Steady-state analysis of an isolated self-excited induction generator driven by regulated and unregulated turbine (original) (raw)
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— Capacitor-excited induction generator offers certain advantages over a conventional synchronous generator as a source of isolated power supply. Main advantages are reduced cost, less maintenance, self protection from short-circuit and overload condition. It is used as variable speed generator for different applications such as wind energy conversion, micro hydropower generation. Therefore it is now a key interest to develop an efficient and viable generator for harnessing the energy from renewable sources. Steady state analysis is important for the design and control point of view to develop an efficient, viable economic and controllable induction generator; we must know the overall performance of the generator. In this work, the steady-state performance of a capacitor excited induction generator driven by an unregulated turbine is analysed both incuding and excluding the iron-losses. The speed is considered as a variable for the unregulated turbine case. The steady-state equivalent circuit is solved using the node admittance method, and the shaft torque is expressed in terms of the rotor current. The newton raphson method is used to solve the system nonlinear equations. For the present investigation, a linear speed-torque characteristic is considered, but the method of analysis applies equally well to nonlinear characteristics.
Steady-State Analysis of Three-Phase Self-Excited Induction Generator for Stand-Alone Applications
Self-excited induction generator offers certain advantages over a conventional synchronous generator as a source of isolated power supply. Main advantages are reduced cost, less maintenance, self protection from short-circuit or overload condition, and brush less rotor. It is used as variable speed generator for different applications such as wind energy conversion, micro hydropower generation. Therefore, it is now a key interest to develop an efficient and viable Generator for harnessing the energy from renewable sources. To develop an efficient, viable, economic and controllable induction generator, we must know the steady-state performance of the generator. Using steady state equivalent circuit model excluding iron losses, steady state performance analysis has been done. Experimental investigations under steady state condition have been done in the laboratory. I. INTRODUCTION Electrical energy is the basic necessity of any country for its overall development. Fossil fuels (Coal, Oil, and Diesel) are the main sources of electrical energy (about 60% in our country). Fast depletion of fossil fuels results insecurity of availability of fossil fuels, subsequent increase in energy cost, the environmental pollution and above all the global warming. This has brought the worldwide attention in reducing the pollution and conservation of the limited conventional fuels by encouraging more and more use of the energy available from the non-conventional/renewable sources such as the wind, the biogas, the tidal waves and the small hydro power stations on the running canals and rivulets etc. The potential of the energy available from the small hydro and the wind sources seems to be quite promising to meet the future energy demands, especially in the remote and isolated areas. However, these systems will become more viable if their cost is reduced to the minimum. Therefore, the squirrel cage rotor induction generators are receiving much attention for such applications due to its low cost and robust construction[1-4]. The Self-Excited Induction Generators (SEIGs) are receiving increased attention from the utilities over the world to obtain the energy from renewable/non-conventional sources for remote and isolated areas. The main problems in the use of induction machine as a generator are related to the varying voltage and frequency, the loss of self-excitation, the overloading of the machine, the transient over voltages due to the capacitance switching or the load loss. But, the robust construction of induction machine specially squirrel cage type rotor, offers maintenance free operation and the least cost of the generating system. This has motivated to facilitate the use of the induction generator in isolated mode with suitable low cost control which could ensure the reliable supply of good quality. Also, such system for power generation could be made efficient and cost effective to compete with the other conventional energy sources[2-5]. The main objectives of this work are as follows:
35 Steady State Analysis of Wind Driven Self Excited Induction Generator
This paper basically deals with the steady state analysis of Self excited induction generators. MATLAB user friendly toolbox has been used to predict the performance of SEIG under different loading conditions. In this paper the algorithm to find the minimum capacitance required to calculate the excitation capacitance has been stated using the steady state analysis. In this model the excitation capacitance and the speed of the SEIG is kept constant and the experimental results and simulated results are verified.
Design Calculation of Three Phase Self Excited Induction Generator Driven by Wind Turbine
2019
The three phase self excited induction generator is driven by prime mover such as a wind turbine for the clean alternative renewable energy in rural area. The dynamic voltage, current, power and frequency developed by the induction generator have been analyzed. The dq modeling approach for transient state analysis in time domain of the three phase self excited induction generator with squirrel cage rotor is presented along with its operating performance evaluations. And calculation of total impedance regulation, capacitance required to excitation, efficiency and torque required to drive the 3.6 kW SEIG are included. Theingi Htun | Hnin Yu Wai | Myo Win Kyaw "Design Calculation of Three-Phase Self-Excited Induction Generator Driven by Wind Turbine" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26728.pdf
International Journal of Emerging Electric Power Systems, 2000
This paper presents the steady-state and transient behavior of a single-phase self-excited induction generator (SEIG) using a three-phase machine with one shunt and one series excitation capacitors for resistive and inductive loads. The generation scheme consists of one three-phase delta connected induction machine and two capacitors -one connected in parallel with one winding and the other in series with a single-phase load. The dynamic model of the system has been developed as a hybrid model considering the stator phase currents in abc reference frame and the rotor currents in stationary d-q axes reference frame as state variables. The simulated and experimental results are presented for different dynamic conditions such as initiation of selfexcitation, load perturbation and short-circuit. The simulated results of the steady-state analysis have been compared with the transient and experimental results and a close agreement between them indicates the accuracy and effectiveness of the approach.
