Use of High-Power Thyristor Technology for Short-Circuit

s

Power Transmission and Distribution

Use of High-Power Thyristor Technology for Short-Circuit Current Limitation in High Voltage Systems

Advanced PowerTransmission Solutions

High Voltage


PTD H 1PD / Re 05-2004 SCCL V 8.0_XP 2

High Voltage

Development of Power Markets

Environmental Constraints

Increasing Power Demand

Strong Competition

Advanced Solutions are required

New Market Conditions

Use of Power ElectronicsNew Technologies



High Voltage

Trends in Power Systems

PrivatisationGlobalisation/Liberalisation

Deregulation - Privatisation: Opening of the markets, Independent Transmission Companies ITCs, Regional Transmission Organisations RTOs

PrivatisationBottlenecks inTransmission

Problem of uncontrolled Loop-FlowsOverloading & Excess of SCC LevelsSystem Instabilities/ Outages

PrivatisationInvestments inPower Systems

System Enhancement & Interconnections:Higher Voltage LevelsNew Transmission TechnologiesRenewable Energies



High Voltage

Transmission Systems in Deregulated Markets

There areThere are 3 typical Situations3 typical Situations in Power Systems:in Power Systems:

Meshed Systems:Meshed Systems: LoadLoad--Flow ProblemsFlow ProblemsWeak Systems:Weak Systems: Stability Problems Stability Problems Strong Systems:Strong Systems: High Fault CurrentsHigh Fault Currents

Grid Power Flow Controller

& B2B as GPFCThe Solutions:The Solutions: SCCL

Short-Circuit Current Limiter



High Voltage

Advanced Power Transmission Systems

Fault-Current Limiter

FCL FCL ––StatusStatustodaytoday



High Voltage

FCL – Principles and Applications

Basically, there are two types Faults Current Limiters:

Fault Current LimitationHigh-temperature Superconducting FCL

FACTS: The SCCL

Fault Current InterruptionIs-Limiter

Electronic Devices (“Small FACTS”)



High Voltage

Fault Current Limitation – an Overview

Possible Locations of Fault Current Limitation in the Systema) Operating Principle of different Devicesb) Application of FCL in the System



High Voltage

Innovations in FACTS Technology

From From FFSCSC toto

TPTPSSCCThyristor-Protected Series Compensation



High Voltage

Sensitive to environmental influences, specific

maintenance required

MOV Protected Thyristor Protected

From FSC to TPSC – the Development

Gap Protected

Long cool-down time

Fast cool-down time



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Thyristor Protected Series Capacitor - TPSC

Long cool-down time of arrester in conventional series capacitor after fault or faults before bank re-insertionReplacement of spark gap and high energy absorption arresters by self-cooled direct-light triggered thyristor (LTT) valvesFast re-insertion of series capacitor due to extremely short cool-down time of LTT valve

to Lineto SubstationW Benefits of 90.000 US$* per

event on 1 line** due to faster availability of a TPSCe.g. reduction from 1200 MW to 600 MW with FSC/MOV *

* 25 US$/MWh x 600 MW x 6 hrs

** 270.000 US$, if all 3 Lines are involved



High Voltage

Benefits of TPSC: High Availability after Fault Clearing

Auto-ReclosureDead-Time

260°C

50°C

TPSCValveTemp.

Thyr. ValveBypass CB

LineBreaker

5 Cycles Fault Clearing Time

0.6 s after the 1st Fault the Valveis back in Pre-fault Condition

Time / s 1.1 1.3 1.50.90.70.5

Standard FSC with MOV requires up to 8 hours to cool down



High Voltage

LTT – Light Triggered Thyristors

LTT: Technical & Economical Advantages

80 % less Electronic ComponentsLess Electric Wiring & Fiber Optic CablesReduced Spare Parts RequirementsWafer-integrated Over-voltage Protection

Maximum Reliability & Availability - Benefits of LTT

Thyristor Valve with Direct-Light Triggering 100 mm Thyristors with integrated Break-over Protection

The safest Valve Technology



High Voltage

View on the LTT Thyristor Stack

The active portion of the valve becomes a straightforward assembly of thyristors, heat sinks, and cooling-water piping



High Voltage

Advanced Power Electronic Components

Direct Light-Triggered Thyristor (LTT)

80 % Less Electronic ComponentsFlame retardant Valves to UL standardsHigh Reliability

Thyristor

Module

Valve Group - Example Indoor for HVDC



High Voltage

Direct Light-Triggered Thyristor (LTT)

80 % Less Electronic ComponentsFlame retardant Valves to UL standardsHigh Reliability

