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Current grid codes require the fault ride-through capability of modern wind turbines. During grid faults the reactive current control of the wind turbines should be used to support the grid voltage. With modern protection devices the fault durations are normally in a range of some hundred milliseconds or less. However this time window may be decisive for the stability of the conventional generators...
Wind energy is the fastest growing source of renewable energy in the power industry and it will continue to grow worldwide as many countries are developing plans for its future development. For power system operators, this increasing contribution of wind energy to the grid poses new challenges that need to be addressed in order to ensure the reliability and security of the electric power grid. One...
The control algorithms proposed in the literature so far for the Double Output Induction Machine Based Variable Speed Constant Frequency (VSCF) stand alone generators suffer from the disadvantage of loss of `field orientation' during sudden load disturbance at the machine terminal. As a result, undesirable transients are observed in the load voltage during such transients. This paper presents a new...
This report is an annual progress report by the Generator Subcommittee of the Electrical Machinery Committee of the IEEE Power and Energy Society, Working Group No. 8 (“IEEE C50.13 Review & Compare”). This working group is tasked to compare the 2005 revision of the IEEE C50.13 standard for large round rotor synchronous generators with recent revisions of comparable International Electrotechnical...
This paper provides an overview of four distinct applications of advanced permanent magnet machine technologies. It describes the specific application benefits that are accomplished with permanent magnet solutions for Oil&Gas, aviation, automotive, and wind turbine applications. The technology development for these four first-of-a-kind machines is presented, each of which advancing the state of...
This paper describes the use of generic wind turbine models to study the comparative inertial response of wind turbine technologies, that is, their response to a frequency event on the grid such as loss of generation. The dynamic models are manufacturer-independent and portable to any dynamic modeling software. Four dominant types of wind turbine technology are modeled; the basic fixed-speed model...
This paper investigates the settings of the generator out of step protection relays (ANSI device 78) for all six gas and steam turbine generators used in a grid connected CHP power plant. Detailed model of the CHP power system is developed in PSCAD/EMTDC tool which includes a representation of the synchronous generator, turbine governor, Automatic Voltage Regulator (AVR), Power System Stabilizer (PSS),...
This paper presents the design and analysis of a direct-coupled radial-flux permanent magnet generator (PMG) for wind turbine applications. The analysis of the design was carried out using finite-element analysis (FEA). The design data is used in optimizing the configuration and magnetic flux density of the PMG. For evaluating the performance of the proposed PMG, the prototype generator is implemented...
The overexcitation limit of synchronous generator plays an important role in the voltage stability of power systems. Achieving maximum use of the overexcitation capability requires adequate coordination between generator control and protection. This paper provides an example of coordination between overexcitation limiter (OEL), field overcurrent protection and automatic voltage regulator (AVR) for...
The use of a series-connected self-excited synchronous generator for isolated distributed generation is investigated. Such a machine may be realized by connecting the stator and rotor windings of a slip-ring induction machine in series, but with reversed phase sequence. The advantage of the machine configuration is high power density and high-speed operation. Both phasor diagram and time-stepping...
Summary form only given. A new method for predicting the rotor angle stability status of a power system immediately after a large disturbance is presented. The proposed two stage method involves estimation of the similarity of post-fault voltage trajectories of the generator buses after the disturbance to some pre-identified templates and then prediction of the stability status using a classifier...
This paper presents the magnetic suspension test results of a bearingless motor/generator for flywheel energy storage systems. A prototype bearingless motor/generator is built on the basis of the computed results by Finite Element Method (FEM). It is an outer rotor-type permanent magnet (PM) synchronous motor/generator and the rotor is wrapped by the flywheel (CFRP). Thus, the motor/generator, the...
This paper illustrates a new technique that identifies coherent clusters of synchronous generators in multi-machine power systems. The technique can be easily implemented in a wide-area measurement system. The importance of fast identification of coherent groups of generators based on wide-area signal measurements lies in its contribution to the design of wide-area based stability control schemes...
This paper proposes a new vector-based hysteresis current regulator (VBHCR) in the rotor-side converter of DFIG to enhance the control performance under unbalanced supply voltage condition. The “Γ-form” is used for the equivalent circuit of the machine to reduce the modeling complexity. This is followed by presenting the principle and practical implementation of the proposed VBHCR in the DFIG application...
Present coordinated controllers of thermal generating unit are mainly designed based on the simplified model of generating unit. In the simplified model, the dynamics of generator are omitted, and thus present controllers can not meet the requirements of various operating states in real multi-machine power systems. In this paper, integral model of generating unit (including the models of boiler, turbine...
Doubly-Fed Induction Generators (DFIGs) are commonly utilized in wind farms nowadays due to their advantages as compared with single fed ones. Control complexities and their unique dynamic characteristics may, however, raise different problems during abnormal or faulty operating conditions. Accordingly, the behavior of the associated protective elements at the Point of Common Coupling Point (PCC)...
The authors have studied the saturation characteristic of equivalent circuit of cylindrical synchronous machine. Using the measured data, the authors have studied the effect on the saturation characteristic of equivalent circuits by the finite element method (FEM) and the electromagnetic transients program (ATP-EMTP).
An efficient discrete-time approach for the computation of the steady-state operating point of a wind park is presented in this paper. The Finite Differences method and a Newton approach are applied to determine the steady-state solution of the wind park. Besides, the incorporation of sparse techniques improves the efficiency of the discrete-time solution in terms of storage and computational effort...
This paper analyzes the impact on transient and frequency stability for a power system at very high wind penetration (40% wind). Wind penetration is based on the doubly-fed induction generator (DFIG), and a systematic approach has been adopted for wind power integration. A sensitivity analysis has been carried out for each wind integration scenario and for different wind generator loading conditions...
A DFIG wind turbine is a variable-speed wind turbine widely used in modern wind power industry. The maximum power extraction of the turbine is affected by (1) electrical characteristics of the generator, (2) aerodynamic characteristics of the turbine blades, and (3) maximum power extraction control strategies. This paper presents a DFIG maximum power extraction study through integrated steady-state...
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