scholarly journals Voltage Control and Braking System of a DFIG during a Fault

2021 ◽  
Vol 16 (1) ◽  
pp. 121-131
Author(s):  
Rabin Mahat ◽  
Khagendra B. Thapa ◽  
Sudip Lamichhane ◽  
Sudip Thapaliya ◽  
Sagar Dhakal
Keyword(s):  
Wind Turbine ◽  
Reactive Power ◽  
Voltage Control ◽  
Simulation Software ◽  
Control Mode ◽  
Grid Voltage ◽  
Braking System ◽  
Control Scheme ◽  
Grid Side ◽  
Voltage Control Mode

This paper describes a voltage control scheme of a doubly fed induction generator (DFIG) wind turbine that can inject more reactive power to the grid during a fault so as to support the grid voltage. To achieve this, the coordinated control scheme using both rotor side converter (RSC) and grid side converters (GSC) controllers of the DFIG are employed simultaneously. The RSC and GSC controllers employ PI controller to operate smoothly. In the voltage control mode, the RSC and GSC are operated. During a fault, both RSC and GSC are used simultaneously to supply the reactive power into the grid (main line) depending on voltage dip condition to support the grid voltage. The proposed system is implemented for single DFIG wind turbine using MATLAB simulation software. The results illustrate that the control strategy injects the reactive power to support the voltage stability during a fault rapidly. Also, the braking system is designed to protect the wind turbine system from over speed. For this purpose, the braking resistors are being used.

scholarly journals Voltage and reactive power optimisation of offshore wind farms based on terminal voltage control mode of DFIG

2017 ◽  
Vol 2017 (13) ◽  
pp. 874-879 ◽  
Author(s):  
Cuihua Tian ◽  
Xuanyao Luo ◽  
Jianpeng Dong ◽  
Baichao Chen ◽  
Jiaxin Yuan
Keyword(s):  
Reactive Power ◽  
Voltage Control ◽  
Wind Farms ◽  
Offshore Wind ◽  
Control Mode ◽  
Offshore Wind Farms ◽  
Terminal Voltage ◽  
Voltage Control Mode

Direct Current-Controlled Distribution Static Synchronous Compensator for Voltage Quality Improvement

2013 ◽  
Vol 648 ◽  
pp. 361-364
Author(s):  
Lei Huang ◽  
Deng Xiang Yang ◽  
Jie Tang ◽  
Qun Feng Zhu
Keyword(s):  
Quality Improvement ◽  
Direct Current ◽  
Reactive Power ◽  
Voltage Control ◽  
Current Control ◽  
Control Mode ◽  
Voltage Source ◽  
Voltage Sag ◽  
Voltage Quality ◽  
Voltage Control Mode

This paper presents a direct current-controlled static reactive power compensator (DSTATCOM) for voltage quality improvement of low-medium distribution network. The main circuit of the DSTATCOM uses VSI-SPWM structure-based voltage source inverter (VSI), and both operation of reference current and control of compensation current are realized in synchronous reference frames. The function of DSTATCOM to mitigate voltage sag and flicker, two common voltage quality problems, is discussed in detail in this paper. According to the forming way of reactive reference current, operation mode of DSTACOM are classified into current control mode and voltage control mode. And under the two operation modes the function of DSTATCOM to mitigate voltage sag and flicker under different control modes is simulated with MATLAB. The simulation results show that the current control mode is suitable for mitigating voltage flicker, while the voltage control mode for voltage sag.

scholarly journals Heuristic Coordinated Voltage Control Schemes in Distribution Network with Distributed Generations

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2849
Author(s):  
Seok-Il Go ◽  
Sang-Yun Yun ◽  
Seon-Ju Ahn ◽  
Hyun-Woo Kim ◽  
Joon-Ho Choi
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Voltage Control ◽  
Distribution Networks ◽  
Control Voltage ◽  
Reactive Power Control ◽  
Distributed Generations ◽  
Control Scheme ◽  
Control Devices ◽  
Node Voltage

