Abstract: A speed governor for a hydroelectric unit includes an error sensing means, an integrator and a gate opening control means connected to the output of the integrator for controlling the degree of opening of the turbine gate apparatus. The governor further comprises a limiter connected between the output of the error sensing means and the input of the integrator for limiting the maximum value of the integrator input signal to a limit value equal to the minimum integrator input signal value which insures the maximum permissible rate of change of the degree of opening of the gate apparatus.

Abstract: An apparatus for automatically controlling the active power produced by the generator of a hydraulic turbine-generator unit, comprising a frequency-responsive summing means having its inputs respectively connected to a reference signal source which develops an assigned power signal, to a power measuring means responsive to the active power produced by the generator, and to a gate opening sensing means responsive to the degree of opening of the hydraulic turbine gate apparatus, and its output connected to a control means for controlling the degree of opening of the gate apparatus. The frequency-responsive summing means is adapted to develop at its output a signal representative of an algebraic sum of the signal applied to its input connected to the reference signal source, the low-frequency components of the signal applied to its input connected to the power measuring means and the high-frequency components of the signal applied to its input connected to the gate opening sensing means.