Current Challenges on the Control of Large Scale Power Systems
Current Challenges on the Control of Large Scale Power Systems
Power system's networks are among the largest and most complex
physical man-made systems. They connect hundreds of million producers
and consumers, cover continents and exhibit very complicated behavior.
As a result, there are many ill-known phenomena caused by the
interaction of a so large number of devices and the large spatial
dimension. The impossibility of knowing information in real time from
remote points of the network prohibits the implementation of any
centralized control of the entire system.
New technologies in control, computers and communications have
allowed the possibility of a future power grid quite different from the
present one. These smart grids will in the near future decrease the
present clear distinction between power producers and power consumers.
During the last 4 years some of these problems were addressed by the
HYCON Network of Excellence funded by the European Commission. The
present work introduces some of HYCON's main results in the control of
large-scale power systems (at production, transmission and distribution
levels) and makes a brief overview about some still open challenges on
this field. It starts by a motivation of the importance of the control
of power systems. This is done by the description of some recent major
incidents (August 14th 2003, US and Canada, and November4th 2006, whole
Europe), and the analysis of their causes, effects and which control
challenges they illustrate. Some of the control challenges studied in
HYCON Network are: Better (larger operation region, more robust) low
level automatic control systems for power generators; Simulation and
verification tools to aid high level decisions; Information gathering
and transmission from different synchronous areas; Distributed control
of energy production from renewable sources; Intermediate energy
storage; Optimized voltage control of electrical power networks
These control challenges have as main sources a series of major
changes occurred in power systems in the last two decades: Connection of
power grids – previously isolated power grids merged in larger systems;
Liberalization of the energy markets – previously monopolistic state
owned companies where privatized; Large-scale introduction of renewables
– 20-20-20 By 2020: to cut 20% of CO2 emissions; 20% energy savings;
and to use 20% of energy production from renewable sources.
On-going changes and/or technologies: New power electronics
development – FACTS; Distributed Generation (simultaneous
costumer/producer duality); are creating new control challenges current
under study: Connection of wind farm and power grid using Flexible
Alternating Current Transmission System (FACTS); Wide Area Measurement
Systems (WAMS); Choice of type, localization (possibly temporary) and
embedded control of Power Electronics Devices; Bi-directional
power-flow, monitoring, pricing and power quality; Virtual/Autonomous
Network modeling; Dynamic demand control.
Finally, this work overviews future changes that may yet
completely re-shape power systems. In particular it may be foreseen the
impacts of large penetration of electrical cars. If a large share of
current fossil power sources are replaced by electrical power in
automobiles, the current power systems would be greatly impacted. At the
same time, such systems could open completely new possibilities if
coupled with current developments as dynamic demand control and roamer
costumer/producer.