SYSTEM TO CONTROL THE FREQUENCY OF A GENERATOR DRIVEN BY AN AUTONOMOUS HYDRAULIC TURBINE

摘要

AbstractThere is disclosed a system for regulating thespeed of an autonomous hydraulic turbine, drivinga constant frequency AC alternator. It uses electri-cal resistors as a control load so that the turbinewater flow remains constant. There is a quartzclock producing a reference frequency, which iscompared with the alternator frequency, using ashift register. This shift register transforms thefrequency differences into an analog signal. Theoutput of this register passes via a filter chainand a PID circuit to an analog-digital converter, tobe transformed into digital bits, to be optical-linkedto the triacs switching the braking load. For a givennumber of bits, a high number of switching possibilitiesof -the control loads exist, assuring a rapid controlof the alternator frequency. Waterhammer conditions inthe penstock are thus also avoided. The control loadsare activated after the first cross-over of thealternator voltage to avoid harmonics of the basicalternator frequency.