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Journal ArticleDOI

Terminal voltage regulation characteristics by static var compensator for a three-phase self-excited induction generator

TL;DR: In this paper, a three-phase self-excited induction generator (SEIG) with squirrel-cage rotor is presented along with its operating performance evaluations for small-scale clean renewable and alternative energy utilizations.
Abstract: In this paper, the practical impedance approach steady-state analysis in the frequency domain for the three-phase self-excited induction generator (SEIG) with squirrel-cage rotor is presented along with its operating performance evaluations. The three-phase SEIG is driven by a variable-speed prime mover(VSPM) in addition to a constant-speed prime mover (CSPM) such as a wind turbine and a micro gas turbine for clean alternative renewable energy in rural areas. The basic steady-state characteristics of the VSPM are considered in the three-phase SEIG approximate equivalent circuit and the operating performance of the three-phase SEIG coupled with a VSPM and/or a CSPM are evaluated and discussed online under the conditions related to the speed changes of the prime mover and the electrical inductive load power variations with simple computation processing procedures. A three-phase SEIG prototype setup with a VSPM is implemented for small-scale clean renewable and alternative energy utilizations. The experimental performance results give good agreement with those obtained from the simulation results. Furthermore, a proportional-integral (PI) closed-loop feedback voltage regulation of the three-phase SEIG driven by the VSPM on the basis of the static var compensator (SVC) composed of the thyristor phase-controlled reactor in parallel with the thyristor switched capacitor and the fixed-excitation capacitor bank is designed and considered for the wind generation as a renewable power conditioner. The simulation analysis and experimental results obtained from the three-phase SEIG with SVC for its voltage regulation prove the practical effectiveness of the additional SVC with the PI-controller-based feedback loop in steady-state operation in terms of high performance with low cost.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a modified fruit fly optimization algorithm (MFOA) combined with a probabilistic approach is proposed to coordinate and optimize the parameters of power system stabilizers (PSSs) and static VAR compensator (SVC) damping controller.
Abstract: A modified fruit fly optimization algorithm (MFOA) combined with a probabilistic approach are proposed in this paper to coordinate and optimize the parameters of power system stabilizers (PSSs) and static VAR compensator (SVC) damping controller for improving the probabilistic small-signal stability of power systems with large-scale wind generation, taking into consideration the stochastic uncertainty of system operating conditions. It is generally accepted that there is a threat to the stability of power system with penetration of wind farm. In addition, the stochastic fluctuations of wind generation make PSSs tuning more difficult. In this paper, PSSs and SVC damping controller are employed for suppressing local and inter-area low frequency oscillation. In order to eliminate the adverse effect between PSSs and SVC damping controller, the MFOA based on the probabilistic eigenvalue is applied to coordinate and optimize their parameters. The effectiveness of the proposed approach is verified on two test systems.

115 citations


Cites background from "Terminal voltage regulation charact..."

  • ...The primary application of SVC in a power system with integration of wind farm is to maintain the busbar voltage and provide reactive power support [9], [10]....

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Journal ArticleDOI
TL;DR: The suitability of self-excited induction generators (SEIGs) to regulate the terminal voltage is a key factor in deciding its use in various applications as discussed by the authors, and the recommendations drawn from this study are helpful in developing a new cost-effective regulating scheme of SEIGs for different industrial applications.
Abstract: Self-excited induction generators (SEIGs) are increasingly being used in small-capacity isolated applications for harnessing both conventional and renewable energy resources. These SEIGs suffer from poor voltage regulation even when driven by constant speed prime movers or fixed head hydro turbines. The suitability of these SEIGs to regulate the terminal voltage is a key factor in deciding its use in various applications. This paper deals with the voltage-regulating (VR) schemes for SEIGs, which are found scattered in the literature, and summarizes their operational aspects and relative suitability. These VR schemes are classified on the basis of shunt and series compensation as classical schemes, schemes based on solid-state switching devices, and schemes based on self-commutating solid-state switching device converters. The recommendations drawn from this study are helpful in developing a new cost-effective regulating scheme of SEIGs for different industrial applications.

114 citations


Cites methods from "Terminal voltage regulation charact..."

  • ...SSC-BASED VR SCHEMES Two most popular and latest VSC-based VR schemes of the SEIG are designed, and their performance is simulated to demonstrate their effectiveness to regulate the voltage of the SEIG, which is discussed as follows....

