System and method for drum level control in a drum of a heat recovery steam generator

摘要

A system includes the HRSG having an economizer disposed along a fluid flow path, and a drum disposed along the fluid flow path downstream of the economizer. The HRSG also includes a drum level control module configured to modulate an amount of the fluid provided to the drum along the fluid flow path and a supplemental control module configured to control an amount of the fluid in a different manner than the drum level control module. The heat recovery steam generator also includes a drum level event controller configured to monitor a rate of change of a level of the fluid in the drum. If the rate of change is over a threshold value, a signal goes to the supplemental control. If the rate of change is less than or equal to the threshold value, the signal goes to the drum level control module.