Title:
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Analysis, modelling and optimal control of water supply and distribution systems
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This thesis is concerned with the developments of analysis, modelling
and optimization techniques and computer program algorithms, with the
ultimate aim of control of water supply and distribution systems to
lead to overall optimal operation.
Typical system features and operational conditions are analyzed, and
the requirements for the overall objective are examined, to determine
an overall control strategy which is subsequently developed and tested
on real systems throughout this thesis. As a prerequisite, short-term
water demand forecasting is extensively studied by employing time
series analysis. Special consideration is given to improving the
forecasting accuracy of the method and its on-line implementation. In
order to speed up the solution time of optimal system operation,
simplified system models -- namely, piecewise macroscopic model and
equivalent network model -- are developed respectively. Then by
employing the piecewise macroscopic model, a nonlinear programming
method is developed to cater for the optimal operation of a class of
multi-source systems without significant storage. The optimal
operation policy obtained by this method is realized at two levels:
the first level calculates the optimized apportioning of water to be
delivered by different sources; the second level decides the least
cost pump schedules to supply the optimized apportioning of water.
Based on the equivalent network model, a linear programming method is
developed for optimization of a class of multi-source, multi-reservoir
systems with a mixture of fixed speed pumps and variable speed and/or
variable throttle pumps. This method yields directly optimized pump
schedules and reservoir trajectories in terms of least cost system
operation.
The integration of the developments results in a scheme which can be
applied to give overall dynamic control of a wide range of water
supply and distribution systems. The application results presented in
this thesis justify the theoretical developments and show that
benefits can be obtained from these developments.
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