International Journal of Applied Power Engineering (IJAPE)
International Journal of Applied Power Engineering (IJAPE), p-ISSN 2252-8792, e-ISSN 2722-2624 focuses on the applied works in the areas of power generation, transmission and distribution, sustainable energy, applications of power control in large power systems, etc. The main objective of IJAPE is to bring out the latest practices in research in the above mentioned areas for efficient and cost effective operations of power systems and electrical energy sources. The journal covers, but not limited to, the following scope: electric power generation, transmission and distribution, utilization of electric power, energy conversion, electrical machinery, sustainable energy, insulation, solar energy, high-power semiconductors, power quality, power economic, FACTS, renewable energy, electromagnetic compatibility, electrical engineering materials, high voltage insulation technologies, high voltage apparatuses, lightning, protection system, power system analysis, SCADA, electrical measurements, and the electrical apparatus connected to such systems. The journal is published by Institute of Advanced Engineering and Science (IAES) in collaboration with Intelektual Pustaka Media Utama (IPMU) and Universitas Ahmad Dahlan (UAD). Beginning with issue 1 of volume 10 (2021), the IJAPE will be published as a three-monthly journal (4 issues/year). Citedness of this journal in Scopus is 188 times, from 87 documents (per Sept 7, 2021).
Reduced Dielectric Losses for Underground Cable Distribution Systems
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 1: April 2012 , pp. 37-46
This paper describes the process to reduce dielectric losses for underground cable distribution system. As already known, that system is an alternative solution to energy distribution systems in urban areas. Influence of large capacitance is a separate issue that needs to be resolved. Large capacitance effect on Express Feeder of 10 miles long has resulted in power losses more than 100 MW per month. In the no-load condition, current dispatch has recorded 10 Amperes, and has increased the voltage at receiving end by 200-500 Volts, with leading power factors. Installation of the inductor to reduce cable loss dielectrics is done by changing the power factor (pf) to 0.85 lagging. After installation of the inductor, which is 5 mH/700 kVAR, dielectric losses is reduced to 3.57%, which is from 105,983 kW to 102,195 kWh per month. The capacitive leakage current has also been reduced from 249.61 Ampere to 245.17 Ampere.
Improving Control Performance in DC Micro-Grids with Distributed Generations
Weilin Li, Huimin Li, Min Luo, Yunfei Zhang,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 1: April 2012 , pp. 1-12
DC micro-grids are attracting more and more attention due to their capability to lead to more efficient integration of distributed generation compared with traditional AC micro-grids. In this paper, a hierarchical control architecture is proposed to improve the control performance of DC micro-grid with distributed generations (DGs), which utilize a global controller (GC) to optimize the overall process and a number of distributed local controllers (LCs) associated with each subsystem. The measurement reliability of each LC is guaranteed by an associated measurement validation module which is developed based on Polynomial Chaos Theory (PCT). The system efficiency and robust is counted in the design of GC, where synergetic control theory is adopted. Numerical simulations have been done to verify the proposed method, and the simulation results show good consistency with theoretical analysis.
Techno-economical Unit Commitment Using Harmony Search Optimization Approach
Mohammad Sadegh Javadi,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 1: April 2012 , pp. 21-28
In this paper, Security-Constrained Unit Commitment (SCUC) model is proposed in a restructured power system. This model consists of a closed-loop modified Unit Commitment (UC) and Security-constrained Optimal Power Flow (SCOPF). The objective of this SCUC model is to obtain the maximum social welfare-based system operating cost while maintaining the system security. In conventional power systems, the demand was forecasted before market operation and determined as a fixed constant. Supplying this demand was therefore considered as a constraint. However, in restructured power system which is based on Standard Market Design (SMD), DISCOs offer the demand and their proposed prices; therefore the demand is modeled as an elastic load. Independent System Operator (ISO) is responsible for operating the power market. The ISO performed the power market using the SCUC software to obtain feasible and economical operation as much as possible. In this paper, Harmony Search Algorithm (HSA) has been implemented to solve SCUC problem. Since the SCUC problem is a non-linear, mixed integer, large scale and non-convex problem, harmony search optimization is addressed as an efficient technique to overcome the aforementioned challenges. The simulation results show that the presented method is both satisfactory and consistent with expectation.
Security Constraint Unit Commitment Considering Line and Unit Contingencies-particle Swarm Optimization
Mohammad Sadegh Javadi,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 1: April 2012 , pp. 13-20
This paper presents a new approach for considering all possible contingencies in short-term power system operation. Based on this new approach, both generator and transmission line outages would be modeled in network-based power system analysis. Multi generator and also parallel transmission lines is modeled in this methodology. We also investigate this claim that feasibility and applicability of this approach is much more than the previous analytical methodologies. Security Constrained Unit commitment (SCUC) program which is carried out by Independent System Operator (ISO), is one of the complex problems which would be handled by this approach. In this paper, a DC-Optimal Power Flow (DCOPF) methodology has been implemented by particle swarm optimization technique. The Lagrangian Relaxation technique is based on the derivatives and the PSO is a non- derivative technique. These approaches are effective tools which can be implemented for short-term and long-term power system analysis, especially for economic analysis of restructured power systems. The DCOPF methodology has been considered for LMP calculation in LR, which is not available in PSO techniques. In the other hand, PSO technique may be able to provide the optimal solution, where LR usually getting stuck at a local optimum in a large scale power system. The simulation results show that the presented methods are both satisfactory and consistent with expectation.
