Study of Failure Rate Model for a Large-Scale Water Supply Network in Southern China Based on Different Diameters

2012 ◽  
Vol 260-261 ◽  
pp. 1200-1205
Author(s):  
Peng Jun Yu ◽  
Jin Xu Nie ◽  
Gang Xu ◽  
Zhi Hong Long ◽  
Zhi Hong Wang ◽  
...  
Keyword(s):  
Control Strategy ◽  
Large Scale ◽  
Southern China ◽  
Paper Analysis ◽  
Current Control ◽  
Transient Model ◽  
Grid Voltage ◽  
Doubly Fed ◽  
Grid Side ◽  
Different Diameters

This paper studies on the electromagnetic transient model of doubly-fed wind turbinegrid-side converter under the imbalanced grid condition. And on this basis, the paper analysis theimpact of doubly-fed converter when grid voltage asymmetric drop. It puts forward a dual PLL anddual current control combination of doubly-fed converter grid side control strategy. This strategyachieves grid voltage positive and negative sequence fast separation when asymmetric grid voltagedrop occur, achieves the active output power secondary fluctuate suppression under the imbalancedgrid voltage condition, avoids DC voltage rise at the fault moment and also achieves converterreactive power support under the imbalanced grid fault. The simulation and experimental resultsshow that the proposed control strategy is correct and with the application value of engineering.

Research on the Control Strategy of DFIG Grid Side Converter under Unbalanced Grid Voltage Conditions

2012 ◽  
Vol 260-261 ◽  
pp. 454-459
Author(s):  
Fei Song ◽  
Dan Zhu ◽  
Kan Tang ◽  
Xue Jing Liu
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Voltage Drop ◽  
Current Control ◽  
Transient Model ◽  
Grid Voltage ◽  
Doubly Fed ◽  
Grid Side ◽  
Grid Side Converter ◽  
The Impact

This paper studies on the electromagnetic transient model of doubly-fed wind turbine grid-side converter under the imbalanced grid condition. And on this basis, the paper analysis the impact of doubly-fed converter when grid voltage asymmetric drop. It puts forward a dual PLL and dual current control combination of doubly-fed converter grid side control strategy. This strategy achieves grid voltage positive and negative sequence fast separation when asymmetric grid voltage drop occur, achieves the active output power secondary fluctuate suppression under the imbalanced grid voltage condition, avoids DC voltage rise at the fault moment and also achieves converter reactive power support under the imbalanced grid fault. The simulation and experimental results show that the proposed control strategy is correct and with the application value of engineering

scholarly journals Research on Zero-Voltage Ride Through Control Strategy of Doubly Fed Wind Turbine

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2287
Author(s):  
Kaina Qin ◽  
Shanshan Wang ◽  
Zhongjian Kang
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Control Strategy ◽  
Large Scale ◽  
Sliding Mode ◽  
Stable Operation ◽  
Wide Range ◽  
Dc Bus ◽  
Doubly Fed ◽  
Zero Voltage

With the rapid increase in the proportion of the installed wind power capacity in the total grid capacity, the state has put forward higher and higher requirements for wind power integration into the grid, among which the most difficult requirement is the zero-voltage ride through (ZVRT) capability of the wind turbine. When the voltage drops deeply, a series of transient processes, such as serious overvoltage, overcurrent, or speed rise, will occur in the motor, which will seriously endanger the safe operation of the wind turbine itself and its control system, and cause large-scale off-grid accident of wind generator. Therefore, it is of great significance to improve the uninterrupted operation ability of the wind turbine. Doubly fed induction generator (DFIG) can achieve the best wind energy tracking control in a wide range of wind speed and has the advantage of flexible power regulation. It is widely used at present, but it is sensitive to the grid voltage. In the current study, the DFIG is taken as the research object. The transient process of the DFIG during a fault is analyzed in detail. The mechanism of the rotor overcurrent and DC bus overvoltage of the DFIG during fault is studied. Additionally, the simulation model is built in DIgSILENT. The active crowbar hardware protection circuit is put into the rotor side of the wind turbine, and the extended state observer and terminal sliding mode control are added to the grid side converter control. Through the cooperative control technology, the rotor overcurrent and DC bus overvoltage can be suppressed to realize the zero-voltage ride-through of the doubly fed wind turbine, and ensure the safe and stable operation of the wind farm. Finally, the simulation results are presented to verify the theoretical analysis and the proposed control strategy.

