The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 13, 1993
Filed:
Dec. 13, 1991
Einar V Larsen, Charlton, NY (US);
Kara Clark, Schenectady, NY (US);
Electric Power Research Institute, Palo Alto, CA (US);
Abstract
A firing control scheme, including a method and apparatus, for secure vernier operation of a thyristor controlled series capacitor (TCSC) in series with a transmission line uses phase controlled firing based on monitored capacitor voltage and line current. The TCSC system has a thyristor switched inductive commutating circuit in parallel with the series capacitor. Vernier operation of the TCSC system is provided by predicting an upcoming firing angle for switching the commutating circuit to conduct a thyristor bypass current pulse therethrough. The current pulse causes an alternating offset component of voltage to appear across the series capacitor, in addition to the normal voltage component. Each current pulse changes the capacitor voltage proportionally to the integrated value of the current pulse. The TCSC system promptly responds to an offset command from a higher-level controller, precisely controls the duty on the bypass thyristors to minimize thyristor damage, and prevents drift of the capacitor voltage away from a desired setting during line current disturbances.