Load Frequency Control of DFIG-isolated and Grid Connected Mode
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 1: April 2012 , pp. 29-36
Wind energy is one of the extraordinary promising sources of renewable energy due to its clean character, free availability and economic viability. A Doubly Fed Induction Generator (DFIG) feeds power from both the stator and the rotor windings at speeds above synchronous speed of the machine. This paper deals the load frequency control of doubly fed induction generator in isolated mode and grid connected mode. The wind turbine model is obtained using MATLAB/ SIMULINK which consists of DFIG, rotor side rectifier, grid side inverter and grid. This model is controlled by conventional controllerand proposed Load Frequency Control (LFC) method. The results are proven that frequency control gives better results in all the aspects
Dynamic Modeling of Autonomous Wind–diesel system with Fixed-speed Wind Turbine
Najafi Hamid Reza, Dastyar Farshad,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 2: August 2012 , pp. 47-64
Wind turbines have often connected to small power systems, operating in parallel to diesel generators, as is typically the case in autonomous wind–diesel installations or small island systems with high wind potential. Hence, the modeling and analysis of the dynamic behavior of wind–diesel power systems in presence of wind power will be important. In this paper, the system under study is modeled by a set of dynamic and algebraic equations (DAE). Dynamic behavior of a wind-diesel system is investigated by the proposed dynamic model. Wind-diesel system consists of wind turbines that are connected to synchronous diesel generator via short transmission line with local load. Dynamic stability of autonomous wind–diesel systems are discussed with emphasis on the eigenvalue analysis and the effective parameters on system stability. In this regards, saddle node bifurcation and hopf bifurcation are also investigated.
Impact of Thyristor Controlled Series Capacitor Insertion on Short-circuit Calculation in Presence Phase to Earth Fault
Mohamed Zellagui, Abdelaziz Chaghi,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 2: August 2012 , pp. 93-104
This research paper presents a study on phase to earth fault short-circuit calculation with fault resistance on a single transmission line 400 kV in eastern Algerian transmission networks at Algerian Company of Electricity and Gas (Sonelgaz Group) compensated by series Flexible AC Transmission System (FACTS) i.e. Thyristor Controlled Series Capacitor (TCSC) installed in midline. The facts are used for controlling transmission voltage, power flow, reactive power, and damping of power system oscillations at high power transfer levels. The direct impacts of TCSC insertion on the total impedance, active power and reactive power a electrical transmission line and also parameters of short-circuit : symmetrical currents, line currents, symmetrical voltages and line voltages are carried out. More the effects of injected voltage by TCSC for three case studies are presented.
Determination of Fault Location and Type in Distribution Systems using Clark Transformation and Neural Network
Mohammad Sarvi, S. M. Torabi,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 2: August 2012 , pp. 75-86
In this paper, an accurate method for determination of fault location and fault type in power distribution systems by neural network is proposed. This method uses neural network to classify and locate normal and composite types of faults as phase to earth, two phases to earth, phase to phase. Also this method can distinguish three phase short circuit from normal network position. In the presented method, neural network is trained by αβ space vector parameters. These parameters are obtained using clarke transformation. Simulation results are presented in the MATLAB software. Two neural networks (MLP and RBF) are investigated and their results are compared with each other. The accuracy and benefit of the proposed method for determination of fault type and location in distribution power systems has been shown in simulation results.
Transmission Loss Allocation Based on Lines Current Flow
Rahmat Aazami, Ali mansori, NosratAllah Mohammad Baigi, Amin Omidian, Ehsan Mohammadian,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 2: August 2012 , pp. 65-74
In this paper, the transmission loss allocation problem has been studied and a new method for loss allocation in pool electricity markets has been proposed. To do that, at first using a transmission line loss equations respect to bus injected currents, the share of each bus from the mentioned transmission line losses has been determined. Then, this method has been applied to the total network transmission lines and the share of each bus from the total losses has been acquired. The proposed method is based on the main network relations and no any simplifying suppose has been used. Finally, the proposed method is studied on a typical network.
Design and Development of Power Electronic Controller for Grid-connected PV Array
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 2: August 2012 , pp. 87-92
Design and simulation of a simple power electronic interface for grid-connected PV array has been proposed using boost converter and line-commutated inverter with maximum power point tracking (MPPT) controller. The output of PV array varies with irradiation, and hence the duty cycle of the PI controller is adjusted automatically to supply a constant DC voltage to the inverter circuit, the output of which is directly connected to the grid. The MPPT controller extracts maximum power from the solar array and feeds it to the single-phase utility grid. The proposed scheme has been modeled in the MATLAB 7.1 software and the complete system has been simulated for open loop and closed loop configurations. The active power fed to the grid is taken for different firing angles in open loop mode and the firing angle for maximum power has been determined. This is compared with the firing angle obtained from the closed loop mode and found that both results agree with each other.
Comparative Study on the Performance of A Coherency-based Simple Dynamic Equivalent with the New Inertial Aggregation
Abdul Malek Miah,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 3: December 2012 , pp. 105-114
Earlier, a simple dynamic equivalent for a power system external area containing a group of coherent generators was proposed in the literature. This equivalent is based on a new concept of decomposition of generators and a two-level generator aggregation. With the knowledge of only the passive network model of the external area and the total inertia constant of all the generators in this area, the parameters of this equivalent are determinable from a set of measurement data taken solely at a set of boundary buses which separates this area from the rest of the system. The proposed equivalent, therefore, does not require any measurement data at the external area generators. This is an important feature of this equivalent. In this paper, the results of a comparative study on the performance of this dynamic equivalent aggregation with the new inertial aggregation in terms of accuracy are presented. The three test systems that were considered in this comparative investigation are the New England 39-bus 10-generator system, the IEEE 162-bus 17-generator system and the IEEE 145-bus 50-generator system.
Investigation and Comparison of the Effect of Facts Devices, Capacitors and Lines Reactance Variations on Voltage Stability Improvement and Loadability Enhancement in Two Area Power System
Navid Ghaffarzadeh, Haniyeh Marefatjo, Iman Soltani,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 3: December 2012 , pp. 145-158
This paper studies the important power system phenomenon and voltage stability by using continuation power flow method. Voltage collapse scenario is presented which can be a serious result of voltage instability and also the parameters that affected by voltage collapse are discussed. In analyzing power system voltage stability, continuation power flow method is utilized which consists of successive load flows. In this paper steady-state modeling of Static VAR Compensator (SVC) and Unified Power Flow Controller (UPFC) and effect of compensator and variation of line reactance on the voltage stability have been studied and Comparison between performance of UPFC and SVC and installation shunt capacitor and variation of line reactance for improve voltage stability has been done.Case studies are carried on 11 bus network in two areas. Simulation is done with PSAT in MATLAB. Continuation Power Flow was implemented using Newton Raphson method. Simulation results show the proper performance of UPFC, SVC, installation shunt capacitor and variation of line reactance to improve voltage control and significantly increase the loadability margin of power systems.
