BACKGROUND

The disclosure relates generally to the modeling and control of power plants. More specifically, embodiments of the disclosure provide an operational methodology to model and control a power plant by modeling and analysis of variant control profiles for the power plant.

Power plants typically include a variety of different turbomachines and/or systems that are used to generate a power output. Two conventional power systems used to generate power include gas turbine systems and combined cycle power plants, which typically include a gas turbine system(s). Conventional combined cycle power plants employ one or multiple gas turbine system(s) operatively coupled to one or multiple steam turbine system(s). The gas turbine system includes a compressor coupled to a gas turbine. The gas turbine is usually coupled to and drives an external component, such as a generator, for producing a load or power output. The steam turbine system includes a high pressure (HP) turbine portion operatively coupled to an intermediate pressure (IP) turbine portion that, in turn, is coupled to a low pressure (LP) turbine. Similar to the gas turbine of the gas turbine system, the HP, IP and LP turbines are employed to drive an external component (e.g., generator). In a typical combined cycle power plant, exhaust gas from the gas turbine is passed to a heat recovery steam generator (HRSG), which may be used to produce and reheat steam to the various turbines of the steam turbine system for enhanced efficiency of the system and/or power plant. Downstream of the HRSG the exhaust gas is released to the atmosphere through a stack.

The increased availability of alternative energy sources, such as various forms of renewable energy, has also increased the complexity of operating combined cycle power plants. Fluctuations in power generation demand on a combined cycle power plant often require the system to shift between different load conditions, varying the amount of generated power over time. The operation of a power plant at different amounts of load may affect several attributes of the power plant, including the internal temperature of various components and/or fuel consumption. In some cases, extended operation at varying loads may adversely affect efficiency or useful life of some components.

BRIEF DESCRIPTION

A first aspect of the disclosure provides a method for operating a combined cycle power plant (CCPP), the method including: operating the CCPP at an ambient condition and a load condition; generating a power plant model of the CCPP for operating at the ambient condition and the load condition; modeling a fuel consumption using a baseline control profile and the power plant model of the CCPP at the ambient condition and the load condition; creating a variant control profile for the CCPP; determining, using the power plant model, whether the variant control profile meets a quality threshold for the CCPP, the quality threshold including at least a fuel efficiency of the CCPP; modifying the variant control profile in response to the variant control profile not meeting the quality threshold; and adjusting the CCPP to use the variant control profile in response to the variant control profile meeting the quality threshold, wherein the variant control profile adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule for the CCPP.

A second aspect of the disclosure provides a program product stored on a computer readable storage medium for operating a combined cycle power plant (CCPP), the computer readable storage medium having program code for causing a computer system to perform actions including: operating the CCPP at an ambient condition and a load condition; generating a power plant model of the CCPP for operating at the ambient condition and the load condition; modeling a fuel consumption using a baseline control profile and the power plant model of the CCPP at the ambient condition and the load condition; creating a variant control profile for the CCPP; determining, using the power plant model, whether the variant control profile meets a quality threshold for the CCPP, the quality threshold including at least a fuel efficiency of the CCPP; modifying the variant control profile in response to the variant control profile not meeting the quality threshold; and adjusting the CCPP to use the variant control profile in response to the variant control profile meeting the quality threshold, wherein the variant control profile adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule for the CCPP.

A third aspect of the disclosure provides a system including: a combined cycle power plant (CCPP) having at least a gas turbine, a heat recovery steam generator (HRSG), a steam turbine (ST), and a condenser; and a system controller in communication with the gas turbine and the HRSG of the CCPP, the system controller being operable to: operate the CCPP at an ambient condition and a load condition; generate a power plant model of the CCPP for operating at the ambient condition and the load condition; model a fuel consumption using a baseline control profile and the power plant model of the CCPP at the ambient condition and the load condition; create a variant control profile for the CCPP; determine, using the power plant model, whether the variant control profile meets a quality threshold for the CCPP, the quality threshold including at least a fuel efficiency of the CCPP; modify the variant control profile in response to the variant control profile not meeting the quality threshold; and adjust the CCPP to use the variant control profile in response to the variant control profile meeting the quality threshold, wherein the variant control profile adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule for the CCPP.

The illustrative aspects of the present disclosure are designed to solve the problems herein described and/or other problems not discussed.

