scholarly journals Power Quality Enhancement in Windfarm by using STATCOM

A FACTS (Flexible AC Transmission) controlled device, STATCOM is the best solution for power compensation in the area of microgrid system. It regulates the reactive power by injecting the reactive current in to the ac/dc hybrid microgrid terminals. The STATCOM is applicable for shunt compensation which has a great role in dynamic performance by controlling its reactive power. The proposed work demonstrated about the enhancement of voltage sag during fault condition. It can improve the wind turbine performance. The main objective for the STATCOM application in windfarm is to improve the system voltage by supplying or absorbing the reactive power into hybrid ac /dc microgrid system. During steady state operation, the fundamental component of the VSC (Voltage source converter) voltage in phase with system voltage, which shows uncontrol action on active power flow. If there is change between these two voltages (lead or lag), then STATCOM can generates (or absorbs) reactive power. This phase shift leads to flow of active power which is responsible for increase or decreases of capacitor voltage. Assumption has been taken by considering the fixed speed of wind turbine. The performance of windfarm with and without STATCOM is examined and analyzed under fault condition by using MATLAB Simulink 2016.

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2699
Author(s):  
Miguel Montilla-DJesus ◽  
Édinson Franco-Mejía ◽  
Edwin Rivas Trujillo ◽  
José Luis Rodriguez-Amenedo ◽  
Santiago Arnaltes

Direct current microgrids (DCMGs) are currently presented as an alternative solution for small systems that feed sensitive electrical loads into DC. According to the scientific literature, DCMG maintains good voltage regulation. However, when the system is in islanded mode, very pronounced voltage variations are presented, compromising the system’s ability to achieve reliable and stable energy management. Therefore, the authors propose a solution, connecting the electrical network through a grid-tied voltage source converter (GVSC) in order to reduce voltage variations. A coordinated control strategy between the DCMG and GVSC is proposed to regulate the DC voltage and find a stable power flow between the various active elements, which feed the load. The results show that the control strategy between the GVSC and DCMG, when tested under different disturbances, improves the performance of the system, making it more reliable and stable. Furthermore, the GVSC supports the AC voltage at the point of common coupling (PCC) without reducing the operating capacity of the DCMG and without exceeding even its most restrictive limit. All simulations were carried out in MATLAB 2020.


Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1643
Author(s):  
Jorge El Mariachet ◽  
Yajuan Guan ◽  
Jose Matas ◽  
Helena Martín ◽  
Mingshen Li ◽  
...  

The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers (P–Q) is essential for a proficient dynamic response against abrupt NLL changes. In this work, a VSI supplying to an NLL was studied, focusing the attention on the P–Q calculation stage. This stage first generated the direct and in-quadrature signals from the measured load current through a second-order generalized integrator (SOGI). Then, the instantaneous power quantities were obtained by multiplying each filtered current by the output voltage, and filtered later by utilizing a SOGI to acquire the averaged P–Q parameters. The proposed algorithm was compared with previous proposals, while keeping the active power steady-state ripple constant, which resulted in a faster calculation of the averaged active power. In this case, the steady-state averaged reactive power presented less ripple than the best proposal to which it was compared. When reducing the velocity of the proposed algorithm for the active power, it also showed a reduction in its steady-state ripple. Simulations, hardware-in-the-loop, and experimental tests were carried out to verify the effectiveness of the proposal.


Author(s):  
A Divya Teja and Dr. N Sambasiva Rao

The use of power electronic converters influences the generation of harmonics and reactive power flow in power system. Therefore, three-phase multilevel improved power quality AC-DC converters are gaining lot of popularity in power conversion applications. This work deals with critical problem of multilevel structure i.e neutral point potential (NPP) variation. In this paper, a simplified current controlled scheme is presented to ensure unity power factor operation. Neutral point potential (NPP) of three-phase, 3-level NPC AC-DC converter is controlled by modifying control signal in the controller using NPP regulator. An auxiliary circuit is being presented in this paper as an alternative option for controlling the neutral point potential of the converter. Comparison has been carried out between these control techniques in terms of power quality. A complete mathematical model is presented for better understanding of both techniques used for NPP control. The presented control techniques has been verified through simulation investigations and validated


Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 831 ◽  
Author(s):  
Janeth Alcalá ◽  
Víctor Cárdenas ◽  
Alejandro Aganza ◽  
Jorge Gudiño-Lau ◽  
Saida Charre

Nowadays, the use of power converters to control active and reactive power in AC–AC grid-connected systems has increased. With respect to indirect AC–AC converters, the tendency is to enable the back-to-back (BTB) voltage source converter (VSC) as an active power filter (APF) to compensate current harmonics. Most of the reported works use the BTB-VSC as an auxiliary topology that, combined with other topologies, is capable of active power regulation, reactive power compensation and current harmonic filtering. With the analysis presented in this work, the framework of the dynamics associated with the control loops is established and it is demonstrated that BTB-VSC can perform the three tasks for which, in the reviewed literature, at least two different topologies are reported. The proposed analysis works to support the performance criteria of the BTB-VSC when it executes the three control actions simultaneously and the total current harmonic distortion is reduced from 27.21% to 6.16% with the selected control strategy.


