nuno taveira enercon - · pdf filenuno taveira enercon gmbh los códigos de red en...

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

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� 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


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� 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


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Operation through remote connection WF �� Dispatch center

• Active power output control

• Wide operational ranges

• Power-frequency control

Grid Codes complianceFault Ride Through



- Voltage control



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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…

*


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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.


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-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



- Voltage control



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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



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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



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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:



- Voltage 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



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)



- Voltage 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



fR

fR + 7 Hz

fR - 7 Hz

100%

Voltage U [% UR]

110% 120%90%80% 145%




- Voltage 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)



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).


f > f nf < f n

� Over frequency

• easy to be implemented

• economical consequences are

negligible

� Underfrequency

• Performance achieved by pitching



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




• 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



��

� 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!



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