Thyristor

Module

Valve Group - Example Outdoor for FACTS

Advanced Power Electronic Components



High Voltage

PLATFORM

7 8 7

1

3

26

1 series capacitor

2 thyristor valve as fast bypass - device

3 current limiting reactor

4 MOV

5 bypass circuit breaker

6 bypass damping reactor

7 platform disconnects with grounding switch

8 bypass disconnect

TPSC Single Line Diagram & Components

4

5



High Voltage

TPSC Vincent – On-Site Recordings: Line Fault Phase BC - June 18, 2002, Line Current in Phase A

Line breakeropen

Bypass switchclose-5000

-2500

0

2500

5000

480 500 520 540 560 580 600

time / msec

Am

ps

Line Curr. Ph A1 Valv.Curr. Ph A1

Line breakeropen

Bypass switchclosed



High Voltage

TPSC Vincent: Line Fault Phase BC - June 18, 2002Peak Valve current in Phase B

Line breakeropen

Bypass switchclose

-35000

-25000

-15000

-5000

5000

15000

25000

35000

480 500 520 540 560 580 600

time / msec

Am

ps

Line Curr. Ph B1 Valv.Curr. Ph B1

Line breakeropen

Bypass switchclosed



High Voltage

Measured Currents & Calculated Junction Temperature Rise: Valve Phase B; external Fault - no Bypass Breaker

-40000

-30000

-20000

-10000

0

10000

20000

0,48000 0,53000 0,58000

t [sec]

I [A

]

0

10

20

30

40

50

60

dTj [

K]



High Voltage

-20000

-10000

0

10000

0,48000 0,53000 0,58000

t [sec]

I [A

]

0

10

20

30

40

50

60

Tvj [

°C]

Measured Currents & Calculated Junction Temperature Rise: Valve Phase C; external Fault - no Bypass Breaker



High Voltage

A closer Look into the TPSC-Fault Detection Strategy

Phase A – no Fault, no Action

Phase C – Staged Action



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TPSC Vincent/USA: 3 TPSC Systems at 500 kV -fully proven in Practice

Outdoor Valves on a PlatformLTT Thyristors, self-cooled

TPSC Technology:



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Innovations in FACTS Technology

From From TPSC TPSC toto

SCCLSCCL

Short-Circuit Current Limiter



High Voltage

SCCL - The New Solution

Bus 1

ACAC

Bus 2

SCCLSCCL

Impedance

X

Low Impedance for Best Load FlowFast Increase of Coupling Impedance

t



High Voltage

SCCL - An Innovative FACTS Device

Bus 1

ACAC

Bus 2

SCC LimitationSCC Limitation

Fast Short-Circuit Current Limitation - by means of High Power Thyristor

Impedance

X

Low Impedance for Best Load FlowFast Increase of Coupling Impedance

t



High Voltage

Excess of SCC-Levels due to System Expansion

Typical Situation in a Ring Network with high SCC

3 ~3 ~

Loads LoadsLoadsLoads

3 ~ 3 ~



High Voltage

Reduction of Short-Circuit Currents with SCCL

Typical Situation in a Ring Network with high SCC

3 ~3 ~

3 ~

Loads LoadsLoadsLoads

SCCLSCCL

Location(s) of SCCL depends on SourceImpedances

B2B as GPFCB2B as GPFC

SCCLSCCL

3 ~



High Voltage

Reduction of Short-Circuit Currents with SCCL

Typical Situation in a Meshed System with high SCC

3 ~ 3 ~

B2B as GPFCB2B as GPFC 500 kV500 kV

115 kV 115 kV

LoadsLoads

Existing Existing

3 ~

Expansion

3 ~

Expansion

SCCLSCCL

Alternatives



High Voltage

Verification of the Short-Circuit Current Limitation

3 ~ 3 ~

500 kV500 kV

115 kV 115 kV

3 ~

Loads

3 ~

Loads

Existing Existing

ExpansionExpansion

SCCLSCCL

Bus 1I1+2

I2I1

VS , ISBus 2



High Voltage

Voltages and Currents without SCCL

Bus 1

Bus 2

V1

I1

I2

I1+2

40 kA eff

80 kA eff

40 kA eff



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Voltages and Currents with SCCL

Bus 1

SCCL

Bus 2

VS

IS

V1

I1

I2

I1+2

40 kA eff

50 kA eff

V2

10 kA eff



High Voltage

SCCL: Internal Signals

VCap

Icap

IByp



High Voltage

SCCL – Short-Circuit Current Limitation with FACTS

To Bus 2

Reactor

Thyristor Valve Housing

BYPASS Breaker

Capacitor Bank

To Bus 1

Communication SCCLSCCL

TPSCTPSC + ReactorReactor

Bus 1

ACAC

Bus 2

ImpedanceX

Zero Ohm for best Load Flow

Fast Increase of Coupling Impedance

t



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SCCL - Side View and Dimensions (Example 110 kV)