Photovoltaic Solar Energy Systems: Market Trends In The United States
Joshua Krautmann, Jinwen Zhu,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 3: December 2012 , pp. 123-128
The world today uses more energy than ever before. As a global society we must find more renewable and efficient sources to obtain our energy. One of these sources might come in the form of something that we interact with everyday, the sun. Photovoltaic solar cells are a growing market in the renewable energy sector. Basic PV cell materials are discussed and the PV market in the United States is analyzed; are PV solar energy systems the answer to our current and future energy needs?
Voltage Stability Based Formation of Voltage Control Areas Considering Impact of Contingencies
Tarun Martolia, M.K. Verma,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 3: December 2012 , pp. 115-122
Voltage instability has been considered as a major threat to power system networks since last three decades. Frequent incidences of grid failures caused by voltage instability have been observed in different parts of the world. Fast voltage stability assessment of power system may be done by formation of voltage control areas, clubbing group of buses in geographically compact region having similar voltage instability problem. This paper presents a new approach for formation of voltage control areas (VCAs) based on sensitivity of reactive power generations with respect to reactive power demands, together with bus voltage variations under voltage stability based critical contingencies. The load buses in geographically compact region showing similar sensitivity of reactive power demand to reactive generations have been clubbed together to form voltage control areas. Since, voltage control areas formed should remain valid under change in operating conditions and network topology, the areas formed based on reactive power sensitivitieshave been modified considering voltage variations at different loadings points under voltage stability based critical contingencies. Voltage stability based Critical contingencies have been selected based on maximum loadability criterion. Case studies have been performed on IEEE 14-bus system. Simulation results performed on IEEE 14-bus system validate VCAs formed even under change in network topology caused by line outages and change in operating conditions caused by variations in real and reactive power demands. The VCAs formed by proposed method have been compared with VCAs formed by few existing approaches. The superiority of proposed approach of voltage control areas formation over few existing approaches has been established on the test system considered.
Compensation of Single-Phase and Three-Phase Voltage Sag and Swell Using Dynamic Voltage Restorer
Haniyeh Marefatjou, Mohammad Sarvi,
International Journal of Applied Power Engineering (IJAPE), Vol 1, No 3: December 2012 , pp. 129-144
DVR is a equipment which was connected in series and adjusting the loading voltage by feeding the voltage in system. The first installation was in 1996. usually DVR installed between sensitive loads feeder and source in distribution system .The main duty, fast support load voltage (by fast detection algorithm) during disturbance to avoid any disconnection. in this paper approaches to compensate for voltage sag and swell as a common disturbance in voltage transmission and distribution networks is presented. A dynamic voltage restorer based on the dq0 algorithm for three-phase and dynamic voltage restorer based on the average detection method for single-phase are discussed, also in this paper we compare the two methods used to compensate the single-phase and three-phase process. result of three-phase and single-phase voltage sag and swell simulation has been presented by MATLAB/SIMULINK.
Power Flow Study and Performance of STATCOM and TCSC in Improvement Voltage Stability and Loadability Amplification in Power System
Haniyeh Marefatjou, Mohammad Sarvi,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 1: April 2013 , pp. 15-26
Power systems operation becomes more important as the load demand increases all over the world. This rapid increase in load demand forces power systems to operate near critical limits due to economical and environmental constraints. The objective in power systems operation is to serve energy with acceptable voltage and frequency to consumers at minimum cost. This paper studies the important power system phenomenon and voltage stability by using continuation power flow method and steady-state modeling of Static Synchronous Compensator (STATCOM) and Thyristor Controlled Series Capacitor (TCSC) for continuation power flow studies has been represented and discussed in details.also this paper studies voltage stability by using continuation power flow method and Comparison between performance of TCSC and STATCOM for improve voltage stability has been done. Case studies are carried on 9 bus network. Simulation is done with PSAT in MATLAB. Power Flow and Continuation Power Flow is was implemented using Newton-Raphson method. Simulation results show the proper performance of TCSC and STATCOM to improve voltage control and power flows on the lines and significantly increase the loadability margin of power systems.
Improving Electrical Power Grid of Jordan and Control the Voltage of Wind Turbines Using Smart Grid Techniques
Nadeem T. Ahmad,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 1: April 2013 , pp. 39-44
In this paper, we improved the national grid of Jordan country by adding a renewable resources specifically a wind turbines generation unites distributed on different places in Jordan to compensate the losses of the power in Jordan and to dispense with using the generation of fuel and gas by representing the national grid of Jordan in ETAB simulator and we solved the voltage problems of wind turbines using a new mythology using smart grid techniques
Participation of Renewable Energy Sources in Restructured Power System
Sandeep Bhongade, B. Tyagi,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 1: April 2013 , pp. 1-14
In the present paper, a frequency control method based on Genetic Algorithm (GA) has been presented. The proposed scheme has been successfully tested on well known IEEE 39- bus test system. A deregulated electricity market scenario has been assumed in the test system. It has been assumed that both the generators and the consumers are participating in the frequency regulation market. Simulation results show that the proposed GAPID Controller along with HVDC link improves the system frequency. The performance studies have been carried out by using the MATLAB SIMULINK for transactions within and across the control area boundaries.
