ALSTOM solution to meet new Grid Codes
for Wind Turbines
Stefan Franko
Power Conversion
March 2004March 2004March 2004
APCG / 4FKO001_00-(Grid-Code-UK).PPT
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 2
Grid Code Forum UK
Content
What is new with Grid Code requirements
ALSTOM solution for variable speed turbines
ALSTOM solution for fixed speed turbines
ALSTOM Converter for wind market application
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 3
Grid Code Forum UK
Huge growth of wind power in the last years,further increase is expected
Wind turbines have a significant impact on the grid that cannot be neglected anymore
Wind turbines have to be included into the stability analysis of the grid
Why new Grid Connection Regulations?
Mains operators demand new Grid Connection Regulations
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 4
Experience with industrial drives under rough conditions for decades, e.g. steel mills, offshore platforms
Experience with converters of all kind and sizes up to 100 MW
Experience with grid stabilisation and the control of power plants for decades, e.g. Power System Stabiliser (PSS)
More than 1000 converters for doubly and fully fed generators for wind turbines in operation
Present in several committees, e.g. FGW, VDN
Our Experience - Your advantage
Grid Code Forum UK
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 5
Grid Code Forum UK
Example: e.on Grid Code
for the high voltage grid (01.08.2003),to be observed at the grid connection point
Frequency range: 47,5 Hz - 51,5 HzVoltage tolerance: +15% / -12%Operation with 80 % grid voltagePower factor: 0.95 ind. - 0.925 cap.Voltage buffering by reactive current (Iq = IN)Ride trough capability
U/UN
100
[ % ]
15
0 3.000 t/ms
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 6
Grid Code Forum UK
Problem definition
for the wind turbines resulting from the grid connection requirements
1. Extended frequency range: 47,5 Hz - [49 Hz - 51 Hz -] 51,5 Hz
2. Extended voltage range: 80 % - [90 % -] 110 % (for permanent operation)
3. Power factor can be chosen from 100 % active to 100 % reactive current to match the demanded reactive power at the grid connection point [cos ϕ = 0,95]
4. Ride through of voltage dips down to 15 % UN[Disconnection at 80 % UN]
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 7
Grid Code Forum UK
Solution for ProWind
Solved by new system managementSolved by new system managementand software adaptationsand software adaptations!!
Solved by Hardware adaptations!Solved by Hardware adaptations!Optional, retrofit possible!Optional, retrofit possible!
1 FrequencyPoint 2 Voltage
3 Reactive power
Point 4 Voltage dip
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 8
Voltage dip without triggering of the Rotor Crowbar (RC):controlled operation, low mechanical stress
Triggering of the Rotor Crowbar:
– Ride through with maximum grid current and fastest possible return to normal operation after the voltage recovery
– Option: Disconnection of the stator and resynchronisation:reduced grid current, low mechanical stress at voltage recovery
Disconnection of the stator
Triggering of the Rotor Crowbar:
Grid Code Forum UK
Characteristics
RC
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 9
Grid Code Forum UK
Simulations , without stator disconnection
Voltage dip down to 20 % UN
t [s]
0
0.5
1
-4
-2
0
2
4
-2
0
2
0 0.1 0.2 0.3 0.4 0.5-4
-2
0
2
ugrid / uN
P / PNQ / PN
M / MN
igrid / iN
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 10
Grid Code Forum UK
Simulations , with stator disconnection
Voltage dip down to 20 % UN
0
0.5
1
-4
-2
0
2
4
-1.5
-1
-0.5
0
0.5
0 0.5 1 1.5-4
-3
-2
-1
01
t [s]
ugrid / uN
P / PNQ / PN
M / MN
igrid / iN
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 11
Grid Code Forum UK
Wind Test Bench
Transformer
10 kV
Voltage change over
1,6 MVA690 V +30 %
Tapping in 70 V steps
GeneratorConverter1,5 MW
Drive1,5 MW
M ~~
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 12
Grid Code Forum UK
Grid operators expect squirrel cage generator to behave like conventional synchronous generator:
– no switch-off during voltage dips– capacitive power supporting during voltage dips
Disadvantage of conventional compensation systems
Capacitors or conventional dynamic compensation (SVC, with TCR, thyristor controlled reactor) delivers with dipping voltage an correspondingly reduced current
Key problem Stall Turbines
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 13
Grid Code Forum UK
Contrary to conventional capacitorcan the self-commuted converter followthe desired value
Key task
Reactive current (overexc.) supporting gridENE grid codes as per 01.8.2003
0
20
40
60
80
100
0 10 20 30 40 50 60 70 80 90 100
Voltage dip [%]
Rea
ctic
ecu
rren
t (IB
/IN)
[%]
Requirement Conv. capacitor
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 14
Technical solution for fixed speed application
Grid Code Forum UK
Self-commuted converter in PWM-inverter technology– Response like a synchronous machine for grid support– „Electronic Synchronous machine (phase-shifter)“– 4-Quadrant inverter PCS: Power Conditioning System
Advantage of PCS in PWM-inverter technology– in spite of voltage dips constant reactive current output– grid support during voltage dips with PCS nominal current
ideal for WT of type „constant speed/Stall control“ – for new individual WT, for new clusters, for new wind-parks – for existing WT / cluster / wind-parks (upgrading)
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 15
PCS - Flexibility by modularity
Grid Code Forum UK
”good trade-off"
Extremum
ExtremumDe-centralallocated to each WT- "per unit" planning- de-central soft starting
Grouping "Cluster"allocated to several WT´s- "per cluster" planning- high economic viability
Centralallocated to entire wind-farm- ”unique" in planning/installation- reduced repetition effect
PCSPower Conditioning System
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 16
PCS - Flexibility by modularity - Economic viable clustering
Grid Code Forum UK
PCS -Grouping
G~
G~
G~
MV power system(e.g. 20-kV)
HV grid(e.g. 110-kV)
WT-n
WT-2
WT-1
PCS -Grouping
G~
G~
G~
WT-n
WT-2
WT-1
PCS for ”cluster-1"
PCS for ”cluster-n"
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 17
Grid Code Forum UK
WT diversity in possible groups– small, middle and large WT– small, middle and large wind-farm
Project design and engineering– Module approach for „typical“, e.g. ±1,5 Mvar; ±3 Mvar; ±6 Mvar– „per-cluster“ standard with high repetition effects– „n+1“ feature for cluster economically viable
Delivery, commissioning, project financing– shorter delivery times, shorter commissioning, lower risk– advantageous cash-flow, lower interest payments/capital bindings– simplified and more convenient balance of payments
Advantages of PCS for clustered WTs
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 18
Grid Code Forum UK
WT „stall-control“ has inductive, load dependent reactive power demand, however– Softstart and synchronising of the WT– Cosφ, controllable between 0,95 inductive/capacitive– Optional cosφ controllable in wider range– Medium voltage (e.g. 20-kV) controllable– Reactive power input/output to grid controllable
Using ALSTOM´s Power Conditioning System, the objectives can be met.
