Instrumentation and Control in Coal-Fired Power Plant
AUTHOR: Hermine Nalbandian
DATE: November 2001
Instrumentation and control is an integral part of a coal-fired power station. A modern, advanced I&C system plays a major role in the profitable operation of a plant by achieving maximum availability, reliability, flexibility, maintainability and efficiency. These systems can also assist in maintaining emissions compliance. The I&C chain begins with sensors that detect measured values. Controllers receive these values, upon which a control strategy is activated. The response, where and when required, moves in final actuating control elements to modify the affect process. This loop repeats over and over during plant operation through a complex and multi-level communications schemes.
"Smart" field devices, including sensors and actuators, continued to be developed in order to simplify and improve the control process. The two main control platforms that are used in coal-fired power stations are the distributed control system (DCS) and the programmable logic control (PLC). Personal computer (PC) based hardware and software have only recently been introduced in power plant control. With the fast development, increasing power and reduced cost of personal computers, PC-based control is expected to become a further platform for future development and growth. Today new coal-fired power plants are, in general, built with modern, advanced DCS/PLC and a large number of existing coal-fired power stations have been retrofitted with advanced digital systems in many countries, throughout the world.