power link universal systems - technology€¦ · power link universal systems simadyn d original...

Power Transmission and Distribution EV-H2_01.98- 1

HVDC PLUSPower Link Universal Systems

EV-H2_01.98-2



HVDC PLUSPower Link Universal SystemsVSC based DC Transmission

- Basic Principle and Applications- Operating Diagram

- Converters- Cable- Control and Protection

!

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Voltage Sourced ConvertersMajor Components

%& #

"

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Voltage Sourced ConvertersTwo Level VSC



Voltage Sourced ConverterTwo Level VSC (Phase Module)

+

–

+

–

ϑ

Vd

2

Vd

2

Vd

2

+

–

Vd

2

VacVac



Voltage Sourced ConvertersBasics

'=IpN + j IqN'=IpN + j IqN

Transformerratio

(1

&RQ

1

capacitive inductive

INq

INp

&RQ

(1

∆

∆

(1

&RQ

∆'

(1

&RQ ∆'

'

'

&RQ

1

∆

'

G

jXT



STATCOM SSSC

UPFC HVDC PLUS - Back to Back- Long Distance

Voltage Sourced ConvertersApplications



Voltage Sourced ConvertersOperating Diagram (I)

λ=

−1.0 1.0−0.8 0.8−0.6 0.6

−0.4 0.4−0.2 0.20

-1.0 1.0

1.0

α =

1 e−1 0.8e−1 0.6e−1 0.4e−1 0.2e−11 0.2e+1 0.4ex+1 0.6e+1 0.8e+1 e+

arcsin(e )

s =1.0 pu

p [pu]

q [pu]inductive

q [pu]capacitive

9

,

,

,

9 ∆9

Re

1S

1

FRQ

1T

φα

N

x

x

x

x

x

x

x

x

x

x

N

N

N

( )

( )( )

pex

qex

N

N

=

=

α

λ α

sin

1 - cos1

λ

-1.0

vN=1.0 pu

2N

nTTx

V

SXe =

N

con

’VV=λ



Voltage Sourced ConvertersOperating Diagram (II)

SDEVRUEHGLQSX

TFDSDFLWLYHLQSX

TLQGXFWLYHLQSX

SIHGLQSX

))

SDEVRUEHGLQSX

TFDSDFLWLYHLQSX

TLQGXFWLYHLQSX

SIHGLQSX

))&& " "



Voltage Sourced ConvertersThree Level VSC



Voltage Sourced ConverterThree Level VSC (Phase Module)

–

+

MM

+

–

–

+

M

ϑ

Vd

2

Vd

2

Vd

2

Vd

2Vac Vac



Valve Technology2-Level vs. 3-Level Converter (I)

** +*+*

&

Harmonics (THD) 100 % approx. 50 %

du/dt 100 % 50 %

"Valve Modules 1 type 3 different types

(extern, intern, mid-point)

Construction compact less compact(mid-point clamping)

VSC standard special control algorithms(mid-point potential)



Valve Technology2-Level vs. 3-Level Converter (II)

** +*+*

,!" smaller larger

100 % 90 %

' smaller larger



*-'./0'1

VDRM 4500 V(6500 V)

2 "

vmax 2800 Vripple imax n.a.(3360 Vripple)

Vmax 2500 Vaverage Imax(ph) 800 ARMS *)(3000 Vaverage)

"" #"!"

*) switching frequency 750 Hz (1000 Hz)

VSC TechnologyIGBT

ITQRM ~3000 A



gradingcircuit

gradingcircuit

gradingcircuit

gradingcircuit

Fibre Optics Interface

Valve Management System

Main Control

GU GU GU GU

Valve TechnologySeries Connection of IGBT



!3""#'./*##"" Protection of Equipment

,)"" )""'* Safe Operation of Diodes during external Faults High Mechanical Robustness of Semiconductor Housings Superior Performance of Fast Diodes compared to

Reverse Conducting IGBT

& ." Control of Voltage Sharing of Series connected IGBTs Overvoltage Protection of IGBTs Current Limiting Functions

Valve TechnologyMain Design Features of Converters (1)



!" "4 "

,"#,"

#

5 "

##""65"3 "*#"

" #" "

#)*! ! "# high Fire Resistance, Reliability and Seismic Robustness

"#) "5"""

Valve TechnologyMain Design Features of Converters (2)



HVDC plusDC Cable Technology 200 MW



7!

