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Response Time of reactive power Based on Different Definitions and Algorithms

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Journal of Modern power Systems and Clean Energy 2021年第2期9卷 440-449页

作者： Taixun Fang Qiwen Zhou Fengfeng Ding Xiaodan Wu Zhao Li Houjun Tang NR Electric Co. Ltd.NanjingChina the Key Laboratory of Control of power Transmission and Transformation Ministry of EducationShanghai Jiao Tong UniversityShanghaiChina

Dynamic reactive power compensation equipment typically requires a fast response to output the necessary reactive *** term"dynamic response time of reactive power"is often used but has never been clearly *** paper summarizes the reactive power calculations under different definitions and algorithms and considers these calculations in terms of signal processing to simulate and analyze the step *** paper subsequently focuses on the widely used instantaneous reactive power algorithm and finally concludes that the dynamic reactive power response time closely depends on the reactive power calculation method *** single-phase instantaneous reactive power algorithm has the fastest response *** reactive power response time of dynamic reactive devices in power systems is a minimum of a quarter of one cycle time for the well-known and widely used single-phase reactive power algorithms.

关键词： Response time reactive power instantaneous reactive power Hilbert transform phase shift synchronous reference frame

An Integrated reactive power Control Strategy for Improving Low Voltage Ride-through Capability

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Chinese Journal of Electrical Engineering 2019年第4期5卷 1-14页

作者： Ehsan Gatavi Ali Hellany Mahmood Nagrial Jamal Rizk School of Computing Engineeringand MathematicsWestern Sydney UniversityNSW 2751Australia

Among all renewable energies,wind power is rapidly growing,whereby it has the most participation to supply *** fed induction generator(DFIG)is the most popular wind turbine,as it can play a very significant role to enhance low voltage ride through(LVRT)*** services such as voltage control and reactive power capability are the main topics in wind power control systems that should be handled profoundly and *** lack of reactive power during fault period can result in instability in generators and/or disconnection of the wind turbine from the power *** main aims of this study are to illustrate the most effective approaches subject to improve the efficiency,stability,and reliability of wind power plant associated with LVRT capability *** effectiveness and efficiency are demonstrated by,firstly,comparison between all types of wind turbines,focusing on the ancillary services,after the existing advanced control *** to the literature,there is a consensus that modifying converter-based control topology is the most effective approach to enhance LVRT capability in DFIG-based wind turbine(WT).Therefore,an advanced integrated control strategy is designed by considering the effect of the rotor side converter(RSC)and the grid side converter(GSC).A model of the wind power plant is presented based on the control ***/Simulink is also used to illustrate the effectiveness of the designed algorithm.

关键词： Doubly fed induction generator low voltage ride-through series dynamic braking resistor reactive power

High-precision time domain reactive power measurement in the presence of interharmonics

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第4期12卷 330-337页

作者： Bei ZHANG Guo WEI Jin-wei SUN Department of Electrical and Computer Engineering Auburn University Auburn 36830 USA School of Electrical Engineering andAutomatton Harbin Institute of Technology Harbin 150001 China

When interharmonics exist in power system signals,large errors emerge in traditional time domain reactive power *** this paper,we present a novel time domain integral method with good effect of restraining interharmonics,synchronization error,and white noise,as well as the principle of the selection of the sampling periods when employing this *** current signal and phase-shifted voltage signal are reconstructed after the harmonic components of signals are extracted,so that the interharmonics are *** influence of the synchronization error on the measurement is reduced through removing the weight coefficients of the reactive *** the simulation,we apply several cosine windows to the proposed method and analyze signals containing both harmonics and *** results show that,in the presence of interharmonics,synchronization error,and white noise (with a fundamental signal-to-noise ratio of 40 dB) all together,the relative errors are within the magnitude of 10 4,which perfectly satisfies the practical requirement.

关键词： Cosine window Interharmonics reactive power Synchronization error Windowed discrete Hilbert transform

High performance decoupled active and reactive power control for three-phase grid-tied inverters using model predictive control

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Protection and Control of Modern power Systems 2021年第1期6卷 311-329页

作者： Mohamed Azab EEET Department Yanbu Industrial CollegeYanbu AL SinaiyahSaudi Arabia EEET Department Faculty of EngineeringBenha UniversityBanhaEgypt

Finite control set-model predictive control (FCS-MPC) is employed in this paper to control the operation of a three-phase grid-connected string inverter based on a direct PQ control scheme. The main objective is to achieve high-performance decoupled control of the active and reactive powers injected to the grid from distributed energy resources (DER).The FCS-MPC scheme instantaneously searches for and applies the optimum inverter switching state that can achieve certain goals, such as minimum deviation between reference and actual power;so that both power components (P and Q) are well controlled to their reference *** addition, an effective method to attenuate undesired cross coupling between the P and Q control loops, which occurs only during transient operation, is investigated. The proposed method is based on the variation of the weight factors of the terms of the FCS-MPC cost function, so a higher weight factor is assigned to the cost function term that is exposed to greater disturbance. Empirical formulae of optimum weight factors as functions of the reference active and reactive power signals are proposed and mathematically derived. The investigated FCS-MPC control scheme is incorporated with the LVRT function to support the grid voltage in fulfilling and accomplishing the up-to-date grid codes. The LVRT algorithm is based on a modification of the references of active and reactive powers as functions of the instantaneous grid voltage such that suitable values of P and Q are injected to the grid during voltage *** performance of the elaborated FCS-MPC PQ scheme is studied under various operating scenarios, including steady-state and transient conditions. Results demonstrate the validity and effectiveness of the proposed scheme with regard to the achievement of high-performance operation and quick response of grid-tied inverters during normal and fault modes.

