A description is presented of the cascade controller, which has made short-term planning and control of the plants in the Guadalupe chain in Colombia feasible. A difficult operating problem has been solved by a controller with a robust and straightforward hardware/software structure. As a result, the plants along the Guadalupe river are now able to participate in the AGC (automatic generation control) of the EMP (Empresas Publicas de Medellin, Colombia) power system. This has added a substantial regulation of water resources and generation capability to the power system. Modern control theory and computer-aided design were used for the design and tuning of the controller program. At an early stage, the applied control strategy was verified to meet the requirements. The final commissioning was free of problems due to meticulous preparations made as early as the design phase. The control strategy does not rely on properties which are unique to the Guadalupe chain. For a similar plant configuration, this approach could be used, especially if the objectives are the same. Design principles, algorithms and operating experience are also given.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
