| Summary: | Concentrated solar power (CSP) is an efficient means of renewable energy that makes use of solar
radiation to produce electricity instead of making use of conventional fossil fuel techniques such as
burning coal. The aim of this study is the simulation and characterisation of a CSP plant in order to
gain a better understanding of the dominant plant dynamics. Due to the nature of the study, the
dissertation is divided into two main parts namely the simulation of a CSP plant model and the
characterisation of the plant model.
Modelling the CSP plant takes the form of developing an accurate Flownex® model of a 40 MW
combined cycle CSP plant. The model includes thermal energy storage as well as making use of a
duct burner. The Flownex® model is based on an existing TRNSYS model of the same plant. The
Flownex® model is verified and validated, by making use of a bottom-up approach, to ensure that
the developed model is in fact correct.
The characterisation part of this dissertation involves evaluating the dynamic responses unique to
that of a CSP plant as stated in the literature. This involves evaluating the dominant dynamic
behaviour, the presence of resonant and anti-resonant modes found within the control bandwidth,
and the change in the dynamics of the plant as the plants’ operating points change throughout the
day.
Once the developed model is validated, characterisation in the form of evaluating the open loop
local linear models of the plant is implemented. In order to do so, these models are developed
based on model identification processes, which include the use of system identification software
such as Matlab® SID Toolbox®.
The dominant dynamic behaviour of the plant model, obtained from the developed local linear
models, represents that of an over damped second order system that changes as the operating
points of the plant change; with the models’ time responses and the bandwidth decreasing and
increasing respectively as the thermal energy inputs to the plant increases. The frequency
response of the developed local linear models also illustrates the presence of resonant and antiresonant
modes found within the control bandwidth of the solar collector field’s temperature
response. These modes however are not found to be present in the mechanical power output
response of the plant.
The use of adaptive control, such as feedforward and gain-scheduled controllers, for the plant
should be developed to compensate for the dynamic behaviours associated with that of a CSP
plant. === MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015
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