Event PrinterTFR Printer

TFR Master Station Human-Machine-Interface

Router

Control Substation

Converter Control &Protection

SER

ConverterTransformerProtection

I/O Unit

Transient FaultRecorder (TFR)

Converter

GU GU

DischargeCircuit

GU

BreakingResistor

GPS ControlledMasterclock

I/O Unit I/O Unit

Auxiliaries, Switch Gear

Control & ProtectionControl and Protection Hierarchy



6,0$'<1'

Subrack

Processorboards

Buffer memoryboards

Input/outputboards

Communicationboards

Function packages

System software

Memory sub-modules

Communicationpartners

Assembledcables

Interfaceboards

Control & ProtectionControl System Simadyn D Hardware & Software



SIMADYN D

Original Hardware

EMTDC

Workstation

Real Time Simulator

(TNA)

Digital off-lineSimulation(EMTDC)

#)""" ","/-# '&82

Control & ProtectionControl Design and Testing



!



200 MW ExampleCalculation Scheme

Id = 714 A DC Cable and associatedTransmission Losses

Bipole, 2 VSC per pole)* Vd = ± 140 kV

m = 0.8

+ 5 % System Voltage~ 1.5 % DC Voltage Drop~ 5 % Dynamic Control Margin~ 3.5 % Tolerances + Reserve(TAP-Changer not considered)

*

VC = 87.3 kV

), cosφN = 0.909cap

SConv = 236 MVA

#-' ! uk = 0.15

total

&*

# 5 V2n = 81.5 kV

"'



200 MW ExampleDesign Point

7UDQVIRUPHU

6E 110.0 MVA 5GF 2.05 Ω 6E 110.0 MVAH[ 0.15 pu H[ 0.15 puHU 0.0000 pu HU 0.0000 pu

4XDQWLWLHVDW'HVLJQ3RLQW

Y1 1.00 pu 3G 99.99 MW 3G 98.94 MW Y1 1.00 puWDS 0.00 % 9G 140.0 kV 9G 138.5 kV WDS 0.00 %P 0.800 pu ,G 714.21 A P 0.808 pu

φ -24.63 DEG φ -155.37 DEGFRVφ 0.9090 pu FRVφ -0.9090 pu

λ 1.0712 λ 1.0704α 7.3 DEG α -7.24 DEG

9& 87.3 kV 9& 87.3 kV91Q 81.5 kV 91Q 81.5 kV

, 779.1 A , 770.8 A

31 100.0 MW 31 -98.9 MW41 -45.8 Mvar 41 -45.4 Mvar

3& 100.0 MW 3& -98.9 MW4& -62.3 Mvar 4& -61.5 Mvar6& 117.8 MVA 6& 116.5 MVA

(TXLYDOHQW'LDJUDP

VC1VN1

α1

Sb1

ex1, er1

tap1

VN2

α2

VC2

Sb2

ex2, er2

tap2

SN1

φN1

Pd1

SC1

φC1

Pd2

SC2

φC2

SN2

φN2Rdc

Vd1

Vd2m1 m2



200 MW ExampleMain Circuit Diagram

I21,S21,

V21

S11,cosφ11

V1N1

Vd

Pd 200 MWVd 140 kVId 714 A

Id

V1N1 400 kVV21 81.5 kVS11 2 x 110. MVAcosφ11 0.909cap

I21 2 x 779 AS21 2 x 118 MVA

STrafo1, ex1

STrafo1 220 MVAex1 0.15

V1N2

Vd

I22,S22,

V22

S12,cosφ12

STrafo2, ex2

V1N2 400 kVV22 81.5 kVS12 2 x 110.0 MVAcosφ12 0.909cap

I22 2 x 779 AS22 2 x 118 MVA

STrafo2 220 MVAex2 0.15



/-/-

" ""

