الفهرس 
BlackoutsOnly 14 pages are availabe for public view
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Abstract
Power systems today are made up of thousands and thousands of different
components. They are widely and, in some cases, massively spread over vast
lands and territories. Hence reliability and security of their operation is no
longer an easy target. Challenges in maintaining healthy operation are
magnified and elevated by the power system size. Despite huge
advancements in different power system components, operations, and
protection technologies, today’s power systems are more vulnerable to
blackouts than ever before. Recorded major blackout incidents have been
classified according to time and location. This showed that the frequency of
their occurrence has increased over time. It is not realistically possible to
completely eliminate blackouts; however, it can be shown that by taking
some reasonably cost-effective measures, occurrence of the blackouts could
be minimized and/or their effects could be mitigated. Clearly, the most
straightforward way is to minimize the risk of inadvertent disturbances by
mitigating, as far as possible, the root causes of system disturbances through
analyses and audits, preventive and corrective actions and Public policy,
Transmission, and future investments. One of the recommended preventive
plans against the wide area disturbances and the blackouts is Wide Area
Protection. With the rapidly growing capabilities in computer and
communication technologies, opportunities are now being available for the
introduction of advanced wide-area protection and control systems which
show great potential. Such systems would receive wide-span information,
e.g. system-wide voltages, angles, active and reactive power flows, etc., and
analyze them, indicating whether the system is on the urge of a
transformation into an unstable state, and thus, issuing wide-span,
coordinated actions that will save the system from proceeding to total
collapse, or even, mitigate the wide-area disturbance effects upon the system.
System splitting, also known as controlled separation, is to split the
interconnected transmission network, deliberately and on purpose, into
islands of load with matching generation at proper splitting points by
opening a selection of transmission lines and ties. After which, load shedding
and sometimes generation rejection should follow in order for the load and
generation to remain within balance, keeping the majority of the system
intact and hence avoid cascading instabilities or even partial or total
blackouts. The study of previous blackouts and outages suggest that if proper
system splitting strategies along with suitable load shedding and minimized
generator rejection had been performed within short time, some blackouts
could have been avoided and mitigated. In this thesis the author is proposing
three simple real-time algorithms that are intended to be operating online,
analyze data from wide-area PMUs placed in different parts of the grid,
process the system state and lines’ status and issue disconnecting actions to
certain lines in the grid to form islands with minimum imbalances of power
between generation and loads, without violating thermal and overloading
constraints of the ties left intact within each island. First a simple approach is
introduced, which takes long times and performs an extensive search for
proper splitting strategies. The author then analyzes the operation of this
preliminary algorithm and comments on ways to enhance its performance.
This will emphasize on how such WAP systems would be designed and
developed and if necessary tailored to fit specific systems or applications.
The author then presents the modified approach that suggests that some of
the work must be done off-line and leave the decision making to be real-time
but within much shorter times. Another technique is explored which is based
on Angle-modulated Particle swarm optimization and its results are
commented on showing potential of such optimization techniques in the field
of controlled separation. At last, a third heuristic technique introduced for the
first time is presented and its results are also highlighted and shown to
achieve the best results when related to time, which makes it a possible
implementation as an on-line, real-time, solution. Then a brief portrait of
how would such system exist in a today’s modern smart grid is made with
some useful guides for further implementation and research.
Keywords: Blackouts, Wide Area Protection, Controlled Separation, Angle
Modulated Particle Swarm Optimization.