Grid Stability Enhancement by LVRT Retrofitting of Existing Wind - - PowerPoint PPT Presentation

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Grid Stability Enhancement by LVRT Retrofitting of Existing Wind - - PowerPoint PPT Presentation

Jun 07, 2023 227 likes •351 views

Grid Stability Enhancement by LVRT Retrofitting of Existing Wind and Solar Power Plants Kristoffer Qvist Nielsen Vice President Global R&D, KK Wind Solutions A/S 1 Contents 1. Introduction 2. Grid codes: why grid codes 3. Impact on grid

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Grid Stability Enhancement by LVRT Retrofitting of Existing Wind and Solar Power Plants

Kristoffer Qvist Nielsen Vice President Global R&D, KK Wind Solutions A/S

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Contents

  • 1. Introduction
  • 2. Grid codes: why grid codes
  • 3. Impact on grid stability
  • 4. Possible solutions
  • 5. Conclusions
  • 6. Acknowledgments

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Specialised systems supplier

for wind power solutions Years of experience

Building on more than 35 years of experience, KK Wind Solutions is a strong partner in electrical systems for wind turbines

+35

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Grid Code regulation for wind

Grid code determines how a generator or a customer load should react to a grid disturbance, with its objective being secure and stable operation of power system

Grid code in the past

  • Old technology, limited controllability

and no observability

  • Allowed simple ON/OFF operation

Impact at higher peneteration

  • A severe fault in the grid can lead to
  • utage of significant wind power

generation, potentially leading to a blackout

  • Due to a sudden frequency event,

generation of as high as 50% can trip

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Time(s) V(pu) 0.5 0.4 0.3 0.2 0.1 1.0 2 3 0.9 0.8 0.7 0.6 1.0 0.5 1.5 2.5 WTG may disconnect fault Dynamic reactive power compensation Steady state operation

LVRT Requirement

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Impact on grid stability

A Danish Case Study

4 4.5 5 5.5 6 6.5 7 7.5 0.2 0.4 0.6 0.8 1 Time (sec) Voltage (pu) Fault at Vester Hassing substation

Onshore capacity per technology Impact on grid security

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Possible solutions

to address diminishing reactive power

  • 1. Must run conventional power

plants (interim measure)

  • Short circuit power
  • Dynamic voltage control
  • Reactive power consumption from old wind

turbines and commutation of HVDC LCC

  • Continuous voltage control

(Active power reserves are bought in separate markets and do not give rise to must-run)

Source: Energinet.dk (Danish TSO)

Must-run is costly

  • 2. Synchronous condensers

(new and refurbished)

  • 3. FACTS devices (STATCOM, SVC etc)
  • 4. More stringent grid code regulation
  • 5. Retrofitting of wind turbines
  • Help in LVRT grid code compliance
  • Dynamic reactive power support
  • Ancillary services
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Retrofitting of wind turbines

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DFIG/ SCIG Transformer

Blades/Drivetrain Wind Turbine

Retrofit Unit Grid

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Dynamic voltage stability

considering dynamic reactive power compensation

4 4.5 5 5.5 6 6.5 7 7.5 0.5 0.6 0.7 0.8 0.9 1 1.1 Time (sec) Voltage (pu) Fault at Vester Hassing substation

4 4.5 5 5.5 6 6.5 7 7.5 0.2 0.4 0.6 0.8 1 Time (sec) Voltage (pu) Fault at Vester Hassing substation
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Conclusions

Wind integration leads to diminishing sources of dynamic reactive power in the grid thus voltage instability/insecurity Retrofitting of wind turbines can be a potential cost effective solution to address the grid stability issue by:

  • Grid code compliance of wind turbines, particularly old ones
  • Supplying dynamic reactive power beyond grid code requirement
  • Supplying grid support ancillary services (steady state and dynamic reactive

power)

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Thank you for your attention

Learn more at kkwindsolutions.com

Acknowledgements:

Zakir Rather (IIT Bombay); Bjørn Rannestad, Kenneth Damm Hansen, Rene Balle (KK Wind Solutions); Flemming Abrahamsen (PowerCon) Energinet.dk (Danish TSO); Aalborg University Denmark; ALSTOM GRID (UK)