per
University of Kashan
Energy Engineering & Management
2345-2951
2251-8061
2018-01
7
4
2
11
article
Multi-Stage Under Frequency Load Shedding Relay in Islanded Distribution Systems
Mehrnoosh Vatani
Vatani.m83@gmail.com
1
Tooraj Amraee
amraee@kntu.ac.ir
2
Alimohamad Ranjbar
amranjbar@sharif.edu
3
Babak Mozaffari
mozafari@srbiau.ac.ir
4
Disconnecting microgrid from main grid, may lead to severe frequency changes. Under frequency load shedding method provides a proper protection scheme by shedding certain amount of loads. Under frequency load shedding relay is used for frequency control of islanded microgrid. Each synchronous distributed generator (DG) of microgrid is equipped with a protective islanding detection device such as rate of change of frequency (ROCOF) relay. When microgrid disconnects from main grid DGs may trip by activation of their anti-islanding device. Therefore, this paper utilizes ROCOF constraint in order to avoid DGs tripping in an islanding condition. A discretized swing equation is used for modeling the system frequency response. Genetic algorithm is employed to minimize the amount of load to be shed. The proposed method is applied to IEEE-34 bus distribution test system.
http://energy.kashanu.ac.ir/article-1-685-en.html
Under frequency load shedding
Genetic algorithm
Islanded microgrid
Rate of change of frequency.
per
University of Kashan
Energy Engineering & Management
2345-2951
2251-8061
2018-01
7
4
12
19
article
Efficiency Enhancement of In0.5Ga0.5P solar Cell by Optimizing Structural Parameters Using Parametric Method
ALIREZA SALEHI
salehi@ kntu.ac.ir
1
saeed zamani
s.zamani@mail.kntu.ac.ir
2
K. N. Toosi
K. N. Toosi
This paper presents the design parameters for a single junction In0.5Ga0.5P solar cell using Silvaco ATLAS tool. Design parameters include thickness and doping concentration of the window, emitter and absorber layers. According to the simulation results, the absorber layer has the greatest effect on cell efficiency, and the emitter and window layers are in second and third positions, respectively. In addition, by optimizing the desired parameters using parametric method, the effect of all parameters investigated simultaneously and optimal amounts of the window, emitter and absorber layers thickness was obtained 0.08 um, 0.07 um and 1.1 um, respectively. As well as, the optimal amount of layers doping concentration was obtained 1 × 1019 , 7.7 × 1018 and 7 × 1017 , respectively. Finally, the optimized solar cell structure was simulated and 19.24% record efficiency was achieved.
http://energy.kashanu.ac.ir/article-1-907-en.html
In0.5Ga0.5P solar cell
Absorber layer
Window layer
Emitter layer
Optimization
Parametric method
Efficiency.
per
University of Kashan
Energy Engineering & Management
2345-2951
2251-8061
2018-01
7
4
20
27
article
Investigating the Effect of Load Uncertainty on Prioritizing Demand Response Programs
d.nazarpour@urmia.ac.ir
1
s.golshannavaz@urmia.ac.ir
2
amahboubkhah@hotmail.com
3
In smart grids paradigm, versatile demand response programs have been devised to accommodate the load flexibilities in optimal scheduling of distribution networks and increasing the techno-economic efficiency of electrification process. The initial models for prioritizing the demand response programs are mainly valid for the case of constant and deterministic load profiles. These models are tackled based on multi-criteria decision making approaches and make use of load’s economic model. This is while, the load demand of end-side consumers are accompanied with uncertainties in their nature. An improper modeling of these uncertainties or excluding of from the developed analytics methods ends in corrupted and unreliable results. To ameliorate the precision of the proposed approach, this study effectively incorporates the load demand uncertainties in prioritizing the demand response programs. The load demand uncertainties are effectively modeled based on normal probability distribution function and represented in the form of adequate number of scenarios. The obtained results are then evaluated based on technique for order preference by similarity to ideal solution (TOPSIS) known as a multi-criteria decision making approach. In this way, the priority of each demand response program is determined. Results demonstrate substantial changes in final ranking of the investigated programs compared to the deterministic load profile in preliminary approaches. This remark approves the significant importance of deploying accurate load demand profiles within prioritizing demand response programs.
http://energy.kashanu.ac.ir/article-1-864-en.html
Prioritizing demand response programs
Economic modeling of load demand
Uncertainty
Multi-criteria decision making approach
Technique for Order Preference by Similarity to Ideal Solution (TOPSIS).
