Regulation system for a steam turbine installation

A regulation system for regulating a predetermined magnitude of a steam turbine installation having a steam generator and a multi-stage turbine including a high-pressure stage having an entrance to said high-pressure stage, said regulation system comprising, in combination:

• a regulation valve arranged between the steam generator and the entrance to the high-pressure stage of the turbine;
• a by-pass valve arranged between the steam generator and the high-pressure stage in parallel to said regulation valve and connected with a location of the high-pressure stage disposed downstream of said entrance to said high-pressure stage;
• a first control circuit including a first control device provided for the regulation valve;
• a second control circuit including a second control device provided for the by-pass valve;
• said first control circuit for the regulation valve delivering a signal which influences said second control device for said by-pass valve such that when the opening of the regulation valve exceeds a predetermined magnitude said second control device for the by-pass valve opens the by-pass valve to a predetermined magnitude;
• and
• a differentiation element connected in parallel with the second control circuit for the by-pass valve for influencing the magnitude of opening of the by-pass valve as a function of variations in the signal received from the first control circuit of the regulation valve.