What Are The Benefits Of Installing
Capacitors?
Power capacitors provide several benefits
to power systems. Among these include power factor correction, system voltage
support, increased system capacity, reduction of power system losses, reactive
power support, and power oscillation damping.
Power Factor Correction.
In general, the efficiency of power
generation, transmission, and distribution equipment is improved when it is
operated near unity power factor. The least expensive way to achieve near unity
power factor is with the application of capacitors.
Capacitors provide a static source of
leading reactive current and can be installed close to the load. Thus, the
maximum efficiency may be realized by reducing the magnetizing (lagging)
current requirements throughout the system.
System Voltage Support.
Power systems are predominately inductive
in nature and during peak load conditions or during system contingencies there
can be a significant voltage drop between the voltage source and the load.
Application of capacitors to a power system results in a voltage increase back
to the voltage source, and also past the application point of the capacitors in
a radial system.
The actual percentage increase of the
system voltage is dependent upon the inductive reactance of the system at the
point of application of the capacitors. The short-circuit impedance at that
point is approximately the same as the inductive reactance; therefore, the
3-phase short-circuit current at that location can be used to determine the
approximate voltage rise.
Increased System Capacity.
The application of shunt or series
capacitors can affect the power system capacity. Application of shunt
capacitors reduces the inductive reactive current on the power system, and thus
reduces the system kVA loading. This can have the effect of increasing system
to serve additional load.
Series capacitors are typically used to
increase the power carrying capability of transmission lines. Series capacitors
insert a voltage in series with the transmission line that is opposite in
polarity to the voltage drop across the line, which decreases the apparent
reactance and increases the power transfer capability of the line.
Power System Loss Reduction.
The installation of capacitors can reduce
the current flow in a power system. Since losses are proportional to the square
of the current, a reduction in current will lead to reduced system losses.
Reactive Power Support.
Capacitors can help support steady-state
stability limits and reactive power requirements at generators.
Power Oscillation Damping.
Controlled
series capacitors can provide an active damping for power oscillations that
many large power systems experience. They can also provide support after
significant disturbances to the power system and allow the system to remain in
synchronous operation.
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