the most favorable prospects for its lower cost of investment, hence widely studied in Malaysia since the 1980s . Nonetheless, the average wind speed in Malaysia is low, thus creating a great challenge for commercial wind power generation. Concerning this issue, appropriate windturbinegenerators (WTGs) that can cope with such wind conditions should be chosen. Micro-type WTG seems to be the best option and will be applied in this study. RE related issues in Malaysia are managed by the Sustainable Energy Development Authority (SEDA) including a monitor and review of the Feed-in Tariff (FiT) system .
T HROUGH the desire for higher efficiency electric mo- tors and an increased use in all-electric transport and renewable energy applications, the demand for permanent magnet machines is increasing. The use of Permanent Magnet Generators (PMGs) in windturbine technology has proved to be an effective solution to many of the challenges faced by conventional generators  . In addition to the requirement of regular maintenance, the high failure rates associated with the use of gearboxes has driven the advancement of direct- drive, gearless systems  . The generators used for these turbines have a significant impact on the overall performance, which, in turn, affects the energy output and subsequently the ability to meet the reduction targets. Unfortunately, the low rotational speed means that the torque rating of these windturbinegenerators can be massive. The torque and the mass of
Condition monitoring systems are increasingly installed in windturbinegenerators with the goal of providing component-specific information to the wind farm operator and hence increase equipment availability through maintenance and operating actions based on this information. In some cases, however, the economic benefits of such systems are unclear. A quantitative measure of these benefits may therefore be of value to utilities and O&M groups involved in planning and operating wind farm installations. The development of a probabilistic model based on discrete-time Markov Chain solved via Monte Carlo methods to meet these requirements is illustrated. Potential value is demonstrated through case study simulations.
The synchronous generators are equipped with independent field winding which control the flux during the transient events. As the flux is independent of grid voltage, calculation of short circuit current is straight forward. Moreover the rotational speed is fixed and it has no slip like IGs. However, in case of asynchronous generators (IGs) flux being dependent on the grid voltage makes the calculation of short circuit current a bit complex and the standard IEC 60909 is not directly applicable . The fault current of IGs does not persist after finite time due to unavailability of flux in the event of terminal faults. The trapped flux diminishes based on IGs time constant . The short circuit current analysis of various types of windturbinegenerators is proposed in  for terminal faults for single machine infinite bus (SMIB) system. The paper addresses the difficulties that distance or over current relays can experience when they are used with different types of wind turbines. Analytical method for calculating the short circuit current is proposed in . The effect of different fault types i.e. symmetrical faults and asymmetrical faults, transformer configuration and reactive power compensation capacitors on different IGs have been shown in . The short circuit current contributions of different IGs for generator terminal faults are simulated using time domain simulations and steady-state calculations in . The authors have proposed a method to calculate the short circuit current for SMIB and the results have been compared
Abstract: —This paper presents the stability- improvement results of four parallel-operated offshore windturbinegenerators (WTGs) connected to an onshore power system using a static synchronous compensator (STATCOM). In this project have the fast advance of high-capacity power-electronics technology, large commercial windturbinegenerators can be practically employed to contribute high generated power to power systems, where wind PMSGs with full back to-back converters have proven to be good choices for high-power WTGs. Basically, the grid side converter of the PMSG- based WTG can be operated as a STATCOM. Many manufacturers also provide this option even for the case when the WTG is not running. But in a real PMSG-based OWF, It has several PMSG-based WTGs operating together, and it is difficult to control reactive power of all WTGs at the same time to supply adequate reactive power to the system. Hence, to guarantee good power quality (PQ) of the system, an additional VAR compensator is\ required. In this project, a STATCOM is proposed as a VAR compensator. It can be concluded from the simulation results that the proposed STATCOM joined with the designed damping controller can effectively improve the stability of the studied SG-based onshore power system under various disturbance conditions .The results are obtained from the MATLAB/SIMULINK environment.
We have developed an LES (Large-Eddy Simulation) code called RIAM- COMPACT (Research Institute for Applied Mechanics, Kyushu University, Computational Prediction of Airflow over Complex Terrain). The analysis domain of this numerical model extends from several meters to several kilo- meters. The model is able to predict airflow over complex terrain with high accuracy and is also now able to estimate the annual power output of windturbinegenerators with the use of field observation data. In the present study, a numerical simulation of turbulent airflow over an existing wind farm was performed using RIAM-COMPACT and high-resolution elevation data. Based on the simulation results, suitable and unsuitable locations for the operation of WTGs (WindTurbineGenerators) were identified. The latter location was subject to the influence of turbulence induced by small topographical varia- tions just upwind of the WTG location.