&79

Connection to weak or isolated SystemsCoupling of asynchronous AC systemsUninterruptable Power SupplyIncreasement of Transmission Capacity

Sea cable transmission for Offshore SystemsLong distance transmission with Cable / OHLCost effective solution with „PE-extruded cable“The only solution for connecting remote passive loads

Dynamic Reactive Power CompensationDynamic Voltage ControlConstant Current CharacteristicsCompact DesignImprovement of Power Quality / Flickercompensation

100 MW per Converter110 MVA per Converter140 kV DC per Converter730 A DC per Converter

200 MW 2 Converters220 MVA 2 Converters+/-140 kV DC 2 Converters730 A DC 2 Converters

Ind./ Cap. Reactive Power220 Mvar 2 Converters140 kV DC 2 Converters

DC Power Transmission with VSC



"#



Valve TechnologyIGBT Converter - Protection

" ""+

0

−

!! "" "

Special control algorithms

DC Chopper

Discharging device and converter trip

" ""

Special control algorithms

Peak current controlusing high transientswitching frequency (>1 kHz)

Converter trip



Transient StudyCharacteristic Faults (Two Level VSC)

)

)

)

)

)

)

)

)



Transient StudyFault F5, Equivalent Circuit



Transient StudyFault F5, Currents



" " !



Station DesignLC Low-Pass Filter

"":"

jωLF

-j

RF

;GωCF

1VVSC VT

lg(ω)

lg(|G(jω)|)G(jω)=

VT

VVSC

&!

" ,:5!#)*,"100 1 10

31 10

41 10

4

1 103

0.01

0.1

1

Vvsc(jw) [pu]n

1.0



"

"



VSCRequirements on Station Design (I)

*IEEE 519, Cigré Guides- National Standards

!"""" ""&* 0Q<=>-1*'ndividual Voltage Distortion Dν: 1.0 %- Total Voltage Distortion (THD): 1.5 %- Telephone Interference Factor (TIF): 40 *)

""" "?1- IT product: 25000

" "" "" "

1

50

2

2

V

VTHD

∑=ν

ν

=

( )1

N

2

2

V

WVTIF

∑=ν

νν

=

( )∑=ν

νν=N

1

2WIIT

*) different practice of local suppliers



VSCRequirements on Station Design (II)

- Loss Evaluation

' - Component Costs

!- Foot print- Number of Components- Relocatability

""&!&!



VSCHarmonic Performance Study (I)

Calculation of Equivalent Source representing Station Topology

DC Voltage Ripple

Tolerance of Components

Unbalance operating Conditions of VSC

Control Requirements

:"#:"#""

Calculation of System Impedance as seen from PCC (system load, generation, system topology, outage and emergency conditions)

Determination of Equivalent Impedance areas

' ! ' !



VSCHarmonic Performance Study (II)

,""- System Frequency Deviation- Initial Mistuning due to Manufacturing Tolerances- Influence of Temperature- Change of Capacitance due to Loss of Capacitor Windings

"#"""#""



