Directional overcurrent relays utilize the voltage phasor as a reference for determining the direction of the fault. This requires measuring both current and voltage and makes the directional overcurrent relays more costly than the non-directional type. In this paper, a new method for detection the fault occurrence and fault direction is proposed, that is based on Teager energy operator. Teager energy operator is a simple algorithm that is used to signal processing and extraction of instantaneous changes in amplitude and frequency of a signal. To this end, the proposed algorithm uses only three consecutive samples of measured current signal for detection of fault and its direction. This method does not require phasor estimation and complex calculations. In addition, the method is very fast. This Algorithm is implemented and verified for different types of fault and several conditions using Matlab/Simulink. The simulation results show that the proposed method is fast and has acceptable accuracy.

Iran is facing large challenges in the area of energy policy. In order to illuminate these challenges and the problems and possibilities, which are present, firstly, the current energy consumption patterns have been analyzed in Iran as well as the energy policy of the Iranian government. Based on this analysis, the alternative concepts have been then formulated for Iran`s future energy. The increase in energy usage in Iran is distinctly out of proportion with the development of economic productivity. Negative structural characteristics of this system are: first, an above average energy intensity; second, an increase in energy consumption in the traffic sector; third, a high growth rate in usage of electric energy; and lastly, an above-average amount of stress to the environment. Traditionally, Iran`s energy policy has focused on satisfying the growing demand for energy by oil and, in the last fifteen years, by successively expanding natural gas. However, the further development of the natural gas supply only makes sense within the context of a holistic energy policy, which takes into account the principles of sustainable development. In the short term, such a policy would take advantage of both considerable energy saving techniques, as well as potential renewable energy sources. In the long term, such a policy would strive for the complete transfer to renewable energy sources and technology.

The problem of neutral current compensation has to be addressed in Wind Energy integrated weak microgrids. This study analyses two types of techniques possible for implementation of neutral current compensation by drawing a comparative research of their application on the same wind energy conversion system. The hybrid microgrid considered in the study comprises a synchronous diesel generator and an inverter-based wind generator. The results and analysis are conducted by time-domain simulations using MATLAB/Simulink software. The use of electronic power converters that also act as an active neutral current compensator or a zig-zag transformer connected with the load mitigates the problem of neutral current compensation to a large extent. The voltage unbalance factor is also significantly reduced due to neutral current compensation and power quality is enhanced. The results provide the actual operational limits possible under the set of given constraints.

During the last decade, serious issues such as the energy demand, depletion of fossil fuels, and their environmental impacts have drawn attention towards the renewable energy sources. In addition, the energy supply chain of Iran is deeply reliant upon fossil fuels. Further obstacles such as electricity blackouts in the hot season and future energy security require us to address these issues. For this reason, the growing consensus is to dominate a sustainable energy system on the grounds of energy, especially the renewable energies, with a low emission and pollution. The mean annual solar radiation in Iran is 2200 kWh/m2, which is greater than the worldwide average, due to locating on the world's Sun Belt. The total installed capacity of solar energy in Iran is not significant; however, it is growing annually. Moreover, the Persian Gulf coasts could provide the possibility of using the tidal energy of the ocean as well as the Caspian Sea coast that are suitable sites for thermal energy. Currently, 550 MW of renewable energy is being built in Iran, and the installed capacity of renewable energy has reached 575 MW. Renewable energy has also led to the employment of 47, 321 people directly and indirectly in the country. The installed capacity of Iran’ s wind power is about 259 MW (45% of the total renewable energies installed capacity), which is mostly located in Manjil and Roodbar. The biogas energy in Iran is mainly produced from domestic and industrial sewage/waste, animal waste, and agricultural product waste.

The sugarcane agro-industry is seen as a great opportunity for economic and industrial development in many sugarcane-producing countries. Important changes happening in recent decades have converted the sugar mill from being just a food producer into a diversified production factory. The sugar mill has become a multipurpose factory since it produces food, energy, and biofuels at present. The key cause of this change is the use of sugarcane agro-industrial residues as feedstock for energy cogeneration and biofuel production.The main aim of this paper is to carry out an assessment on sugarcane feedstock availability and its energy use in the sugar mill. The trade-off on sugarcane bagasse energy use (electricity cogeneration vs. bioethanol production), considering the agro-industrial development level, is analyzed in this work, too. The better options in each case are highlighted. The main environmental and techno-economic aspects concerning the sugarcane agro-industry were taken into account during the assessment process. The most promising trends of the sugarcane agro-industry and the barriers to overcome in its implementation are pointed out.

This research focuses on the effect of passive methods in the field of energy storage, produce energy by using renewable energies, and also to achieve the construction patterns of residential buildings in the climate conditions of Shiraz, with the aim reducing energy consumption. Statistics show that in Iran, fuel consumption in residential and commercial buildings with an average annual growth of 7. It is about 2.37% of the country's total fuel consumption. One way to minimize energy consumption in this sector is to increase the role of zero-energy buildings. Zero-energy buildings provide technical ways to consume less energy in buildings. These buildings are designed and built so that all or a large part of these provide the energy they need through the combination of energy saving and the use of renewable energy technology. In this research, after studying the climate condition of the city of Shiraz, a building in the Energy Plus software, the simulation and climatic data of the Shiraz station was introduced to the software. To achieve the most optimal conditions of energy consumption in the climatic conditions of Shiraz, each of the building elements Residential was optimized. The simulation shows that it is possible to reduce the energy consumption of the building by using passive building materials and designs, including double-glazed glass, Wall insulation, etc. On the other hand, by using solar energy, using pvsyst software, you can supply the energy needed by the building.