Patent ID: 7392656
Filing Date: 2008-07-01
Classification: F01D,F01K,F05D

Abstract:
1. A steam turbine plant comprising: an extraction system which extracts a portion of main steam from an intermediate stage of a steam turbine and delivers the extracted steam to a demander; and a steam extraction control system for controlling steam extraction of the extraction system; wherein the extraction system includes an extraction steam flowmeter and an extraction steam stop valve; and the steam extraction control system is configured to set a warning flow and an extracted steam stop flow as restrictive flow values with respect to a flow of the extracted steam whereby when an extracted steam flow measurement value from the flowmeter reaches the warning flow, a warning is issued and after a lapse of a predetermined time period an opening instruction is sent to the stop valve so as to bring the stop valve into a fixed open state for restriction of the extracted steam flow, and when in the restriction state the extracted steam flow is further increased and the extracted steam flow measurement value reaches the extracted steam stop flow, a fully-closing instruction is sent to the stop valve so as to fully close the stop valve for stoppage of steam extraction.