument transformers with digital output

   Författare :Jon Ivar Juvik; RISE; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; instrument transformers; measurement uncertainty; current transformers; phase displacement; phase measurement; calibration; potential transformers; phase error; digital signal processing;

   Sammanfattning : .... LÄS MER

3. 2. Lifetime modeling and management of transformers

   Författare :Johanna Rosenlind; Rajeev Thottappillill; Zhong Dong Wang; KTH; []
   Nyckelord :transformers; lifetime modeling; asset management; thermal modeling; lifetime estimation;

   Sammanfattning : This work have studied and developed lifetime estimation methods for the power transformer and how these could be used for asset management purposes. It is researchperformed in the intersection of the fields of reliability theory, statistical analysis, and stochastic process theory applied to lifetime estimations and management of transformers. LÄS MER

4. 3. Differential Protection for Arbitrary Three-Phase Power Transformers

   Författare :Zoran Gajic; Industriell elektroteknik och automation; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electric power systems; power transformers; differential protection; power system protection;

   Sammanfattning : This thesis describes how to provide standardized, current based, differential protection for any three-phase power transformer, including phase-shifting transformers with variable phase angle shift and transformers of all construction types and internal on-load tap-changer configurations. The use of standard transformer differential protection for such applications is considered impossible in the protective relaying standards and practices currently applied. LÄS MER

5. 4. Magnetizing Currents in Power Transformers : Measurements, Simulations, and Diagnostic Methods

   Författare :Claes Carrander; Hans Edin; Göran Engdahl; Rajeev Thottappillil; Amr Adly; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transformer core; diagnostics; three-phase; no-load; hysteresis; modeling; resonance; remanence; delta; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis demonstrates a method for transformer core diagnostics. The method uses the no-load current of the transformer as an indicator, and gives different characteristic signatures for different types of faults or defects. Using the no-load current for the diagnostic gives high sensitivity. LÄS MER

7. 5. Multiple Aspects of Dynamic Rating in the Power System

   Författare :Seyede Fatemeh Hajeforosh; Math Bollen; Sarah Rönnberg; Alfredo Vaccaro; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dynamic rating; Transmission lines; Overload Protection; Stochastic analysis; Hosting capacity; Transformers; Electric Power Engineering; Elkraftteknik;

   Sammanfattning : Increased consumption and increased use of renewable energy make overhead lines and transformers more often congested. Dynamic rating (DR) uses a time-depending maximum permissible current instead of a long-term-fixed rating; it is an effective solution to upgrade the capacity of existing grid assets to minimize this congestion. LÄS MER