29-12-2012, 05:29 PM
STATCOM (Static Synchronous Compensator)
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It is a device connected in derivation, basically
composed of a coupling transformer, that serves of link
between the electrical power system (EPS) and the
voltage synchronous controller (VSC), that generates
the voltage wave comparing it to the one of the electric
system to realize the exchange of reactive power. The
control system of the STATCOM adjusts at each
moment the inverse voltage so that the current injected
In the network is in cuadrature to the network voltage,
in these conditions P=0 and Q=0.
In its most general way, the STATCOM can be
modeled as a regulated voltage source Vi connected to
a voltage bar Vs through a transformer.
Application of the Three-Phase STATCOM in Voltage Stability
Voltage stability is one of the biggest problems in power systems.
Engineers and researchers have met with the purpose of discussing and
trying to consolidate a definition regarding to voltage stability, besides
proposing techniques and methodologies for their analysis. Most of these
techniques are based on the search of the point in which the system’s
Jacobian becomes singular; this point is referred as the point of voltage
collapse or maximum load ability point.
The series and shunt compensation are able to increase the maximum
transfer capabilities of power network .Concerning to voltage stability, such
compensation has the purpose of injecting reactive power to maintain the
voltage magnitude in the nodes close to the nominal values, besides, to
reduce line currents and therefore the total system losses. At the present
time, thanks to the development in the power electronics devices, the voltage
magnitude in some node of the system can be adjusted through sophisticated
and versatile devices named FACTS. One of them is the static synchronous
compensator (STATCOM).
Thus, the three-phase STATCOM model is integrated into the steady state
formulation. In the simulations, the STATCOM´s node where is connected, is
represented as a PV type node. This node can change to PQ type when, during
the process, one of the limits in the device’s voltage magnitude is violated.