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