Nysted Off-shore Windfarm

Nysted Off-shore Windfarm
Jan Havsager
Elkraft System
Independent System Operator
Overview of presentation
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History
Major system concerns
The Project
Gained experiences
Basic problems
Development and prognosis for wind turbine
capacity in East Denmark
installed wind turbine capacity
MW
3000
2500
built on shore
2000
built off-shore
1500
1000
1998 off shore plan
plangrundlag 2003
500
0
1970 1980 1990 2000 2010 2020 2030
year
¾Kraftværksplaceringer
¾400 kV net
¾132 kV net
¾Vindmølleplaceringer
Network Capacity
• Off-shore and On-shore wind turbines are
located in areas with relative weak transmission
network
• First Off-shore wind farm required
reinforcements to the 132 kV network. (Local
Bottle-necks removed)
• Future Off-shore wind farms will require
additional reinforcements if production
restrictions must be avoided
Ancillary services
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Primary control (MW/Hz)
Secondary control (MW/minute)
Voltage control (Mvar)
Fault-ride-through capability (Stability)
Voltage Quality support
– Harmonics
– Flicker
– Voltage Dips
Simulation of voltage collapse 1999
Without SVC
With SVC
Investigated alternative transmission
connection and reinforcements
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1 AC connection
1.a Dynamic compensation
1.b 400 kV overhead line
1.c 400 kV cabel
2 HVDC connection
2.a Local HVDC connection
2.b Central HVDC connection
3 HVDC reinforcement
4 combination of AC og HVDC connection
Location of the Nysted
wind farm
Near Rødsand, 10 km south of
the coast of Lolland, Denmark
Construction Projects
Key Figures of the wind farm
• Number of turbines:
72
• Contractor:
Bonus Energy
• Generator output per turbine:
2.3 MW
• Height of hub above sea level:
68.8 m
• Rotor diameter:
82.4 m
• Construction period:
2002-2003
33 kV interconnecting network
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48 km 3-core 33 kV XLPE submarine cable
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Built-in fibre optic cables for thermal monitoring and
communication
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Various capacity
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Contractor: ABB Cables
132/33 kV offshore
substation
The substation contains:
• 180 MVA triple-winding transformer 132/33/33 kV.
The transformer is oil-cooled with intensified fan
cooling
• 132 kV circuit-breaker (GIS unit)
• 33 kV busbar comprising 12 bays
• 400 kVA transformer 33/0.4 kV for local power supply
• 90 kVA diesel generator as a backup for local power
supply
• Local distribution equipment including batteries,
rectifiers and distribution boards
• Boards for SRO and measuring equipment
• Main Contractor: Bladt Industries
On shore grid connection
• 3 * 18 km single core 132 kV
XLPE
1200 mm2 Al
• Fibre optic cables for thermal
monitoring and communication
Extensions at the grid connection
point,
Radsted 132 kV substation
• 40 MVAr shunt reactor
• 132 kV Bus bar protection
• Combined fault and acquisition
recorder
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The offshore 132/33 kV
substation
Sketch of the basic
substation platform
The enclosed substation platform on site
Offshore grid connection and
reinforcements
• 22 km 3-core 132 kV
XLPE 760 mm2 Cu
submarine cable with
built-in fibre optic
cables for thermal
monitoring and
communication
• Non-magnetic sea
armouring, stainless
steel and PE
FILM
Wind turbine in general
Wind turbine concepts
Background – observed problems
• After building Nysted
Havmøllepark (NHP),
SEAS has measured
disturbing variations in the
voltage in Radsted (RAD).
• At full wind production
NHP consumes approx. 50
Mvar from RAD, giving a
voltage dip of 5-8 kV.
Radsted 132 kV, Start: 18/11-04 kl. 3:00 Local time.
White: Voltage i kV
Red: Active Power [MW]
Green: Reactive Power [Mvar]
Dynamic simulations
no SVC
SVC +/- 50 Mvar
SVC +/- 100 Mvar
Distributed temperature
measurements
Hot Spot after 2 days with high
production
Location of HOT SPOT
What is Reactive Power
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Electric Current and Magnetic Fields
Current and voltage in a reactor
Current and voltage in a Condenser
Basic proporties of the AC Grid
Relation to reactive power ?
General principle to Power systems Voltage
Control
Electric Current and Magnetic
Fields
Current flow
S
N
Seen from the side
Magnetic compass
S
Seen from above
N
Current(I) and voltage(V) in a
+
V reactor
reactor
+
U
Magnetic field
-
V
U
I
A Reactor is an electric conductor
Which is wound in loops.
If a current is flowing in the conductor, the current will circulate
around an area, limited by the
Conductor. This will create a
magnetic field, which will counteract the current.
I
tid
The voltage jumps to the maximum level, the current grows from zero,
The current follows after the voltage.
Strøm og spænding i en
kondensator
kondensator
+
U
En kondensator består
Af to elektrisk ledende plaDer placeret tæt sammen,
Men isoleret fra hinanden.
+ V I
-
V
U
I
tid
Strømmen springer straks til maksimalværdien, spændingen vokser op fra nul,
Strømmen kan siges at være foran spændingen.
Grundlæggende egenskaber i
vekselstrømsnet
Transmissionsnet
Resistans
Elforbrug
spole
spole
G
kondensatorer
Resistans
Hvad har alt det med reaktiv effekt at gøre ?
Hvad er betydningen af reaktiv effekt ?
• Den reaktive effekt er den effekt, der
lagres som magnetisk og elektrisk energi i
magnetfelterne og de elektriske felter.
• Den reaktive effekt skaber spændingsfald
og spændingsstigninger i
transmissionsnettet.
• For at kontrollere spændingerne skal man
tilføre eller udtage reaktiv effekt de rigtige
steder i transmissionsnettet
Overordnet princip for elsystemets
spændingskontrol
Formasket 400 og 132 kV net
G
Formasket 50 eller 30 kV net
10 kV radialer
Kobbelbare
Reaktive
komponenter