The voltage and reactive power control (Volt/VAR Control, VVC) in distribution networks has become a challenging issue with the increasing utilization of distributed generations (DGs). In this paper, a heuristic-based coordinated voltage control scheme that considers distribution voltage control devices, i.e., on-load tap changers (OLTC) and step voltage regulators (SVR), as well as reactive power control devices, i.e., DGs, are proposed. Conventional voltage control methods using non-linear node voltage equations require complex computation. In this paper, the formulation of simplified node voltage equations accounting for changes in tap position of distribution voltage control devices and reactive power changes of reactive power control devices are presented. A heuristic coordinated voltage control scheme using the proposed simplified node voltage equations is proposed. A coordinated voltage control scheme to achieve voltage control for nominal voltage and conservative voltage reduction (CVR) is presented. The results of the proposed schemes are compared with the results from the quadratic optimization method to confirm that the proposed schemes yields suitably similar results. Furthermore, a tap scheduling method is proposed to reduce the number of tap changes while controlling network voltage. The tap position is readjusted using a voltage control performance index (PI). Simulation results confirm that when using this method the number of tap changes is reduced. The proposed scheme not only produces reasonable performance in terms of control voltage of networks but also reduces the number of tap changes made by OLTC. The proposed control method is an alternative candidate for a system to be applied to practical distribution networks due to its simplified calculations and robust performance.

RTDS-Based Simulate Analysis of AC Filters Switch Method in HVDC Converter for Voltage Stability

2013 ◽  
Vol 756-759 ◽  
pp. 4250-4253
Author(s):  
Xiao Jun Zhu ◽  
Tao Chen ◽  
Wei Fang ◽  
Luo Jiang Qian ◽  
Yi Yu Wen
Keyword(s):  
Voltage Stability ◽  
Power Transmission ◽  
Voltage Control ◽  
Salient Feature ◽  
Fast Response ◽  
Control Mode ◽  
Reactive Control ◽  
Voltage Level ◽  
Action Sequence ◽  
Voltage Control Mode

In most of the AC-DC hybrid power transmission system AC filters is widely applied to stabilize voltage level in addition to filter harmonic. However, the voltage stability of AC bus is greatly influenced by action sequence of switching AC filters in group. The paper presents the concept of reactive characteristics of the convertor and AC filters, using reactive and voltage control mode to switch them. The modeling, control, and principle of operation for the AC-side switching filters are described. The voltage level is controlled via regulating action of switching filters by step. The salient feature of the proposed control modes is that voltage control contributes to keep the voltage level, and reactive control has no fast response on guaranteeing voltage stability, but two methods can apply to different occasions based on the requirements of voltage stability. All analysis and control system designs are verified through building a RTDS model in a typical ±500kV power system.

scholarly journals Super-Twisting Sliding Mode Control for Gearless PMSG-Based Wind Turbine

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Mojtaba Nasiri ◽  
Saleh Mobayen ◽  
Quan Min Zhu
Keyword(s):  
Wind Turbine ◽  
Reactive Power ◽  
Low Voltage ◽  
Sliding Mode ◽  
Synchronous Generator ◽  
Voltage Regulation ◽  
Point Tracking ◽  
Chattering Free ◽  
Grid Codes ◽  
Grid Side

In recent years, the complexities of wind turbine control are raised while implementing grid codes in voltage sag conditions. In fact, wind turbines should stay connected to the grid and inject reactive power according to the new grid codes. Accordingly, this paper presents a new control algorithm based on super-twisting sliding mode for a gearless wind turbine by a permanent magnet synchronous generator (PMSG). The PMSG is connected to the grid via the back-to-back converter. In the proposed method, the machine side converter regulates the DC-link voltage. This strategy improves low-voltage ride through (LVRT) capability. In addition, the grid side inverter provides the maximum power point tracking (MPPT) control. It should be noted that the super-twisting sliding mode (STSM) control is implemented to effectively deal with nonlinear relationship between DC-link voltage and the input control signal. The main features of the designed controller are being chattering-free and its robustness against external disturbances such as grid fault conditions. Simulations are performed on the MATLAB/Simulink platform. This controller is compared with Proportional-Integral (PI) and the first-order sliding mode (FOSM) controllers to illustrate the DC-link voltage regulation capability in the normal and grid fault conditions. Then, to show the MPPT implementation of the proposed controller, wind speed is changed with time. The simulation results show designed STSM controller better performance and robustness under different conditions.

scholarly journals Optimal Transient Search Algorithm-Based PI Controllers for Enhancing Low Voltage Ride-Through Ability of Grid-Linked PMSG-Based Wind Turbine

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1807
Author(s):  
Mohammed H. Qais ◽  
Hany M. Hasanien ◽  
Saad Alghuwainem
Keyword(s):  
Wind Turbine ◽  
Low Voltage ◽  
Search Algorithm ◽  
Fitness Function ◽  
Synchronous Generator ◽  
Pi Control ◽  
Low Voltage Ride Through ◽  
Control Scheme ◽  
Pi Controllers ◽  
Grid Side

