Co-Ordination of multiple
Controllers using Non Linear – Control Techniques
nonlinear-control techniques have been applied for the design of FACTS
controllers. These techniques are likely to yield greatly improved controllers,
as they include the effects of system nonlinearities.
Ø Some of
these methods are described briefly in the following text. One
nonlinear-control technique in which the system nonlinearities are expressed as
system changes constituting a function of time is the adaptive control.
Ø If the
number of controller parameters to be optimized is not too large, a cost-penalty function technique can be used, which is based on nonlinear
effective technique commonly used for enhancing transient stability during
large disturbances is the discontinuous
control or bang-bang control.
nonlinear-control technique is the normal
forms, which includes the effects of higher-order terms in Taylor’s series
to represent power systems especially during high-power transfers. For damping
low-frequency oscillations, FACTS controllers can be designed using the dissipation technique, which is based on
the concept that passive systems always absorb energy. For designing the
controls of FACTS controllers in large power systems, the energy, or Lyapunov,
technique can be used. For stability enhancement, nonlinear fuzzy and neural
net techniques are presently being researched.
Ø In the
future, these techniques may be extended for coordination of FACTS controllers.
One possible approach could be to first do a “coarse” coordination using
linear-control techniques, followed by a “fine” coordination employing the
“The Quantitative treatment of control
of multiple controllers using linear control techniques.
of multiple controllers using non linear control techniques.