Sökning: "math"

Visar resultat 6 - 10 av 94 avhandlingar innehållade ordet math.

1. 6. Applications of Unsupervised Deep Learning for Analysing Time-Varying Power Quality Big Data

   Författare :Roger Alves de Oliveira; Math Bollen; Sarah Rönnberg; Matti Lehtonen; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; power quality; power system harmonics; electric power distribution; interharmonics; big data analytics; pattern analysis; unsupervised learning; deep learning; artificial intelligence; geomagnetically induced currents; Electric Power Engineering; Elkraftteknik;

   Sammanfattning : Continuous power quality monitoring allows grid stakeholders to obtain information about the performance of the network and costumer facilities. Moreover, the analysis of continuous monitoring allows researchers to obtain knowledge on power quality phenomena. Power quality measurements result in a large amount of data. LÄS MER

3. 7. Propagation of Supraharmonics in Low-Voltage Networks

   Författare :Angela Espin Delgado; Sarah Rönnberg; Math Bollen; Jos Knockaert; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; supraharmonics; waveform distortion; low-voltage; high-frequency harmonics; Electric Power Engineering; Elkraftteknik;

   Sammanfattning : The need for measures towards a sustainable use of energy has incited the proliferation of devices and systems for the efficient use of electricity. Energy-efficient appliances, equipment for the electrification of transportation, electricity generators from renewable energy sources, and communication protocols, e.g. LÄS MER

4. 8. 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

5. 9. Stability of Low-Frequency AC Railways : Models and Transient Stability

   Författare :John Laury; Lars Abrahamsson; Math Bollen; Pablo Arboleya; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electric Power Engineering; Elkraftteknik;

   Sammanfattning : Low-frequency AC railway grids are unique in the sense that a only few countries around the world uses them, still however, they are an important parts of their countries infrastructures. Due to the usage of a dierent frequency than the public grid of the country, conversion of frequency is needed for the interconnection. LÄS MER

7. 10. Managing uncertainties through efficient calculation of transients and harmonic propagation in power systems

   Författare :Oscar Lennerhag; Math Bollen; Jan Lundquist; David Thomas; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Overvoltages; harmonics; uncertainties; stochastic methods; Electric Power Engineering; Elkraftteknik;

   Sammanfattning : The electric power system is undergoing changes including large-scale introduction of renewable energy sources together with HVDC/FACTS, changes in the network such as increased amount of high voltage cables, industrial electrification, and changes in the load composition. These changes will impact the system in different ways and lead to challenges that must be addressed to facilitate planning, dimensioning, and operation of the system in a secure and economical way. LÄS MER