Power System Operation & Analysis Research Papers (original) (raw)

This paper presents an effective algorithm to locate Single Line to Ground (SLG) fault at a transmission line. Post fault voltages and currents from both substation terminals were
used as the input parameters to the algorithm. Discrete Fourier Transform (DFT) was used to extract the magnitudes and phase angles of three phase voltages and currents. The modeling of the transmission line along with the algorithm was performed using Matlab/Simulink package. The results of fault location for SLG faults along the transmission line demonstrated the validity of the algorithm used even for high resistance earth fault.

- by
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- Power Systems, Power System, Fault Detection, Electric Power Systems

Technology advancement for renewable energy resources and its integration to the distribution network (DN) has garnered substantial interest in the last few decades. Integrating such resources has proven to reduce power losses and improve the reliability of DN. However, the growing number of these resources in DN has imposed additional operational and control issues in voltage regulation, system stability, and protection coordination. Incorporation of various types of distributed generators (DG) into DN causes significant changes in the system. These including new fault current sources, new fault levels, a blinding effect in the protection scheme, reduction in the reach of relays, and decrement in the detection of lowlevel fault currents for existing relays. Such changes will jeopardize the effectiveness of the entire protection scheme in the DN. This research aims to propose a robust protection scheme in which the relay coordination settings are optimized based on the network layout. The potential impacts of DGs on the DN are mitigated by utilizing a user-defined overcurrent-based relay characteristic to obtain the minimum operating time while satisfying protection coordination constraints. A hybrid optimization algorithm based on Metaheuristic and Linear Programming that has the capability to attain the optimal solution and reduces computational time is proposed in this work. The performance of the proposed technique is tested on radial DN integrated with microgrid (MG). The results obtained show the proposed technique has successfully reduced the relay operating time while meeting the protection coordination requirements for dynamic operating modes of a network.

- by Hazlie Mokhlis
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- Computer Science, Renewable Energy, Power System, Smart Grid

Monte Carlo simulation is a computerized practice of mathematics that enables individuals to consider the threat in quantitative study and decision building. This technique is used by specialists in such various areas like finance, project supervision, energy, manufacturing, engineering, research and development, insurance, oil and gas, transport and the environment. In power system, existing systems are always required to be modified in order to meet the growing load densities. Power flow studies are required. Power flow study has great importance in planning during the expansion of power system as well as for determining the best operational conditions. This study involves information related to real power, reactive power, angle and voltage on each bus. Monte Carlo simulation provides a conclusion with a range of possible results and the probability of happening for choice of anything that could happen. This shows the extreme options and the most conventional solutions at the same time with all the possible significances for focus solutions. In this research, probability of the states of the generators are calculated for IEEE-30 bus system for load transferring and forecasting based on reserve capacity of generators. Simulation environment is created in Matlab. Different characteristics curves are plotted for decision building and understanding relationships between key parameters of power systems.

Substation Network and Load Distribution
Substation Network Design
Civil Works Specification
Various Subsystems in Substation and Their Functions
Substation Equipment and Their Functions
Design of Capacity of Transmission Lines
Calculation of Line Constants and SIL
Bus Bar Arrangement
Power Transformer
Substation Earthing
Circuit Breaker
Isolator
Current Transformer
Capacitor Voltage Transformer
Lightning Surge
Switching Surge
Lightning Arrester
Surge Absorber
References

Auto-reclose relay is an important relay used to reenergize a line after the line was tripped by main protection relay due to fault occurrence. Failure of auto-reclose relay to reenergize the line will make power can't be transmitted through the line and power system will be in stress condition. Knowledge of auto-reclose protection scheme is quite difficult to be understood and only few power system software has auto-reclose model for power system study and the software are costly. This research is about modelling auto-reclose relay and its' scheme using Matlab Simulink. The developed model has been developed with some limitations to simplify the modelling process and the results gained show the capability of Matlab Simulink software to be used to model the scheme for education and research purpose.