2014 ◽  
Vol 626 ◽  
pp. 184-189
Author(s):  
A.S. Monikandan ◽  
N. Kesavan Nair

The Interline Power Flow Controller (IPFC) is a voltage-source-converter (VSC)-based flexible ac transmission system (FACTS) controller for series compensation in a multiline transmission system of a substation. The capability of injecting series voltages with controllable magnitude and phase angle makes it a powerful tool for better utilization of existing transmission lines in a multiline transmission system. IPFC is used to regulate active and reactive power flow in a multiline system, usually. In this paper, a control method for IPFC is proposed to control magnitude and phase angle of one sending bus of a substation. All degrees of freedom of IPFC and decoupled synchronous frame concept are used in the proposed control structure. Simulation results in Matlab/Simulink are presented to show the capability of IPFC in compensating the bus voltage.


Author(s):  
Adeesh Sharma ◽  
Himmat Singh

In this paper, A Distribution Static Synchronous Compensator (D-STATCOM) is used for improving the power factor, power quality and to control power flow control in the distribution line. It used to give reactive and active power compensation in the distribution line. The power depends on the power factor of the loads connected to the transmission line. In this paper we have used a new DSTATCOM using modified SVPWM technique. The previous DSTATCOM are basically controlled by PWM, or SPWM technique which produce high harmonics distortion but using SVPWM technique distortion reduces to maximum possible level. In our system we also have examined the losses due to DSTATCOM when connected in the distribution system. To decrease the reactive power and to minimize the undesirable load to require maintains the flow of reactive power. As a result, the power a factor of the load descant, leading to the limitation of the active power flow in the line. The D-STATCOM is a power electronics based on advanced device can be used to control power flow in the distribution line. The construction of system is able to recover the drop-in bus voltage when any loading effect arises, but due to 5th harmonic performance of DSTATCOM reduces somewhere.


Inventions ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 25
Author(s):  
Ahmed F. Ebrahim ◽  
Ahmed A. Saad ◽  
Osama Mohammed

The fast development of the residential sector regarding the additional integration of renewable distributed energy sources and the modern expansion usage of essential DC electrical equipment may cause severe power quality problems. For example, the integration of rooftop photovoltaic (PV) may cause unbalance, and voltage fluctuation, which can add constraints for further PV integrations to the network, and the deployment of DC native loads with their nonlinear behavior adds harmonics to the network. This paper demonstrates the smart integration of a DC microgrid to the neighborhood low-voltage distribution network (NLVDN). The DC microgrid is connected to the NLVDN through a three-phase voltage source inverter (VSI), in which the VSI works as a distribution static compensator (DSTATCOM). Unlike previous STATCOM work in the literature, the proposed controller of the VSI of the DC smart building allows for many functions: (a) it enables bidirectional active/reactive power flow between the DC building and the AC grid at point of common coupling (PCC); (b) it compensates for the legacy unbalance in the distribution network, providing harmonics elimination and power factor correction capability at PCC; and (c) it provides voltage support at PCC. The proposed controller was validated by Matlab/Simulink and by experimental implementation at the lab.


Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 733 ◽  
Author(s):  
Wei Yan ◽  
Chong Ding ◽  
Zhouyang Ren ◽  
Wei-Jen Lee

Existing continuation power flow (CPF) models mainly focus on the regional independent systems, which are not suitable for multi-area AC/DC interconnected systems because the market trading behaviors and security control for power allocation of tie-lines are ignored. This study presents a novel CPF model and its decoupling algorithm for multi-area AC/DC interconnected systems incorporating a voltage source converter (VSC)-based multi-terminal direct current (MTDC) network. This CPF model includes the following unique features: (1) In view of the bilateral power trading contracts among regional subsystems, the nonlinear constraint equations of directional trading active power via interface are derived, and the multi-balancing machine strategy is introduced to realize the active power balance of each subsystem. (2) An accurate simulation method for the security control behaviors of the power allocation in tie-lines is proposed, which includes a specific selection strategy for automatic generation control units and a generation re-dispatch strategy. These two strategies work together to prevent the serious overload in tie-lines during load growth and improve the voltage stability margin of the interconnected bulk systems. (3) The switching characteristic of reactive power control behaviors of VSC stations is simulated in the CPF calculation. In the end, a novel decoupling CPF algorithm based on bi-directional iteration is presented to realize the decomposition and coordination calculation. This decoupling algorithm preserves the precision and convergence of integrated CPF algorithms, and it has an apparent advantage on the calculation speed. Furthermore, this decoupling algorithm also can easily reflects the effects of the control mode changes of VSC stations to the voltage stability margin of AC system. Case studies and comparative analysis on the IEEE two-area RTS-96 system indicate the effectiveness and validity of the proposed CPF model and corresponding decoupling algorithm.


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