Power Systems

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.

The increasing wind power generation requires the updating of the computational tools that support decision making in the operation and planning of electric power systems. This work describes a methodology to model the spatial correlations among wind speeds probability distributions in probabilistic power flow. The proposed methodology is based on Nataf transformation and Monte Carlo Simulation. The proposed methodology is illustrated in case studies with the IEEE 24 bus test system, highlighting the importance of adequately considering such correlations.

CIES2020: As Energias Renováveis na Transição Energética: Livro de Comunicações do XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia Solar. Helder Gonçalves, Manuel Romero (Ed.). Lisboa, Portugal: LNEG, 3-5 Novembro, 2020, p. 107-112. ISBN: 978-989-675-076-3

Currently, power systems (PS) already accommodate a substantial penetration of DG and operate in competitive environments. In the future PS will have to deal with large-scale integration of DG and other distributed energy resources (DER), such as storage means, and provide to market agents the means to ensure a flexible and secure operation. This cannot be done with the traditional PS operation. SCADA (supervisory control and data acquisition) is a vital infrastructure for PS. Current SCADA adaptation to accommodate the new needs of future PS does not allow to address all the requirements. In this paper we present a new conceptual design of an intelligent SCADA, with a more decentralized, flexible, and intelligent approach, adaptive to the context (context awareness). Once a situation is characterized, data and control options available to each entity are re-defined according to this context, taking into account operation normative and a priori established contracts. The paper includes a case-study of using future SCADA features to use DER to deal with incident situations, preventing blackouts.

This section presents an overview of the California ISO Ancillary Services (A/S) market with explanations of some of the design features used in the A/S markets and settlement process. This section is intended to give the settlement analyst and energy scheduler a basic understanding of the A/S design features and to describe how the settlement charges are derived. The actual settlement equations and components for the specific charge types are included in the following ISO Settlement Guide sections. Some of the key principals of the A/S market (self-provision, on demand obligation and SC to SC transactions) are discussed in detail in this section. A/S procurement ensures the ISO has adequate reserve generation capacity to maintain the electric system reliability, and system frequency, by matching generation and load at all times under both normal and abnormal conditions. California is the first restructured electric marketplace to obtain A/S through a competitive bidding process. This Market based process demonstrates that system reliability can be maintained by relying on open markets for these essential services.

This paper presents the design of Earthing system for 400 KV substation and calculation of its parameters. Successful operation of entire power system depends to a considerable extent on efficient and satisfactory performance of substations. Hence substations in general can be considered as heart of overall power system. In any substation, a well designed grounding plays an important role. Since absence of safe and effective grounding system can result in mal-operation or non-operation of control and protective devices, grounding system design deserves considerable attention for all the substations. Grounding system has to be safe as it is directly concerned with safety of persons working within the substation. Main purpose of this work is designing safe and cost effective grounding systems for HV / EHV substations situated at such locations where soil of the substation site is not uniform. Initially significance of Earthing is explained & methodology for design of substation ground...

Linear Programming (LP) is a widely used tool for solving many linear/non-linear power-system optimization problems such as transmission planning, constrainedsecurity dispatch, optimal power flow, emergency control, etc. Variants of simplex-based methodologies are generally used to solve the underlying LP problems. In this paper an implementation of the newly developed Dual Affine (DA) algorithm (a variant of Karmarkar's interior point method) is described in detail and some computational results are presented. This algorithm is particularly suitable for problems with a large number of constraints, and is applicable to linear and nonlinear optimization problems. In contrast with the simplex method, the number of iterations required by the DA algorithm to solve large-scale problems is relatively small, generally between 20 -60, irrespective of problem size; this feature makes the DA method very fast in practical applications. The DA algorithm has been implemented considering the sparsity of the constraint matrix. The normal equation that is required t o be solved in every iteration is solved using a preconditioned conjugate gradient method.

At the planning of combined heat and power (CHP)-based micro-grid, its distributed energy resources (DER) capacity is to be selected and deployed in such a way that it becomes economically self-sufficient to cater all the loads of the system without utility's participation. Economic deployment of DERs is meant to select optimal locations, optimal sizes, and optimal technologies. Optimal locations and sizes, which are independent of CHP-based DERs types, are selected, here, by loss sensitivity index (LSI) and by loss minimization using particle swarm optimization (PSO) method, respectively. In a micro-grid, both fuel costs and NO x emissions are, mainly, dependent on types of DERs used. So the main focus of the present paper is to incorporate originality in ideas to evaluate how different optimal output sets of DER-mix, operating within their respective capacity limits, could share an electrical tracking demand, economically, among micro-turbines and diesel generators of various sizes, satisfying different heat demands, on the basis of multi-objective optimization compromising between fuel cost and emission in a 4-DER 14-bus radial micro-grid. Optimization is done using differential evolution (DE) technique under real power demand equality constraint, heat balance inequality constraint, and DER capacity limits constraint. DE results are compared with PSO.

