Adaptive predictive expert control of superheated steam temperature in a coalfired power plant

This paper describes the application of an adaptive predictive expert (ADEX) control solution to the attemperation process for superheated steam temperature control in the ScottishPower coal-fired power station at Cockenzie near Edinburgh in Scotland. The project comprised two phases, the first of which was a trial to establish the feasibility and potential benefits of ADEX compared with the existing control system by using a software platform on PC connected to the plant Programmable Logic Controller (PLC) via Object linking and embedding for Process Control (OPC), and the second phase was to verify and install a permanent, robust solution using an ADEX controller module with a digital link to the plant PLC. The overall objective of the project was to reduce steam temperature variations caused by load changes and other perturbations in order to protect the steam turbine (Unit 3) and to minimize thermal stresses in the attemperation pipework and boiler and so minimize premature failures along with associated cost risk. In the first phase, ADEX demonstrated a 50% improvement in reducing steam temperature variation overall compared with the existing method, and the subsequent installation of the ADEX controller module provided the necessary robustness and backups for a final industrial solution. The results of both phases are displayed graphically. Copyright © 2012 John Wiley & Sons, Ltd.