Protection of Electrical Power Systems in Maritime Applications: Analysis of Directional Overcurrent Protection Methods
Translated title
Protection of Electrical Power Systems in Maritime Applications
Author
Hansen, Mikkel Hingebjerg
Term
4. term
Education
Publication year
2021
Submitted on
2021-05-28
Pages
105
Abstract
This thesis examines how different polarization methods used in directional overcurrent protection can be applied in relay protection schemes for maritime power systems. Directional overcurrent protection trips a relay only when fault current flows in a specified direction, allowing the faulted section to be isolated while the rest of the system keeps running. Polarization methods provide the reference signal (from voltage or current) the relay uses to determine that direction. Maritime power systems often differ from land-based grids in ways that make common protection schemes unreliable or inapplicable, and losing critical onboard loads can have severe consequences. The goal is to support the design of protection that is reliable, fast, and selective. To this end, the thesis develops a generic model of a maritime power system and several relay models based on different directional overcurrent algorithms. One relay model is validated experimentally, and the relays’ performance in a maritime system is explored through simulations. The relay models are then assessed within proposed protection schemes, and key design considerations for maritime protection are identified.
Specialet undersøger, hvordan forskellige polarisationsmetoder i retningsbestemt overstrømsbeskyttelse kan bruges i relæbeskyttelsesskemaer for maritime elsystemer. Retningsbestemt overstrømsbeskyttelse udløser kun relæet, når en fejlstrøm løber i en bestemt retning, så den fejlramte del kan frakobles, mens resten af systemet fortsætter driften. Polarisationsmetoder giver det referencesignal (fra spænding eller strøm), som relæet bruger til at bestemme strømretningen. Maritime elsystemer adskiller sig ofte fra landbaserede net på måder, der gør almindelige beskyttelsesskemaer upålidelige eller uanvendelige, og tab af kritiske laster ombord kan have alvorlige konsekvenser. Målet er at støtte udviklingen af beskyttelse, der er pålidelig, hurtig og selektiv. Derfor udvikles en generel model af et maritimt elsystem samt flere relæmodeller baseret på forskellige algoritmer for retningsbestemt overstrømsbeskyttelse. En relæmodel valideres eksperimentelt, og relæernes ydeevne i et maritimt system undersøges via simuleringer. Relæmodellerne vurderes i sammenhæng med foreslåede beskyttelsesskemaer, og centrale hensyn ved udvikling af beskyttelse til maritime elsystemer identificeres.
[This apstract has been rewritten with the help of AI based on the project's original abstract]