Steady State Analysis of Self-Excited Induction Generator
Lalit Goyal & Om Prakash Mahela , 2013
Induction generators are increasingly used in non-conventional energy systems such as wind, mini/micro hydro etc. In isolated systems, squirrel cage induction generators with capacitor excitation, known as self-excited induction generators (SEIG), are very popular. Steady state analysis for such machines is essential to estimate the behavoir under actual operating conditions. A 5.5KW induction machine excited with symmetrical capacitor bank and loaded with resistive or resistive-inductive load was the subject of investigation. A simple mathematical model is proposed to compute the steady-state performance of self-excited induction generator by nodal admittance model. MATLAB programming is used to solve the proposed model. The results confirms the validity and accuracy of the MATLAB based modeling of self- excited induction generator.
Analysis of wind driven self-excited induction generator supplying isolated DC loads
Journal of Electrical Systems and Information Technology, 2017
This paper presents the analysis, modelling and simulation of wind-driven self-excited induction generator (SEIG). The three-phase SEIG is driven by a variable-speed prime mover to represent a wind turbine. Also, the paper investigates the dynamic performance of the SEIG during start-up, increasing or decreasing the load or rotor speed. The value of the excitation capacitance required for the SEIG is calculated to give suitable saturation level to assure self-excitation and to avoid heavy saturation levels. Matching of the maximum power available from the wind turbine is performed through varying the load value. The effect of AC-DC power conversion on the generator is investigated. The system simulation is carried out using MATLAB/SIMULINK toolbox program.
A Simplified Approach for Steady-State Analysis of the Isolated Self-Excited Induction Generator
International Conference on Aerospace Sciences and Aviation Technology, 1989
This paperpresents a new approach for analysing the steadystate performance of the isolated self-excited induction generator feeding R-L load using the conventional equivalent circuit of the machine. The approach is shown to be very efficient in analysing such systems under steady-state operation. Effects of various system parameters on the steadystate Performance have been studied. It is shown that the analysis can be used to predict the terminal capacitance required to maintain a constant terminal voltage. The presented .simulation results provide guidelines for optimum design of such systems.
State modelling of self-excited induction generator for wind power applications
Wind Energy, 2006
The increase in wind power production with self-excited induction generators (SEIGs) has led to new kinds of protection and stability problems. Suitable state models of a wind plant with SEIGs must accurately simulate balanced and unbalanced transient phenomena for adequate calibration and control of protection devices. However, the SEIG models currently available are unable to simulate the neutral current following unbalanced faults for forecasting the SEIG insulation and protection needed against some network stresses. In addition, the saturation model commonly used is not flexible when deriving a state model. This article presents an effective electromechanical state model for transient analysis of a saturated SEIG for wind power applications. A neutral connection through impedance is included for exact modelling of a Park wye-connected SEIG. Simple-shunt and short-shunt (series) configurations are explored. A comparative analysis of the effects of these two types of configuration on the steady state and transient performances of an SEIG is presented. Numerical and experimental data obtained with a 380 V, 5•5 kVA, 11•9 A, 50 Hz induction generator are presented to attest to the effectiveness of the proposed SEIG modelling framework. Among the results obtained, simulations show that the simple-shunt configuration produces poor voltage regulation, possible voltage collapse and inherent protection against short-circuit faults, while the short-shunt connection provides better voltage variation but needs to be well protected against short-circuit faults.
Wind Driven Induction Generator Study with Static and Dynamic Loads
This paper presents the performance of a stand-alone self-excited induction generator (SEIG) under balanced/ un-balanced excitation with balanced RLC and dynamic load. Squirrel cage induction motor has been taken as a dynamic load. SEIG is driven with fixed pitch wind energy system. An approach based on three-phase induction machine model is employed to derive dynamic equations of an isolated SEIG under balanced/unbalanced conditions of excitation and balanced static and dynamic loads. The SEIG model with balanced/un-balanced excitation and balanced load has been simulated using MATLAB/SIMULINK.