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U.S. Department of Energy
Office of Scientific and Technical Information

Transmission line voltage detector for static var generator

Patent ·
OSTI ID:5943414
A controlled static VAR generator is described including static power switches controlled for coupling a reactive power source onto AC transmission lines for power factor compensation thereof and detection means responsive to the AC transmission line voltage for providing a control signal representative of the amplitude of the line voltage, the control signal being applied to the static power switches; the detection means comprising: means responsive to the AC transmission line voltage for deriving a time related signal V(t) representative thereof and of fundamental frequency ..omega..=2..pi..f; means synchronized with the AC transmission line voltage for providing a first signal representative of cos (..omega..t) and a second signal representative of sin (..omega..t); first multiplier means for providing with the time related signal V(t) and the cos (..omega..t) representative signal a signal representative of a first product V(t)Xcos (..omega..t); second multiplier means for providing with the time related signal V(t) and the sin (..omega..t) representative signal a signal representative of a second product V(t)Xsin (..omega..t); first means for integrating through the fundamental period T the first product representative signal to derive the Fourier coefficient; second means for integrating through the fundamental period T the second product representative signal to derive the Fourier coefficient; and means responsive to the first and second integrating means for deriving the control signal as a voltage amplitude representative signal V.
Assignee:
Westinghouse Electric Corp., Pittsburgh, PA
Patent Number(s):
US 4811236
OSTI ID:
5943414
Country of Publication:
United States
Language:
English