per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
1
16
article
Determining the Maximum Capacity of Distributed Generation for Maintaining the Recloser-Fuse Coordination in Distribution Systems
A Farzanehrafat
1
AM Javadian
2
MR Haghifam
3
MT Bathaee
4
Traditional electric distribution systems are radial in nature, and are supplied through a main source. These networks have a very simple protection system, and its implementation is also very simple. Distributed generation (DG) is defined as energy sources connected to distribution systems. Presence of such energy resources in distribution systems is being extended rapidly because of its useful advantages, but such advantages can be achieved if the relevant concerns are deliberately taken into account. For example, penetration of DG currents results is not having a radial distribution network, and consequently losing protection coordination. This paper has analyzed and derived a set of equations of general characteristics of protection devices to represent such protection coordination and operating range constraints. This new approach is presented for determining the maximum capacity of distributed generation for maintaining the protection coordination. The proposed approach was implemented using MATLAB and Power Factory DIgSILENT on a simple distribution network and the numerical results is presented.
http://necjournals.ir/article-1-75-en.pdf
Distribution system
Distributed generation
Protection coordination
Recloser
per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
17
34
article
An Analytical Nonlinear Model for the Average Daily Consumption Duration of the Peak Load in Iran
H Shakouri G.
1
J Nazarzadeh
2
Electricity consumption in Iran has a high growth rate. It is important to analyze reasons of this phenomenon by a proper model that can include all affective factors. Based on the system approach, the two physical factors of energy, i.e. power and time, have to be investigated separately. There are so many models to predict the energy demand as well as other models studying the peak load growth. Meantime, there are a few researches on the average time of electricity consumption. This paper proposes a model on one of the two components of the Electrical Energy Demand: the Power and the Time, to investigate how each of the factors like climate, income and price affects energy consumption. This paper tries to separate long – run and short – run factors by focusing on a model for the latter. Considering various combinations of these factors in company with different types of nonlinear relationship, a nonlinear model is constructed to show how the average daily consumption time of the whole simultaneous peak load at the country changes with the climate, economic and/or social factors. For the variety of different combinations of these factors, also different possible candidate nonlinear functions, a vast number of models are analyzed and surveyed. Then a set of selected models is introduced and the best one is chosen via a fuzzy decision-making process. The winner model shows that besides deviations of the weather temperature from a certain moderate climate, any changes in the relative energy conveyors prices, also the per capita income will influence the time that an electrical device is used averagely during a day.
http://necjournals.ir/article-1-76-en.pdf
Energy Consumption
Energy models
Electricity Demand Forecast
Electirciy Consumption Duration
Peak Load Demand
Nonlinear Modeling
per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
35
44
article
A New Approach for Short Term Load Forecasting Based on Finding Similar Days
AH Vahabie
1
S Barghinia
2
N Vafadar
3
H Berahmandpour
4
Short term load forecasting (STLF) plays an important role for the power system operational planners and also most of the participants in the nowadays power markets. With the importance of the STLF in power system operation and power markets, many methods for arriving careful results, are represented. In this paper, an approach for STLF is proposed. The proposed approach is based on finding similar days. This approach is much simple than intelligent methods such as artificial neural networks (ANN) and fuzzy expert system (FES). The results of this method for Iran National Power System (INPS) is compared with ANN and FES results for STLF. The results shows that the idea of finding similar days used for STLF, can improve greatly the performance of the STLF.
