EXCITATION CONTROL SYSTEM

摘要

PURPOSE:To reduce the capacity of a cycloconverter by forming an unbalanced state in a difference between a set point and an actual value when slip is kept within a predetermined range. CONSTITUTION:A command-value computing circuit 15 computes the opening command value HV of a governor valve for a hydraulic turbine and a speed command value NO on the basis of a static head H and an output command PO. A phase-angel computing section 16 adds a difference between the speed command value NO and an output signal P, and outputs an added value as it is when slip frequency is kept outside a predetermined range and outputs a value acquired by multiplying the added value by a fixed value when slip frequency is kept within the prescribed range. A secondary-winding excitation- quantity computing section 17 sets the quantity of a secondary winding excited of an induction motor on the basis of an output from the phase-angle computing section 16, the speed signal N and an output from a voltage regulating section 18.