scholarly journals Wind farm active power dispatch for output power maximizing based on a wind turbine control strategy for load minimizing

Author(s):  
Baohua Zhang ◽  
Weihao Hu ◽  
Peng Hou ◽  
Mohsen Soltani ◽  
Zhe Chen
2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Jianxiao Zou ◽  
Junping Yao ◽  
Qingze Zou ◽  
Hongbing Xu ◽  
Zhenzhen Zhang

With more and more wind farms integrated into the power grid, the stability and security of the grid can be significantly affected by the wind-farm-generated power, due to the intermittent and volatile nature of the wind-farm-generated power. Therefore, control of the wind-farm power to meet the stability and quality requirements becomes important. Active control of wind-farm power, however, is challenging because the wind-farm output power can only be reliably predicted for a short period of time (i.e., ultrashort term power prediction), and large variations exist in the wind-turbine output power. In this paper, an optimal active power control scheme is proposed to maximize the running time of each wind turbine, and minimize the on-and/or-off switching of wind turbines, resulting in substantial reduction of wind-turbine wear and thereby, maintenance cost, and extension of wind-turbine lifetime, all together, a significant saving of operation cost of the whole wind farm. The proposed approach is illustrated by implementing it to the active power allocation of a wind-farm model in simulation.


2012 ◽  
Vol 588-589 ◽  
pp. 574-577 ◽  
Author(s):  
Yan Juan Wu ◽  
Lin Chuan Li

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.


Author(s):  
Congshan Li ◽  
Pu Zhong ◽  
Ping He ◽  
Yan Liu ◽  
Yan Fang ◽  
...  

: Two VSC-MTDC control strategies with different combinations of controllers are proposed to eliminate transient fluctuations in the DC voltage stability, resulting from a power imbalance in a VSC-MTDC connected to wind farms. First, an analysis is performed of a topological model of a VSC converter station and a VSC-MTDC, as well as of a mathematical model of a wind turbine. Then, the principles and characteristics of DC voltage slope control, constant active power control, and inner loop current control used in the VSC-MTDC are introduced. Finally, the PSCAD/EMTDC platform is used to establish an electromagnetic transient model of a wind farm connected to a parallel three-terminal VSC-HVDC. An analysis is performed for three cases of single-phase grounding faults on the rectifier and inverter sides of a converter station and of the withdrawal of the converter station on the rectifier side. Next, the fault response characteristics of VSC-MTDC are compared and analyzed. The simulation results verify the effectiveness of the two control strategies, both of which enable the system to maintain DC voltage stability and active power balance in the event of a fault. Background: The use of a VSC-MTDC to connect wind power to the grid has attracted considerable attention in recent years. A suitable VSC-MTDC control method can enable the stable operation of a power grid. Objective: The study aims to eliminate transient fluctuations in the DC voltage stability resulting from a power imbalance in a VSC-MTDC connected to a wind farm. Method: First, the topological structure and a model of a three-terminal VSC-HVDC system connected to wind farms are studied. Second, an analysis is performed of the outer loop DC voltage slope control, constant active power control and inner loop current control of the converter station of a VSC-MTDC. Two different control strategies are proposed for the parallel three-terminal VSC-HVDC system: the first is DC voltage slope control for the rectifier station and constant active power control for the inverter station, and the second is DC voltage slope control for the inverter station and constant active power for the rectifier station. Finally, a parallel three-terminal VSC-HVDC model is built based on the PSCAD/EMTDC platform and used to verify the accuracy and effectiveness of the proposed control strategy. Results: The results of simulation analysis of the faults on the rectifier and inverter sides of the system show that both strategies can restore the system to the stable operation. The effectiveness of the proposed control strategy is thus verified. Conclusion: The control strategy proposed in this paper provides a technical reference for designing a VSC-MTDC system for wind farms.


Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 530 ◽  
Author(s):  
Wei Li ◽  
Dean Kong ◽  
Qiang Xu ◽  
Xiaoyu Wang ◽  
Xiang Zhao ◽  
...  

In this paper, an industrial application-oriented wind farm automatic generation control strategy is proposed to stabilize the wind farm power output under power limitation conditions. A wind farm with 20 units that are connected beneath four transmission lines is the selected control object. First, the power-tracking dynamic characteristic of wind turbines is modeled as a first-order inertial model. Based on the wind farm topology, the wind turbines are grouped into four clusters to fully use the clusters’ smoothing effect. A method for frequency-domain aggregation and approximation is used to obtain the clusters’ power-tracking equivalent model. From the reported analysis, a model predictive control strategy is proposed in this paper to optimize the rapidity and stability of the power-tracking performance. In this method, the power set-point for the wind farm is dispatched to the clusters. Then, the active power control is distributed from the cluster to the wind turbines using the conventional proportional distribution strategy. Ultra-short-term wind speed prediction is also included in this paper to assess the real-time performance. The proposed strategy was tested using a simulated wind farm based on an industrial wind farm. Good power-tracking performance was achieved in several scenarios, and the results demonstrate that the performance markedly improved using the proposed strategy compared with the conventional strategy.


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