Automatic Generation Control of Multi-Area Power System with Generating Rate Constraints Using Computational Intelligence Techniques
P. Subbaraj, K. Manickavasagam,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 1: April 2013 , pp. 27-38
In a large inter-connected system, large and small generating stations are synchronously connected and hence all stations must have the same frequency. The system frequency deviation is the sensitive indicator of real power imbalance. The main objectives of AGC are to maintain constant frequency and tie-line errors with in prescribed limit. This paper presents two new approaches for Automatic Generation Control using i) combined Fuzzy Logic and Artificial Neural Network Controller (FLANNC) and ii) Hybrid Neuro Fuzzy Controller (HNFC) with gauss membership functions. The simulation model is created for four-area interconnected power system. In this four area system, three areas consist of steam turbines and one area consists of hydro turbine. The components of ACE, frequency deviation (F) and tie line error (Ptie) are obtained through simulation model and used to produce the required control action to achieve AGC using i) FLANNC and ii) HNFC with gauss membership functions. The simulation results show that the proposed controllers overcome the drawbacks associated with conventional integral controller, Fuzzy Logic Controller (FLC), Artificial Neural Network controller (ANNC) and HNFC with gbell membership functions.
Pilot Solar Thermal Power Plant Station in Southwest Louisiana
Terrence Chambers, Jonathan R Raush, G.H. Massiha,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 1: April 2013 , pp. 45-52
Solar thermal plants are basically power plants that generate electricity from high-temperature heat. The difference between them and conventional power plants is that instead of deriving energy from gas, coal or oil, the sun provides the energy that drives the turbines. In this paper we will give a brief demonstration of solar thermal power and different system designs of solar thermal power plants. Then we will see the feasibility of implementing solar power plants in Louisiana which currently depends mostly on its conventional power plants which use traditional fuels such as gas, oil, and coal. This study was a part of a proposal that was funded by the US the Department of Energy to construct solar thermal plant near Lafayette, Louisiana. The power plant is currently under the construction and it will be completed by Summer of 2013.
Smart Power Transmission System Using FACTS Device
Qazi Waqar Ali, Azzam ul Asar,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 2: August 2013 , pp. 61-70
Making of smart grids puts mounting pressure on the nation’s aging electric power transmission system. Just planting additional towers and stringing more line won’t practice the nation’s electric power transmission infrastructure to meet up the energy challenges ahead. Smart grids stand geared up to play a much larger role in the energy equation for reduction of transmission line losses. The FACTS controllers come out with the capability of enhancing transmission system control, reliability, and operation. This paper will discuss and express how Static Synchronous Compensator (STATCOM) has effectively been applied to power system for efficiently regulating system voltage and thus increase system load ability. This paper investigates the effects of (STATCOM) on voltage stability of a power system at different positions.The simulation analysis of this paper can be used as guideline for power industry. The study is thereby simulated using the MATLAB/SIMULINK software and simulation results show that STATCOM is effective in midpoint voltage regulation on transmission line. In this paper comparison is also performed between STATCOM and SVC under fault condition and it is proved that STATCOM have the capacity to provide more capacitive power for the period of a fault than SVC.
A Fuzzy-PD Controller to Improve the Performance of HVDC System
Mohammad Sarvi, Majid Keshmiri,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 2: August 2013 , pp. 79-88
In this paper, a fuzzy self adjustment controller has been designed for using in control of a high voltage direct current (HVDC) system. Fuzzy logic method via fuzzy rules based on simple experimental logical proofs, selects the coefficient of PD controller. In order to investigate the performance and accuracy of the proposed control method, a Cigre system is considered and analyzed. The proposed fuzzy - PD controller is compared with conventional PD controller. To achieve this purpose, the operations of designed controllers are investigated for different conditions. Fuzzy controllers used to control of inverter and rectifier converters, improve significantly system responses and performances as well as DC power recovering, especially on hard faults. The HVDC control system with fuzzy controllers in soft faults and variations with small amplitude, are similar conventional control, but on hard faults and variation with large amplitude, the performances are improved in compare with conventional control.
Optimal Placement of D-STATCOM Using Hybrid Genetic and Ant Colony Algorithm to Losses Reduction
Askar Bagherinasab, Mahmoud Zadehbagheri, Saifulnizam Abdul Khalid, Majid Gandomkar, Naziha Ahmad Azli,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 2: August 2013 , pp. 53-60
In this work, a modern algorithm by hybrid genetic algorithm and ant colony algorithm is designed to placement and then simulated to determine the amount of reactive power by D-STATCOM. Also this method will be able to minimize the power system losses that contain power loss in transmission lines. Furthermore, in this design a IEEE 30-bus model depicted and three D-STATCOM are located in this system according to Economic Considerations. The optimal placement of each D-STATCOM is computed by the ant colony algorithm. In order to optimize placement for each D-STATCOM, two groups of ant are selected, which respectively located in near nest and far from the nest. Moreover, for every output simulation of D-STATCOM that is used to produce or absorb of reactive power, a genetic algorithm to minimizing the total network losses is applied. Finally, the result of this simulation shows net losses reduction about 150% that it verifies the new algorithm performance.
Distributed Generation Allocation to Improve Steady State Voltage Stability of Distribution Networks Using Imperialist Competitive Algorithm
Navid Ghaffarzadeh, Masoud Akbari, Amir Khanjanzadeh,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 2: August 2013 , pp. 71-78
In this paper, a new method is proposed to optimal distributed generation allocation for stability enhancement in radial distribution networks. Voltage stability is related with stable load and acceptable voltage in all buses of system. According to the time spectrum of the incident of the phenomena the instability is divided into steady state and transient voltage instability. The analysis is accomplished using a steady state voltage stability index which can be evaluated at each node of the distribution system. Different optimal locations and capacities are used to check this effect. The location of DG is more important in comparison with the capacities and has the main effect on the network voltage stability. Effects of capacity and location on increasing steady state voltage stability in radial distribution networks are evaluated through Imperialist Competitive Algorithm (ICA) and at the end the results are compared to particle swarm optimization and genetic algorithm on the terms of speed, accuracy and convergence.
Feasibility Study of a Grid Connected Hybrid Wind/PV System
Hussein AL-Masri, Fathi Amoura,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 2: August 2013 , pp. 89-98
This paper investigates the feasibility of a grid connected, large-scale hybrid wind/PV system. From data available an area called RasElnaqab in Jordan is chosen because it enjoys both high average wind speed of 6.13 m/s and high average solar radiation of 5.9KWhr/m2 /day. MATLAB and HOMER software’s are used for sizing and economical analysis respectively. Results show that76124 SUNTECH PV panels and 38 GW87-1.5MW wind turbines are the optimal choice. The net present cost (NPC) is 130,115,936$, the cost of energy (COE) is 0.049$/KWhr with a renewable fraction of 74.1%.A stepby-step process to determine the optimal sizing of Hybrid Wind/PV system is presented and it can be applied anywhere.
