07-08-2012, 02:19 PM
DISTRIBUTED SYSTEM OF POWER QUALITY IMPROVEMENT
DISTRIBUTED SYSTEM OF POWER QUALITY.ppt (Size: 3.57 MB / Downloads: 39)
In supply system are:
consumers who negatively influence the power quality
controlled source of reactive power (static compensators, idle synchronous motors and generators with excitation current control),
active power filters and distributed power sources (PV systems, wing generators etc.).
There are also other systems dedicated for specific use:
voltage stabilizers and high harmonics parallel active filters,
AC adjustable speed drives (ASDs) with VSI inverter
etc.
DETERMINING THE REFERENCE SIGNALS
Is it possible to determine the reference signals for the power quality improvement system on the basis of solely the voltage signals acquired at selected points of the supply system?
Genetic algorithms were employed in order to solve the formulated multi-criterial optimisation task.
Distinguishing features of Genetic Algorithms are:
AG do not transform directly parameters of a task but their coded forms,
AG make a ransack, starting from a population of points, not from a single one,
AG use only the goal function. It is no need to have derivatives or any other auxiliary information,
AG employ probabilistic not deterministic rules of selection,
The goal function can be freely formed including multicriterion optimization.
CONCLUSIONS
In this case Genetic Algorithms were employed in order to solve the formulated multicriterial optimisation task. In general case the objective can be e.g.: minimization of energy losses in the system and/or minimization of harmonics generation cost (by different current sources). These tasks can be approached independently or, on their basis, can be formulated the task of global optimization where they will be used as constraints in solving the optimization task, e.g. the distortion minimization.