Experience in the Development and Implementation of Modern Systems of Automatic Frequency and Power Control of Large Power Units with Direct-Flow Boilers

This work reflects many years of experience in the development and implementation of an automated process control system at traditional power units with a capacity of 300 to 800 MW. It is part of a series of articles devoted to multiply connected automatic control systems, their development in accordance with modern requirements for maintaining the frequency and power of the power system. The interrelations of the main circuits of automatic control of power units and ways to neutralize the negative interrelations between them are described in detail. The problems of regulating the frequency and power of power units and solving power system problems are considered. A simplified matrix of the power unit control object is presented. Three types of autonomy (autonomy I, II, and III) and the relationship between the main leading and driven operating parameters of the power unit are considered. The advantages of the combined variant of the implementation of the Standard unit load control systems (LCS) are shown, which makes it possible to use each technological solution regardless of the current mode of operation of the power unit. A method for neutralizing the interconnections between local automatic control systems (LACS) both in the LCS-1 structure and in the combined LCS is described in detail by switching on compensation devices with the implementation of the invariance of the main controlled variables during disturbances in the boiler’s operation. Methods have been developed and improved to improve the dynamics of regulation of important technological parameters. The developed structural solutions for equipment automation are widely used in the implementation of distributed automated control systems. The schemes of the main channels of automatic control of the power units considered in the article are given, in the process of adjusting the process control systems of which positive results were obtained. The implementation of the optimal settings for the main control loops ensures an increase in the quality of the control processes of the power unit as a whole.