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2.2.1.1 HP Steam Bypass Control

The HP steam bypass control valves are used to bypass HP steam to the CRH steam header. Different bypass control functions are required depending on the condition of the plant. During GT/HRSG initial startup, the HP steam bypass valves control minimum reheat steam flow through the HRSG. After minimum reheat flow has been established, the bypass valve controls HP steam header pressure. ***After the steam turbine transfers to HP sliding pressure control***, the bypass valve provides over pressure protection. Sliding pressure controls occurs when the ST MCV is at Valve Wide Open (VWO) position and header pressure begins to increase.

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