Power System Stabiliser Capability of Offshore Wind Power Plants

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• Power System Stabiliser Capability of Offshore
  Wind Power Plants
• Copenhagen, 16th April 2012
• José Luis Domínguez-García
• Oriol Gomis-Bellmunt
• Fernando Bianchi
• Andreas Sumper
• Antoni Sudrià-Andreu

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Overview
Introduction Power system stability
background Objectives Power System
Stabiliser for Wind Turbine System
simulations Comparison of different PSS
schemes Effect of the cable length on
the PSS capability Conclusions
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Power system stability background
- Rotor angle stability ? maintain or restore the
equilibrium between the electromagnetic torque
and the mechanical torque. - Small Signal
stability ? A power system under a small
disturbance is considered in small signal
stability. A small disturbance can be, for
example, minor changes in load or in generation
on the power system.
- Inter-area modes 0.1 0.7 Hz - Local or
Intra-area modes 0.7- 2 Hz
Problem solved by PSS
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Data in GW
Objectives
Wind Power has rapidly increased its penetration
to power systems reducing the global inertia of
the system.
Data in MW
Source Wind in Power (2012) EWEA
Offshore is growing faster in the last years.
Source Wind in Power (2012) EWEA
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Objectives

• TSO are requiring some support,
• Fault Ride Through
• Reactive Power regulation
• Frequency Support
• Damp Power System Oscillations (In a Future)

Since Offshore Wind Power Plants are far from the
shore and Wind Power are connected far from
conventional generation. OWPP can only affect
to inter-area oscillation modes
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Objectives
Wind Power neither engage nor induce oscillation
modes to power systems, because of their
technologies both FSWT and VSWT.
FSWT ? Can contribute with their inertia.
(Limited Regulation) VSWT ? Can regulate the
power delivered by the converter.
OWPP ? Communication required (to any signal
non-local)
OWPP PSS controller with using local signals
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Power System Stabiliser for Wind Turbine
Conventional PSS scheme for Synchronous machines
Inputs Any signal affected by the
oscillation. - Active Power, - Frequency, -
Angle synch. generators - Voltages
Outputs Any signal capable to vary the power
flow of the power system - Active Power on the
WT - Reactive Power on the WT - Voltage on WT
terminal or CCP
Simplifications WT does not need to fix exactly
the phase of the Synch. Generators because it
affects the power flows.
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Power System Stabiliser for Wind Turbine
Input OWPP terminal voltage ? Local Signal No
WAMS communications required
Output Active Power and/or Reactive Power
reference of the OWPP
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Power System Stabiliser for Wind Turbine
Parameter Design
?m 0.1
0.1-1.5Hz
Band Pass Filter
?wh 2
Kp 104
Proportional Controller
Designed to obtain good response
Kq -105
?xmin -0.15 p.u
Limiter
For all the controllers
?xmax 0.15 p.u
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System under study
OWPP ? Aggregate model 2 synchronous generation
areas 2 large tie-lines connecting areas OWPP
connected to 1 tie-line FAULT ? Three-Phase
fault in 1 of the connection tie-lines with the
following line disconnection
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Case I Comparison of different PSS schemes
Assuming a constant location of the OWPP,
different PSS schemes have been compared
Active Power flowing among areas
Voltage mag. at the OWPP terminal
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Case II Effect of the cable length on the PSS
capability
Assuming a the same PSS scheme on the OWPP
(PQ-PSS), under various OWPP cable connection
length
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Conclusions

• PSS controllers have shown promising damping
  properties
• PQ PSS presented the best damping behaviour
• The length of the cable reduces the
  observability of the oscillation
• Even in case of long cable, OWPP-PSS provides
  satisfactory damping capability
• PSS schemes without communications can provide
  good damping to the system, even being far away
  from the point of interaction

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Thank you for your attention! Questions?