فشصه تیشیذه یبّ ذٌتسّ . یاشجا یاشب ِهبًشب يیا بّ صا شٍس یبّ یتٍبفته ُدبفتسا ُذض داذعت بلغا ِک تسا یه صضَپ ظبخ عًَ ذٌچ سد اس بّسبب صا یدٍذحه .ذٌّد ِلبقه يیا سد صا شٍس ییبجببج سبب فشصه تیشیذه یاشب ِکبضضیس ذٌوضَّ ی ِک ُذض ُدبفتسا ِلئسه يیا ا بب کيپ صّبک فاذّ سبب ٍ نتسيس ٌِیضّ یبّ یاشب ييکشتطه طسَت ِکبض سد عٌَته یبّسبب یسٌَيسک ٍ یسٌَيس بیاشض بب تاسر مبحدصا نتیسَگلا ( H-PSO-SCAC ) 1 لح ُذض ، س شب یدبٌْطيپ ِهبًشب یاشجا شثا سپ ذيلَت ِکبضضیس ساصبب سد بّ فذّبب یعبوتجا ُبفس حطس دَبْب یسسشبدسَه تسا ِتفشگساشق . ِيبض یصبس ِکبض یٍس بّ ِکبضضیس ِس لهبض یذٌوضَّ ی یتعٌص ٍ یسبجت ،یگًبخ ی مبجًا ُذض ِک یبّسبب صا یفلتخه عاًَا یاساد لببق لشتٌک ذٌتسّ ِهبًشب ِک تسا ىآ صا یکبح جیبتً . کيپ صّبک بجَه یدبٌْطيپ ی ،سبب ٌِیضّ ی يکشتطه ٌِیضّ ٍ ي سبب لدبعت ٍ ُذض ذيلَت یبّ ٍ س حطس دَبْب ُشْب ذید صا یعبوتجا ُبف سادشب لببًد ِب اس دساد . ُطاٍ بّ ی لک ي ذ ی : لببق یبّسبب ِکبض ،لشتٌک ،ذٌوضَّ ی یعبوتجا ُبفس نتیسَگلا ، H-PSO-SCAC توس تیشیذه ، بضبقت DSM 2

This paper presents an application of the steady state network equivalents and expert system for voltage and reactive power (VAR) control in large-scale power systems. A steady state network equivalencing technique is used to construct the "three tier" subsystem which is adequate to solve voltage violation problems. An expert system utilises the sensitivity tree method to select the optimal set of control actions to alleviate the voltage problem. The expert system was developed using the VP-EXPERT system shell. VP-EXPERT interacts with the power system analysis software providing analysis of the network sensitivity matrix and data for the knowledge base. Practical application of the developed expert system is demonstrated on the example of the HydroElectric Commission (HEC) power system of Tasmania, however the proposed approach is not limited by the system size.

IC switching current is the main noise source of many power integrity issues in printed circuit boards. Accurate measurement of the current waveforms is critical for an effective power distribution network design. In this paper, using a giant magnetoimpedance (GMI) probe for this purpose is studied. A side-band detection and demodulation system is built up to measure various time-domain waveforms using an oscilloscope. It is found that the GMI probes are potentially suitable for this kind of time-domain measurements, but probe designs and measurement setups need further improvements for this application.

The use of autonomous hybrid power system is being popular due to the continuous increasing gap between demand and supply of conventional energy sources and intermittent nature of renewable energy sources. Normally, the renewable energy source such as wind using induction generator generate electricity but induction generators require reactive power for its operation and this demand is continuously changing by the variation of load and wind power. Though synchronous generator used in hybrid system for generating power through diesel system is supplying reactive power to the system but another source having fast response for reactive power supply is required to fulfill this demand. In this paper, the SVC and STATCOM are used and compared as a reactive power compensator.