PCS Mode of operation „Production by windenergy“
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 19
Grid Code Forum UK
WT „stall-control“ is to generate reactive current into grid (e.on)
– with an conventional WT this is not possible– with conventional fixed/controllable compensation systems this is
practically not possible
Regenerative reactive current export only possible, if– large numbers of additional capacitors have to be installed, which in
normal op „Production by wind energy“ are totally useless– higher cost at low benefit = economic not viable
Using ALSTOM´s Power Conditioning System, the objectives can be met.
PCS Mode of operation „response to power system faults“
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 20
Grid Code Forum UK
Solution - Reduction of reactive power
PCS - capacitive operation
reactive power generator(under excited)
reactive power grid(reduction)
reactive power PCScapacitive/overexcited
G~
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 21
Grid Code Forum UK
Solution - Increase of reactive power
PCS - inductive operation
reactive power generator(under excited)reactive power grid
(increase)
reactive power PCSinductive/under-excited
G~
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 22
Grid Code Forum UK
Conclusion
ALSTOM Power Conversion has profound experience with wind turbines and grid stability
We provide customer oriented solutions from the turbine shaft to the grid connection
ProWind converter:– optional solution for new grid connection requirement– short-term availability, retrofit possible– low mechanical stress
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 23
ProWind - Drive Converter
Advanced technology deriving from more than 1000 installed systems
Flexible design thanks to standardised components and modules
User-friendly construction and high reliability
Space reduced by 30 %
Power range from 0,5 to 5 MW
Modular and compact drive converter for wind turbines
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 24
ProWind - Drive Converter
Standardised modules for air- or water cooling Design meets extreme environmental requirements(-25 °C to +50 °C)Protection class up to IP 54
Optional outdoor containers
Design
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 25
Each ProWind drive is fully factory tested to IEC standards including integrated system testing with the original generator Diagnostics and services– Spare parts delivery service within 24-hours for most items – Field service representatives provide emergency response– Tele-service– Customised maintenance contracts
Service-friendly construction– Identical components – Low weight and compact size – User-friendly microprocessor control unit
Operational reliability is our commitment
ProWind - Commissioning and Services
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 26
5 MW Drive System
Consisting of:– Permanent excited generator– Frequency converter– Transformer– Switchgear
Optimised for offshore applications
Worlds largest WEC located in Bremerhaven/Germany
ErectionSummer 2004
System solutions for wind energy converters
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 27
High power density due to optimised gearbox- and generator conceptMedium voltage converter and transformer in offshore-containerPermanent magnets synchronous generator
“MULTIBRID” Wind Energy Converter
5 MW Drive System
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 28
UPS
V <>
I >I >>
f <>
20 kV 6 MVA
3,0 kV
20 kV 160 kVA0,4 kV
G
5,3 MVAVR = 3,0 kV
Transformer-ContainerGrid connected Switchgear in
Tower
3 ∼50 Hz20 kV
Sea cable
Converter-Container
Overview
5 MW Drive System
M
M M
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 29
Phase leg ALSPA VDM 7000
Pulse converter GTOLiquid cooledMachine voltage: 3 kVPower: ≥ 5 MWPower factor: controllable
Medium Voltage Converter
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 30
High operational safety:– Redundant ventilation– „Worst case“ construction
Factory tests according to IEC standards including system testing with the original generator
Resulting in minimised commissioning time
Easy access and serviceability
Comprehensive service offerings
Customised maintenance contracts
Highest availability and reliability
Commissioning and Services
03.2004 APCG / 4FKO001_00-(Grid-Code-UK).PPT / FRANKO 31
Tailor made drive solutions for your wind turbine
Redundancy / high reliability
Significantly simplified installation and start-up on site due to fully tested drive system
Easy access and serviceability
Comprehensive service offerings
Your benefits at a glance
5 MW Drive System
www.alstom.com