Systems, program products, and methods for detecting thermal stability within gas turbine systems are disclosed. The systems may include a computing device(s) in communication with a gas turbine system, and a plurality of sensors positioned within or adjacent the gas turbine system. The sensor(s) may measure operational characteristics of the gas turbine system. The computing device(s) may be configured to detect thermal stability within the gas turbine system by performing processes including calculating a lag output for each of the plurality of measured operational characteristics. The calculated lag output may be based on a difference between a calculated lag for the measured operational characteristics and the measured operational characteristic itself. The calculated lag output may be also be based on a time constant for the measured operational characteristics. The computing device(s) may also determine when each of the calculated lag outputs are below a predetermined threshold.

A steel plant control device includes a subtractor, a PI controller, a first-order lag controller, and an adder. In a band that is lower than a first frequency f1, a gain of the PI controller is higher than a gain of the first-order lag controller; in a band from the first frequency f1 to a second frequency f2, the gain of the first-order lag controller is higher than the gain of the PI controller; and in a band that is higher than the second frequency f2, the gain of the PI controller is higher than the gain of the first-order lag controller.

Systems, program products, and methods for detecting thermal stability within gas turbine systems are disclosed. The systems may include a computing device(s) in communication with a gas turbine system, and a plurality of sensors positioned within or adjacent the gas turbine system. The sensor(s) may measure operational characteristics of the gas turbine system. The computing device(s) may be configured to detect thermal stability within the gas turbine system by performing processes including calculating a lag output for each of the plurality of measured operational characteristics. The calculated lag output may be based on a difference between a calculated lag for the measured operational characteristics and the measured operational characteristic itself. The calculated lag output may be also be based on a time constant for the measured operational characteristics. The computing device(s) may also determine when each of the calculated lag outputs are below a predetermined threshold.

A steel plant control device includes a subtractor, a PI controller, a first-order lag controller, and an adder. In a band that is lower than a first frequency f1, a gain of the PI controller is higher than a gain of the first-order lag controller; in a band from the first frequency f1 to a second frequency f2, the gain of the first-order lag controller is higher than the gain of the PI controller; and in a band that is higher than the second frequency f2, the gain of the PI controller is higher than the gain of the first-order lag controller.