International Journal of Advanced Renewable Energy Research
Volume:1 Issue: 4, 2012

Contra-rotor Axial Flux Brushless Induction Generators (CRAFBIGs) have several advantages over other conventional inductions generators. In this paper a novel approach for modeling of a CRAFBIG is presented. This model allows the prediction of steady state performance of the CRAFBIGs. To validate the proposed modeling approach, a prototype of a CRAFBIG was constructed and tested. The results of experiment revealed the effectiveness of the proposed modeling approach for prediction of steady state performance of CRAFBIGs.

Nowadays, renewable energies have taken special place in power systems, and most of the distributed generations (DGs) in the power system also utilize these types of energy resources. Due to the DGs advantages, including the use of renewable energy which are not polluting environment and owning endless nature, the use of these resources to produce electrical energy in the world are being increased. One problem with such generators is the unwanted islanding phenomenon. In this paper, a new technique to detect islanding conditions has been proposed, and since the method is a combination of previous methods, its performance is much more appropriate than those previous methods. This method is efficient either for DGs connecting to the network through inverter or without inverter. Since the technique is a hybrid method of previous methods so it has so much better performance than the previous methods. Simulation results which are carried out on the software PSCAD/EMTDC shows the good performance of this method.

The oscillating water column (OWC) device is one of the commonly used wave energy convertor, OWC comprises a partly submerged structure open below the water surface, inside which air is trapped the above the water free surface. The oscillating motion of the internal free surface produced by the incident waves causes the air to flow through the turbines that drive the electric generators. One of the important factors in the analysis of OWC performance is the outgoing air pressure for turbine circulation and electricity generation. This paper considers the efficiency of OWC using finite difference numerical simulation. For fixed OWC device in potential equation solution, the radiation potential term is ignored. However, the significance of this modeling is assuming the inertial water free surface of the OWC as a floating rigid body. Hence, the radiation potential term is considered in the model leading to more accurate results. Analysis is performed in frequency domain based on linear wave theory and potential flow. The results were validated against experimental data.

When air moves, it has kinetic energy- the energy evolved whenever any mass is in motion. The kinetic energy of the wind can be put to work by capturing and converting it to other forms of energy such as electrical or mechanical power, with the help of appropriate technology. The wind power thus obtained is clean and should be considered an important component of any longterm energy strategy. To establish as a sustainable source of electricity it is required to investigate three major aspects of wind generated electricity: power generation using turbines, transmission mechanism, and power losses. In this paper we provide a review of existing generation and transmission technologies used in wind generated electricity along with a discussion of different types of transmission losses.

In renewable hybrid system, climatic changes decrease the reliability of load supply. For that, diesel generators are used as auxiliary sources and combined with the wind-PV-battery hybrid system, which ensure a reliable supply without interruption. This paper discusses an optimization solution including sensitivity analysis for a hybrid system of renewable energy, and shows that the importance of the emergency generator in order to increasing the reliability and the economy cost of the system. HOMER developed by National Renewable Energy Laboratory (NREL) is used for our analysis. The sensitivity analysis is done based on wind speed data and solar radiation as variables in Kish island in Iran.

Pakistan is an energy deficit country and the electricity mix of the country is heavily tilted towards imported oil that is approx. 35 percent; which makes its electricity sector highly vulnerable. Pakistan is blessed with abundance of wind resource. A satellite mapping conducted by USAID in collaboration with NREL suggests a gross potential of 346,000 MW that can be generated with wind energy all across the country. Out of this estimated potential a single corridor along the Gharo‐Keti Bandar area in the southern coastal region offers a potential of 50,000 MW. However, Pakistan was a late entrant to the avenue of commercial‐scale wind development. Pakistan’s Wind Energy Programme was initiated in 2004 at a time when no verifiable resource data, policy and regulatory framework were in place. Pakistan’s first ever Renewable Energy Policy was issued in December 2006, which along with several liberal incentives, introduced the unique concept of wind risk, whereby the investor is made immune to the risk of variability of wind speed. Currently various projects with a cumulative capacity of 1200 MW are at various stages of development. Pakistan’s first ever commercial‐scale wind energy project has been completed by Zorlu Enerji of Turkey in 2009. Due to the current political and financial climate surrounding the country, wind projects have stalled as perceived risks have forced both the lenders and investors to adopt a very careful approach. To combat this and catalyze the sector, State Bank of Pakistan has announced a Refinancing Facility for projects up to 10 MW till June 2012. Asian Development Bank also through its Renewable Energy Development Sector Investment Program (REDSIP) for Pakistan is back stopping country risk and payment risk of power purchaser for first few projects of 50 MW.

The study offers comprehensive details on the analysis of wind gust in different windy sites in Bangladesh. Gust is the irregular wind behavior. The data has been collected from 18 wind monitoring stations which have been installed for searching wind power potential under the project entitled “Wind Energy Resource Mapping in Bangladesh”. Wind gust factor has been calculated for different locations and analyzed. It also finds out the wind force and torque acting on the power grid towers, wind turbines tower and blades. It has been obtained the effect of wind gust on turbine base constructions and broken it blades. The total theoretical power of the wind gust has been calculated. In every station, wind gust velocity has been obtained mainly from March to September. The measured gust varies from gale to violent storm type gust. But in some cases Hurricane class gust has been obtained.