Performance of Grid-connected Photovoltaic System in Equatorial Rainforest Fully Humid Climate of Malaysia
Mohamad Zhafran Hussin, A. M. Omar, Z. M. Zain, S. Shaari,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 3: December 2013 , pp. 105-114
This paper presents a result obtained from a comparative study among three different photovoltaic (PV) module technologies for grid-connected photovoltaic system (GCPV) under Malaysia’s real operating conditions. The obtained results were slightly different from the performance ratio (PR) investigation which showed the average annual performance of 78.2% for polycrystalline, 94.6% for a-Si thin-film and 81% for monocrystalline PV technologies over four years monitored period. The outdoor evaluation results showed that a-Si thin-film PV modules demonstrate the highest and better in terms of final yield, performance ratio and PV array/system efficiency over the entire monitored period. In other hands, a-Si thin-film demonstrated the reliability and better in system performance
A Simple Approach for Optimal Generation Scheduling to Maximize GENCOs Profit Using PPD Table and ABC Algorithm Under Deregulated Environment
Kaliyamoorthy Asokan, R. Ashokkumar,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 3: December 2013 , pp. 125-140
In this paper an attempt has been made to solve the profit based unit commitment problem (PBUC) using pre-prepared power demand (PPD) table with an artificial bee colony (ABC) algorithm. The PPD-ABC algorithm appears to be a robust and reliable optimization algorithm for the solution of PBUC problem. The profit based unit commitment problem is considered as a stochastic optimization problem in which the objective is to maximize their own profit and the decisions are needed to satisfy the standard operating constraints. The PBUC problem is solved by the proposed methodology in two stages. In the first step, the unit commitment scheduling is performed by considering the pre-prepared power demand (PPD) table and then the problem of fuel cost and revenue function is solved using ABC Algorithm. The PPD table suggests the operator to decide the units to be put into generation there by reducing the complexity of the problem. The proposed approach is demonstrated on 10 units 24 hour and 50 units 24 hour test systems and numerical results are tabulated. Simulation result shows that this approach effectively maximizes the GENCO’s profit than those obtained by other optimizing methods.
Experimental Study of A Vacuumed Solar Still System
Omar Badran, Nabil Beithou, Aiman Al Alawin, Ahmad Awad, Yaser Abdelhadi, Anwar Al-Mofleh,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 3: December 2013 , pp. 99-104
This experimental study presents a thermal design of a passive solar water distillation system with vacuum. The designed model consists of a glass cover, basin water equipped with reflecting mirror and insulation, and controlled vacuum pump to create vacuum inside the still to decrease the saturation temperature of water and in order to increase the yield. Feed water in the basin is heated by solar energy, and the evaporated water is condensed by inner glass cover. The temperatures at different locations in the system, the received amount of solar radiation, and the distilled water produced were determined. The highest temperature developed inside the distilling device was 51˚ C at ambient temperature of 24˚ C, the daily water production was 1.2 L/m2.day, and the efficiency of the solar still was 15%.
Multi Area Economic Dispatch Using Secant Method and Tie Line Matrix
Sudhakar AVV, Chandram Karri, Jayalaxmi A,
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 3: December 2013 , pp. 115-124
In this paper, Secant method and tie line matrix are proposed to solve multi area economic dispatch (MAED) problem with tie line loss. Generator limits of all generators in each area are calculated at given area power demands plus export (or import) using secant method and the generator limits of all generators are modified as modified generator limits. Central economic dispatch (CED) problem is used to determine the output powers of all generators and finally power flows in all tie lines are determined from tie line matrix. Here, Secant method is applied to solve the CED problem. A modified tie line matrix is used to find power flow in each tie line and then tie line loss is calculated from the power flow in each tie line. The proposed approach has been tested on two-area (two generators in each area) system and four-area (four generators in each area) system. It is observed from various cases that the proposed approach provides optimally best solution in terms of cost with tie line loss with less computational burden.
Probabilistic Q-margin Calculations Considering Dependency of Uncertain Load and Wind Generation
International Journal of Applied Power Engineering (IJAPE), Vol 2, No 3: December 2013 , pp. 141-148
This paper presents a novel probabilistic approach for computation of the reactive power margin (or Q-margin) of a power system with large-scale uncertain wind generation. Conventionally, Q-margin has been used as an index for indicating the system voltage stability level on system operation and planning. The conventional Q-margin method needs to be modified to fully accommodate uncertainties due to wind generation. This paper proposes a new Q-margin computation method using Q-matrix and the expected Q-margin (EQM). Q-matrix is a generic uncertainty matrix representing a discrete joint distribution of load and wind generation and the EQM, calculated from the Q-matrix, is a specific probabilistic variable that supersedes the conventional Q-margin. The proposed method is verified with the IEEE 39-bus test system including wind generation.
Modeling Simulation and Design of Photovoltaic Array with MPPT Control Techniques
Sangita Ramesh Nandurkar, Mini Rajeev,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 41-50
The Renewable energy is important part of power generation system due to diminution of fossils fuel. Energy production from photovoltaic (PV) is widely accepted as it is clean, available in abundance, & free of cost. This paper deals with modeling of PV array including the effects of temperature and irradiation. The DC-DC converter is used for boosting low voltage of the PV array to high DC voltage. Since the efficiency of a PV array is around 13% which is low, it is desirable to operate the module at the peak power point to improve the utilization of the PV array. A maximum power point tracker (MPPT) is used for extracting the maximum power from the solar PV array and transferring that power to the load. To track maximum power point (MPP) Perturb & Observe (P & O) algorithm is used which periodically perturbs the array voltage or current and compare PV output power with that of previous perturbation cycle which controls duty cycle of DC-DC converter. The entire system is simulated in MATLAB /SIMULINK and simulation results are presented.
