DC AC INVERTER TOPOLOGY FOR CONTROL AND STABLE OPERATION OF HVDC
Advisor:
Dr. Tahir Izhar
Abstract:
The shortage of power is the major crisis we are facing these days in Pakistan. It has developed
an urge to shift our attention to the more reliable and efficient methods for the power generation
and transmission. As the power flow control is very difficult in AC systems, so the transfer of
power is done over long distances with less power losses using HVDC links. Common
applications of HVDC transmission technology have continuously based on interconnecting
asynchronous AC systems, essentially for economic transportation of electric energy from
remote resources. Therefore, NTDC has joined hand with private energy generation companies
to overcome the shortfall of energy and laid 878 km long 660kv HVDC line from Matiari to
Lahore having the capacity to transmit the power of 4000MW. Stability problems, such as inter area
oscillations,
have
become
increasingly
common
in
large
interconnected
power
systems
and
the
primary
function
of
HVDC
controls
are
fast
and
flexible
power
control
between
the
terminals
under
steady
state
and
transient
operation,
better
stability
of
ac
system,
fast
protection
of
ac
and
dc
system faults. The main focus of our project is to analyze all these issues in HVDC lines
being laid in Pakistan using the simulation software Power System Simulation for Engineers
(PSS/E) and to compare the results with National Transmission and Dispatch Company(NTDC)
studies. Moreover, we are also aimed to study different multilevel inverter topologies and to
implement the conventional HVDC 12 pulse Voltage source inverter topology (VSI) to
understand the concept of HVDC deeply. The gating signals for the switching devices are
generated using SPWM technique as result 12 pulses are generated output. The proposed
topology reduces the amount of harmonic currents drawn from the utility lines and gives excellent
performance in case of unbalancing in the practical power systems with much less component as
compared to other 12 pulse inverter topologies. Hence it is low and is more feasible.
cost