VSCHarmonics on AC Side

Im

Re

Rmin Rmax

ZN

ind

cap

Zeq

ZNVeq VN

PCCAC System

ZF

TransformerVSC

ZT

FT

FVSCeq

TF

TFeq

ZZZ

VV

ZZZZ

Z

+=

+=

VVSC



2 Level VSCVoltage and Current Waveshapes

-125,0

-75,0

-25,0

25,0

75,0

125,0

2,0ϑ/π

9FRQLQN9

)RXULHU$QDO\VLVRI9FRQLQ

0,0

10,0

20,0

30,0

5 7 11 13 17 19 23 25 29 31 35 37 41 43 47 49

)RXULHU$QDO\VLVRI,FRQLQ

0,0

10,0

20,0

30,0

5 7 11 13 17 19 23 25 29 31 35 37 41 43 47 49

-1,5

-1,0

-0,5

0,0

0,5

1,0

1,5

0,5 1,0 1,5ϑ/π

,LQN$

#V =@#1G =A-

$B' CB&

φ1 $@@FDSN =DE

#V =@#1G =A-

$B' CB&

φ1 $@@FDSN =DE

2,0



Zeq

Iν eq

33

R’ = 0.0366 Ω/kmL’ = 0.23 mH/kmC’ = 0.32 µFl = 125 km

ν

Cd Cd

VSCHarmonics on DC Side

!"!"

Cd = 50 µF

1 10 1000.1

1

10

100

Zeq



$

* !"*



LCC HVDC vs. HVDC PLUSBasic Circuit Diagram

LCC HVDC HVDC PLUS

) " Thyristors GTO or IGCT or IGBT,and Diodes

Thyristor Bridges Voltage Sourced Converters



LCC HVDC HVDC PLUS

reactive power demand depends on active power

filter- and C-banksrequired (Q ca. 50% P)

LCC HVDC vs. HVDC PLUSPower Diagram (Converter+Transformer)

Q capacitive

independent active and reactive power control

capacitive as well as inductive reactive power

P

Q inductive

Q capacitive

P

Q inductive



LCC HVDC HVDC PLUS

)!

*!

""":"

)""#:#!) "

LCC HVDC vs. HVDC PLUSMain Features

20 .. 1500 MW

± 50 .. 500 kV

min 2 .. 3 xtransmitted power

system frequency

20 .. 100 MW

± 50 .. 150 kV

no particularrequirements

depends onconverter technology

up to kHz-range(Harmonic

optimization possible)



LCC HVDC HVDC PLUS

LCC HVDC vs. HVDC PLUSApplications today

OHL Transmission of high powerover long distances

Coupling of asynchronous systems

Sea cable

Load flow control

Multi terminal HVDC

All LCC HVDC applicationsin the lower and middle

power range

Feeding islanded systemswith small or without any

local generation

Wind parksOil- and Gas platforms

MinesRailway supplies

Long distance transmissionBack to Back



LCC HVDC vs. HVDC PLUSMulti Terminal HVDC

LCC HVDC HVDC PLUS

Power reversal requires change of DC voltage polarity

Sub terminals with additional Circuit Breakers and

Symmetric insulation to ground

Fixed DC voltage polarity

No particular requirements for sub terminals



LCC HVDC vs. HVDC PLUSFilters and Reactive Power Compensation

LCC HVDC HVDC PLUS

," *3-," *3-

filter- and C-banks switched according to Q-management

large filter unitsΣQF ca. 50% P

restricted Q-Control

filters normally connected

filter size determined by harmonic performance

Q control independent from P

Compensation in discrete steps

Breaker switched

DOV ~ Bank Size

Stepless compensation

Less filter components

Dynamic voltage control

'# "



LCC HVDC vs. HVDC PLUSDesign Aspects (Dynamic Over Voltages)

LCC HVDC HVDC PLUS

5F" 5F"

'# "

Higher DOV due tolarger capacitive reactive power

Higher Component Rating, e.g.:

Smaller DOV mainly due to loss of Active Power

• Circuit Breakers (capacitive switching)• Valves

System Stability

Economic System Design

Less Impact on Transmission System



LCC HVDC vs. HVDC PLUSDesign Aspects (Transient Over Voltage Protection)

LCC HVDC HVDC PLUS

31 5

64 2

Valve Arrester

Valve voltagelimited by valve arrester

Valve voltage limitedby DC capacitor and DC chopper

No valve arresters

C

DCChopper

)"" "")"" ""

Lσ Lσ

Lsmooth

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