Search for dissertations about: "three-phase"

Showing result 1 - 5 of 76 swedish dissertations containing the word three-phase.

  1. 1. Differential Protection for Arbitrary Three-Phase Power Transformers

    University dissertation from Department of Industrial Electrical Engineering and Automation, Lund Institute of Technology

    Author : Zoran Gajic; [2008]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electric power systems; power transformers; differential protection; power system protection;

    Abstract : 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. READ MORE

  2. 2. Faults detection and diagnosis for three phase induction machines

    University dissertation from Luleå : Luleå tekniska universitet

    Author : Mohammed Obaid Mustafa; Luleå tekniska universitet.; [2012]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Reglerteknik; Control Engineering;

    Abstract : Three phase induction motors have been intensively utilized in industrial applications, mainly due to their efficiency and reliability. These motors have good properties such as: increased stability and robustness, durability, large power to weight ratio, low production costs and controllability easiness. READ MORE

  3. 3. Magnetizing Currents in Power Transformers Measurements, Simulations, and Diagnostic Methods

    University dissertation from Stockholm : KTH Royal Institute of Technology

    Author : Claes Carrander; KTH.; [2017]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transformer core; diagnostics; three-phase; no-load; hysteresis; modeling; resonance; remanence; delta; Electrical Engineering; Elektro- och systemteknik;

    Abstract : 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. READ MORE

  4. 4. On methods of measuring magnetic properties of power transformers

    University dissertation from Stockholm, Sweden : Kungliga Tekniska högskolan

    Author : Claes Carrander; KTH.; [2015]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; No-load; magnetizing current; losses; diagnostics; delta; three-phase; power transformer; magnetic core; electrical steel; measurements; simulation; Electrical Engineering; Elektro- och systemteknik;

    Abstract : The core of a power transformer can weigh hundreds of tons, and represents a significant part of the total ownership cost of the transformer, in terms of both the construction cost and of the monetary cost of losses. It is therefore desirable to have a method of diagnosing the core to ensure optimal performance, and to enable the operator to plan repairs of damaged or defective cores. READ MORE

  5. 5. Three Phase Controlled Fault Interruption Using High Voltage SF6 Circuit Breakers

    University dissertation from Stockholm, Sweden : Kungliga Tekniska högskolan

    Author : Richard Thomas; [2007]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; controlled switching; high voltage; hypothesis testing; circuit breakers; fault interruption; least mean squares regression; power system protection;

    Abstract : A method is presented for implementing controlled fault interruption,using high voltage, SF6 circuit breakers on three phase high voltage powernetworks. The main goal of the method is to synchronize the opening or tripcommands to each phase of a circuit breaker with respect to target currentzero times so that each phase will interrupt with a preselected arcingtime. READ MORE