9,7 m (32 feet)

ma

x. 7

m (

23

fe

et)



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SCCL - TOP View and Dimensions

16 m (53 feet)

10

,5 m

(3

4 f

ee

t)



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SCCL - Single Line Diagram



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A unique A unique

FACTS FACTS

SolutionSolution

SCCL from Siemens - The Solution of the 21st Century

for for SSRSSR

& & PODPOD

with Dynamic with Dynamic

AddAdd--OnOn



High Voltage

First Add-On: Power Oscillation DampingWith POD Control: Fast & effective Damping

No POD Control: System close to Instability



High Voltage

SCCLSCCL

ApplicationsApplications

ConclusionsConclusions

SCCL from Siemens - The Solution of the 21st Century



High Voltage

SCCL - Examples of Applications

Bus 1 Bus 2

System designed for 3 Infeeds

Excess of allowed SCC LevelsExcess of allowed SCC Levels

115 kV

3 ~

Expansion

3 ~

Existing

3 ~

Existing

3 ~



High Voltage

SCCL - Examples of Applications

SCCLSCCL

Bus 1 Bus 2

SCC LimitationSCC Limitation

System now designed for 4 Infeeds

115 kV

Enables Connection of Enables Connection of additional Generation additional Generation on the 115 kV Systemon the 115 kV System

3 ~

Existing

3 ~

Existing

3 ~

3 ~

Expansion



High Voltage

SCCL versus Conventional Reactor

Only Current Limiting Reactor ?Only Current Limiting Reactor ?Voltage Drop - needs Compensation

SCCL SCCL -- The better Alternative:The better Alternative:No Risk of Voltage Collapse

Reactive Power remains balanced

No Impact on Grid Load Flow

Increase of First Swing Stability

Dynamic Add-Ons for SSR & Power Oscillation Damping

Mechanically or ThyristorSwitched Capacitor

Bus 1

ACAC

Bus 2

Bus 1 Bus 2

AC AC



High Voltage

SCCL - Designed for maximal Availability

Not with our Technology:Not with our Technology:High PowerHigh Power LTT ThyristorLTT Thyristor -- 110 kA peak,110 kA peak, self coolingself coolingProtection withProtection with WIN TDCWIN TDC -- aa standard standard in HVDC, FACTS and Drivesin HVDC, FACTS and DrivesMeasurements Measurements -- redundantredundant (optically powered)(optically powered) transducerstransducersno auxiliary power suppliesno auxiliary power supplies on the platform neededon the platform needed

Constraints on Electronic Breaker Solutions ?Constraints on Electronic Breaker Solutions ?

SCCL: designed for harsh Environment & Multiple Fault Contingencies

The Operation Principle:The Operation Principle:Fail safeFail safe -- thyristor will be shorted in case of malfunctionthyristor will be shorted in case of malfunctionBackup byBackup by waferwafer--integrated overintegrated over--voltage protectionvoltage protectionFast switch onFast switch on -- instead of delayed switch offinstead of delayed switch offRedundantRedundant number ofnumber of thyristorsthyristorsMinimal steady state lossesMinimal steady state losses (reactor)(reactor)Minimal MaintenanceMinimal Maintenance -- 10 h10 h per per annoanno (0.1 % ) (0.1 % )



High Voltage

SCCL - The new Solution for Power Systems

SCCL - to avoid an extremely cost-intensive complete Substation Upgrade

SCCL - The Principle is Current Limitation - not Interruption

Highlights of SCCL:Highlights of SCCL:One additional ReactorOne additional Reactor -- Replacing the Line ImpedanceReplacing the Line ImpedanceAs fast as As fast as the futurethe future HTS Fault Current LimiterHTS Fault Current LimiterNo Modification No Modification of existingof existing Protection SchemesProtection SchemesOperates onOperates on Single Phase BasisSingle Phase BasisDynamic AddDynamic Add--on available on available -- for SSR and Power Oscillationfor SSR and Power Oscillation

Benefits



High Voltage

Lessons learned:HVDC and FACTS are essential for Transmission



High Voltage

Need for Advanced Transmission Solutions

This is This is unavoidableunavoidable ... but ... but HVDC & FACTS HVDC & FACTS can support can support RecoveryRecovery

ReductionReductionof Outageof OutageTimes &Times &moremore StabilityStability

BlackoutBlackoutIncreasing Increasing

OscillationsOscillations

If there is no If there is no HVDCHVDC,, no no FACTS FACTS ......



High Voltage

Intelligent Solutions for Power Transmission

with HVDC & with HVDC &

FACTS from FACTS from

SiemensSiemens

Thank You for your Attention!

Documents

Use of High-Power Thyristor Technology for Short-Circuit