Heat Recovery Steam Generator Health Assessment Basing on Reconciled Measurement

Long-term monitoring and diagnostic of power plants is a permanent issue for the energy companies. In particular with the increase of flexible operation (e.g. daily start-up and shutdown cycles, part load operations) the definition of proper diagnostic indicators becomes mandatory. Different monitoring strategies were developed, implemented and tested for the main components of a combined cycle power plant (e.g. Gas Turbine, Heat Recovery Steam Generator, Steam Turbine, Pumps) to prevent fault/failure or to plan/evaluate the maintenance activities.This work focuses on the first principles health assessment of the Heat Recovery Steam Generator (HRSG). The impact of ambient conditions on the gas turbine outlet temperature and mass flow rate and thus on the HRSG behavior is presented referring to the control strategies of the Gas Turbine (GT). To validate the measurements a preprocessing phase basing on Data Reconciliation was performed, aimed at improving the accuracy of the estimation of exhaust mass flow rate entering the HRSG. Gas Turbine and HRSG nergy balances are exploited to reduce the uncertainties of the results, eliminate the outlier data sets and obtain consistent data. Moreover an evaluation of the sensitivity of the indicator will be made basing on field measurements before and after a maintenance intervention.Copyright © 2014 by ASME