Performance Modeling of a Modern Gas Turbine for Dispatch Optimization

Abstract

As electricity demand from individual power plants is expected to fluctuate increasingly due to the growing share of renewables, operators of large Combined Cycle Gas Turbine power plants will have to deal with increasing load variations and rapid load changes. To keep up reliability and availability of the plants, it is useful to accurately keep track of plant performance by comparing actual cycle data with a steady state base case model. This paper presents various aspects of the performance modeling of Alstom’s GT26 gas turbine as recently installed in the Netherlands. The modeling environment is GSP, a component based zero-dimensional software tool. Firstly, the modeling strategy is presented, taking into account the specific features of this sequential combustion gas turbine. Secondly, the method of processing field measurements to model inputs is shown and furthermore, the influence of measurement uncertainty on model parameter estimation is assessed. Procedures will be proposed to use this model in daily operation, to keep track of actual component loading. Later on, the recorded performance data can be used to evaluate maintenance as a function of actual operational history, as a basis for future strategies.

Optimisation Potentials for the Heat Recovery in a Semi-closed Oxyfuel-combustion Combined Cycle with a Reheat Gas Turbine

“…In modern conventional combined cycle applications there are two main reasons for which the use of recuperation is not useful. The first reason is that the compressor outlet temperature of 550°C is nearly as high as the turbine outlet temperature in case of the GT26 [4]. The second reason is that the exhaust gas can be efficiently used in a steam process.…”

“…ISO turbine inlet temperatures (ISO-TIT), polytropic efficiencies of the compressor and the turbine, mechanical efficiency, pressure losses etc., are then fitted to match the design data given in Table 1. The compressor pressure Steam Water ratio of 32.8 and more detailed information like compressor outlet temperatures and cooling flows are taken from Boksteen et al [4]. As described by Güthe [5] the fuel mass flow to the EV and SEV combustors are divided approx.…”

“…The parameter b is determined for each nozzle and each blade from the reference gas turbine using the cooling mass flows from [4] and a maximum blade temperature of 850°C. The OTCs are set to cool the first two cooling flows (see Fig.…”