Gas turbine plant with detector of extraordinary state

A gas turbine plant includes a combustion section (3), a turbine section (2), an exhaust section (12), a temperature detecting unit (13), and a monitoring unit (15). The combustion section combusts fuel using air to generate combustion gas. The turbine section is driven with the combustion gas from the combustion section. The exhaust section is connected to the turbine section to exhaust the combustion gas from the turbine section. The temperature detecting unit is provided in the exhaust section to measure a temperature of the combustion gas. The monitoring unit generates a warning signal based on a tolerable level and data corresponding to a temporal change of the temperature measured by the temperature detecting unit to indicate an extraordinary state of the gas turbine plant.