scholarly journals An Intelligent Control Scheme for DFIG Wind Farm to Control the Voltage Fluctuations

Author(s):  
Bharath. M

<p>In this project we investigates the control of doubly-fed induction generator (DFIG) based wind farms for compensating voltage fluctuations in weak networks. Under an unbalanced power grid voltage conditions, the DFIG’s stator side active power, reactive power, and electromagnetic torque will generate twice-multiplied frequency pulse quantities. The proposed control methodology exploits the potential of the series-DFIG scheme to avoid that grid voltage unbalances compromise the machine operation, and to compensate voltage unbalances at the point of common coupling (PCC), preventing adverse effects on loads connected next to the PCC. The modeling of the system has been discussed and also the system parameters are plotted. MATLAB Simulink has been used as the tool to evaluate the system. The grid parameter variations are also discussed.</p>

2021 ◽  
Vol 4 (2) ◽  
pp. 33
Author(s):  
Jannatul Mawa Akanto ◽  
Md. Rifat Hazari ◽  
Mohammad Abdul Mannan

According to the grid code specifications, low voltage ride-through (LVRT) is one of the key factors for grid-tied wind farms (WFs). Since fixed-speed wind turbines with squirrel cage induction generators (FSWT-SCIGs) require an adequate quantity of reactive power throughout the transient period, conventional WF consisting of SCIG do not typically have LVRT capabilities that may cause instability in the power system. However, variable-speed wind turbines with doubly fed induction generators (VSWT-DFIGs) have an adequate amount of LVRT enhancement competency, and the active and reactive power transmitted to the grid can also be controlled. Moreover, DFIG is quite expensive because of its partial rating (AC/DC/AC) converter than SCIG. Accordingly, combined installation of both WFs could be an effective solution. Hence, this paper illustrated a new rotor-side converter (RSC) control scheme, which played a significant role in ensuring the LVRT aptitude for a wide range of hybrid WF consisting of both FSWT-SCIGs and VSWT-DFIGs. What is more, the proposed RSC controller of DFIG was configured to deliver an ample quantity of reactive power to the SCIG during the fault state to make the overall system stable. Simulation analyses were performed for both proposed and traditional controllers of RSC of the DFIG in the PSCAD/EMTDC environment to observe the proposed controller response. Overall, the presented control scheme could guarantee the LVRT aptitude of large-scale SCIG.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Asaad Shemshadi ◽  
Pourya Khorampour

Abstract In recent years, the use of wind energy to generate electricity in the world has been accelerating and growing. Wind farms are unstable when dynamic voltage fluctuations occur, especially sudden and sudden changes in load, and show oscillating performance at their output. In this paper, the Unified Power Flow Controller (UPFC) has been simulated and studied by Matlab software to improve the dynamic stability and transient behavior of the wind power plant in the event of sudden load changes. The simulation results show that by controlling the UPFC series inverter, voltage fluctuations in the PCC bus are prevented and the UPFC parallel inverter injects power after changing the load for faster recovery and stability of the PCC bus voltage and thus the stability of the wind farm. The UPFC can control the active and reactive power at the transmission line, and in fact, controls the output of the wind turbine with the generator from both sides to the fluctuations caused by sudden load changes that play a role such as sudden disturbances and oscillating errors. Also, the presence of UPFC in the system reduces power fluctuations.


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.


2014 ◽  
Vol 1070-1072 ◽  
pp. 224-227
Author(s):  
Li Lin ◽  
Kai Li

Current control strategy of reactive power and voltage for wind power integration is separate control of single wind farm (WF), which cannot achieve the optimal allocation of reactive power and is not beneficial for the optimization of voltage stability and network loss. In this paper, a coordinated control strategy of reactive power and voltage for wind farm cluster is proposed, which takes the voltage stability at point of common coupling (PCC) and economic operation as the optimization goals. The coordinated control strategy is realized through the platform of Cybercontrol industrial configuration, and the application testing verifies the effectiveness of the proposed strategy.


