distributed power flow controller

DISTRIBUTED POWER FLOW CONTROLLER FOR COMPENSATING REACTIVE POWER IN

TRANSMISSION SYSTEMS

PRESENTER:KESAVA VARMA

OBJECTIVES

• To compensate reactive power in transmission line.

• To overcome the disadvantages of Unified Power Flow controller(UPFC).

INTRODUCTIONThe growing demand and the aging of networks make it desirable to control the power flow in power-transmission systems fast and reliably.The FACTS is defined by “power electronic based system and other static equipment that provide control of one or more ac-transmission system parameters to enhance controllability and increase power transfer capability’’,and can be utilized for power flow control.

Unified Power Flow Controller

UPFC is a combination of static synchronous compensator (STATCOM)and static synchronous series compensator(SSSC).

Function Of UPFC:

• The active power exchange takes place through dc link provided in the UPFC.

• The shunt converter controls the voltage of dc capacitor by absorbing or generating active power from the bus.

• The series converter injects voltage with controllable magnitude and phase.

THE DPFC

Main difference of UPFC and DPFC

1. Eliminating the common dc link2.Distributing the series converter

DPFC Configuration

Active Power Exchange Between DPFC Converters

Simplified Representation Of DPFC

Operation Of DPFC:

• The shunt converter converts active power in at fundamental frequency to active power at harmonic frequency and gives back to the transmission line.

• Now the series converter converts this active power at harmonic frequency to active power at fundamental frequency.

DPFC connected to a simple power system

Additional devices for DPFC

• A delta to star and star to delta transformer is essentailly needed for DPFC.

• Several series converters are neededfor DPFC with individual capacitors.

DPFC control scheme:

• To control multiple converters, DPFC consists of three type of controllers

• Central control• Shunt control• Series control

• Central converter generates the reference signals for both series and shunt converter

• Each series converter and shunt converter has its own controller. `

Simulink Model Of DPFC:

Simulink Model Of Series Converter

Advantages Of DPFC

• High Control Capability: All the parameters like line impedance , transmission angle and controlled voltage with specific phase angle and magnitude.

• High Reliability: Usage of number of series converters

• Low cost