- by Muhd Hafizi Idris and +1
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- Power Systems, Power System, Electric Power Systems, Power System Protection

- by MUHAMMAD USAMA
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- Renewable Energy, Power System, Smart Grid, Power System Protection Engineering

The course covers techniques for power system modeling and simulation, providing a framework for analysis of system design, operation, and economics. PowerWorld Simulator will be used for development and demonstration of system models. Course participants will learn to develop power system models, perform system analysis, and to create visual simulations that illustrate their results.

Photovoltaic (PV) array which is composed of modules is considered as the fundamental power conversionunit of a PV generator system. The PV array has nonlinear characteristics and it is quite expensive and takesmuch time to get the operating curves of PV array under varying operating conditions. In order to overcome these obstacles, common and simple models of solar panel have been developed and integrated to many engineeringsoftware including Matlab/Simulink. However, these models are not adequate for application involving hybrid energysystem since they need a flexible tuning of some parameters in the system and not easily understandable for readersto use by themselves. Therefore, this paper presents a step-by-step procedure for the simulation of PV cells/modules/arrays with Tag tools in Matlab/Simulink. A 200-Watt solar panel is used as reference model. The output characteristics curves of the model match the characteristics of the solar panel after simulation. The mathematical modeling of the PVwas demonstrated step by step, Wind Turbine performance was simulated and observed, the output voltage of the turbine was 240V matched the calculated value. A step-by-step procedure for simulating a PV array with Tag tools, using friendly icons and dialogs in Matlab/Simulink block libraries is shown in this work. This modeling procedure serves as an aid to help people understand the I-V and P-V operating curves of PV module. The research is the first step to study a hybrid system where a PV power generation connecting to other renewable energy production sources like wind or biomass energy systems is applied and simplified.

Improved and controlled power quality is one of the essential and fundamental need in any power driven industry for optimum utilization of resources. However critical problems in power quality have been recognized such as sags, swells, harmonic distortions and other interruptions. Out of these sags and swells are predominantly found and have severe impact on the electrical devices or electrical machines and therefore needs to be compensated at an earliest to ensure any mal-operation or failure. To crack these problems custom power devices are used like unified power-quality conditioner (UPQC), distribution-STATCOM (DSTATCOM) and dynamic voltage restorer (DVR). The DVR is a one of the custom power device used for the compensation of voltage sag and swell with an advantage of active/reactive power control. A major volume of literature reported in past several years on different configurations of DVR and different control technique used in it. In context of this a detailed review on DVR has been presented with different possible power circuit topologies and control techniques available to reconcile these power quality issues. This review article will contribute in better selection of control strategy and power circuit for optimum performance of DVR for a particular requirement. Also it presents a very helpful investigation for the researcher in this field.

Analisa sistem tenaga (William D. Stevenson JR) diterjemahkan oleh Budiono Mismail

- by Bobby Simanjuntak
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- Electrical Engineering, Power System, Electrical, Electric Power Systems

Black start (BS) capability assessment is important for system planners to prepare the power system restoration (PSR) plan. To achieve a faster restoration process, installing new BS generators can be beneficial in accelerating system restoration. While additional BS capability does not automatically benefit the restoration process, power systems have to update the PSR plan and quantify the benefit based on appropriate criteria. In this paper, a decision support tool, developed in an EPRI project, using Generic Restoration Milestones (GRMs)-based strategy is utilized to provide a quantitative way for assessing the optimal installation location and amount of BS capability. Based on the proposed criteria, the benefit from additional BS capability is quantified in terms of system restoration time. The IEEE Reliability Test System (RTS) 24-bus test system is used for validation of the proposed strategy, using the System Restoration Navigator (SRN) restoration tool. It is shown that power systems can benefit from new BS generators to reduce the restoration time. However, there is a threshold beyond which system restoration time cannot be further reduced from additional BS capability. Economic considerations should be taken into account when assessing additional BS capabilities.

