Nuno Taveira
ENERCON GmbH
Los códigos de red en sistemas aislados, consecuenc ia para los fabricantesGrid codes in isolated systems, consequences for ma nufacturers
Agenda
� Grid codes: new requirements
� Main topics of the grid codes for island systems
� Fault Ride Through (including Zero Volts ride through)
� Remote commutation between the controls: U / Q / cos phi
Sales - Technical Support, November 2010
ENERCON GmbH 2010 2
� Active power output control
� Wide operational ranges
� Power-frequency control
� Conclusions
Grid Codes requirementsConventional generation vrs Wind energy
Why wind farms are demanded to have so strong requi rements in certain countries or areas?
� Gradual exchange of conventional power based on big generators plants by renewable energy sources (wind, solar, biomass, waves..)
� Centralized systems are giving place
Sales - Technical Support, November 2010
ENERCON GmbH 2010 3
� Centralized systems are giving place to distributed generation (typical from renewables)
� System services provided by conventional power plants (Inertia, FRT, voltage control, primary control) must be guaranteed by the Wind turbines /Wind Farms
Grid Codes requirementsThe main topics of future requirements in Canarias
• Fault Ride Through (including Zero Volts ride through)
• Remote commutation between:
- Voltage control
- Reactive Power control
- Power factor control
Sales - Technical Support, November 2010
ENERCON GmbH 2010 4
Operation through remote connection WF �� Dispatch center
• Active power output control
• Wide operational ranges
• Power-frequency control
Grid Codes complianceFault Ride Through
• Fault Ride Through (including Zero Volts ride through)
• Remote commutation between:
- Voltage control
- Reactive Power control
Sales - Technical Support, November 2010
ENERCON GmbH 2010 5
- Power factor control
• Active power output control
• Wide operational ranges
• Power-frequency control
Grid Codes in islandsFault Ride Through – PO12.2 SEIE draft version
• During voltage dips as a result of short circuits on
the grid the Wind Farms have to remain connected
• In case of Spain (península and SEIE) the
symetrical and unsymetrical faults are distiguish
• The Zero voltage* is required (like in the 2007
Canarian tender) “el hueco canario”
Keep connected??? Yes, but is not enough…
*
Sales - Technical Support, November 2010
ENERCON GmbH 2010 6
Keep connected??? Yes, but is not enough…•The WFs are required to inject/consume a certain amount of reactive current depending on the under/ overvoltage• The WF are required to inject active current during undervoltage (mandatory injection from 0,85pu down to 0.5 pu.)
Although challenging demands ENERCON WECs fulfill these requirements!
-100%
-80%
-60%
-40%
-20%
0%
20%
40%
60%
-60% -50% -40% -30% -20% -10% 0% 10% 20% 30% 40%
∆∆∆∆U/UR
∆∆∆∆Ireactive /IR
Example from actual Grid code requirements Reactive current as a function of the Voltage dip
• The wind farm has to provide a reactive current
during faults to support the voltage at point of
connection.
• Depending on the actual voltage level the WEC
provides or absorbs dynamically reactive current.
Sales - Technical Support, November 2010
ENERCON GmbH 2010 7
-120%
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2p.u.
0 1 2 3 4s
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2p.u.
0 2 4 6s
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2p.u.
0 2 4 6s
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2p.u.
0 2 4 6s
Black Curve: Voltage Blue Curve: Reactive Current
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25p.u.