This paper depicts a new attempt to apply a novel transient search optimization (TSO) algorithm to optimally design the proportional-integral (PI) controllers. Optimal PI controllers are utilized in all converters of a grid-linked permanent magnet synchronous generator (PMSG) powered by a variable-speed wind turbine. The converters of such wind energy systems contain a generator-side converter (GSC) and a grid-side inverter (GSI). Both of these converters are optimally controlled by the proposed TSO-based PI controllers using a vector control scheme. The GSC is responsible for regulating the maximum power point, the reactive generator power, and the generator currents. In addition, the GSI is essentially controlled to control the point of common coupling (PCC) voltage, DC link voltage, and the grid currents. The TSO is applied to minimize the fitness function, which has the sum of these variables’ squared error. The optimization problem’s constraints include the range of the proportional and integral gains of the PI controllers. All the simulation studies, including the TSO code, are implemented using PSCAD software. This represents a salient and new contribution of this study, where the TSO is coded using Fortran language within PSCAD software. The TSO-PI control scheme’s effectiveness is compared with that achieved by using a recent grey wolf optimization (GWO) algorithm–PI control scheme. The validity of the proposed TSO–PI controllers is tested under several network disturbances, such as subjecting the system to balanced and unbalanced faults. With the optimal TSO–PI controller, the low voltage ride-through ability of the grid-linked PMSG can be further improved.

scholarly journals Dynamic Modeling and Performance Analysis of PMSG- based Variable Speed WTG: Case Study of Adama Wind Farm I, Ethiopia

2021 ◽  
Vol 12 (2) ◽  
pp. 155-172
Author(s):  
Zenachew Muluneh ◽  
Gebremichael Teame
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Power Flow ◽  
Wind Farm ◽  
Reactive Power ◽  
Maximum Energy ◽  
Current Control ◽  
Speed Ratio ◽  
Variable Speed ◽  
Grid Side

In this paper, the performance of Permanent Magnet Synchronous Generator (PMSG) -based Variable Speed Wind Turbine Generator (WTG) at Adama Wind Farm I (WTG), connected to a grid is studied. To study the performance of the WTG, both machine and grid side converters are modeled and analyzed very well. On the machine side, maximum power point tracking (MPPT) for maximum energy extraction is done using the direct speed control (DSC) technique, which is linked with the optimal tip speed ratio for each wind speed value considered. On the grid side, dc-link voltage and reactive power flow to the grid are controlled. For this purpose, first, the simulation model of the system is prepared in MATLAB Simulink considering the dynamic mathematical model of the PMSG, and Wind Turbine Aerodynamic model using the user-defined function blocks. Then, the PI regulators designed for direct speed, torque (current) control, and dc-link voltage are employed in the model. Moreover, to study and analyze the behavior of the system in a variable speed operation, a wind speed starting from cut-in wind speed (3m/s) to the rated wind speed (11m/s) is applied in 4s. The simulation result of the existing system model shows that the actual values of performance variables correspond well with the analytical values of the system. In addition, the chosen control algorithms applied in the control system of the generator-side converter are hence verified.

scholarly journals Intensifications reactive power during of asymmetric network outages in dual-stator winding generators

2021 ◽  
Vol 12 (4) ◽  
pp. 2451
Author(s):  
Qasim Al Azze ◽  
Balasim М. Hussein ◽  
Hayder Salim Hameed
Keyword(s):  
Wind Turbine ◽  
Reactive Power ◽  
Stator Winding ◽  
Working Process ◽  
Main Interest ◽  
Grid Connection ◽  
And Performance ◽  
Grid Side ◽  
Grid Side Converter ◽  
Secondary Side

<span lang="EN-US">The paper proposes a protection to dual stator generator, reluctance rotor, from asymmetrical fault. Which prevents the dual stator generator, reluctance rotor, from electrical sage through working process in order to avoid any interruption in the generator-grid connection. The procedure consummated with injecting suitable reactive power during the fault period. The proposed method that makes it possible for wind turbine application via dual stator winding generators (DSWRG) synchronous mod to stay connected to the grid during asymmetrical faults. It has been built according to trusted simulating mode considering all tested parameters according to experiment work. The expirment, consider the DC link side stability and care about the behavior and performance of machine side parameter. As well the machineability is evaluated to ride through asymmetrical fault by observing the secondary side current which has a big role in saving grid side converter. The control takes a response within 200 ms after fault trigger recognition. The generator ability of dynamically remaining connected stable and existing in the network, which is sustained a series voltage disturbance by injecting appropriate amount of reactive power. The main interest required in this paper is the capability of a machine to overcome the asymmetrical fault.</span>

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