28-09-2013, 04:54 PM
Advanced FACTS Devices and Applications: Performance, Power Quality and Cost Considerations
Devices and Applications.ppt (Size: 1.23 MB / Downloads: 376)
FACTS
The Concept
History / Background - Origin of FACTS, Opportunities, Trends
System Architectures and Limitations
Power Flow Control on AC Systems
Application Studies and Implementation
Basic Switching Devices
Conditioners: SVC, STATCOM, TCSC, UPFC, SMES
Specification, Cost Considerations and Technology Trends
Impact of FACTS in interconnected networks
Market Assessment, Deregulation and Predictions
The Concept and Challenges
A transmission system can carry power up to its thermal loading limits. But in practice the system has the following constraints:
-Transmission stability limits
-Voltage limits
-Loop flows
Transmission stability limits: limits of transmittable power with which a transmission system can ride through major faults in the system with its power transmission capability intact.
Voltage limits: limits of power transmission where the system voltage can be kept within permitted deviations from nominal.
Loop flows can be a problem as they are governed by the laws of nature which may not be coincident with the contracted path. This means that power which is to be sent from point ”A” to point ”B” in a grid will not necessarily take the shortest, direct route, but will go uncontrolled and fan out to take unwanted paths available in the grid.
The Concept
FACTS devices
FACTS are designed to remove such constraints and to meet planners´, investors´ and operators´ goals without their having to undertake major system additions. This offers ways of attaining an increase of power transmission capacity at optimum conditions, i.e. at maximum availability, minimum transmission losses, and minimum environmental impact. Plus, of course, at minimum investment cost and time expenditure.
The term ”FACTS” covers several power electronics based systems used for AC power transmission. Given the nature of power electronics equipment, FACTS solutions will be particularly justifiable in applications requiring one or more of the following qualities:
-Rapid dynamic response
-Ability for frequent variations in output
-Smoothly adjustable output.
Important applications in power transmission involving FACTS and Power Quality devices:
SVC (Static Var Compensators), Fixed * as well as Thyristor-Controlled Series Capacitors (TCSC) and Statcom. Still others are PST (Phase-shifting Transformers), IPC (Interphase Power Controllers), UPFC (Universal Power Flow Controllers), and DVR (Dynamic Voltage Restorers).
FACTS Technology - Possible Benefits
Control of power flow as ordered. Increase the loading capability of lines to their thermal capabilities, including short term and seasonal.
Increase the system security through raising the transient stability limit, limiting short-circuit currents and overloads, managing cascading blackouts and damping electromechanical oscillations of power systems and machines.
Provide secure tie lines connections to neighboring utilities and regions thereby decreasing overall generation reserve requirements on both sides.
Provide greater flexibility in siting new generation.
Reduce reactive power flows, thus allowing the lines to carry more active power.
Reduce loop flows.
Increase utilization of lowest cost generation.
Conclusions
A Balanced and Cautious Application
The acceptance of the new tools and technologies will take time, due to the computational requirements and educational barriers.
The flexibility and adaptability of these new techniques indicate that they will become part of the tools for solving power quality problems in this increasingly complex electrical environment.
The implementation and use of these advanced techniques needs to be done with much care and sensitivity. They should not replace the engineering understanding of the electromagnetic nature of the problems that need to be solved.