- by Julie Julie
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- Power Systems, Renewable Energy, Fuzzy Logic, Power System

The power system blackout history of last two decades is presented.Conventional load shedding techniques, their types and limitations are presented.Applications of intelligent techniques in load shedding are presented.Intelligent techniques include ANN, fuzzy logic, ANFIS, genetic algorithm and PSO.The discussion and comparison between these techniques are provided.Recent blackouts around the world question the reliability of conventional and adaptive load shedding techniques in avoiding such power outages. To address this issue, reliable techniques are required to provide fast and accurate load shedding to prevent collapse in the power system. Computational intelligence techniques, due to their robustness and flexibility in dealing with complex non-linear systems, could be an option in addressing this problem. Computational intelligence includes techniques like artificial neural networks, genetic algorithms, fuzzy logic control, adaptive neuro-fuzzy inference system, and particle swarm optimization. Research in these techniques is being undertaken in order to discover means for more efficient and reliable load shedding. This paper provides an overview of these techniques as applied to load shedding in a power system. This paper also compares the advantages of computational intelligence techniques over conventional load shedding techniques. Finally, this paper discusses the limitation of computational intelligence techniques, which restricts their usage in load shedding in real time.

- by J.A. Laghari
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- Power Systems, Genetic Algorithms, Power System, Fuzzy Logic Control

This paper describes the modeling of distance relay using Matlab/Simulink package. SimPowerSystem toolbox was used for detailed modeling of distance relay, transmission line and fault simulation. Inside the modeling, single line to ground (SLG) fault was choose to be the fault type and Mho type distance characteristic was choose to be as the protection scheme. A graphical user interface (GUI) was created using GUI package inside Matlab for the developed model. With the interactive environment of graphical user interface, the difficulties in teaching of distance relay for undergraduate students can be eliminated.

- by Muhd Hafizi Idris
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- Power Systems, Power System, Fault Detection, Electric Power Systems

- Power System Representation
- Introduction to PowerWorld Simulator (Distribution Systems)

Today, the power flow or load flow algorithm may be defined as an iterative procedure for approximating the steady state condition of a given power system. This methodology has sufficed for a long time and has been effective enough to meet power system planning demands, in most cases. However, a dilemma exists. The present basic power flow model, the Newton-Raphson, is not appreciably improvable in terms of speed of convergence and accuracy of solution. In fact, these two defining parameters oppose each other. The most successful attempts to improve upon the basic model either trade accuracy for speed (as in the Fast Decoupled Load Flow, which reduces the class of solvable problems) or vice versa (as in the Second Order Load Flow, which significantly complicates the algorithm. This paper proposes an alternative to the Newton-Raphson algorithm, namely an artificial neural network (ANN) method based on the backpropagation (BPN) learning algorithm. BPN, which has a feed forward network architecture and eliminates the divergence problems associated with iteration as well as significantly reducing the time of convergence. The accuracy of solution is determined by the range and amount of training provided; therefore, speed of convergence and accuracy of solution are independent of each other. A network architecture was developed and implemented and the results are detailed in this paper.

- by Michael Cooke
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- Artificial Intelligence, Power System, Neural Networks, Electric Power Systems

Abstract:
Investigation and online monitoring of power system stability have become vital factors to electric utility suppliers. At present power system utilities operate very close to the limit of system stability owing to an increasing number of new economic and environmental restrictions. Researchers have been trying to find out the most effective way for online system status monitoring, so that necessary precautions can be taken prior to voltage collapse. Several methods have been proposed for analysing voltage collapse phenomena. An effective method for online system status monitoring and thus voltage collapse prediction is described. The basic methodology implied in this technique is the investigation of each line of the system through calculating line stability indices. The proposed method was tested on the IEEE 24-bus reliability test system and has been found to be accurate and precise in voltage collapse prediction. A comparative study with other methods has also been carried out indicating that the proposed method has some advantages over the others.

In power systems with the high penetration of renewable energies such as wind powers, accuracy in predicting power system state is really important, especially in bidding strategies, risk management and operational decisions. In this paper, the impact of STATic COMpensator (STATCOM) and Static Series Synchronous Compensator (SSSC) on predictability of power system is studied. For this investigation, predictability
indices are utilized. This paper clarifies some important questions and concerns about power system such as; do the STATCOM and SSSC improve or impair the predictability of system state? Also, this paper warns the operator of system about ignoring the predictability concept in FACTS included power systems. Moreover, the necessity of utilizing predictability indices in optimization problems beside conventional objectives, such as losses, is discussed. The results are discussed on IEEE 14 and 57 bus test systems.

