Enhanced Flexibility for Steam Power Plants via Model Based Feedforward Control

The recent energy market developments along with an ongoing increase of renewable energy feed-in set new demands on flexibility and maneuverability of large-scale steam power plants. Some aspects of these increased demands can be met by a model based feedforward control concept. The model based feedforward control concept fits perfectly into existing control concepts by simply replacing the existing feedforward control strategy without affecting the feedback control. The aims of the improved control concept are twofold: Enhanced load following capabilities shall be achieved while ensuring efficient operation of the power plant. Efficient operation is important from an economic point of view as well as in terms of life time consumption of actuators and other components. These are conflictive goals that need to be compromised adequately. Therefore, the process dynamics have to be taken into account. While other boundary conditions like actuator limitations are already at their limits, better knowledge of the process dynamics and its use in the control concept is likely to show considerable potential for improvement. In order to capture the process dynamics appropriately, a detailed dynamic model that is valid over a wide operation range is necessary. This process model as well as some aspects of model based feedforward control in steam power plants is subject of this contribution.