Safe control of air cushion surge chambers in hydropower systems

This paper presents an eective theory for safe control of air cushion surgechambers (acscs) in hydropower systems. on the basis of the emergency pressuresand heights of air in chambers, the acceptable limits of the monitoring parameters forthree kinds of control mode are derived theoretically to control the air compressor. theprerequisites for each control mode are determined by considering air leakage and thesolution. by analyzing these prerequisites, the selection criteria are established to determinethe appropriate control mode for a practical hydropower system with acsc. according tothe presented control scheme, the air compressor need not be actuated for any variationin air temperature, and the operating conditions of the hydropower system need not beconsidered for safe control of acscs. those are favorable for the safety and economy ofthe hydropower plant. to detail and validate the derived limits and selection criteria fordierent control modes, the safe control theory is applied to the practical hydropower plant,and a graphic analysis is conducted on the basis of the perfect gas law and the relationshipof the initial steady-state pressure and height of the enclosed air in the chambers.