Patents by Inventor Hjörtur Jóhannsson

Hjörtur Jóhannsson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Assessment of power systems
    Patent number: 10024892
    Abstract: The present invention relates to a method for assessment of a power system and an early warning system for a power system, the method being based on aperiodic small signal instabilities. The power system has a plurality of generators comprising one or more synchronous machines and is represented by a plurality of nodes of power injection, injecting power into a network having a plurality of nodes and branches. The method for assessment of the power system comprises determining a present state of the power system, calculating system Thevenin impedances from each node of power injection in the power system on the basis of the determined present state of the power system, calculating injection impedances from each node of power injection in the power system on the basis of the determined present state of the power system, determining a stability boundary for each generator based on the calculated system Thevenin impedances and the calculated injection impedances.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: July 17, 2018
    Assignee: DANMARKS TEKNISKE UNIVERSITET
    Inventor: Hjörtur Jóhannsson
  • METHOD OF DETERMINING REMEDIAL CONTROL ACTIONS FOR A POWER SYSTEM IN AN INSECURE STATE
    Publication number: 20150005967
    Abstract: A method of determining remedial control actions for a power system in an insecure and unstable operating condition is provided. The power system has a plurality of generators injecting power into a network and each generator has a generator injection impedance and a stability boundary in the injection impedance plane. A system safety boundary is calculated based on a predetermined network operating safety margin for each generator, the generator injection impedance is compared with the safety boundary and it is determined whether each generator is safe or unsafe. A remedial control action is determined comprising a scheme for re-dispatching power generation for each unsafe generator to thereby establish a secure operating condition for the power system.
    Type: Application
    Filed: December 20, 2012
    Publication date: January 1, 2015
    Inventors: Hjörtur Jóhannsson, Johannes Tilman Gabriel Weckesser
  • ASSESSMENT OF POWER SYSTEMS
    Publication number: 20140343881
    Abstract: The present invention relates to a method for assessment of a power system and an early warning system for a power system, the method being based on aperiodic small signal instabilities. The power system has a plurality of generators comprising one or more synchronous machines and is represented by a plurality of nodes of power injection, injecting power into a network having a plurality of nodes and branches. The method for assessment of the power system comprises determining a present state of the power system, calculating system Thevenin impedances from each node of power injection in the power system on the basis of the determined present state of the power system, calculating injection impedances from each node of power injection in the power system on the basis of the determined present state of the power system, determining a stability boundary for each generator based on the calculated system Thevenin impedances and the calculated injection impedances.
    Type: Application
    Filed: May 30, 2012
    Publication date: November 20, 2014
    Applicant: DANMARKS TEKNISKE UNIVERSITET
    Inventor: Hjörtur Jóhannsson