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The composition of natural gas may vary significantly, and load power varies randomly. Traditional control design approaches consider a fixed operating point in the hope that the resulting controller is robust enough to stabilize the system for different operating conditions. On the other hand, adaptive control incorporates the time-varying dynamical properties of the model and considers the disturbances acting at the fuel cell-microturbine hybrid power plant. It may be possible to identify the parameters of the adaptive controller. This scheme is called direct adaptive control, because we are going to obtain directly the required controller parameters through their estimation in an appropriately redefined plant model. An adaptive minimum variance controller is developed in this paper. Index Terms--Fuel cells, gas turbines, power generation, simulation.

This paper investigates the effects of HVdc line faults, line de-energization, and line re-energization on the transient torsional stresses of steam turbine-generator (T-G) units. The studies are conducted on a bipole HVdc syste which connects a T-G set to a large ac system. The shaft transient stresses of the T-G set as a result of HVac line fault, fault clearing, and automatic reclosure are also determined when the HVdc transmission system is replaced by an equivalent double-line HVac system. The EMTDC program is used for the simulation studies. The studies conclude that transient shaft stresses as a result of HVdc line fault and its subsequent switching events are (1) significantly less severe tha those of HVac faults and subsequent switchings, and (2) not sensitive to the fault location and disturbance duration.

This paper presents the analysis carried out for designing and developing a prototype expert system capable of managing the electrical system of an industrial plant. The electric network of the plant, including significant gas turbine and steam turbine generation facilities, is presented. The modeling phase of the system for successive analysis by simulation using a commercial power system code is also reported. The load-shedding problem is then considered and the related engineering aspects are briefly recalled. The guidelines for the realization of a load-shedding scheme for industrial electrical plants based also on advanced artificial intelligence tools such as expert systems are proposed. The expert system is used online to prepare lookup load-shedding tables capable of accounting for actual process conditions. Offline validation of the proposed shedding is then operated by static and/or dynamic simulation. The use of a prototype rule-based expert system is expected to permit the achievement of a better flexibility in the realization of load-shedding schemes for improving the process continuity and management. Index Terms--Adaptive control, expert systems, gas turbine generation, industrial electrical systems, load shedding.