In recent years, studies on electric vehicles have increased rapidly and the reason for these studies can be summarized in two sections. The first is the reduction of the emission values of vehicles by the goverment aim of zero emissions. Combustion engines are abandoned especially in industrial vehicles operating in closed environments. The second reason is due to technical reasons. Electric motors operate with higher efficiency than combustion engines. Compared to combustion engines, electric motors have close to ideal torque characteristics, thus achieving maximum drive power at startup. Due to the characteristic of the electric motors, the vehicle can achieve higher acceleration. In electric vehicles, gearbox and clutch are often not required due to the drive torque characteristic. On the other hand, the control of the electric motors makes the motor management easier. Electric motors are driven by the common force due to the electromagnetic field. Electromagnetic field is provided electrically. Therefore, the required energy must be stored electrically. Batteries are used as electrical energy storage. However, according to the technological level reached, the energy capacities of batteries are lower than those of fossil fuels. In this study, a comparison of the battery types used primarily in vehicles is made. Lead acid batteries are widely used in industrial type vehicles. As the battery capacity is limited, it is necessary to determine the optimized battery capacity according to the vehicle operating conditions. If the battery capacity that does not meet the requirements, negatively affects the performance of the vehicle as it cannot provide sufficient current and shortening of the battery's life due to the battery's deep discharge. Therefore, the battery capacity must be optimized according to the vehicle operating conditions. There are sufficient studies on the battery characteristics and chemistry of the batteries [1-6]. In this study, the performance behavior of the batteries on the vehicle was evaluated in terms of volage/current and consumption.

- by Serhat Karnap and +1
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- Electrical Engineering, Power System, Vehicle Dynamics, Electric Vehicles

Current market environment, ever growing difference between depleting energy resources and increasing power demand and increased expectations of customers from utility companies has made it necessary to adopt some good operational policies by electric utility companies. So the focus of utility companies has shifted towards increased customer focus, enhanced performance and to provide reliable supply at low cost. The electric power system must be operated in a way to schedule generations economically of generation facilities. In last two decades many evolutionary techniques has been developed to solve the optimization problems. Particle swarm optimization has acquired much recognition due to less memory requirement and its inherent simplicity. Particle swarm optimization technique proved to be having strong potential for solving complex and high dimensional optimization problem. PSO is free from local minimum solution convergence which is often encountered while solving nonlinear and non-convex optimization problem through conventional techniques. This paper presents a summarized view of application of PSO for solving power economic dispatch problem.

In reliability assessment of bulk power systems, two methods have been largely studied and used: contingency enumeration and non-sequential Monte Carlo simulation. Both have their wellknown advantages and drawbacks. Contingency enumeration is conceptually simple and usually requires low computational effort. Conversely, Monte Carlo simulation is computationally harder, but much more versatile to model random aspects. This paper depicts some major aspects regarding both methods. It also shows that it is not a matter of choosing the definite and unique technique, but how they can be used in a complementary way. A real power system, based on the Brazilian interconnected electrical system, and the commercial program NH2 are used to illustrate that both methods are feasible to bulk power systems, and can be used in order to achieve complementary results.

This article investigates the economic benefits of smart
grid automation investments. A system consisting of 7 substations
and 14 feeders is used in the evaluation. Here benefits that can be
quantified in terms of dollar savings are considered, termed “hard
dollar” benefits. Smart grid investment evaluations to be considered
include investments in improved efficiency, more cost effective use of
existing system capacity with automated switches, and coordinated
control of capacitor banks and voltage regulators. These smart grid
evaluations are sequentially ordered, resulting in a series of incremental
hard dollar benefits. Hard dollar benefits come from improved
efficiency, delaying large capital equipment investments, shortened
storm restoration times, and reduced customer energy use. Analyses
used in the evaluation involve hourly power flow analysis over
multiple years and Monte Carlo simulations of switching operations
during storms using a reconfiguration for a restoration algorithm.
The economic analysis uses the time-varying value of the locational
marginal price. Algorithms used include reconfiguration for restoration
involving either manual or automated switches and coordinated
control involving two modes of control. Field validations of phase
balancing and capacitor design results are presented. The evaluation
shows that investments in automation can improve performancewhile
simultaneously lowering costs.

