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:
Aug. 08, 1978
Filed:
Dec. 27, 1976
Donald M Demarest, Wallingford, PA (US);
Bernard D Leete, Newtown Square, PA (US);
General Electric Company, Philadelphia, PA (US);
Abstract
An HVDC electric power delivery system having a floating current order current control subsystem is described. The system is comprised by power converters at each end of an HVDC power conductor link each of which includes a plurality of controllable electric valves connected between alternating current and the direct current electric power conductors together with means for cyclically firing the valves in a predetermined sequence and at firing angles measured with respect to the alternating voltage that can be varied to control the flow of power between the alternating current system and the direct current system. Each of the power converters further includes a regulator for comparing a plurality of input control signals which respectively represent different predetermined operating characteristics of the HVDC system during operation and for deriving an output error control signal that controls the firing angles of the valves. The present invention makes available a floating current order control subsystem which is coupled to the regulator of each power converter for supplying thereto as one of the input control signals a floating current order control signal representative of the magnitude of the direct current flowing in the direct current power conductors plus a predetermined current margin whose polarity is determined by the direction of power flow. The floating current order control subsystem further includes rate limiting means for limiting the rate of change of the floating current order control signal to some predetermined rate of change value either in an increasing or decreasing magnitude direction and maximum and minimum boundary setting limits for setting predetermined maximum and minimum magnitude value limits above and below which the floating current order control signal is not allowed to change the load current magnitude so that the load current magnitude is maintained within predetermined maximum and minimum load current values.