| 摘要 |
<p>17TU-2889 TURBINE BYPASS DESUPERHEATER CONTROL SYSTEM An adaptive control system for controlling the temperature of desuperheated steam in a turbine bypass system. In one embodiment of the invention, redundant temperature sensors downstream of desuperheating water sprays provide an indication of the actual steam temperature after desuperheating has occurred. The highest value of temperature is automatically selected for control and to provide an error signal to a controller. The controller output, indicative of the deviation from a desired temperature, is multiplied by a factor porportional to steam flow in the bypass system. The multiplied signal is then utilized to porportionally position one or more water control valves to spray more or less water into the bypassed steam. The control system thus automatically adapts itself to variations in steam flow. Preferably, the steam flow is taken as the product of the position of a steam flow throttling valve in the bypass line and the steam supply pressure ahead of the valve. Additionally, operating parameters such as temperature and differential pressures are monitored and continuously compared against limiting values to provide automatic protection action if any of the conditions being monitored warrant such action.</p> |