- by Danling Cheng and +1
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- Power System, Electric Power Systems, Power System Protection, Power System Protection Engineering

Voltage instability is one of the major issue in HVAC power network operating at 50 Hz frequency due to limited power transfer capability and distance limit. The stable operation of power system must be kept within limits to increase the efficiency of power transmission system. In this research Low Frequency AC (LFAC) transmission system has been proposed as a new power transmission technology to reduce the losses of transmission network and controlling the reactive power using Flexible AC transmission device. A LFAC Transmission lines operates at 16.7Hz frequency for transmission of power from source to load and use two Frequency converters at source and load side. The normal operation of power system depends on the reactive power flowing through the power transmission lines, which can be adjusted by a flexible AC transmission device; Static synchronous compensator. LFAC transmission lines with STATCOM controller improve the Power system voltage stability under various disturbances and enhance the power transmission capability as compare to HVAC transmission. The simulations are done in Matlab Simulink 2017a .The Output of Matlab Simulink model shows that voltage will become Stable and reactive power is compensated for best performance for power system.

Increasing demand for electricity, contingency, practical limitation in launching new transmission lines making the transmission network of Bangladesh Power System (BPS) very stressed. The stressed system quickly attains small signal stability and transient stability limit. These stabilities ensure the stable operation of the power system when subjected to small and large disturbances. This paper explores the improvement of small signal stability and Transient stability of BPS using alternative Thyristor Controlled Series Compensator (TCSC), Static VAR Compensator (SVC) and TCSC, Static Synchronous Compensator (STATCOM) based series shunt compensation. TCSC based series compensation is kept similar while using alternative shunt compensation by means of SVC and STATCOM. As the East West Interconnectors (EWIs) of BPS is the gateway of power exchange between East and West grid so the compensative devices are installed in these interconnectors. To tune the oscillation damper controller the Modal analysis technique is adopted. Tuned controller in return increases the small signal stability and transient stability limit.

Contingency analysis is the study of the outage of elements such as transmission lines, transformers and generators, and investigation of the resulting effects on line power flows and bus voltages of the remaining system. It represents an... more

Contingency analysis is the study of the outage of elements such as transmission lines,
transformers and generators, and investigation of the resulting effects on line power
flows and bus voltages of the remaining system. It represents an important tool to
study the effect of elements outages in power system security during operation and
planning

- by Muhammad Usama
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- Computer Science, Renewable Energy, Power System, Smart Grid

Reconfiguration, by exchanging the functional links between the elements of the system, represents one of the most important measures which can improve the operational performance of a distribution system. The authors propose an original method, aiming at achieving such optimization through the reconfiguration of distribution systems taking into account various criteria in a flexible and robust approach. The novelty of the method consists in: the criteria for optimization are evaluated on active power distribution systems (containing distributed generators connected directly to the main distribution system and microgrids operated in grid-connected mode); the original formulation (Pareto optimality) of the optimization problem and an original genetic algorithm (based on NSGA-II) to solve the problem in a non-prohibitive execution time. The comparative tests performed on test systems have demonstrated the accuracy and promptness of the proposed algorithm.

- by Roberto Villafafila-Robles
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- Engineering, Artificial Intelligence, Power Systems, Renewable Energy

Reconfiguration, by exchanging the functional links between the elements of the system, represents one of the most important easures which can improve the operational performance of a distribution system. The authors propose an original method, aiming at achieving such optimization through the reconfiguration of distribution systems taking into account various criteria in a flexible and robust approach. The novelty of the method consists in: the criteria for optimization are evaluated on active power distribution systems (containing distributed generators connected directly to the main distribution system and microgrids operated in grid-connected mode); the original formulation (Pareto optimality) of the optimization problem and an original genetic algorithm (based on NSGA-II) to solve the problem in a non-prohibitive execution time. The comparative tests performed on test systems have demonstrated the accuracy and promptness of the proposed algorithm.