scholarly journals Coordinated Control of RSC and GSC for DFIG System under Harmonically Distorted Grid Considering Inter-Harmonics

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 28 ◽  
Author(s):  
Bo Pang ◽  
Hui Dai ◽  
Feng Li ◽  
Heng Nian
Keyword(s):  
Theoretical Analysis ◽  
Control Strategy ◽  
Coordinated Control ◽  
Delay Compensation ◽  
Pass Filter ◽  
Grid Connection ◽  
Distorted Grid ◽  
Negative Impacts ◽  
Doubly Fed ◽  
Grid Side

For improving the performance of a doubly fed induction generator (DFIG) system under a harmonically distorted grid, this paper proposes a coordinated control strategy which is effective for grid inter-harmonics as well as grid integer harmonics. In order to suppress the negative impacts caused by grid harmonics, including inter-harmonics, this paper introduces an additional harmonics suppression controller, which contains a Chebyshev high-pass filter and a modified lead element considering the delay compensation. The proposed controller is employed in the rotor side converter (RSC) and grid side converter (GSC). Based on the proposed harmonics suppression controller, a coordinated control strategy between RSC and GSC is developed, in which the control targets, including the sinusoidal output current, constant power, or steady generator torque, can be achieved for DFIG, while GSC is responsible for maintaining the sinusoidal total current to guarantee the power quality of the grid connection. The effectiveness of the proposed method is verified by the theoretical analysis, and the experimental results derived using a 1 kW DFIG system validate the correctness of the theoretical analysis.

The Control Strategy Study of Doubly-Fed Wind Turbine Participated in Frequency Regulation

2012 ◽  
Vol 512-515 ◽  
pp. 788-793
Author(s):  
Xiao Hua Zhou ◽  
Ming Qiang Wang ◽  
Wei Wei Zou
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Large Scale ◽  
Control Strategies ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Strategy Study ◽  
Fuzzy Control Strategy ◽  
Doubly Fed ◽  
System Frequency

Traditional decoupling control strategy of doubly-fed induction generator (DFIG) wind turbine makes little contribution to system inertia and do not participate in the system frequency control, the synchronization of large-scale wind power requires wind turbine have the ability to participate in the regulation of power system frequency. This paper adds a frequency control segment to traditional DFIG wind turbine and considers the doubly-fed wind turbine operating on the state of the super-synchronous speed, by analysis the effect of inertia and proportional control strategies, a fuzzy control strategy which combines the advantages of the former two control strategies is proposed, simulation results show that this control strategy can more effectively improve the system frequency response.

Improving Active Output Capacity of Large-Scale Wind Farm by Installation STATCOM

2012 ◽  
Vol 588-589 ◽  
pp. 574-577 ◽  
Author(s):  
Yan Juan Wu ◽  
Lin Chuan Li
Keyword(s):  
Control Strategy ◽  
Large Scale ◽  
Wind Farm ◽  
Transient Stability ◽  
Reactive Power ◽  
Feedforward Control ◽  
Wind Farms ◽  
Active Power ◽  
Utilization Efficiency ◽  
Grid Voltage

Some faults will result wind turbine generators off-grid due to low grid voltage , furthermore, large-scale wind farms tripping can result in severe system oscillation and aggravate system transient instability . In view of this, static compensator (STATCOM) is installed in the grid containing large-scale wind farm. A voltage feedforward control strategy is proposed to adjust the reactive power of STATCOM compensation and ensure that the grid voltage is quickly restored to a safe range. The mathematical model of the doubly-fed induction wind generator (DFIG) is proposed. The control strategy of DFIG uses PI control for rotor angular velocity and active power. 4-machine system simulation results show that the STATCOM reactive power compensation significantly improve output active power of large-scale wind farm satisfying transient stability, reduce the probability of the tripping, and improve the utilization efficiency of wind farms.

scholarly journals Control strategy of doubly-fed induction generator during the grid voltage swell

2019 ◽  
Vol 2019 (16) ◽  
pp. 1807-1811
Author(s):  
Zou Le ◽  
Wu Xueguang ◽  
Kou Longze ◽  
Liu Dong ◽  
Li Fangyuan ◽  
...  
Keyword(s):  
Control Strategy ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Grid Voltage ◽  
Voltage Swell ◽  
Doubly Fed
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