Post on 16-Jul-2015
transcript
A
Seminar
On
“POWER FACTOR IMPROVEMENT
USING UPFC”
Content
Introduction of power factor improvement
Power factor
Effect of low power factor
FACTS
Benefits of FACTS
FACTS Devices
Introduction to UPFC
Circuit description
Operation of UPFC
Application
Conclusion
INTRODUCTION
Electrical energy generated, transmitted, distributed in the form of alternating current. Therefore power factor plays an important role.
Power factor is highly undesirable as it causes an increase in current, result in additional losses of active power in all the elements of power system
For good quality of power supply, it is necessary to have power factor as close as unity.
Power factor
The cosine angle between voltage and current in an AC
circuit.
The ratio of resistance to impedance.
The ratio of active power to the apparent power.
Power triangle
Kw
KVAKVAr
q
θ
• Apparent power= VI in KVA
• Active power = VI cosθ in KW
• Reactive power = VI sinθ in KVAr
Effect of low power factor
Large KVA rating of equipment
Greater conductor size
Large copper losses
Poor voltage regulation
FACTS
Flexible AC Transmission System (Facts) is a new integrated concept based on power electronic switching converters and dynamic controllers to enhance the system utilization and power transfer capacity as well as the stability, security, reliability and power quality of AC
system interconnections.FACTS technologies improved transmission system operation with minimum investment, environmental impact and implementation time compared to the construction of new transmission line.
BENEFITS OF FACTS
Regulation of power flows in prescribed transmission routes.
Reduces the need for construction of new transmission lines,capacitors and reactors.
Provides greater ability to transfer power between controlledareas.
These devices help to damp the power oscillations that coulddamage the equipment.
BENEFITS OF FACTS
Improves the transient stability of the system.
Controls real and reactive power flow in the line
independently.
Damping of oscillations which can threaten security or limit
the usable line capacity.
FACTS Devices
Name Type Main function Controller
SVC shunt voltage control Thyristor
TCSC series power flow control Thyristor
TCPAR series & power flow control Thyristor
shunt
STATCOM shunt Voltage control GTO
SSSC series power flow control GTO
UPFC shunt & voltage and power GTO
series flow control
INTRODUCTION TO UPFC
The UPFC concept describe in 1995 by L. Gyugyi.
The UPFC is a device which can control simultaneously all threeparameters of line power flow
Such "new" FACTS device combines together the features of two"old" FACTS devices:
1. STATCOM
2. SSSC
Control active and reactive power in transmission line
These two devices are two Voltage Source Inverters (VSI’s)connected respectively in shunt with the transmission line through ashunt transformer and in series with the transmission line through aseries transformer, connected to each other by a common dc linkincluding a storage capacitor.
CIRCUIT DESCRIPTION The basic configuration of a UPFC, which is installed
between the sending-end Vs and the receiving-end VR. TheUPFC consists of a combination of a series device and ashunt device, the dc terminals of which are connected to acommon dc link capacitor .
Fig1: Basic configuration of UPFC
Operation of UPFC Series inverter- used for active and reactive line power flow
Shunt inverter used for voltage regulation
UPFC extensively used in power system because of theirability to provide flexible power flow controller
Application
Using HVDC transmission system
Use of UPFC for optimal power flow control
For improving micro grid voltage profile
For enhancement of voltage profile & minimization of losses
Increase transient stability of inter area power system
For damping power system ossicilation
conclusion
UPFC is FACT device used to control active &
reactive power flow. The overall result over the
power system is that it improved the power factor.
So it bring the present power system at better
economy level
Thank you