- by Bogdan Tomoiaga and +2
- •
- Genetics, Artificial Intelligence, Power Systems, Renewable Energy

This paper presents the design and modeling of an off-grid hybrid stand-alone system for fulfilling the load requirements of an off-grid household located in remote Benin City, Edo State in Nigeria. Using a 48 V DC bus, the system was sized using Homer Pro software. Optimization results-which presents various systems' designs-show that the most cost effective and efficient system is the hybrid system consisting of a 1.23 kW photovoltaic (PV) array, four 12 V batteries, 1.6 kW inverter and a 4.8 kW diesel generator. Moreover, the hybrid system is found to be a better solution in terms of its techno-economic performance compared to the diesel generator only system. Sensitivity analysis is carried out to test the adaptability of the hybrid system to a load variation of 20%, and Solar PV input variation of 10%. Results unveil that the lowest cost investment (i.e., investment in the PV-battery system) may not give the best returns. This supports the selection of the aforesaid hybrid configuration to satisfy the household's load.

- by Jordan Journal of Electrical Engineering (JJEE) and +1
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- Electrical Engineering, Homer, Power Systems, Power Electronics

- by MOHD RAFI ADZMAN
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- Computer Science, Power Systems, Power System, Electric Power Systems

This paper provides a complete stability and harmonic rejection analysis of a single-phase inverter with a passive-damped LCL filter intended for Renewable Energy Systems (RES), through a rigorous mathematical modeling. The harmonic rejection of the system was analyzed considering distorted grid conditions. The stability analysis of the inverter was carried out regarding the influence of both the current sensor location and the Harmonic Compensator (HC). Matlab/Simulink simulation results are presented to validate the analysis done.

- by Sebastian Manrique
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- Photovoltaics, Power Electronics, Power Quality, Power System

The topology (transmission line) switching to achieve economic and reliability gains in the power grid has been proposed some time ago. This approach did not gain much attention until recently when large penetration of renewable generation created incentives to use transmission line switching to control sudden changes in power flows and mitigate contingencies caused by the generation variability. This paper explores implementation issues related to circuit breaker (CB) monitoring, relay setting coordination and detection of relay misoperations in the context of the topology switching sequence implementation. The paper covers risk-based assessment of CB status needed for determination of reliable switching sequences; it indicates how relay settings may be changed due to switching actions; it also provides an on-line algorithm for detection of relay misoperations, which identifies the lines that may be switched back to service after being trip erroneously by a relay.

Neste trabalho são descritas as linhas gerais de uma metodologia para previsão de carga capaz
de fornecer previsões até 48 horas à frente, com resolução temporal de 10, 15, 30 e 60 minutos. A
metodologia de previsão baseia-se no uso combinado de um modelo de lógica nebulosa para a previsão
do perfil horário da curva de carga até 48 horas á frente, de uma rede neural polinomial para prever
valores diários da demanda mínima e da demanda de ponta e da interpolação spline para obter previsões
com diferentes resoluções de tempo. O desempenho da metodologia proposta é ilustrado pelos resultados
obtidos em um experimento computacional com os registros de carga do Sistema Interligado Nacional
(SIN).

- by Surya Hardi
- •
- Computer Science, Power Systems, Power System, Fault Detection

- by Mahmoud Moghavvemi and +1
- •
- Renewable Energy, Power System, Power System Protection Engineering, Power System Operation & Analysis

The flexible ramp reserve of dispatchable generators is a key effective means to compensate the fast fluctuation of wind power generators and the forecast error of demand. This paper proposes a stochastic Network Constrained Unit Commitment (NCUC) model to determine, on daily horizon, the optimal schedule of generation units along with the required flexible ramp and spinning reserves under uncertainties of wind power and demand. Point estimate method (PEM) is utilized to reduce the number of scenarios that model wind power and demand uncertainties. In addition to PEM scenarios, some worst-case scenarios based on regional wind and demand variations are defined and incorporated in the proposed model. The NCUC model includes for these scenarios various technical constraints of generation units and operation constraints of the network. To ensure computational tractability of NCUC model, the AC network operation constraints are linearized. The proposed mixed integer linear programming (MILP) NCUC model is tested using the IEEE 118-bus system. The obtained results show better units scheduling than the conventional (deterministic) NCUC model.