2013 ◽  
Vol 724-725 ◽  
pp. 619-622 ◽  
Author(s):  
Chia Yu Hsu ◽  
Ta Hsiu Tseng ◽  
Pei Hwa Huang

The main purpose of this paper is to study the enhancement of the Low-Voltage-Ride-Through (LVRT) capability of the wind farm with the installment of the Static Synchronous Compensator (STATCOM) and the Static Var Compensator (SVC). With more penetration of wind energy from on-shore and off-shore wind farms, utilities have been starting to set up the regulation requiring the wind turbine generators to remain connected to the grid when a fault takes place in the system which is referred to as Low-Voltage-Ride-Through (LVRT). A wind farm composed with doubly fed induction generators is used as the study system. Both the STATCOM and the SVC are utilized as the devices for enhancing the LVRT capability of the wind farm. The results are demonstrated for comparing the performance of the two devices in the improvement of voltage dynamic characteristics of the study system.


2021 ◽  
Vol 16 (1) ◽  
pp. 61-67
Author(s):  
Kishan Jayasawal ◽  
Khagendra Thapa

The grid codes define low voltage ride-through (LVRT) as capability of wind turbine generator (WTG) to support the grid voltage by injecting reactive power and suppress the rise of DC-link voltage and inrush rotor current in the rotor side converter (RSC) of the doubly fed induction generator (DFIG) during a fault. Moreover, the rotor current increases significantly during severe disturbances if any protection schemes are not employed. Therefore, the protection schemes must be used to avoid the damage to the converter during a fault. This paper proposes an enhanced LVRT control scheme of a DFIG employing a crowbar in the RSC side and braking chopper across the DC-link capacitor. The DFIG is highly delicate to grid voltage fluctuation during a fault because the DFIG is directly linked to the grid via stator. During severe fault the crowbar regulates the rotor current within an acceptable range and the braking chopper discharges the DC-link capacitor via resistor within a safe limit. The proposed LVRT control scheme is performed for a 2.4-MW DFIG using a MATLAB/SIMULINK simulator. The results delineate that the proposed control scheme is able to rapidly decrease the rotor current and repress the escalation in DC-link voltage during a grid fault.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6413
Author(s):  
Feng-Chang Gu ◽  
Hung-Cheng Chen

Large-scale wind farms in commercial operations have demonstrated growing influence on the stability of an electricity network and the power quality thereof. Variations in the output power of large-scale wind farms cause voltage fluctuations in the corresponding electrical networks. To achieve low-voltage ride-through capability in a doubly fed induction generator (DFIG) during a fault event, this study proposes a real-time reactive power control strategy for effective DFIG application and a static synchronous compensator (STATCOM) for reactive power compensation. Mathematic models were developed for the DFIG and STATCOM, followed by the development of an indirect control scheme for the STATCOM based on decoupling dual-loop current control. Moreover, a real-world case study on a commercial wind farm comprising 23 DFIGs was conducted. The voltage regulation performance of the proposed reactive power control scheme against a fault event was also simulated. The simulation results revealed that enhanced fault ride-through capability and prompt recovery of the output voltage provided by a wind turbine generator could be achieved using the DFIG along with the STATCOM in the event of a three-phase short-circuit fault.


2013 ◽  
Vol 770 ◽  
pp. 213-216
Author(s):  
Wen Xuan Cai ◽  
Ke Wu Zou ◽  
Hai Bo Qi

A large number of wind farms have been built in recent years, it is growing that the wind generating sets share of the total. On the other side, as the controllability of wind generating set is far weaker than the thermal generator set or hydro electric generating set. It leads to many problems for the power grid, such as voltage fluctuation or flicker generated in the process of continued operating or switching operation. It will bring a bad influence on power quality of local grid. Combined with practical conditions in Hebei Hongfeng wind farm, in this paper aiming at wind generating set output fluctuation, the reactive power compensation and the grid stability, mainly setting out from several aspects, analyzes the main reasons of grid voltage fluctuation or flicker caused by wind power generation. It is also analyzed that lowering the grid voltage instability.


2013 ◽  
Vol 433-435 ◽  
pp. 1330-1335 ◽  
Author(s):  
Zhen Yu Xu ◽  
Bin Meng ◽  
Jian He ◽  
Shao Hua Jiao

Under the influence of the view that reactive power compensation on-spot, the study on control of reactive power and voltage in wind farms focused on a single wind farm optimal reactive voltage control. China's wind power resources are relatively concentrated and a region often have several or even a dozen wind farms. Wind farm thought as a unit to adjust often leads to irrational reactive power flow. Wind farm groups and collection substations must be thought together as a whole to manage. This paper makes use of collection substations to support area voltage, coordinates reactive power output of the wind farm groups based on the voltage sensitivity and improves the overall grid voltage level of the wind farm groups areas. Simulation results proved that the program can improve the regional power grid voltage level.


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