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Journal ArticleDOI
TL;DR: In this paper, the steady-state performance of a self-excited induction generator (SEIG) under various operating conditions is evaluated using a MATLAB-based solver.
Abstract: Self-excited induction generators (SEIG) are increasingly being used in isolated areas to generate electrical energy from both conventional and nonconventional energy sources. This paper proposes a novel method of evaluating the steady-state performance characteristics of a SEIG under various operating conditions. The criteria for the constant terminal voltage and the constant-stator-current operations are also derived and embedded into the system of equations. Unlike the previous methods of analysis, the problem is formulated in a simple and straightforward way without going through lengthy and tedious derivation for the coefficients of a set of nonlinear equations. The formulated problem is then solved using a numerical-based routine ldquofsolverdquo given in MATLAB. The effectiveness of the proposed method is then evaluated on a 220-V, 1.5-kW induction generator for various operating conditions. Some of the simulation results obtained by the proposed method are also compared with the corresponding experimental values and are found to be in very good agreement.

108 citations


Cites background from "Terminal voltage regulation charact..."

  • ...Mathematically, the earlier relationship can be expressed in many ways, such as an exponential function [1], [19], a linear function [7]–[12], [20], a piece-wise linear function [15], [21], [22], or a higher order polynomial [18], [23], [24]....

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  • ...Maintaining constant voltage or constant current requires continuous control of excitation capacitor, which can be achieved by using a static var compensator [22] or a static compensator [23]....

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Journal ArticleDOI
TL;DR: Different control principles, indirect vector control and deadbeat current control, are developed for a voltage source pulsewidth-modulation (PWM) converter and the three-phase variable-speed squirrel-cage IG to regulate dc link and generator voltages with the newly designed phase-locked loop circuit.
Abstract: This paper describes simple control structures for the vector-controlled stand-alone induction generator (IG) used to operate under variable speeds. Different control principles, indirect vector control and deadbeat current control, are developed for a voltage source pulsewidth-modulation (PWM) converter and the three-phase variable-speed squirrel-cage IG to regulate dc link and generator voltages with the newly designed phase-locked loop circuit. The required reactive power for the variable-speed IG is supplied by means of the PWM converter and a capacitor bank to buildup the voltage of the IG without the need for a battery, to reduce the rating of the PWM converter with the need for only three sensors, and to eliminate the harmonics generated by the PWM converter. These proposed schemes can be used efficiently for variable-speed wind energy conversion systems. The measurements of the IG systems at various speeds and loads are given and show that these systems are capable of good ac and dc voltage regulations

105 citations

Proceedings ArticleDOI
28 Nov 2005
TL;DR: In this article, the static reactive compensator (STATCOM) based on voltage source converter (VSC) PWM technique is proposed to stabilize grid connected squirrel cage wind generator system.
Abstract: Recently voltage-source or current-source inverter based various FACTS devices have been used for flexible power flow control, secure loading and damping of power system oscillation. Some of those are used also to improve transient and dynamic stability of wind power generation system (WPGS). In this paper, we propose the static reactive compensator (STATCOM) based on voltage source converter (VSC) PWM technique to stabilize grid connected squirrel cage wind generator system. A simple control strategy of STATCOM is adopted where only measurement of rms voltage at the wind generator terminal is needed, i.e. there is no need of reactive power measurement. Fuzzy logic controller is used as the control methodology of STATCOM, rather than conventional PI controller. The voltage sag and swell improvement of WPGS is compared with both fuzzy and PI controller. Moreover, the steady state capacitor value used with induction generator is reduced by certain percentage when STATCOM is used with WPGS. Comprehensive results are presented to assess the performance of the STATCOM connected with WPGS, where the simulations have been done by PSCAD/EMTDC.

62 citations


Cites methods from "Terminal voltage regulation charact..."

  • ...Abstract- Recently voltage-source or current-source inverter voltage of induction generator by compensating the reactive based various FACTS devices have been used for flexible power power [4]....

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References
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01 Feb 1994
TL;DR: In this article, the static var compensator is now mature technology that is widely used for transmission applications and a standardization of basic models is recommended, and is recommended in this paper.
Abstract: The static var compensator is now mature technology that is widely used for transmission applications. Electric utility industry standardization of basic models is needed, and is recommended in this paper. Description and model requirements for more detailed representations, including supplementary function modules, are included. In addition to transient stability program modeling, requirements for power flow and longer-term dynamics programs are given.

