A power system is a complex arrangement comprising
of numerous generators, transmission lines, variety of loads, switches,
compensators and transformers (Taylor, 2014). Such a network is non-linear and non-stationary,
and in practice it is prone to several faults and disturbances. As a
consequence of increasing power demand, some transmission lines are more loaded
than was planned when they were built. At the same time, the construction of
new generating units and transmission circuits becomes more difficult because
of economic reasons and growing environmental concerns (Lebroy, 2008).
of numerous generators, transmission lines, variety of loads, switches,
compensators and transformers (Taylor, 2014). Such a network is non-linear and non-stationary,
and in practice it is prone to several faults and disturbances. As a
consequence of increasing power demand, some transmission lines are more loaded
than was planned when they were built. At the same time, the construction of
new generating units and transmission circuits becomes more difficult because
of economic reasons and growing environmental concerns (Lebroy, 2008).
Making existing line as well as new ones more
efficient and economical becomes a compelling alternative. Optimum power transmission
and distribution also entails the reduction of transfer losses and provision of
adequate power quality and availability at the receiving end. The purpose of
the interconnected transmission network is to pool power plants and load centres
in order to minimize the total power generation capacity, fuel cost and at the
same time to meet the load demand (Devitt, 2011).
efficient and economical becomes a compelling alternative. Optimum power transmission
and distribution also entails the reduction of transfer losses and provision of
adequate power quality and availability at the receiving end. The purpose of
the interconnected transmission network is to pool power plants and load centres
in order to minimize the total power generation capacity, fuel cost and at the
same time to meet the load demand (Devitt, 2011).
In general, if a power delivery system was made up
of radial lines from individual local generators without being part of a grid
system, more generation sources would be needed to serve the load with same
reliability and the cost of electricity would be much higher (Lebroy, 2008). In
this point of view, grid system is an alternative to a new generation
resources. As power transfer grows, the power system becomes increasingly more
complex to operate and the system becomes less secure. It may lead to a large
power flow with inadequate control, excessive reactive power in various parts
of the system and large dynamic swings between different parts of the system,
thus the full potential of transmission interconnections cannot be utilized
(Musa & Musa, 2015).
of radial lines from individual local generators without being part of a grid
system, more generation sources would be needed to serve the load with same
reliability and the cost of electricity would be much higher (Lebroy, 2008). In
this point of view, grid system is an alternative to a new generation
resources. As power transfer grows, the power system becomes increasingly more
complex to operate and the system becomes less secure. It may lead to a large
power flow with inadequate control, excessive reactive power in various parts
of the system and large dynamic swings between different parts of the system,
thus the full potential of transmission interconnections cannot be utilized
(Musa & Musa, 2015).
Restructuring has greatly reduced the degree to
which grid operators can manage the generation side of the relationship, so the
emphasis here is upon enhanced system performance through improvements in transmission
capabilities alone (Xiao-Ping, Christian & Bikash, 2006). Reinforcing a
power system can be done by increasing the voltage level or adding transmission
lines. However, these solutions require considerable investment which is
difficult to recover. Power system can be effectively improved by the use of Flexible
AC transmission system (FACTS) devices. FACTS devices can be a solution to
these problems. FACTS devices have shown very promising steady-state
performances because of the extremely fast control action associated with
FACTS-device operations, they have been very promising candidates for
utilization in power system damping enhancement (Nwohu, 2007).
which grid operators can manage the generation side of the relationship, so the
emphasis here is upon enhanced system performance through improvements in transmission
capabilities alone (Xiao-Ping, Christian & Bikash, 2006). Reinforcing a
power system can be done by increasing the voltage level or adding transmission
lines. However, these solutions require considerable investment which is
difficult to recover. Power system can be effectively improved by the use of Flexible
AC transmission system (FACTS) devices. FACTS devices can be a solution to
these problems. FACTS devices have shown very promising steady-state
performances because of the extremely fast control action associated with
FACTS-device operations, they have been very promising candidates for
utilization in power system damping enhancement (Nwohu, 2007).
A Unified Power Flow Controller (UPFC) is the most
promising device among the FACTS family. It has the ability to adjust the three
control parameters, i.e. the bus voltage, transmission line reactance, and
phase angle between two bus voltages, either simultaneously or independently. A
UPFC performs this through the control of the in-phase voltage, quadrature
voltage and shunt compensation (Xiao-Ping et
al., 2006). UPFC can also be used not only for power flow control, but also
for power system stabilizing control (Kothari & Tambey, 2003).
promising device among the FACTS family. It has the ability to adjust the three
control parameters, i.e. the bus voltage, transmission line reactance, and
phase angle between two bus voltages, either simultaneously or independently. A
UPFC performs this through the control of the in-phase voltage, quadrature
voltage and shunt compensation (Xiao-Ping et
al., 2006). UPFC can also be used not only for power flow control, but also
for power system stabilizing control (Kothari & Tambey, 2003).
