Review Article

A Condensed Introduction to the Doubly Fed Induction Generator Wind Energy Conversion Systems

Table 1

DFIG WECS internal faults, their effects, and proposed solutions.

Component affectedEffectCausesRiskSolutions

TurbineBlade fractureExcessive loading from wind gusts or icingBlade pieces and dislodged ice flying off risking damage to other turbines and personnelEmergency shutdown in high gust or ice situations
Deicing systems incorporated in rotor blades
Lightning strikeStrikes by lightningFireLightning earthing system incorporated in rotor blade
Hydraulic failureControl system malfunction, environmental degradationLoss of timely control
Fire from leaking oil
Timely preventive maintenance

GearboxGearbox failureInsufficient lubricationWorn or fractured gears,
fire
Use of sufficient and correct high quality lubricants
Sufficient lubricant cooling system

GeneratorWindings open circuit,
winding insulation failure
High operating temperatures,
transient voltages and currents
Reduced or stoppage of power productionRegulation of voltages and currents to ensure stable operating temperatures

PECSemiconductor device failure
Failure of bond wire connection
Thermal cyclingOutput power fluctuationsControl that reduces thermal variations
DC-link capacitor failuresVoltage fluctuations,
harmonic currents
Reduced output power,
increased fluctuations in output currents
Control that reduces voltage variations across the capacitor