Fuzzy Logic Controller Based Single Buck Boost Converter for Solar PV Cell
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 1-8
This paper deals with solar power production controlled by Fuzzy Logic Controller (FLC) and Single Input Buck-Boost (SIBB) converter. Since the solar energy is continuously varying, according to the irradiation the FLC generates control pulses to switch on the MOSFET device. To analyze the real time feasibility of this method, the system is simulated by using MATLAB/Simulink 2010a. A simulation model of the system is developed with solar Photovoltaic (PV) cell, FLC and SIBB in contradiction of the real world conditions. The results are presented and discussed in this paper.
Harmonic Voltage Distortions in Power Systems Due to Non Linear Loads
Aryan Kaushik, Jyothi Varanasi,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 67-74
Harmonics are found to have deleterious effects on power system equipments including transformers, capacitor banks, rotating machines, switchgears and protective relays. Transformers, motors and switchgears may experience increased losses and excessive heating. Shunt filters are effective in minimizing voltage distortions. This paper describes the voltage distortions generated by non linear loads. The harmonic specifications such as harmonic factor, characteristic harmonic and non-characteristic harmonic are considered while explaining the paper. ‘MiPower’ software is used to compute the harmonic distortions in a sample power system. Accurate harmonic models are established for a non linear load. To reduce the harmonic voltages impressed upon specific parts of the sample power system, passive filters are installed at two buses. With the implementation of a passive filter at the bus with non linear load, the harmonics are greatly reduced. For the specified power system, at all the buses the total harmonic distortion has been evaluated.
A Survey on Quality Changes in Positive, Negative and Combined Switching Strategies in Control of Three Phase Matrix Converter
Mohammad Sarvi, Iman Soltani, Hossein Faramarzi,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 51-66
In this paper uses positive, negative and combined switching strategies for three phase ac/ac matrix converter .the author compares these strategies. The performance comparison of these three strategies is made under balanced operation. The simulation of three phase matrix converter feeding a three phase load was accomplished by means of the matlab/simulink software. After the simulation the comparison of the waveforms THD in three switching sequence is done. It must be mentioned that the duty cycle of the whole switches in the converter is according to Venturini switching algorithm
Combined Operation of SVC, PSS and Increasing Inertia of Machine for Power System Transient Stability Enhancement
Bablesh Kumar Jha, Ramjee Prasad Gupta, Upendra Prasad,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 15-22
In this paper improvement of transient stability by coordination of PSS (Power System Stabilizer) and SVC (Static var Compensator) and increasing inertia of synchronous machine has been observed. Because single method is not sufficient for improving stability. For this purpose a 9 bus multi machine system has been considered. Transient stability improvement has been tested subjected to three phase fault at bus 3 after 0.5 second and fault has been cleared after 1 second. By the use of PSS, SVC and by increasing inertia method for the test system the electromechanical oscillation for generator electrical power has been reduced and the steady state power transfer has been enhanced. In this paper the Inertia of the machine is not so much increased. Because after increasing inertia of the machine rotor will be havier.so that it is kept always within limit as considering its reliability and economy. And field voltage is also kept limited
Performance Analysis of Voltage Stability Against Sudden Load Changes in Voltage Controlled Inverters for Distributed Generation
Arvind H. Kadam, Keerthi Unni, Sushil Thale,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 33-40
Distributed Generation (DG) is playing an important role in the field of electricity generation by being a viable alternative to the Centralized Power Generation (CPG). Although, distributed generation has many advantages, it has some issues in the fields of protection, power control, stability, islanding detection etc. Amongst all the issues, this paper attempts to highlight the issue of voltage stability under sudden changes in loading conditions in a distributed generation systems operating in stand-alone mode. Proper design and tuning of compensators for closed loop operation in DG systems can ensure voltage stability. As the load demand increases, the output voltage of DG usually dips for a short time owing to the weak (smaller capacity) nature of renewable sources, after which it returns to steady state. This fall in the voltage profile could prove to be harmful if the settling time is more. The simulation and hardware results illustrate that, accurate compensator design, is one of the key factor in maintaining the voltage stability in DG system. This paper explores the effect of proper compensator design in maintaining voltage stability of DG.
Load Flow Analysis for Process – Tank Loading Power Generation Networks Interconnection
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 9-14
Establishment of interconnection links between Process -Tank Loading electrical networks bring some advantages as there are excess capacity at Process which can be utilized in principle to feed Tank Loading. Some result of power system study will be as an input for operational purposes. Concerning Motor Starting Studies and Load Flow Studies and taking into account that the transformer is off load tap changing, the best tapping position for Isolation Transformer is at -5% (primary side). The best technical power generation configuration is proposed with configuration 2 (two) Process -TEG and 1 (one) Tank Loading-TEG running with 2 (two) interconnection, provided with appropriate load shedding system. Bare in mind that during smooth power transfer from each Process-TEG which requires 3 (three) Process-TEG running in parallel, there is an issue on kA capacity of Process switchgear. Existing setting of protection relay shall be reviewed according to the result of protection coordination study
Remediation of Old Substations for Arc Flash hazard
Zakir Husain, Deepak Kumar, Khushbu Thakur,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 1: April 2014 , pp. 23-32
Arc Flash is much different from the conventional shock hazard in the sense that it doesn’t involve direct contact of human beings with the live or energized part. The arcing energy involves high temperature of up to or beyond 20000K. This paper presents a case study of arc flash hazard analysis carried out in older industrial plant and the technological and work procedure changes that can be incorporated to reduce the incident energy level and thus provide a safer environment for the working personnels in plant.
Assessment of Electric Field Distribution Inside 500/220 kV Open Distribution Substations During Working Conditions
Sayed A. Ward, Samy M. Ghania, Essam M. Shaalan,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 115-123
The high level electric field intensity produced by high voltage (HV) equipments inside 500/220 kV substations is harmful for the human (staff) health. Therefore the minimum health and safety requirements regarding the exposure of workers to the risk arising from electric fields produced inside these substations is still considered as a competitive topic for utility designers, world health organization (WHO) and biomedical field researchers. It is very important to have knowledge about levels distribution of electric field intensity within these high voltage substations as early stage in the process of substation design. This paper presents results of investigation 50Hz electric field intensity distribution inside 500/220 kV power transmission substations in Cairo, Egypt. This paper presents a method for assessment the distribution of 50HZ electric field intensity distribution inside this substation, this method of analysis is based on the charge simulation technique (CSM). This study will serve for planning service works or for inspection of equipment on HV power transmission substations.