per
University of Kashan
Energy Engineering & Management
2345-2951
2251-8061
2018-01
7
4
28
41
article
Probabilistic Study of Voltage in Distribution Network Considering Wind Turbine and Static Load Model with Gamma Distribution
Meghdad Tourandaz Kenari
m_tourandaz@sbu.ac.ir
1
Mohammad Sadegh Sepasian
m_sepasian@sbu.ac.ir
2
Mehrdad Setayesh Nazar
setayeshnazar@gmail.com
3
Shahid Beheshti University
Shahid Beheshti University
Shahid Beheshti University
Uncertainty analysis of voltage in distribution system is the main feature of current study. This paper presents a probabilistic analysis of radial distribution networks considering wind power resources. The wind turbines are modeled as probability distribution functions. Also, the loads are modeled with Gaussian and gamma distributions. Monte Carlo simulation is used for the probabilistic load flow process. The proposed method is applied to the IEEE 33-bus distribution test system and the results are analyzed. The results validate the correctness and efficiency of the proposed technique.
http://energy.kashanu.ac.ir/article-1-655-en.html
Distribution networks
Gamma probability distribution
Monte carlo simulation
Probabilistic load flow
Static load model
Voltage assessment
Wind distributed generations
per
University of Kashan
Energy Engineering & Management
2345-2951
2251-8061
2018-01
7
4
42
51
article
Optimal Pump Scheduling for Water Distribution Networks Regarding to the Pump Maintenance
Mahmood Akbari
makbari@kashanu.ac.ir
1
Ebrahim Bannazadeh
ebannazadehghomi@ymail.com
2
University of Kashan
: In water distribution networks, a significant amount of electricity is used to pump the water into the tanks. Planning and pump schedule could have an important role in energy consumption management and reducing the related cost. The aim of this study is to determine the optimal pump schedule on a 24-hour basis in which aims to minimize the cost of electrical energy, whilst meeting the required time varying consumer with regard to restrictions relating to the minimization of maintenance pumps. For this purpose, the pump schedule optimization problem with pumping water from the wells to the tank is formulated in the form of an Integer Non-Linear Programming model (INLP) and solved by the branch and bound method. In addition to minimizing the energy consumption cost, the model includes a constraint to limit the number of pumps that are switched to reduce the pumps maintenance costs. To illustrate the effectiveness of the model, the water network of Noosh-Abad city in the outskirts of Kashan city is considered as a case study. The results show that the formulated model in this study can meet the both mentioned objectives, so that the outputs of the model compared to the historical operation, both in terms of energy costs and the depreciation of the pumps is in much better situation. In particular, in the case of strict maintenance control, the energy cost is about 15% lower than that of the historical operation.
http://energy.kashanu.ac.ir/article-1-892-en.html
Energy consumption management
Pump maintenance
Optimization
Pump schedule
Integer Non-Linear Programming.
per
University of Kashan
Energy Engineering & Management
2345-2951
2251-8061
2018-01
7
4
52
61
article
Improvement of thermal performance of the floor heating system using the metallic bridges
Rahim Hassanzadeh
hassanzadeh.rahim@gmail.com
1
Samaneh Arman
Samaneh.arman@mee.uut.ac.ir
2
This research is a numerical investigation of the thermal performance of the floor heating system integrated with metallic bridges. For this goal, aluminum and galvanized metallic bridges with 0.5 mm thickness were embedded within the free space of the pipes. Two different bridge lengths of P/S=1/3, 2/3, and 1 were studied in this paper in which P and S are the bridge length and free space between two adjacent pipes, respectively. On the other hand, for the floor heating system, two water fluid temperatures of 40◦C and 50◦C were considered. Several results have been obtained in this study. For example, thermal performance of the floor heating system enhances with maximum 12.82% and 6.41% for 40◦C and 12.88% and 6.43% for 50◦C using metallic bridges in comparison to the conventional case (without metallic bridges) in which the rate of heat transfer enhancement of heating panel using the aluminum bridge was 6.05% higher than that of galvanized bridge. Additionally, by increasing the bridge length from P/S=2/3 to P/S=1, the thermal performance of the floor heating system increases up to maximum 7.04%.
http://energy.kashanu.ac.ir/article-1-630-en.html
Floor heating system
Metallic bridge
Energy management
Heat transfer