System and method for operating steam turbine with transient elevated back pressure

摘要

A method and control system for implementing a transient protection logic algorithm 400 to avoid a turbine exhaust pressure trip 30 due to a short duration transient on turbine exhaust pressure 30 caused by a large reduction in turbine flow coupled with a transient increase in turbine exhaust pressure 30, which specifically occurs during full load rejections. When full load rejection conditions are sensed by power load unbalance 50 and confirmed by secondary means, normal trip settings 20 for turbine exhaust pressure 5 are blocked for a delay period 95 while transient operating limits are in place.