Tambayoli Irrigation Area (Provincial Authority) located in North Morowali Regency has an area of hectares, functional area 904 hectares, the realization of planting area I (MT. I) = 622 Ha, Planting Period II (MT. II) = 634 Ha. The Mamosalato Irr has an area of 374 Ha, 152 Ha Functional Area, the realization of planting area I (MT. I) = 90 Ha, Planting Period II (MT. II) = 123 Ha. The irrigation area in these 2 (two) there are several Irrigation Areas which are irrigation areas that can be classified as technical irrigation networks because they have permanent tapping structures and structures for those who water flow. In irrigated areas, irrigation network operations and maintenance are rarely carried out. Therefore, it is necessary to evaluate the operation performance and maintenance of irrigation networks to determine the of the irrigation system's performance. The purpose of this study is to determine the performance of the authority of the Province D.I irrigation OP. Tambayoli and D.I. Mamosalato. Methods of data analysis were carried out by means of surveys and d the performance of the D.I. irrigation system. Tambayoli is 71.31%, which means that the performance is good (70%-79%) while the performance of the irrigation sy performance and needs attention (<55%), this is because D.I. Mamosalato received very little attention from the local government and the central government.

This paper presents an improved version of a graphical application for managing and analyzing Electrical Power
Systems. The design of the application accommodates the integration of visual representation of HV and LV
systems, information management and planning studies. Features and the look and feel of the application have
also been presented. Few standard IEEE networks have been created using this application. Summary of usability
testing is provided. This application can be used effectively to train students and even utility engineers in system
analysis, management as well as to develop a sense of appreciation towards graphical tools in system analysis.
This application can be freely downloaded from the author’s SkyDrive: http://sdrv.ms/12aErO2

- by MKS Sastry
- •
- Computer Graphics, Power System, Graphical Models, Electric Power Systems
- by Afandi, A.N.
- •
- Electrical Engineering, Power Systems, Power Quality, Power System

During system restoration, it is critical to utilize the available black-start (BS) units to provide cranking power to non-black-start (NBS) units in such a way that the overall system generation capability will be maximized. The corresponding optimization problem is combinatorial with complex practical constraints that can vary with time. This paper provides a new formulation of generator start-up sequencing as a mixed integer linear programming (MILP) problem. The linear formulation leads to an optimal solution to this important problem that clearly outperforms heuristic or enumerative techniques in quality of solutions or computational speed. The proposed generator start-up strategy is intended to provide an initial starting sequence of all BS or NBS units. The method can provide updates on the system MW generation capability as the restoration process progresses. The IEEE 39-Bus system, American Electric Power (AEP), and Entergy test cases are used for validation of the generation capability optimization. Simulation results demonstrate that the proposed MILP-based generator start-up sequencing algorithm is highly efficient.

- by Julie Julie
- •
- Power System, Optimization techniques, Smart Grid, Power System Operation & Analysis

Large-scale and ubiquitous penetration of wind power generation to power systems necessitates more conservative provision of system reliability by ensuring adequately committed reserve and observance of transmission constraints. In addition, wind power curtailment due to the technical limitations of system operations, such as transmission congestion, should be efficiently mitigated. To this aim, this paper presents a congestion risk-aware unit commitment formulation in a two-settlement market environment. The uncertainty impact of multicorrelated wind power and contingencies on the risk of transmission congestion for each line, called the Line Transfer Margins (LTM), is incorporated using basic statistical data on the nodal wind power forecast and probability of credible line-outages across the system. The LTMs, formulated free of any distributional assumptions, collectively provide a measure for transmission reserves, which effectively mitigate the likelihood of transmission congestion, reserve undeliverability, and wind power curtailment in the real-time economic dispatch. The effectiveness of the proposed approach is verified through comparative case studies on IEEE RTS-96 for various wind power and LTM scenarios.