The PMSG in windturbine system are the challenging task which is obtained from the recent research work. The PMSG technique was used here based on the wind speed. From PMSG it has introduced comparison between two generators that is SPMSG and IPMSG. Various approaches are presented to improve the dependability of the system during the deficiency of grid like fuzzy logic control (FLC), direct drive flux switching wind generator, horizontal axis small windturbine (HAWT). The FLC is used in integrated and complex system; it has high precision and rapid operation. Lower speed and longer run time of the system and lack of real time response these all are the major drawback. The Direct drive wind generator is used to reduce the operating cost and also used to reduce the cost of maintenance. The Direct drive has large size drawback and it has heavy mass. Horizontal axis small windturbine was used to gives the turbine blades at the optimum angle of attack and it gives high efficiency. But the drawback is it cannot move perpendicular to the wind. Several methodological works have not been exhibited in the literature to address this issue. These disadvantages and issues have motivated to do this research work.
In this paper, a 6 MW surface-mounted Nd-Fe-B (SM Nd- Fe-B) generator is designed by following the work of McDonald and Bhuiyan , using flexible boundary limit for optimization to allow the maximum air-gap diameter. This 6 MW generator is then upgraded to 8 and 10 MW and compared with 6 MW SM Nd-Fe-B generator after optimization for offshore windturbine application. These are analytically designed and optimized in MATLAB and verified using finite element software. Two different objective functions are used for optimization to compare the best performance machine. Further optimizations were carried out for a 6 MW Nd-Fe-B generator using different neodymium magnet grades (N35 to N52) and operating temperature (“H” grade where maximum operating temperature 120°C and “Regular” grade where maximum operating temperature 80°C). In addition, steps were taken to estimate the effect of magnet temperature. A detailed thermal model is used to calculate the cooling airflow requirements to bring the magnet operating temperature from 120°C to 80°C. A number of fans and heat exchangers are used for the cooling system. The process of controlling cooling air flow for variable losses also shown after that.
two types. One is fixed speed windturbine and another one is variable windturbine. The most common type of windturbine is the fixed-speed windturbine with the induction generator directly connected to the grid. This system has a number of drawbacks, however. The reactive power and, therefore, the grid voltage level cannot be controlled. Most of the drawbacks of fixed windturbine are avoided when variable-speed wind turbines are used. These turbines improve the dynamic behavior of the turbine and reduce the noise at low wind speeds. But in variable speed windturbine power electronics converter is needed which makes the variable speed operation possible. Basically, a windturbine can be equipped with any type of three-phase generator, such as synchronous generator and asynchronous generator. Out of these, doubly fed induction generator which is type of asynchronous generator is more preferable because of its several advantages. The DFIG technology allows extracting maximum energy from the wind for low wind speeds by optimizing the turbine speed, while minimizing mechanical stresses on the turbine during gusts of wind. The optimum turbine speed producing maximum mechanical energy for a given wind speed is proportional to the wind speed. Another advantage of the DFIG technology is the ability for power electronic converters to generate or absorb reactive power, thus eliminating the need for installing capacitor banks as in the case of squirrel-cage induction generator. Some researchers believe that the DFIG should be used only for the purpose for which it has been installed, i.e., supplying active power only. The paper describes the current status regarding generators and power electronics for windturbine.
Wind power is one of the fastest growing electricity generation sources with 20% annual growth rate for the past 10 years. The vast majority of wind turbines that currently installed using one of the three main types of electromechanical conversion system: Squirrel cage induction generator, Doubly fed induction generator and Direct drive synchronous generator. Often, they are directly connected to the transmission grid and will, sooner or later, replace conventional power plants. Such wind farms will be expected to meet very high technical requirements, such as to perform frequency and voltage control, to regulate active and reactive power and to provide quick responses during transient and dynamic situations in the power system
The aim of this work is to improve the power quality for Distributed Generation (DG). Power quality is the combination of voltage quality and current quality. The electrical power quality is more concerned issue. The main problems are transient distortions in the line voltage such as swells, sags and voltage asymmetries. Distributed Generation (DG) also called as near load site generation, decentralized generation, generates electricity from the many small energy sources.In recent years, such as photovoltaic generation systems, windgenerators and micro gas turbines, etc., have increased with the deregulation of the power market. Under such circumstances the environment surrounding the electric power industry has become ever more complicated and provides high-quality power in a stable manner which becomes an important topic. Here DG is assumed to include PV panel. Advantages of this system are constant power supply, constant voltage magnitude, un-interrupted power supply.
etc. Many times there is not enough coal to generate the full load demand. In this case we can use non-conventional energy sources such as solar, wind, biogas, etc. to compensate the power generated by conventional energy sources. Grid synchronization is the combination of two or more grids to fulfill the load demand. When main grid does not satisfy the load demand then it is synchronized with another grid to meet the load requirement. In this arrangement we are considering main grid as conventional grid and another one as non- conventional grid.