http://necjournals.ir/article-1-77-en.pdf
Power Market
Power System Operation
Short Term Load Forecasting
Similar Days
per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
45
66
article
Modeling and Analyzing Daylight Saving Time Impact on Electricity Consumption: A Simulation Approach Based on Seemingly Unrelated Regressions
SM Sajjadi
sm_sajjadi@aut.ac.ir
1
SM Asadzadeh
Asadzadeh@engmail.ut.ac.it
2
The main purpose of this paper is to study the effect of daylight saving time (DST) policy on electricity consumption in Tehran province. A simulation approach based on econometric models is developed. The econometric model used is a set of 24 regression equations called seemingly unrelated regressions (SUR). A simulation approach based on SUR equations is employed to analyze different scenarios. Three DST scenarios are introduced and analyzed: DST, Extended DST and Double DST. Result of simulation approach based on the SUR model using data in years 2004-2006 indicates that the following electricity decreasing and peak-cut-off potentials exist under different scenarios. Under DST scenario there is 162886 MWh decreasing potential in electricity consumption (equal to 0.87 % of first six months consumption). The peak-cut-off potential in this scenario is 102 MW or 1.9 %. Under Extended DST scenario these amounts are a bit more. There is 176732 MWh decreasing potential in electricity consumption (0.82 % of 8 months –from Esfand to Mehrconsumption). In extended DST, the peak can be cut by 97 MW or 1.9 %. In double DST scenario a potential of 68474 MWh (equal to 0.36 % of first six months consumption) exists but under this scenario the peak increases by 482 MW (9.3%). The analysis of DST impact on electricity consumption in Tehran province can be extended to the other provinces in the country using similar data. The simulation tool developed and used in this paper is a useful tool to explore the precise impact of DST on electricity nation wide.
http://necjournals.ir/article-1-78-en.pdf
Daylight saving time
electricity consumption
Tehran province
seemingly unrelated regressions
per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
67
80
article
Determination of Energy Consumption Criterion and Ranking of Fan Coils in Iran
A Abbassi
1
R Effatnejad
2
SM Sadeghzadeh
3
A Salehian
4
In present paper, the method of fan coils standard test performance has been described. Mean energy consumption of Iranian manfactured fan coils has been determined experimentally. Energy consumption ranking of internal manufactured fan coils has been suggested by comparison between energy consumption (W/CFM or W/1000Btu/h) of internal and external manufactured fan coils for three period of three years.
http://necjournals.ir/article-1-79-en.pdf
Energy labeling of fancoils
Energy consumption
Cooling capacity
Heating capacity
Performance test
Index of energy consumption
per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
81
94
article
Stability Improvement of Fixed Speed Wind Turbines Using Braking Resistor
H Aliabadi
1
R Ghazi
2
Nowadays, stability of wind turbines is an important issue during disturbances of network. In some countries according to the existing regulations wind turbines are allowed connect to grid provided that could keep their stability following voltage sags or disturbances. This paper investigates the stability improvement of a grid connected fixed speed wind farms following disturbances such as faults, using braking resistors. In this study the complete model for wind farm is employed by considering the aerodynamical, mechanical and electrical feature of the system. The stability performance of the system is examined by simulation studies using the DIgSILENT software under different levels of compensation, delay time of circuit breakers following the gird fault conditions. Computer simulation results show the combination of braking resistors and reactive compensation can significantly improve the stability of grid connected wind turbines. Finally, for breaking resistor switching operation, the comparison has been made between two methods of speed signal and voltage signal process.
http://necjournals.ir/article-1-80-en.pdf
Braking Resistor
Induction Generator
Wind Turbine
Transient Stability
Reactive Compensation.
per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
95
111
article
Flicker study on variable speed wind turbine with DFIG and it’s mitigation with grid side converter of turbine
M Abadi Marzooni
1
M Mohamadian
2
A Yazdian
3
AM Javadian
4
Grid connected wind turbine may produce flicker during continues operation. In this paper flicker emission of variable speed wind turbine with a doubly fed induction generators is investigated during continuous operation, and the dependence of flicker emission on mean wind speed, wind turbulence intensity, short circuit capacity ratio and grid impedance angle are analyzed. Flicker mitigation is realized by output reactive control of turbine that is down with grid side converter of DFIG. For current control of this converter, two methods are suggested. This methods are voltage control and var control. The ability of flicker mitigating and required reactive power and converter rating of this two methods are analyzed in this paper. The result of simulation shows the good performance of this method for flicker mitigating.
http://necjournals.ir/article-1-81-en.pdf
Variable speed wind turbine
Doubly Fed Induction Generator
flicker
per
Iranian National Energy Committee
Iranian Journal of Energy
1028-3706
2322-1240
2008-04
11
1
109
118
article
1
2
3
4
5
http://necjournals.ir/article-1-82-en.pdf