- by Sajjad Abedi
- •
- Congestion Control, Risk Management, Power System Operation & Analysis, Wind Power

Power system analysis, which includes steady state, transient and dynamic, traditionally has been relegated to an off line or planning activity. This means that the system is only designed to respond to contingencies that have been adequately simulated prior to implementation of the design. Practically, this limits the adaptability of the system when confronted with new or unstudied phenomenon. The usual system response is to isolate the affected area temporarily until the system is stabilized or the disturbance is redirected out of the system. This down time or unmet demand time could be minimized if the system could predict the onset of contingencies and react in a more timely fashion. In order to accomplish this system monitoring, contingency analysis and control or correction must be in real time. The problem, of course, is that the steady state of the system must be known prior to performing a transient or dynamic analysis, since these former analyses determine the deviation from the steady state. Moreover, classical steady state determination or power flow analysis methods are time consuming and potentially unstable. In [1], a method for eliminating the possibility of non-convergence and significantly improving the processing time of power flow analysis is described. In this paper a method of performing steady state, transient and control analyses simultaneously is proposed. This method utilizes a parallel architecture of heterogeneous neural networks to perform power flow analysis, transient stability and fault analysis, and automatic generation control (AGC). The simulation is performed on a set of networked computers employing PVM (parallel virtual machines) technology for intermachine communication.

- by Michael Cooke and +1
- •
- Power Systems, Power System, Electric Power Systems, Power Electrical Engineering

In this paper the authors tried to design a under excitation limiter and a power system stabilizer which can operate without any kind of interaction. The under excitation limiter (UEL) is intended to prevent reduction of generator excitation to a level where the steady state stability limit or the stator core end-region heating limit is exceeded. The power system stabilizer (PSS) uses auxiliary stabilizing signals to control the excitation system so as to improve power system dynamic performance.

- by farzad mirzaei
- •
- Stability, Power System Operation & Analysis

Reconfiguration of a power distribution system consists in changing the functional links among its elements and represents one of the most important actions for the improvement of system performance in operation. In the last few years, some authors have proposed approaches based on Pareto optimality for problem formulation of reconfiguration, with active power losses and reliability indices as objectives. The study highlights the optimization importance of reliability indices which refer to the interruption frequency, especially because, in the context of smart grids, the fastness of the reconfiguration method contributes, by itself, to reduce the duration of interruptions. There is no unique recognition concerning which approach is the most suitable to be used in order to solve the reconfiguration as a Pareto-optimal problem. The most important aspect is the way in which the specific information of the problem field is modelled in the implementation. Also, the dimension of a Pareto-front can vary widely from a test system to another.

Hotel NIRMALA SARI Denpasar memiliki 400 kamar, namun 20 kamar diantaranya tidak dapat dioperasikan karena sedang dalam keadaan direnovasi. Hotel tersebut memiliki data yang terkait dengan operasional dalam tahun 20x2 sbb :

- by Phyta Widyasari
- •
- Power System Operation & Analysis

Reliability analysis has been supporting
energy operations planning studies in a very significant way,
specially to obtain predictive indexes of peak load supply.
During the last couple of years, due to high growth rates of
peak load, Brazilian organism for Coordination of the
Interconnected Operation (GCOI) decided to implement
reliability studies in the short-term operations planning. The
multi-area methodology that has been used in the long-term
planning was extended and now, important information to the
short-term planning, like probability distribution function of
the EPNS, is available.

Summary form only given. This work presents a methodology for calculating the optimal generation capacity reserve and siting in power systems planning. The proposed methodology is based on a least-cost planning approach which considers along the planning horizon, the capacity reserve investment costs and the operational expected costs, comprising thermal generation and interruption costs. This problem is solved by using the Benders decomposition technique in which investment and operation subproblems solutions are obtained iteratively and separately thus allowing the use of tailor-made algorithms for each subproblem. The operation subproblem corresponds to a probabilistic evaluation of the minimum operation cost in composite generation/transmission systems, in which the system states are selected through Monte Carlo simulation or state enumeration and the system performance is analysed by a nonlinear optimal power flow solved by an interior point algorithm. The proposed methodology is illustrated in a case study with a modification of the IEEE Reliability Test System (MRTS).