System for minimizing valve throttling losses in a steam turbine power

Abstract

A system which integrates the controls of a steam turbine power plant for minimizing power plant energy losses substantially caused by steam flow valve throttling is disclosed. The steam turbine power plant includes boiler pressure controls for controlling the boiler throttle pressure of a steam producing boiler and turbine-generator controls for positioning a plurality of turbine steam admission values to regulate the steam flow conducted through a steam turbine which governs the electrical energy generated by an electrical generator at a desired power generation level. The turbine-generator controls predetermines a plurality of valve position states to establish a predetermined valve grouping sequential positioning pattern for the steam admission valves to regulate steam flow through the steam turbine across the range of power generation, each predetermined state substantially corresponding to a minimum of valve throttling losses. The steam admission valves may be positioned at a present valve position state, which is other than one of the predetermined states, as a result of a change in desired power generation level. The disclosed system responds to this condition by governing the boiler pressure controls to adjust the boiler throttle pressure at a desired rate and in a direction to cause steam admission valves to be repositioned according to the sequential positioning pattern to a selected one of the predetermined efficient valve position states. The repositioning of the steam admission valves is performed by maintaining the generated energy substantially at the new desired power generation level.