Recent Trends On Flexible AC Transmission Systems (FACTS)

Maharshi Pandya(4th sem, EE, Indus University)

Mayank Patel(4th sem, EE, Indus University)

Note: This Presentation based on Review About FACTS. Not Any other Research.

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

Cont.…

• Thyristor controlled reactor/Thyristor switched capacitor, TCR/TSC

TCR/TSC combinations are characterized by

– Continuous control

– No transients

– Elimination of harmonics via filters or TSR control

– Low losses

– Redundancy

– Flexible control and operation

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

TCSC (Thyristor controlled series capacitor)

• The TCSC behaves as a tunable parallel LC-circuit to the line current. As the impedance of XL is varied from its maximum (infinity) toward its minimum wL, the TCSC increases its capacitive impedance

Combined shunt and series connected controllers (hybrid)

UPFC (Unified Power Flow Controllers)

• The Most Complete And Versatile (And Costly) FACTS Device Is The UPFC, Able To Independently And Simultaneously Control Active Power Flow, Reactive Power Flow And Nodal Voltage Magnitude. The UPFC Has Been So Far Applied Only In Three Installations Worldwide (Two In The United States, One In South Korea)

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