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*J.C. Miras, Undergraduate Student
Project, Department of Electrical and Electronics Engineering,
University of the Philippines, Diliman,(2004)
Conclusion In this
paper, we discussed and verified the effectiveness of the proposed
methodology of optimal allocation of fixed and switched capacitors for
unbalanced radial distribution feeders. In test case 1, it was proven
experimentally, that AI-based Genetic Algorithm (GA) is superior than SQP
in terms of the generated savings. It was also observed that although GA
operations are based on stochastic processes, the output solution for
several trials converges on almost the same amount of savings.
GA is domain independent. It
works on coded structures of variables instead of the actual variables.
The only information needed is the objective function. For that reason, we
had come up to a formulation that considers most of the simplifying
assumptions employed by previous researchers.
GA is well suited to
unconstrained combinatorial optimization problems. Constraints can be
incorporated by adding a penalty to the objective function for any
constraint violations. We did not consider the lower voltage limit as a
constraint since it is not the primary objective of the project. Moreover,
increasing the voltage profile above the lower limit must be handled by
voltage regulators and not by shunt capacitors since shunt capacitors are
primary used for loss reduction. On the other hand, based on the generated
solution of the GA method, no over-voltages occurred at all load levels
after compensation. This is because the additional losses due to
over-voltages act as an adaptive penalty function for the fitness value
that guide the search process to the permissible solution.
There
are no defined rules on selecting GA parameters like population size and
mutation probability. Thus, determination of GA parameters are user
dependent. There are,
however, researchers that propose methods of selecting GA parameters that
are close to optimal for a better GA performance.
GA is like an iterative
process. For each generation, fitness of each individual is evaluated
using objective function. Hence, GA runs slower than other optimization
methods.
Most of distribution feeders
feature a non-three-phase lateral feeders. Using sensitivity analysis, it
was observed that these laterals have a high sensitivity factor. Test case
4 shows that savings significantly increased if single phase and two-phase
lateral feeders are considered on the optimization process.
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Introduction Problem
Formulation and Solution Implementation,
Testing and Results Testing
and Results (continued1)
Testing
and Results (continued2)
Conclusion
and References
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