| 摘要 |
PURPOSE:To prevent an unnecessary stop of a turbine, by providing a means, such that when a specific valve of the plural main stop valves in a steam turbine placed in a condition except full opening from a full opening condition is detected, the other valves placed in a closed condition is inhibited. CONSTITUTION:A limit switch 11, whose contact is opened at full opening, is provided to a specific valve of the plural main stop valve (MSV) in a steam turbine, and a relay A is connected in series to said contact. A contact 22a of the relay A and a contact 34a of a relay K in series to contacts 31-33, closed under 90% or more opening of the rest of the MSVs, are connected in series for relays B-D whose contacts 23a-25a are inserted in series to solenoid valves 26-28 opening and closing the rest of the MSVs. At full opening of the all MSVs, even if the contact 11 is closed by failure, the relay K operates to open the contact 34a, and the solenoid valves 26-28 of the rest of the MSVs are not excited and held in a full opening condition, then an unnecessary stop of the turbine is prevented. |