Comparison of FACTS Devices for Two Area Power System Stability Enhancement using MATLAB Modelling
J. N. Rai, Naimul Hasan, B. B. Arora,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 130-139
Modern Power Transmission networks are becoming increasingly stressed due to growing demand and restrictions on building new lines. Losing stability is one of the major threat of such a stressed system following a disturbance. Flexible ac transmission system (FACTS) devices are found to be very effective in a transmission network for better utilization of its existing facilities without sacrificing the desired stability margin. The static synchronous compensator (STATCOM) and Static Var Compensator (SVC) are the shunt devices of the flexible AC transmission systems (FACTS) family. When system voltage is low, STATCOM generates reactive power and when system voltage is high it absorbs reactive power whereas the Static Var compensator provides the fast acting dynamic compensation in case of severe faults. In this Paper, the performance of SVC is compared with the performance of STATCOM. Proposed controllers are implemented using MATLAB/SIMULINK. Simulation results indicate that the STATCOM controller installed with two machine systems provides better damping characteristics in rotor angle as compared to two machine system installed with SVC. Thus, transient stability enhancement of the two machine system installed with STATCOM is better than that installed with SVC.
Ash Cooler Heat Recovery Under Energy Conservation Scheme
Vikash R Gupta, Lalatendu Pattanayak,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 105-114
A healthy fluidization state in circulating fluidized-bed combustion (CFBC) combustor is attributed to proper quantity of hot bed material (ash), which acts as a thermal fly-wheel. It receives & stores thermal energy from the burning of fuel (lignite) & distributes uniformly throughout the combustor & helps in maintaining a sustained combustion. The quantity of bed ash inside the combustor or size of the bed, depends upon boiler load & subsequently upon combustor temperature, lignite feed rate and ash % in lignite. As these parameters varies during process continuously, sometimes it becomes necessary to drain out the ash from the combustor. As & when differential pressure across the bed is increased from a justified level, draining of hot bed ash starts into Ash Coolers. Bed ash is drained at very high temperature of 850 oC & it also contains burning particles of lignite. This paper describes the heat recovery from bed ash, unloaded from the combustor into ash cooler, by pre-heating the condensate water of turbine cycle in a 125 MW CFB boiler of Surat Lignite Power Plant in India. The thermal performance of ash cooler was derived by doing a heat balance calculation based on the measured temperature of ash and cooling water with different load. From the heat balance calculation influence of ash temperature and ash amount on heat transfer coefficient is determined. Simulation is carried out around main turbine cycle indicates improved thermal economy of the unit, higher plant thermal efficiency, lower plant heat rate and reduce fuel consumption rate. Also simulation result shows that the heat transfer coefficient increase with ash amount and decreases with increase in ash temperature.
Hybrid Generation Power System for Domestic Applications
Qazi Waqar Ali, Muhammad Aamir, Arshad Nawaz, Zaki Udin, Shahid Ullah,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 82-89
This work presents the plan and model of the control strategy for the interconnection of the hybrid energy system able to regulating this load’s voltage and controlling the energy generation with the energy options. The control strategy contains controlling the energy generated through each energy source, in a hierarchical mode using sliding/dropping mode control, while consuming consideration elements that have an impact on each electrical power source and transform the energy generated in order to suitable circumstances for lower power and domestic programs. The cross alternative energy system consists of photovoltaic cellular material, fuel cellular material and battery packs. A numerical equation in order to estimate the perfect voltage involving photovoltaic systems for virtually every solar irradiance and temperature circumstances is suggested. Simulations of a single or a lot more systems interconnected towards the load with the entire proposed control scheme, under different ecological and weight conditions, usually are introduced to indicate this efficiency with the procedure.
Influence of Static VAR Compensator for Undervoltage Load Shedding to Avoid Voltage Instability
Reshma Rajan, Venkateswara Rao, G. V. Nagesh Kumar,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 124-129
In the recent years, operation of power systems at lower stability margins has increased the importance of system protection methods that protect the system stability against various disturbances. Among these methods, the load shedding serves as an effective and last-resort tool to prevent system frequency/voltage instability. The analysis of recent blackouts suggests that voltage collapse and voltage-related problems are also important concerns in maintaining system stability. For this reason, voltage also needs to be taken into account in load shedding schemes. This paper considers both parameters in designing a load shedding scheme to determine the amount of load to be shed and its appropriate location .The amount of load to be shed from each bus is decided using the fixed step size method and it’s location has been identified by using voltage collapse proximity index method. SVC is shunt connected FACTS device used to improve the voltage profile of the system. In this paper impact of SVC on load shedding for IEEE 14 bus system has been presented and analyzed.
Modeling and Simulation of SVPWM Based Application
Ashish Porwal, Ketan Baria, Anuradha Deshpande,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 140-148
Recent developments in power electronics and semiconductor technology have lead to widespread use of power electronic converters in the power electronic systems. A number of Pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply from a three-phase voltage source inverter. Among the different PWM techniques proposed for voltage fed inverters, the sinusoidal PWM technique has been popularly accepted. But there is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization, reduced harmonics, reduced switching losses and better dc bus utilization. This project focuses on step by step development of SVPWM technique. Simulation results are obtained using MATLAB/Simulink software for effectiveness of the study.
