Abstract: A cross arm is provided, for use in a support structure for conductors within an electrical grid. The cross arm is made of a cementitious composite and has a rough āCā cross sectional shape. Pairs of the cross arms are attached to utility poles in a parallel position on opposite sides of the utility pole. Alternatively, a single cross arm may be attached to a utility pole. Embedded metal or glass fibre reinforced polymer bars extend along the length of the cross arms.
Type:
Application
Filed:
December 11, 2009
Publication date:
June 16, 2011
Applicants:
British Columbia Transmission Corporation, Lafarge Canada Inc.
Inventors:
Juan Ignacio CARIAGA CRESPO, Adelana R. GILPIN-JACKSON, Janos Csaba TOTH
Abstract: A system and method for estimating parameters of transmission lines employing phasor measurement units is provided, wherein measurements are provided from the phasor measurement units relating to a transmission line. These measurements are filtered to remove invalid measurements. Using the remaining valid measurements, resistance, reactance and grounding admittance are calculated and estimated and checked for errors.
Type:
Grant
Filed:
September 25, 2007
Date of Patent:
May 4, 2010
Assignee:
British Columbia Transmission Corporation
Abstract: A method of identifying voltage instability in a power system via identification of a weakest line and bus that contribute to the collapse of the system is provided. The method includes periodically calculating an extended line stability index for the transmission lines monitored in the power system; and using the extended line stability index to determine the distance of an operation state in the power system from a collapse point of the system caused by voltage instability.
Type:
Application
Filed:
September 25, 2007
Publication date:
January 29, 2009
Applicant:
BRITISH COLUMBIA TRANSMISSION CORPORATION
Inventors:
Wenyuan Li, Juan Yu, Yang Wang, Paul Choudhury, Jun Sun
Abstract: A system and method for estimating parameters of transmission lines employing phasor measurement units is provided, wherein measurements are provided from the phasor measurement units relating to a transmission line. These measurements are filtered to remove invalid measurements. Using the remaining valid measurements, resistance, reactance and grounding admittance are calculated and estimated and checked for errors.
Type:
Application
Filed:
September 25, 2007
Publication date:
January 29, 2009
Applicant:
BRITISH COLUMBIA TRANSMISSION CORPORATION
Abstract: A method of state estimation is provided, including: (a) acquiring a plurality of positive sequence voltage and current phasor measurements; (b) designating a reference positive sequence voltage phasor measurement from the acquired phasor measurements; (c) correcting the acquired phasor measurements to account for the reference phasor measurement; (d) calculating complex power having a real component and an imaginary component, using the corrected positive sequence voltage and current phasor measurement; (e) using the real component of said complex power as a calculated mega-watt and the imaginary component of the complex power as a calculated mega-volt-ampere; and (f) using the mega-watt and mega volt-ampere calculations in a state estimation algorithm.
Type:
Application
Filed:
August 24, 2007
Publication date:
March 6, 2008
Applicant:
BRITISH COLUMBIA TRANSMISSION CORPORATION
Inventors:
Djorde Atanackovic, Greg Dwernychuk, Jose Clapauch