0 3 6 9s
Grid Codes complianceRemote commutation between controls: U-Q-cos φ
• Fault Ride Through (including Zero Volts ride through)
• Remote commutation between:
- Voltage control
- Reactive Power control
Sales - Technical Support, November 2010
ENERCON GmbH 2010 8
- Power factor control
• Active power output control
• Wide operational ranges
• Power-frequency control
1. Grid Voltage jumps (caused
by externalswitching action)
Voltage returns into the
dead band
• Remote commutation between these controls:
• Voltage droop control
• Reactive power control
• Power factor control
Grid voltage jumps (by external switching action)
Voltage returns into the deadband
Grid Codes complianceRemote commutation between controls: U-Q-cos φ
Sales - Technical Support, November 2010
ENERCON GmbH 2010 9
3. WF maximises Qabs within ~600ms
Changing power factor setpointfrom 0.95cap to 1 to lower thevoltage by dispatch center
WF maximizes Qabs within ~600ms
Voltage control as done by conventional power plants
� Basic performance:Full reactive power capability between 20% and 100% rated active power output
� Q+ Option: Optional extension of the range
� STATCOM Option:Reactive power is fully independent available from the wind
P
Grid Codes complianceRemote commutation between controls: U-Q-cos φ
Sales - Technical Support, November 2010
ENERCON GmbH 2010 10
Q
WEC - Configuration FT FTQ FTS FTQS
Q+ Option X X
STATCOM Option X X
Reactive Power capability of the our WECs is the basis for the Voltage control on Wind Farms
Grid Codes requirementsRemote commutation between controls:
• Fault Ride Through (including Zero Volts ride through)
• Remote commutation between:
- Voltage control
- Reactive Power control
Sales - Technical Support, November 2010
ENERCON GmbH 2010 11
- Power factor control
• Active power output control
• Wide operational ranges
• Power-frequency control
Example: Wind farm Killybegs with 6 x E-70 connected to 38kV in Rep. of Ireland
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0MW
• Any maximum active
power set value
0…100%Prated is
possible
Grid Codes requirementsActive power control + Power gradient adjustment
Sales - Technical Support, November 2010
ENERCON GmbH 2010 12
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10:30 10:40 10:50 11:00 11:10 11:20 11:30 11:40 11:50 12:00 12:10
2.10.08
h:m
1 MW/min ← │→ 4 MW/minas set active power gradient
• No time limitation
• Active power
gradient adjustable
Grid Codes requirementsPower-frequency control (primary control)
• Fault Ride Through (including Zero Volts ride through)
• Remote commutation between:
- Voltage control
- Reactive Power control
Sales - Technical Support, November 2010
ENERCON GmbH 2010 13
- Power factor control
• Active power output control
• Wide operational ranges
• Power-frequency control
Frequency f [Hz]
fR + 7 Hz
With UVRT Option:Up to 5 seconds per event
Normal continuous operation
max. 60
sec.
With UVRT Option:Up to 5 seconds per event
Grid Codes requirementsOperational ranges
Sales - Technical Support, November 2010
ENERCON GmbH 2010 14
fR
fR + 7 Hz
fR - 7 Hz
100%
Voltage U [% UR]
110% 120%90%80% 145%
Grid Codes requirementsPower-frequency control (primary control)
• Fault Ride Through (including Zero Volts ride through)
• Remote commutation between:
- Voltage control
- Reactive Power control
Sales - Technical Support, November 2010
ENERCON GmbH 2010 15
- Power factor control
• Active power output control
• Wide operational ranges
• Power-frequency control
Grid Codes requirementsPower-frequency control (primary control)
• Adjustable gain (15<k<50)
• Real reserve of power in each moment must be communicated to the dispatch center
• Deload of 5% (B to A) under dispatch center setpoint by System operator (Rep. of Ireland)
Sales - Technical Support, November 2010
ENERCON GmbH 2010 16
Today almost all renew. energy generation isbased (partly) on inverters.
Grid frequency is decoupled from the rotatingfrequency of the machine.
Important difference to conventionalgeneration (where it is physically linked).
Grid Codes requirementsPower-frequency control (primary control)
f > f nf < f n
� Over frequency
• easy to be implemented
• economical consequences are
negligible
� Underfrequency
• Performance achieved by pitching
Sales - Technical Support, November 2010
ENERCON GmbH 2010 17
wind speed
Prated
Prated–x%Preserve as percentage of Pactual
• Performance achieved by pitching
WEC blades prior to the incident.
• Activated based on prior signal
from control centre + WEC
frequency measurement
• Online communication to WF
necessary (e.g. OPC)
• Economical consequences : if
used as permanent reserve!
• Kinetic energy from rotating mass delivered to the grid
• Important in order to limit the rate of change of frequency following a sudden generation loss
Grid Codes requirementsPower-frequency control (primary control)
Sales - Technical Support, November 2010
ENERCON GmbH 2010 18
• Inertia response and primary control will be key issues the security of the systemand the continuous grid integration of Wind Energy.
• PO12.2 draft requirements are the highest we know in the world regarding thissubject!
Grid Codes requirementsConclusions
� High wind energy penetration in isolated grid demands a huge R&D effort by the manufacturers
� Isolated grids means sensible grids where the short circuit power ratio is typically small
� Power quality issues have also an important role and have to be analyzed case by case
� Harmonization of the grid codes, also in isolated
Sales - Technical Support, November 2010
ENERCON GmbH 2010 19
����
� Harmonization of the grid codes, also in isolated grids, will permit the development of the solutions by the manufacturers with a global appliance
� ENERCON is prepared to be a technological partner in Canarias in order to fulfill the targets of the Renewable energy plan for this and next decades.
Gracias por vuestra atención!
Sales - Technical Support, November 2010
ENERCON GmbH 2010 20