Implementation of Hybrid Generation Power System in Pakistan
Qazi Waqar Ali, Muhammad Aamir, Arshad Nawaz, Zaki Udin, Shahid Ullah,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 75-81
A solar-wind hybrid power generation system has been presented here. The application based system illustrated in this paper is designed on the basis of the solar and wind data for Pakistan. The power generated by the system is intended for domestic use. The most common source of unconventional power in homes is battery based UPS (Uninterrupted power supply) inverter. The UPS inverter charges the battery with conventional grid power. This system will charge the battery of UPS inverter by using only wind and solar power, which will make the system cost effective and more reliable. The reason for using both solar and wind is that recent studies have proven that combined system can be more productive and consistent and other thing is that neither of them can be used for continuous power generation. In the system illustrated in this paper the solar-wind system provides power periodically which is controlled by electronic methods and a microcontroller is used to monitor the power from both the inputs. The switching action is provided from the microcontroller to the battery charging based on the power received from solar photovoltaic panel and wind generators. In this paper, an efficient system has been presented comprising of solar panel, wind generator, charge controller and charge storage unit (battery). Solar panel is selected as the main input and the wind resource will be used only in the absence of the solar photovoltaic (PV) output.
Towards An Accurate Modeling of Frequency-dependent Wind Farm Components Under Transient Conditions
M. A. Abd-Allah, Mahmoud N. Ali, A. Said,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 2: August 2014 , pp. 90-104
Frequency dependence complete model is set up for describing the lightning transient behavior of the wind turbines (WTs).To get an appropriate wind turbine model, a high frequency models of surge arrester protecting the boost transformer, transformer and ground electrode soil ionization are implemented. The transient responses and Ground Potential Rise (GPR) can be obtained at different locations in the WTs and connected grid in the time domain as well as in the frequency domain using Fast Fourier Transform (FFT). To check the validity of the model, Surge arresters protection level at different locations, at i.e. LV, MV and HV, is compared with ABB manufacture data sheet, Also a comparison has been made between simple and frequency dependence model of overall wind farm components using ATP/EMTP. This paper provides an accurate simulation of wind farm components under transient condition.
Investigation of Electric Field Distribution Inside 500/220 kV Transformation Substations during Different Working Conditions
Sayed A. Ward, Samy M. Ghania, Essam M Shaalan,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 3: December 2014 , pp. 175-189
This study depicts the electric field distributions inside a typical 500/220 kV open distribution substation under actual loading conditions and during different working conditions, Hot-Stick position and Bar-Hand position. The electric field is investigated for different workers heights of 1m, 1.5m and 1.8m above ground during normal working condition (Hot-Stick position) inside this substation. This in addition to assessment of the electric field at a height levels of 8m, 11m, 14m and 17m above ground as positions for live line maintenance under 220 kV Busbars, 500 kV Busbars, 220 kV Incoming and Outgoing feeders and 500 kV Incoming and Outgoing feeders respectively. In this study the simulation results of the electric field obtained using three dimensional (3D) computer model for existing typical high voltage transformation substation are compared with field values measured inside this typical substation and presented and discussed not only in the form of contour maps but also in the form 3D surface and wireframe maps. The simulation results are good matched and agreed with measured values. This in addition to the electric field will be tabulated and compared to international guidelines for personnel exposure to electric field. This study will serve for planning service works or for inspection of equipment inside high voltage (HV) power transformation substations.
Enhancing Photoelectric Conversion Efficiency of Solar Panel by Water Cooling
M Mohamed Musthafa,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 3: December 2014 , pp. 199-204
Photovoltaic solar cell generates electricity by receiving solar irradiance. The electrical efficiency of photovoltaic (PV) cell is adversely affected by the significant increase of cell operating temperature during absorption of solar radiation. This undesirable effect can be partially avoided by cooling the back side of the photovoltaic panel using water absorption sponge which was fixed on of PV panel and maintain wet condition by circulation of drop by drop water. The objective of the present work is to reduce the temperature of the solar cell in order to increase its electrical efficiency. Experiments were performed with and without water cooling. A linear trend between the efficiency and temperature was found. Without cooling, the temperature of the panel was high and solar cells were achieved an efficiency of 8–9%. However, when the panel was operated under water cooling condition, the temperature dropped maximally by 40C leading to an increase in efficiency of solar cells by 12%.
An Application of Ulam-Hyers Stability in DC Motors
Abasalt Bodaghi, Naser Pargali,
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 3: December 2014 , pp. 149-156
In this paper, a generalization to nonlinear systems is proposed and applied to the motor dynamic, rotor model and stator model in DC motor equation. We argue that Ulam-Hyers stability concept is quite significant in design problems and in design analysis for the class of DC motor’s parameters. We prove the stability of nonlinear partial differential equation by using Banach’s contraction principle. As an application, the Ulam-Hyers stability of DC motor dynamics equations is investigated. To the best of our knowledge this is the first time Ulam-Hyers stability is considered from the applications point of view.
Economic Load Dispatch for Multi-Generator Systems with Units Having Nonlinear and Discontinuous Cost Curves Using Gravity Search Algorithm
International Journal of Applied Power Engineering (IJAPE), Vol 3, No 3: December 2014 , pp. 166-174
Economic Load Dispatch aims at distributing the load demand between various generation stations in a system such that the total cost of generation is minimum. This is of vital importance since it not only reduces the operation cost of the generation utility but also helps in conserving fast dwindling energy resources. Modern day power systems are large interconnected systems with a large number of generator units each having its own cost curve. Ideally the cost function of a unit is a quadratic function of the power generated by the unit and the cost curve obtained is a smooth parabola. But in practice cost curves deviate from the idealised one due the several reasons such as valve point effect, multi fuel operation, existence of forbidden zones etc. and as such may not be continuous or analytic. Also for a large interconnected system it becomes essential to consider the effect of transmission losses. Conventional numerical method based approaches work well with systems without losses but for large systems with losses obtaining convergence becomes difficult as the number of iterations required as well as the computational time are very high. These methods fail entirely if non ideal cost curves are considered. Hence soft computing based methods become essential. Here Gravity Search Algorithm(GSA) has been used to for finding economic load scheduling in a multi generator system, given a certain load demand, and taking into consideration the effects of practical constraints on the idealised load curve. The algorithms for finding the economic scheduling has been written in Matlab and has provided satisfactory results based on the given tolerance values. Also the traditional and soft computing based approaches have been compared to demonstrate the advantages of one over the other.