Low-frequency oscillations of wind power systems caused by doubly-fed induction generators

2017 ◽  
Vol 104 ◽  
pp. 129-138 ◽  
Author(s):  
Shenghu Li
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Low Frequency ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Low Frequency Oscillations ◽  
Wind Power Systems ◽  
Doubly Fed

Operation Characteristics of Zone 3 Distance Protection in Wind Power Systems with Fixed-Speed Induction Generators

2011 ◽  
Vol 12 (4) ◽  
Author(s):  
Shenghu Li
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Reactive Power ◽  
Flow Analysis ◽  
Load Flow ◽  
Synchronous Generators ◽  
Induction Generators ◽  
Load Flow Analysis ◽  
Wind Power Systems ◽  
Operation Characteristics

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.

A Novel Performance Enhancement Scheme for Doubly-Fed Induction Generator-Based Wind Power Systems under Voltage Sags and Swells

2017 ◽  
Vol 18 (4) ◽  
Author(s):  
Tapash Das ◽  
Jingxin Zhang ◽  
Hemanshu Pota
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Power Management ◽  
Reactive Power ◽  
Performance Enhancement ◽  
Protection System ◽  
Voltage Sags ◽  
Grid Voltage ◽  
Wind Power Systems ◽  
Doubly Fed

AbstractWind power is a major contributor in the renewable energy sector but it faces some issues regarding modern grid-code compliance. Popular wind power systems based on Doubly-Fed Induction Generators (DFIG) need additional protection under grid voltage disturbances. They also need to support the grid voltage under such transient occurrences. This paper presents a novel performance enhancement scheme for DFIGs subjected to symmetrical and asymmetrical voltage sags and swells at the Point of Common Coupling (PCC). The scheme comprises a protection system and a reactive power management system working simultaneously under the command of a supervisory control system. The protection system protects the DFIG converter by limiting the overcurrent in the Rotor Side Converter (RSC) of the DFIG and keeping the dc-link capacitor voltage within an acceptable range; whereas, the reactive power management supports the grid voltage by either injecting or absorbing reactive power to reduce the magnitude of voltage sags and swells. It is found that the performance of the DFIG wind generation system improves significantly under the proposed scheme. A grid-connected 9-MW DFIG wind farm is used for simulation in MATLAB/Simscape Power Systems.

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