242 citations

Journal ArticleDOI
10 Dec 2002
TL;DR: In this article, the effect of magnetizing inductance on self-excitation was discussed and the loading analysis of an isolated induction generator, and how the operating frequency and generated voltage were affected by the change in operating slip value for regulated and unregulated rotor speed.
Abstract: This paper presents the effect of magnetizing inductance on self-excitation. It also describes the loading analysis of an isolated induction generator, and how the operating frequency and generated voltage are affected by the change in operating slip value for regulated and unregulated rotor speed. Wind-powered self-excited induction generators have an input wind which is not controllable, but they can be set to operate within a given variation of speed. The experimental and simulated results for a dynamic generated voltage, frequency, and power are presented. The dynamic electromagnetic torque produced by the induction generator is also given. A dSPACE DS1102 digital signal processor card is used for data acquisition and for control of the driven speed.

183 citations

Journal ArticleDOI
01 May 1990
TL;DR: In this article, the authors derived the minimum capacitance required for self-excitation and the output frequencies under no-load, inductive and resistive loads, and showed that there is a speed threshold below which no excitation is possible no matter what the capacitance value.
Abstract: Advanced knowledge of the minimum capacitor value required for self-excitation of an induction generator is of practical interest. To find this capacitor value two nonlinear equations have to be solved. Different numerical methods for solving these equations are known from previous literature. However, these solutions involve some guessing in a trial-and-error procedure. A new simple and direct method is developed to find the capacitance requirement under RL load. Exact values are derived for the minimum capacitance required for self-excitation and the output frequencies under no-load, inductive and resistive loads. These calculated values can be used to predict theoretically the minimum value of the terminal capacitance required for self-excitation. For stable operation C must be chosen to be slightly greater than C/sub min/. Furthermore, it is found that there is a speed threshold, below which no excitation is possible no matter what the capacitor value. This threshold is called the cut-off speed. Expressions for this speed under no-load and inductive load are also given.

161 citations


"Terminal voltage regulation charact..." refers background in this paper

  • ...…INTRODUCTION THE three-phase induction machine with a squirrel-cagerotor or a wound rotor could work as a three-phase induction generator either connected to the utility ac power distribution line or operated in the self-excitation power generation mode with an additional stator…...

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Journal ArticleDOI
TL;DR: In this article, a simple exciter scheme based on using a static reactive power generator implemented with fixed capacitors and thyristor controlled inductors is proposed. But the feasibility of the proposed scheme with naturally commutated thyristors is verified by measurements on a test setup employing a standard 15-hp induction motor.
Abstract: The utilization of the squirrel cage induction motor as an autonomous induction generator is briefly reviewed. In view of potential new applications, the discussion focuses on a simple exciter scheme based on using a static reactive power generator implemented with fixed capacitors and thyristor controlled inductors. The feasibility of the proposed scheme with naturally commutated thyristors is verified by measurements on a test setup employing a standard 15-hp induction motor.

142 citations


"Terminal voltage regulation charact..." refers methods in this paper

  • ...The adjustable excitation capacitor value can be achieved by many control strategies using power electronics technology [ 8 ]–[14]....

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  • ...The voltage regulation of the three-phase SEIG driven by a CSPM using static var compensator (SVC) of the thyristor-controlled reactor (TCR) with a fixed capacitor (FC) has been presented as an experimental work in [ 8 ]....

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Journal ArticleDOI
TL;DR: In this article, a new strategy for controlling voltage and frequency of a self-excited induction generator (SEIG) is presented, which operates in the linear region of the core magnetizing curve, so that efficiency and performance are upgraded.
Abstract: A new strategy for controlling voltage and frequency of a self excited induction generator (SEIG) is presented. The SEIG operates in the linear region of the core magnetizing curve, so that efficiency and performance are upgraded. An external excitation circuit, comprising permanently connected capacitors and electronically switched inductances is used. The external circuit allows to compensate for the generator reactive demand. A detailed analysis is performed, showing some salient aspects related to the connection of the external excitation circuit on the control performance. Asynchronous switching is used, but some important considerations must be taken into account related to the instantaneous phase angle between stator voltage and external inductor current at the switching instant, if good transient response is desired. Sliding mode controllers are proposed, showing good dynamic response and robust behavior upon changes in load and generator parameters. Computer simulations are used to demonstrate the validity of the proposed scheme.

141 citations