The large quantities of measurement information gathered throughout a plant process make the closing of the mass and energy balance nearly impossible without the help of additional tools. For this reason, a variety of plant monitoring tools for closing plant balances was developed. A major problem with the current tools lies in the non-consideration of redundant measurements which are available throughout the entire plant process.
The online monitoring reconciliation system is based on the process data reconciliation according to VDI 2048 standard and is using all redundant measurements within the process to close mass and energy balances. As a result, the most realistic process with the lowest uncertainty can be monitored. This system is installed in more than 35 NPPs worldwide and is used
○ as a basis for correction of feed water mass flow and feed water temperature measurements (recover of lost Megawatts).
○ as a basis for correction of Taverage (Tav) (recover of steam generator outlet pressure in PWRs).
○ for maintaining the thermal core power and the feed water mass flow under continuous operation conditions.
○ for automatic detection of erroneous measurements and measurement drift.
○ for detection of inner leakages, non-condensable gases and system losses.
○ for calculating non measured values (e.g. heat transfer coefficients, ΔT, preheater loads,…).
○ as a monitoring system for the main thermodynamic process.
○ for verifying warranty tests more accurate.
○ as a application of condition-based maintenance and component monitoring.
○ for What-if scenarios (simulation, not PDR)
This paper describes the methodology according to VDI 2048 (use of Gaussian correction principle and quality criterias). The benefits gained from the use of the online monitoring system are demonstrated.
