VARIABLE-SPEED GENERATOR

PURPOSE:To improve stability by using a difference between power required for a control spot and an output capable of being made to correspond by other periodic machines as a power command value for a variable speed machine. CONSTITUTION:A command-value computing section 15 outputs an opening command value V for a governor valve 12 for a hydraulic turbine 13 and a speed command value N) on the basis of static head H ad an output command value P0. A phase-angle computing section 16 computes the phase angle DELTAdeltaof a secondary winding for an induction generator 100 on the basis of the output command value P0, effective power P, the speed command value N0 and a speed signal N. An excitation-quantity setting section 17 sets the quantity of the secondary winding excited by the speed signal N, the phase angle DELTAdelta and an output from a voltage regulating section 18. A proportional arithmetic section 60 compensates the output command value P0 on the generation of a grounding accident, outputs a compensated commend value P01, and absorbs the unbalanced energy of a system.