Thermal efficiency diagnostic method and apparatus of a combined power generation plant

Claim 1

A thermal efficiency diagnostic method of a combined power generation plant including a gas turbine facility and a steam turbine facility, comprising the steps of: preparing measurement values of parameters including at least one of temperature, pressure, flow rate and electric power output relative to an energy input and an energy output with regard to respective equipment of the combined power generation plant, and recording a design value of each equipment; extracting a portion of the measurement value as measurement data that has high accuracy, which is a fixed value, as standard parameters through optimum state estimation of a heat balance; extracting a portion of the measurement value as another measurement data which significantly affects diagnostic results and which is difficult to measure with high accuracy and deemed to be low accuracy, as key parameters; calculating an entire probability of the heat balance by using a number of calculation data of the heat balance as reference parameters, which are then compared with their reference values to calculate a probability of each of the reference parameters; conducting and determining an optimum state estimation of the heat balance by adjusting the key parameters to be consistent with the standard parameters, so that each deviation of reference parameters becomes minimum as a whole and the probability becomes maximum in the combined power generation plant; comparing the optimum state estimation of the heat balance with a heat balance based on the design value; analyzing a degree of contribution of performance of each of the respective equipment to a thermal efficiency; and specifying the equipment that causes a heat efficiency deterioration in accordance with the degree of contribution of the performance of each equipment.