关键词： Model predictive control Finite control set Grid-connected inverter Active power reactive power Distributed generation Low voltage ride through PQ theory FCS-MPC LVRT

Risk analysis of power systems for both real and reactive power

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Journal of Modern power Systems and Clean Energy 2013年第2期1卷 150-158页

作者： Wenping QIN Peng WANG Xiaoqing HAN Fanhua MENG Taiyuan University of Technology Taiyuan 030024China School of EEE Nanyang Technological UniversitySingapore 639798Singapore

With the high penetration of renewable energy sources,the reliability of power systems becomes more vulnerable than ever because of the greater uncertainty and intermittence in power *** power plays an important role in the power system reliability,because it is closely related to the system voltage stability and voltage ***,reactive power-related reliability issues are seldom emphasized in conventional power reliability *** article investigates power system reliability of real and reactive *** and reactive power shortages and the associated voltage violations due to system failures are considered on reliability evaluation of power systems.A three-stage load-shedding technique for post contingencies is implemented to determine the contributions of real and reactive power on the system reliability and to find an optimal way to release network *** results provide the detailed information on power system planning and operation for system planners and operators from real and reactive power aspects.

关键词： reactive power Risk analysis Reliability Voltage stability

Real-time Dispatchable Region of Renewable Generation Constrained by reactive power and Voltage Profiles in AC power Networks

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CSEE Journal of power and Energy Systems 2020年第3期6卷 528-536页

作者： Yanqi Liu Zhigang Li Q.H.Wu Haibo Zhang School of Electric power Engineering South China University of TechnologyGuangzhou 510641China State Key Laboratory of Alternate Electrical power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

A large amount of renewable energy generation(REG)has been integrated into power systems,challenging the operational security of power *** a real-time dispatch,system operators need to estimate the ability of the power network to accommodate REG with a limited reserve *** real-time dispatchable region(RTDR)is defined as the largest range of a power injection that the power network can accommodate in a certain dispatch interval for a given dispatch base ***-of-the-art research on the RTDR adopts a DC power flow model regardless of the voltage profiles and reactive power,which can overlook potentially insecure operational states of the *** address this issue,this paper proposes an AC power flow based RTDR model simultaneously considering the reactive power and voltage profiles *** nonlinear constraints in our model are approximated using a linear power flow model together with a polytope approximation technique for quadratic *** adaptive constraint generation algorithm is used to calculate the *** results using the IEEE 5-bus and 30-bus systems illustrate the advantages of the proposed model.

关键词： Dispatchable region linearization renewable energy generation reactive power

reactive power in One-phase Circuits with Periodical Voltages - reactive power Compensation

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Journal of Energy and power Engineering 2010年第9期4卷 60-64页

作者： S. Slabosz Institute of Electrical power Engineering Wroclaw University of Technology Wroclaw 50-370 Poland

The article states about reactive power compensation methods for circuits with non-sinusoidal voltages. An basic introduction to reactive power theory has been given, together with the optimal capacitance selection theory. There have been presented selected theories application in order to compensate the reactive power in one-phase circuits. The measurement results before the compensation have been discussed and measurement results after compensation of an actual object supplied from an non-sinusoidal voltage source were presented. The algorithms of optimal capacity selection were given, which connected in parallel to the circuit with inductive character will cause current root-mean-square value minimization. The measurement results after applying the reactive power minimization algorithm have shown improvement in compensation of strongly nonlinear receivers supplied with distorted signals.

关键词： Electrical theoretical electric measurements reactive power power compensation

Accurate reactive power Controller and power Factor Correction Using Fuzzy Logic

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Journal of Energy and power Engineering 2013年第6期7卷 1163-1171页

作者： Muhammad M.A.S. Mahmoud Al Hosn Gas Co. Projects Div. UAE

This paper presents the use of fuzzy logic technique to control the reactive power of load and hence improve the source power factor. A shunt compensator is proposed, which consists of a voltage controlled reactor by full-wave thyristor bridge in parallel with a capacitor. The proposed voltage control technique composed of two independent fuzzy controllers, primary and secondary. The PFC （primary fuzzy controller） is designed based on linearization method to introduce to the network the nearest value of reactive power （VAR） required to correct the power factor. The SFC （secondary fuzzy controller） is designed to achieve accurate compensation for the required VAR to achieve the pre-set power factor value. Simulations for 15 different practical study cases are presented to evaluate the performance of the controller, and the results show how the designed controller is fast and accurate. Harmonics analyses are carried out up to the 13th harmonic to determine the requirement of harmonics filter.

关键词： power systems reactive power power factor fuzzy logic control.

Evaluation of Shunt reactive power Compensation Effect on ATC Using Linear Methods

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Journal of Energy and power Engineering 2012年第5期6卷 784-791页

作者： Ibraheem Naresh Kumar Yadav Department of Electrical Engineering Jammia Millia Islamia (Central University) New Delhi 110024 India Department of Electrical Engineering Deenbandhu Chhotu Ram University of Science & Technology Murthal (Sonepat)Haryana 131039 India

Most power transfer studies involve contingencies and multi pattern scenarios that often can only be performed in reasonable time with the use of linear methods. In these works, the effect of reactive power flows in line loading is neglected while formulating the problem for ATC （available transfer capability） calculations. This paper presents the determination of shunt reactive power compensation in the presence of FACTS （flexible AC transmission system） devices like： SSSC （static synchronous series compensator） and UPFC （unified power flow controller） for enhancement of power transfer capability of a power system incorporating the reactive power flows in ATC calculations. In doing so, redistribution of power flow takes place and therefore improves ATC of the system. Studies on a sample 5-bus power system model are carried out to illustrate the effect of shunt compensation along with line flow control.

关键词： Linear ATC reactive power FACTS devices power flow constraints operating and limiting circles.