Voltage and Power Factor Control for Wind Generation

1
Voltage and Power Factor Control for Wind
Generation

• Reigh Walling
• GE Energy

2
Voltage and Power Factor Control

• Wind generation is inherently variable
• Diurnal variations
• Erratic short-term variations (gusting)
• Without mitigation, can create unacceptable
  voltage variations on distribution interconnects
• Smaller wind plants less diversity
• Low X/R ratio more ?V per ?P
• Voltage issues
• Customer complaints
• Wear-out of step voltage regulators, capacitor
  switches

3
Comparison of Technologies

• Induction generators (fixed and variable R)
• No inherent vernier voltage regulation capability
• Supplemental equipment added when required
• Double-fed asynchronous generators
• Fully variable, high-speed Q, pf, or Vreg
  response
• Full conversion with VSI
• Fully variable, high-speed Q, pf, or Vreg response

4
Induction Wind Generators

• Switched capacitors often used to meet pf range
  requirements
• Smooth regulation requires SVC, STATCOM, etc.

5
Double-Fed Asynch Generators

• Supply or absorb VARs, as desired
• High-speed controllability
• Supplemental devices are not needed

6
Voltage Performance Comparison

• Flicker Induction Pst 0.07, DFAG Pst 0.008

7
Actual Performance Measurements

• Wind plant using GE 1.5 MW turbines (DFAG)
• GE Wind Farm Management System

8
Conclusions

• Voltage variation and flicker are significant for
  wind interconnection to distribution
• Ability to mitigate impact depends greatly on
  wind generation technology
• Fast V, Q, or pf regulation easily available with
  DFAG and full conversion
• Should vernier pf or voltage control be required?
• Should tariffs allow payments to wind generator
  for ancillary voltage regulation service?