نشریه انرژی ایران
سال دوازدهم شماره 2 (پیاپی 43، تابستان 1388)

Today, the increasing need for maximum utilization of existing transmission systems and developing new types of static and controllable reactive power Compensating devices, the necessity of shunt capacitors in the distribution system is made more and more evident. Because the loads of a distribution network was not permanently employed and change during every hours a day and to prevent increases in network voltage due to capacitors existence, capacitor switching must done effectively so that in times that voltage increases, the installed capacity can be controlled.In this paper a control scheme to determine the optimal capacity of switched capacitors in distribution networks using genetic algorithm is presented and optimized capacity with the aim of maximizing the benefits from network and HV / MV transformers loss reduction, with considering costs in Purchase, installation and maintenance of capacitors were obtained. Finally, the maximum number of capacitor banks on each load node, with considering the daily changes, optimum mode of capacitors switching is determined.

The daily increase of organic waste materials resulting from different activities in the country is one of the main factors for the pollution of environment. Today, with regard to the low level of the output of using traditional methods, the high cost of disposal waste materials and environmental pollutions, the use of modern methods such as anaerobic digestion for the production of biogas has been prevailing. The collected biogas from the process of anaerobic digestion, as a renewable energy source similar to natural gas but with a less methane and heating value is usable. Today, with the help of technologies of filtration and proper preparation, access to biogas with features fully similar to natural gas has become possible [1]. At present biogas is one of the main sources of supplying electrical and thermal energy and also an appropriate option to be used in four stroke engine, diesel engine, sterling engine, gas turbine, gas micro turbine and fuel cell to produce electricity [2]. The use of biogas for different reasons which returns to socio-economic and environmental advantages has been noticed in CHP for the production of energy in the world [3, 4]. The production of biogas from the technology of anaerobic digestion and its application in CHP power plants in Iran can not only supply part of the energy demands in the country, but it can materialize moving in line with the sustainable development. In this article, the necessity of the development of CHP plants with biogas fuels in the country will be dealt based on studies performed from the economic, environmental and social aspects. Also to prove the importance of the establishment of these kinds of power plants from the economic point of view, necessary calculations has been done as a case study for a CHP power plant with a biogas fuel.

In this paper photovoltaic as an attractive power generation method among other renewable energy features has been studied and concentrated. Extracting power from Sun is attracting attention increasingly and day by day because of clean nature and it’s no fuel requirement. Producing standard power from the point of view of power quality has obligated researchers to focus on output PV system parameters and control it in an appropriate way.In Dc part PV modules has been modeled and also DC/DC converter has been designed and simulated especially for PV application. An important topic in this section witch directly affects whole system efficiency is the techniques of maximum point of Power (MPPT). Applied method in this work is incremental conductance method which has been selected among other techniques as the best one duo to previous studies. In AC part which is the main concern of paper, new method for controlling point of common coupling is introduced that is specially working in large scale PV power plants. It is suggested in this paper to identified PV bus bar in power grid as a PŪ bus and apply it in load flow calculations. In this regard the second main idea of paper is reactive power injection which is studied under voltage control and stabilizing idea.

Compressed Air Energy Storage (CAES) technology has become an acceptable solution in managing peak load power demand with the ever-increasing emphasis on combining renewable baseload electricity generation. In these power plants, the unused energy during off-peak periods is stored in huge underground salt caverns to be consumed later for electricity generation following a reheat in a gas turbine during the peak hours, thereby allowing 2/3 of the turbine energy which is utilized for compressing air to be available for electricity generation during the peak hours. In this article, CAES plants and operational researches obtained during the last three decades of experiments with two plants of 290 MW at Hantrof, Germany and 110 MW at Alabama, USA have been explained, also, latest generations of these CAES plants and their developments in conjunction with the potentials of Iran in utilizing her salt domes for optimum power production are discussed.

Regarding the availability and enormous amount of natural gas in Iran and as a suitable substitute, it has become an alternative fuel for running internal combustion engines. In this paper five different composition of Iranian natural gas from the pollution and performance point of view in dedicated (100% CNG) engine, namely 135Ti are studied. It should be noted that in all other investigations the pure methane has been applied. While, in the current work a multi-component gas mixture was employed. Two zone combustion model has been developed for obtaining the amount and properties of the combustion products and pollutants including The other investigation in this thesis includes the calculation of adiabatic flame temperature for Iranian natural gases using a single zone model. In the next step, optimized gas components are utilized as a fuel for mentioned engine. The computational results based on this model are compared with the ones obtained by experiment, In which good agreement would exist.

In this Paper, Burner Management System and relevant protections survey on LOSHAN Thermal Power Plant. The new control system is dedicated to combustion safety and operator assistance in the starting and stopping of fuel preparation and burning equipment and for the preventing misoperation designed according to NFPA 85 standard for restrain of boiler explosion. However, The new design modified logic for boiler purge, interlocks for burners start up and shutdown and boiler protections and logic main valves in boiler.

This paper investigates the power sector status among other economic sectors and also the interrelationship between this sector and other sectors using an input-output analysis. The Hirschman - Rasmussen forward and backward linkages index shows that among 64 sectors, the rank of power sector in demand for the output of other sectors and the supply of other sectors input is 27 and 17 respectively. The power sector has the highest rank among other energy sectors from forward linkages point of view and has the 4th rank after coal, gasoline and gasoil in backward linkages point of view. Steal, metal spar, cement, plaster and lime, steel and ironic products and water industries have the highest responsiveness from the growth in power sector value added while land carriage, financial services, insurance and banking, railroads, forestation and educational services industries have the minimum responsiveness from the electricity sector growth. An increase in the power sector value added has the most effect on the output of industrial sector. The power sector also has the highest output multiplier among other energy sectors so that a 1 Rial increase in the final demand for this energy carrier can increase the output of the whole sectors by 2 Rials. Gasoil, kerosene and gasoline have the highest output multiplier after power sector; however there is not a considerable difference between the output multiplier of various energy sectors.