Patents by Inventor Sture Lindahl
Sture Lindahl 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).
-
Patent number: 7759910Abstract: A high voltage AC transmission cable system for transmitting power between two points, each connected to one or more power networks, and a method to operate the system. At least one transformer is arranged at each end of the AC transmission cable, wherein at least one of the transformers is arranged to operate the transformer at a voltage whereby losses due to reactive power transport and dielectric losses are minimized. The AC cable is run at a variable voltage regulated such that the voltage is a function of the load for the transmission cable. This operating voltage is not necessarily the same as the nominal voltages in the connection points. A control and communication system and a graphical user interface for carrying out the method are also provided.Type: GrantFiled: September 13, 2004Date of Patent: July 20, 2010Assignee: ABB Research Ltd.Inventors: Sture Lindahl, Kenneth Johansson, Udo Fromm, Stefan Johansson
-
Patent number: 7732943Abstract: A method for determining/dimensioning measures for restoring an electrical power system, which experiences or is heading for a voltage instability, to a steady-state condition, wherein there is no immediate risk of instability. An actual voltage/phase angle in the electrical power system is determined. The power unbalance within at least one sub-area in the electrical power system is determined. Suitable power-balancing measures are determined. The extent of the respective measures is determined. The power-balancing measures are carried out. Also, a device for carrying out the method.Type: GrantFiled: December 23, 2004Date of Patent: June 8, 2010Assignee: ABB ABInventors: Daniel Karlsson, Sture Lindahl
-
Patent number: 7719285Abstract: The present invention relates to a ground fault detection arrangement for a synchronous three-phase electrical machine, and an electrical system comprising a ground fault detection arrangement and a synchronous three-phase electrical machine. The ground fault detection arrangement injects an off-nominal frequency voltage between a neutral point of the synchronous three-phase electrical machine and ground and measure resultant currents to detect a ground fault.Type: GrantFiled: February 18, 2009Date of Patent: May 18, 2010Assignee: ABB Research Ltd.Inventors: Stefan G. Johansson, Marek Fulczyk, Tord Bengtsson, Sture Lindahl, Gabriel Olguin
-
Publication number: 20090171509Abstract: A farm including a plurality of electric power generation units connected to a grid point of a power network. The power generation units are organized in a plurality of upstream branches. Each upstream branch is separable from an adjacent downstream branch by an interrupter.Type: ApplicationFiled: December 27, 2004Publication date: July 2, 2009Applicant: ABB RESEARCH LTD.Inventors: Sture Lindahl, Juhani Mantere, Lars Gertmar, Hans Christian Christensen, Erik Kolby-Nielsen, Leif-Erik Wraae
-
Publication number: 20090160454Abstract: The present invention relates to a ground fault detection arrangement for a synchronous three-phase electrical machine, and an electrical system comprising a ground fault detection arrangement and a synchronous three-phase electrical machine. The ground fault detection arrangement injects an off-nominal frequency voltage between a neutral point of the synchronous three-phase electrical machine and ground and measure resultant currents to detect a ground fault.Type: ApplicationFiled: February 18, 2009Publication date: June 25, 2009Inventors: Stefan G. Johansson, Marek Fulczyk, Tord Bengtsson, Sture Lindahl, Gabriel Olguin
-
Patent number: 7447568Abstract: A device for controlling at a fault condition. An apparatus is connected by a connection line to a grid point of a transmission net in an electric power network. A voltage raising apparatus includes a first branch connected to the grid point including a switching element and a second branch including a current resisting means. The voltage raising apparatus includes a computer for signal processing of a sensed fault condition on the network and for affecting the operation of the switching element such that on a fault condition at least part of the current is diverted through the voltage raising apparatus and for evaluation of further actions.Type: GrantFiled: December 22, 2004Date of Patent: November 4, 2008Assignee: ABB Research Ltd.Inventors: Hans Christian Christensen, Lars Gertmar, Sture Lindahl, Juhani Mantere, Erik Koldby Nielsen, Leif-Erik Wraae
-
Publication number: 20070257561Abstract: A method for determining/dimensioning measures for restoring an electrical power system, which experiences or is heading for a voltage instability, to a steady-state condition, wherein there is no immediate risk of instability. An actual voltage/phase angle in the electrical power system is determined. The power unbalance within at least one sub-area in the electrical power system is determined. Suitable power-balancing measures are determined. The extent of the respective measures is determined. The power-balancing measures are carried out. Also, a device for carrying out the method.Type: ApplicationFiled: December 23, 2004Publication date: November 8, 2007Applicant: ABB ABInventors: Daniel Karlsson, Sture Lindahl
-
Publication number: 20070217105Abstract: A device for controlling at a fault condition. An apparatus is connected by a connection line to a grid point of a transmission net in an electric power network. A voltage raising apparatus includes a first branch connected to the grid point including a switching element and a second branch including a current resisting means. The voltage raising apparatus includes a computer for signal processing of a sensed fault condition on the network and for affecting the operation of the switching element such that on a fault condition at least part of the current is diverted through the voltage raising apparatus and for evaluation of further actions.Type: ApplicationFiled: December 22, 2004Publication date: September 20, 2007Applicant: ABB RESEARCH LTD.Inventors: Hans Christensen, Lars Gertmar, Sture Lindahl, Juhani Mantere, Erik Koldby Nielsen, Leif-Erik Wraae
-
Publication number: 20070114978Abstract: A high voltage AC transmission cable system for transmitting power between two points, each connected to one or more power networks, and a method to operate the system. At least one transformer is arranged at each end of the AC transmission cable, wherein at least one of the transformers is arranged to operate the transformer at a voltage whereby losses due to reactive power transport and dielectric losses are minimized. The AC cable is run at a variable voltage regulated such that the voltage is a function of the load for the transmission cable. This operating voltage is not necessarily the same as the nominal voltages in the connection points. A control and communication system and a graphical user interface for carrying out the method are also provided.Type: ApplicationFiled: September 13, 2004Publication date: May 24, 2007Applicant: ABB RESEARCH LTDInventors: Sture Lindahl, Kenneth Johansson, Udo Fromm, Stefan Johansson
-
Patent number: 6954345Abstract: A generator for producing high voltages and having at least one generator winding (12) is connected via a generator circuit (10) to a network (19), which generator circuit has means (15, . . . , 17) for protection against overvoltages. Improved protection against higher voltages is achieved in that the at least one generator winding (12) is subdivided into a number of winding sections (12a-c) whose winding insulation is designed such that the insulation level is graduated, and in that the overvoltage protection means have a number of overvoltage protection elements (15, . . . , 17), which are associated with the respective individual winding sections (12a-c) and whose response levels are matched to the requirements of the associated winding section.Type: GrantFiled: July 22, 2002Date of Patent: October 11, 2005Assignee: Alstom Technology Ltd.Inventors: Richard Blatter, Reinhard Joho, Sture Lindahl, Erland Soerensen
-
Publication number: 20030020352Abstract: A generator for producing high voltages and having at least one generator winding (12) is connected via a generator circuit (10) to a network (19), which generator circuit has means (15, . . . , 17) for protection against overvoltages. Improved protection against higher voltages is achieved in that the at least one generator winding (12) is subdivided into a number of winding sections (12a-c) whose winding insulation is designed such that the insulation level is graduated, and in that the overvoltage protection means have a number of overvoltage protection elements (15, . . . , 17), which are associated with the respective individual winding sections (12a-c) and whose response levels are matched to the requirements of the associated winding section.Type: ApplicationFiled: July 22, 2002Publication date: January 30, 2003Inventors: Richard Blatter, Reinhard Joho, Sture Lindahl, Erland Soerensen