d compensation

8/13/2019 D Compensation

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International Conference on VSC Technolgy for HVDC & FACTS Devices

CENTRAL POWERRESEARCH INSTITUTE

FACTS ForDynamic Compensation

InPower Transmission

M.M. Babu NarayananCTA, PRDC

Power Research & Development Consultants Pvt. Ltd.; Bangalore.Ph No: +91-80- 23192159/68/23192209; E-mail : [email protected];www.prdcinfotech.com;
http://www.prdcinfotech.com/mailto:[email protected]:[email protected]://www.prdcinfotech.com/http://www.prdcinfotech.com/mailto:[email protected]


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I nternational Conference on VSC Technolgy for HVDC & FACTS Devices


Need for Voltage & reactive power support

Static & Dynamic reactive powersupport needed to:

Supply reactive powerrequirements of customer demand

Supply reactive power losses inT&D systems

Provide adequate system voltagecontrol


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Why Dynamic Voltage & reactive power

support ?

Necessary to avoid voltage instability &widespread system collapse in the event ofcertain contingencies

Essential during power system disturbanceslike faults


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Voltage & reactive power support


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Flexible AC Transmission Systems (FACTS) are thename given to the application of power electronicsdevices to control the power flows and other quantitiesin power systems.

As per IEEE definition

FACTS Controllers: A power electronic based system &other static equipment that provide control of one ormore AC transmission parameters.

Reactive power controlFACTS devices


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FACTS Concepts


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To increase the power transfer capability oftransmission networks

To provide direct control of power flow overdesignated transmission routes.

Dynamic voltage control to:

Limit over-voltages over long, lightly loaded

lines

Prevent voltage depressions or even collapses

in heavily loaded or faulty systems.

Application of FACTS Technology


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FACTS opportunities


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FACTS

Thyristor

Based

TCPAR

TCSC

SVC

VSC

Based

STATCOM SSSC SPS UPFC IPFC

Classification of FACTS devices


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SVCs are

available

since 1970

First SVCdemonstrationwas inNebraska andcommercializedby GE in 1974

More than 800SVCs installedworldwideboth inUtilities and inIndustries

2 Nos. SVC,140 MVAR(each) atKanpur since1992

Static Var Compensator (SVC)

SVC: A thyristor controlled, variable reactance, shunt FACTSdevice which can generate /absorb reactive power at a busto control specific parameters of power system


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11

SVC Configurations


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12

Power transfer has doubled - with large SVCPower transfer increases substantiallywith

realistic SVC

Power Transfer improvement by SVC


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The object is to achieve one or more of the followingeffects:

Reduction in the disturbing influence byminimizing the fault severity andduration.

Increase of synchronizing forces.

Reduction of accelerating torque throughcontrol of prime-mover mechanical power.

Reduction of accelerating torque byapplying artificial load.

Transient stability enhancement by SVC


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Transient stability enhancement by SVC


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Power systems with low SC fault MVA levels / long

transmission lines (weak systems)

Buses where voltage variations are significantly effected

under light and peak load conditions

Bus Voltage Regulation by SVC


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CASE STUDY:

POWER TRANSFER STUDIES USING SVC

SINGLE MACHINE INFINITE BUSSYSTEM


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RTDS simulation of SMIB system

+150/-

150 MVAR


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21

Power transfer limitswith damping control

(a) WithoutSVC

(b) With SVC


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SVC at Kanpur; 2Nos.,140 MVAR each


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Active & Reactive Power control inSTATCOM


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Active & Reactive Power control inSTATCOM

Active power is primarily determined byangle


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Active Power exchange withSTATCOM


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27

Case study

Operating strategy:

MSCs to yield the major

reactive power supportduring slow varyingconditions in the system.

This leaves STATCOM to

rapidly respond todisturbances in the gridrequiring fast voltagesupport

Courtesy: ABB


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Cascading faults hit the 138 kVgrid. One such case of 5 cycle

fault with STATCOM responseshown below:

STATCOM control system firstdisables the MSCs followingdisturbance & drives VSC to its

maximum capacitive output.

Maximum capacitive outputachieved in about 1 cycle.

After fault clearing, VSC

current ramped down to itsinitial pre-fault value in acontrolled manner.

STATCOM ready to support thegrid for any other disturbances


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Series FACTS Controllers -TCSC

Shunt capacitors must typically be connected at the mid

point of line whereas no such requirement exists for

series compensation


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Impact of series compensation on power transmission capability


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Applications of variable seriescompensation -TCSC

Power flow control

Enhancing transient stability

Damping of power swings Sub-synchronous resonance damping

Fixed value of C madecontrollable by varyinginductive reactance throughfiring angle control


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Operation of Thyristor Controlled Series

Compensator (TCSC)

A variable inductor connected in shunt with fixed capacitor


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Damping effects of TCSC


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Power oscillation damping

RaipurRourkela 400 kV TCSC ( 2 nos.)

Capacitor reactance: Fixed: 54.7 (40%)

Variable: 6.83 (5%)

Rated capacitive reactive power : Fixed: 394 Mvar

variable: 71 Mvar

Case study :1


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Grid stabilization for large power transfers on the 412Km inter- regional Raipur- Rourkela 400kV D/C tie-line

Damping out low frequency inter-area oscillations(typically in the range below 1Hz) by Power

Oscillation (POD) controllers of TCSC

Purpose of TCSC at Raipur


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Power oscillation damping with & without POD

control in Raipur TCSC


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Control the power flow over the 400kV Kanpur-

Ballabhgarh line

Providing positive damping support to theNorthern Regional Power system.

NREB system exhibits two critical low frequency modes

of frequency around 0.70Hz - Eastern UP, Rajasthan

TCSC controller at Ballabhgarh influences the low

frequency mode of eastern-up machines

TCSC OF KANPUR-BALLABHGARH LINE

Case study: 2


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CENTRAL POWERRESEARCH INSTITUTE400 kV TCSC SCHEME FOR KANPUR-BALLABHGARH LINE


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Major parameters of Kanpur-Ballabhgarh line & TCSC


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BLBGR2

MANDLA

BLBGN2

AGRA4

JAPPN4

BHIWADI4

FRDBDG

DADRI4

MRDNG4

FROMRIHND4

PANKI4

SPLTBLG

UNCHR2

PANKI2

RIHND4

TO DADRI

G.T

G.T

G.T

KNPRN480MVAR

BLBGR4

50MVAR

50MVAR

50MVAR

50MVAR

80MVAR

80MVAR

80MVAR

80MVAR

63MVAR

460MVAR

G.T

50MVAR

50MVAR

50MVAR

50MVAR

80MVAR

690MVAR

REDUCED NREB SYSTEM REPRESENTATION


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14 infinite sources behind a series impedance. 22nos of 400kV lines.

11nos of 220kV lines. 10nos of fictitious line were modeled as series

impedance between buses. One HVDC bipolar link (Rihand - Dadri)rated

total capacity 1500 MW. One SVC at Kanpur rated at 280 MVAR. TCSC (27% fixed 8%-20% variable) on the Kanpur

Ballabhgarh Line.

Reduced NREB system representation

C O S C S


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Outage of HVDC line with current basedcontroller

SatisfactoryDamping

Created disturbance

in the Steady state



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CENTRAL POWERRESEARCH INSTITUTEOutage of HVDC line with voltage based

controller

Better Damping

Created disturbance

in the Steady state



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Outage of Panki-

Muradnagar Line

Without

Damping Controller



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Outage of Panki-

Muradnagar Line

With

Damping Controller



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Conclusions



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d compensation

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