MODERN FACTS DEVICES AND ITS COMPENSATION TECHNIQUES

Relation between cost and Power Transmission

a α 1 ∕ (VL2 *cosϕ )

Area of the conductor is inversely proportional to square of voltage transmitted and its power factor value

To lower cost we need two important parameters •High Voltage in transmission lines•Power factor value nearer to one

How power factor of Transmission line is affected?

•Presence of thick insulators and long transmission lines

•There is improper distribution of load factors

•For example -inductors are said to consume reactive power and capacitors are said to supply it.

•Improper distribution of these loads causes power factor to drop below one.

POWER FACTOR CORRECTION IN LOADS

• A high power factor is generally desirable in atransmission system to reduce transmissionlosses

• For power factor correction , power

electronic devices such as the Static VARcompensator or STATCOM are used.

These devices are called FACTS Devices

Voltage Regulation and stability

• How the Voltage in Transmission line be controlled?

•The control of voltage and reactive power is a majorissue in power system operation.• To reduce transmission losses and to maintain theability of the system to withstand and prevent voltagecollapse.•Reactive power is the very important parameter tocontrol the voltage in transmission lines

History of FACTS Devices

• Dr. Narain Hingorani is the father of FACTStechnology.

• C. J. Slatt Substation near Arlington, Oregon

• This is a 500 kV, 3-phase 60 Hz substation

FLEXIBLE AC TRANSMISSION SYSTEMS (FACTS)

FACTS Categories

•Series Connected ‐FACTS Devices•Shunt Connected ‐FACTS Devices•Combined Series‐series Connected ‐FACTS

Device• Combined Series‐shunt Connected ‐FACTS

Device

SERIES COMPENSATION

• Improper load distribution in transmission line

• In case inductance is prominent in the transmission line we suffer Voltage drop.

• To compensate, series capacitors are connected.

• Capacitors add voltage to line current.

• Effect of Inductance thus eliminated.

• In case capacitance is prominent in the transmission line we suffer low current in transmission line.

• To compensate, shunt inductors are connected.

• inductors add current to line voltage.

• Effect of Capacitance thus eliminated.

SHUNT COMPENSATION

Types of Shunt Compensation

• SHUNT CAPACITIVE COMPENSATION

• SHUNT INDUCTIVE COMPENSATION

Different FACTS controllers

Static VAR compensator

• It is for providing fast-acting reactive power on high-voltage electricity transmission networks.

• It is used for regulating voltage, power factor, harmonics and stabilizing the system.

• designed to bring the system closer to unity power factor.

Static VAR compensator

Types of Static VAR compensator

• Transmission SVC : Connected to the powersystem, to regulate the transmission voltage.

• Industrial SVC : Connected near largeindustrial loads, to improve power quality .

STATCOM

• It is a regulating device used on alternating current electricity transmission networks.

• To reduce poor power factor and poor voltage regulation.

• It is based on a power electronics voltage-source converter

• act as either a source or sink of reactive AC power

STATCOM

Unified Power Flow Controller

• Latest in series connected Facts Controllers.

• The UPFC is a combination of a staticsynchronous compensator and a staticsynchronous series compensator.

• It allows function such as stability control to suppress power system oscillations and transient stability of power system.

Unified Power Flow Controller

Generalized Unified Power Flow Controller

• Three converters one shunt ,twoseries power controller.

• active and reactive powercompensation.

Generalized Unified Power Flow Controller

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