Flexible AC Transmission Systems (FACTS)

Nawazish Ali

12063122-047

Outline

• Overview Of The Transmission Planning Process

• Role Of Power Electronics Device In Power System

• Introduction Of FACTS

• Benefits Of FACTS Technology

• Types Of FACTS Controllers

• Recants uses FACTS devices

• Conclusion

• References

Overview Of The Transmission Planning

Process

• Is A Very Complex Process And Recent Trends And Challenges Make It Even

More Complicated In the past, before the electricity market liberalization.

• Its aim to minimize the generation costs.

• minimizing transmission costs (investment and operation).

• Use of static and dynamic technical constraints.

Role Of Power Electronics Device In

Power System

• Switching operation because Availability Of High Power Semiconductor

Devices

• Decentralized Renewable Energy Generation Sources

• Increased Power Transfer With Existing Transmission System

• Effective Control Of Power Flow Needed In A Deregulated Environment

• Norms For Power Quality

Introduction On FACTS

• Flexible AC Transmission Systems (FACTS) are the name given to the application of power electronics devices to control the power flows and other quantities in power systems.

• “Alternating current transmission systems incorporating power electronic based and other static controllers to enhance controllability and increase power transfer capability.”

• The design of the different schemes and configurations of FACTS devices is based on the combination of traditional power system components (such as transformers, reactors, switches, and capacitors) with power electronics elements (such as various types of transistors and thyristors)

Benefits of FACTS

• To increase the power transfer capability of transmission networks.

• To provide direct control of power flow over designated

transmission routes.

• Control of power flow as ordered so that it follows on the prescribed

transmission corridors.

• Increase the loading capability of lines to their thermal

capabilities

FACTS CONTROLLERS

SHUNT

• Static Var Compensator

• Static Synchronous Compensator

• STATCOM

SERIES

• Thyristor Controlled Series Compensator (TCSC)

• Static Synchronous Series Compensator

• Fault Current Limiter (SC+FPD)

HYBRID

• Dynamic Power Flow Controller (DFC)

• HVDC Light/HVDCLightB2B/UPFC

Shunt connected controllers

Static Var Compensator

• The SVC is an excellent tool for achieving dynamic voltage

control of power systems. Increased efficiency in power

systems

• The global trend is towards ever larger power networks,

longer transmission lines, and higher consumption. Energy

is also becoming increasingly expensive. To cope, power

transmission and distribution systems have to become more

efficient. It has increasing power transmission and

distribution capacity at a lower cost.

SVC used as a voltage stabilization

• SVC is the preferred tool for dynamic reactive power support in high voltage transmission grids. it will counteract the often hazardous voltage depressions that follow in conjunction with faults in the grid. These highly dynamic events, where the ever increasing use of induction motors (like those in air-conditioning units and wind power turbine-generators) stresses the grid, will need an SVC to maintain the grid voltage and safeguard the fault ride-through capability.

• Static var compensator includes the following major components

1. Control system

2. Thyristor valves

3. Capacitor banks

4. reactors

Basic SVC schemes

• Thyristor controlled reactor and fixed capacitor,

TCR/FC TCR/FCs are characterized by

– Continuous control

– No transients

– Elimination of harmonics by tuning the FCs as filters

– Compact design

• Thyristor switched capacitor, TSC

TSCs are characterized by

– Stepped control

– No transients

– No harmonics

– Low losses

– Redundancy and flexibility

The Benefits Of SVC To Power

Transmission

• Stabilized voltages in weak systems

• Reduced transmission losses

• Increased transmission capacity, to reduce, defer or eliminate the need for new lines.

• Higher transient stability limit

• Increased damping of minor disturbances

• Greater voltage control and stability

• Power oscillation damping.

Series connected controllers

Combined shunt and series connected

controllers (hybrid)

Device Capabilities

Device capabilities SVC STATCOM TCSC SSSC TCPST UPFC

Transmission Capacity Small Small Strong Strong Strong Strong

Power Flow Control Small Small Medium Strong Medium Strong

Transient Stability Small Medium Strong Strong Medium Strong

Voltage stability Strong Strong Small Small Small Strong

Power Oscillation

Damping

Medium Medium Medium Medium Medium Strong

Control of Wind Farm

Reactive Power O/p

Yes Yes No No No Yes

Investment Cost Small Medium Small Medium Medium Strong

Conclusion

• The above discussion reflects various work and philophies are

covered in the area of FACTS. The potential role that FACT may

play towards the development of the future Indian transmission

system. In fact, FACT elements may provide Indian TSOs with

effective solutions to the several criticalities they encounter. Finally,

it has to be noted that in a highly meshed network, as the Indian

FACTS become extensively deployed, they will deliver real benefits

only when subjected to a coordinated and hierarchical control.

Reference

[1] BOOK POWER GENERATION ENGINEERING. AUTHOR R.P AJWALIA

(ATUL PARAKASHAN)

[2] A. L’ABBATE, G. MIGLIAVACCA, U. HÄGER X, C. REHTANZ X ERSE

(ENEA - RICERCA SUL SISTEMA ELETTRICO) [FORMER CESI RICERCA]

SPA, MILAN, ITALY TECHNICAL UNIVERSITY OF DORTMUND, DORTMUND,

GERMANY

[3] EUROPEAN TRANSMISSION SYSTEM

[4] V. KAKKAR, HEAD OF DEPTT (EEE), AND N. K. AGARWAL, ASSIST.

PROF. (EEE) VITS GHAZIABAD.

[5] L. GYUGYI, N.G. HINGORANI, “UNDERSTANDING FACTS,”IEEE PRESS, 1ST EDITION, DECEMBER 1999.[6] M.H. RASHID, “POWER ELECTRONICS,” PRENTICE HALL, 3RD EDITION,

2004.

Thank You