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The paper describes how gas turbine based plants (open cycle and combined cycle) can be profitably used in power system restoration for supplying restoration areas. In recent times, in fact, several gas turbine sections entered the power system due to the improved efficiency of gas turbines and to the development of high efficiency combined-cycle plants. These units can be easily improved to provide black-start capability and can therefore largely increase the black-start capacity of the entire system. Restoration islands to be used for minimizing the time to supply critical areas, such as urban and industrial zones, can support the usual restoration paths designed to provide cranking power to large steam units. The paper presents the defining criteria for the procedures to be followed during restoration. An example referred to as an urban area is reported with simulation results. The Italian System Operator recently carried out some tests on an open cycle gas turbine aimed at checking the island operation of the unit. Some results are described.

The present paper reports the main results of a comprehensive international survey that, on behalf of the Italian independent system operator, the authors have carried out into the main strategies, critical issues and practical experiences related to the restoration plans of a wide set of deregulated systems worldwide. For many ISOs, people directly involved in designing, testing and updating restoration plans have been contacted and interviewed, in order to focus general issues and to outline common improvement trends. Taking the international survey as a starting point, the paper also proposes and discusses possible innovative enhancements being studied for the Italian system, aimed at increasing the effectiveness of the restoration service.