Equipment for the automatic resynchronization of a synchronous generator

Claim 1

The combination with a machine group comprising an alternating current generator driven by a prime mover such as a steam turbine of apparatus for effectinG automatic resynchronization of said machine group following a slip of the generator out of synchronism, said re-synchronizing apparatus including means for producing a signal proportion to generator slip, means controlled by said slip signal for disconnecting the field circuit of said generator from its source of energization, means for re-connecting said field circuit to its energizing source to re-synchronize the generator only when the slip value sk determined from a number of slip periods lies within the range: sk < OR = square root 2 . Ms max/ omega n . TA wherein omega n 2 pi fn; fn rated frequency TA inertia constant of the machine group Ms max maximum value of the synchronous moment means deriving a stabilization signal variable with the slip, a voltage regulator connected to and controlled by the line to which the output of said generator is connected, and a summing device receiving as inputs thereto said stabilization signal and the output from said voltage regulator and which produces therefrom an output which is connected to said source of energization for said field circuit to correspondingly control the current supplied to the field circuit subsequent to reconnection thereof.