This thesis is about how power electronics can be implemented on embedded System programs. Majoring in power electronics and controlling using an embedded system is the purpose of this project. By employing power electronics component that can handle big current and voltage this battery charger should provide more efficient solutions to the charging process. The charger was designed using is a DC/DC buck converter, switched using MOSFET at high switching frequencies. The microcontroller rapidly switches a power MOSFET between saturation and cut off with a variable duty cycle whose average is the desired output voltage.
The main advantage of this method is greater efficiency because the switching transistor dissipates little power in the saturated state and none in the off state. Other advantages include smaller size and lighter weight from the elimination of low-frequency transformers and lower heat generation from the higher efficiency. Disadvantages include greater complexity, the generation of high amplitude, high-Frequency energy that the low-pass filter must block to avoid EMI, and a ripple voltage at the switching frequency.
The analysis of the charging system was conducted in the lab under various conditions, a dc power source was used as the energy source and the buck converter ensured maximum power transfer by optimal resistance matching of the source to the battery.

In many physical insulation systems it is often necessary to establish the approximate estimate of the breakdown voltage for nonstandard impulse voltages. The disruptive effect method, which is an analytical method, has some success in such estimations. However, it does not cater to waveforms that are of the bidirectionally oscillating impulse type. Such voltages occur frequently within transformer windings. A new method called unconditionally sequential approach is proposed in order to serve as a measure of insulation strength under bidirectionally oscillating voltages. The method is validated by experiments on test specimens. The utility of the method is shown by an assessment of tap stresses in a 50/25 MVA power transformer. Abstract: The Bayesian network is a probabilistic graphical model in which a problem is structured as a set of variables (parameters) and probabilistic relationships among them. The Bayesian network has been effectively used to incorporate expert knowledge and historical data for revising the prior belief in the light of new evidence in many fields. However, little research has been done to apply the Bayesian network for fault location in power delivery systems. We construct a Bayesian network on the basis of expert knowledge and historical data for fault diagnosis on a distribution feeder in Taiwan. The experimental results validate the practical viability of the proposed approach.

The reconfiguration of a power distribution system, by exchanging the functional links between its elements, represents one of the most important procedures to improve the performance in the operation of a distribution system. The optimization through reconfiguration (or optimal reconfiguration) of a power distribution system is not a new problem but still represents a difficult one and is specified in some strategies for smart grids. The paper addresses this problem as a single objective one, where, as main criterion, active power losses have been chosen. There is no unique acceptance regarding which approach (based on heuristics, meta-heuristics, genetic algorithms, etc.) is the most proper to use in order to solve this problem. The most important thing is how the specific knowledge of the problem domain is used and modeled in the implementation. Moreover, the indices which can quantify the quality of a reconfiguration method consist in runtime and the obtained solution and these indices can be confirmed only by experimental results. In order to solve the problem (to search and find the optimal solution) an original genetic algorithm based on connected graphs is proposed. Comparative tests performed on some test systems demonstrated the accuracy and the promptness of the proposed algorithm.

This paper presents a mho distance relay simulation based on the phase comparison technique using a typical electrical power systems analysis software for two cases: when the operation state is close to the static voltage limit and during a dynamic perturbation in the system. The paper evaluates the impedance variations caused by complex voltage values, the mho polarization, and the comparator operating region into the complex plane. In addition, the paper found the information for the dynamic perturbations from the outputs considering a mid-term stability program. The simulation of the mho-phase comparator in the static voltage proximity limit detects unit distance elements with impedance measured close to reach the threshold in the steady-state. Dynamic mho simulations in the complex plane are successfully tested by plotting time phase difference curves on the comparator input signals. Relay programmers can use these curves to analyze other phase comparators applications and the c...

The main frequency is an important parameter of an electrical power system. The frequency can change over a small range due to generation-load mismatches. Some power system protection and control applications, e.g., frequency relay for load shedding, load-frequency controller, require accurate and fast estimation of the frequency. Most digital algorithms for measuring frequency have acceptable accuracy if voltage waveforms are not distorted. However, due to nonlinear devices, e.g., semiconductor rectifiers, electric arc furnaces, the voltage waveforms can include higher harmonics. The paper presents a new method of measurement of power system frequency, based on digital filtering and Prony's estimation method. Simulation results confirm, that the proposed method is more accurate than others, e.g., than the method based on the measurement of angular velocity of the rotating voltage phasor.

A lot of attention is being paid to wind energy due to the focus on renewable energy. Malaysia is situated in the equatorial region and its climate is governed by the monsoons. Wind resource in Malaysia varies from one location to another. Wind speed is better offshore compared to onshore, so more contribution by offshore wind powers in terms of electricity generation. Wind energy potentiality and techno- economic feasibility of offshore wind farms in Malaysia is investigated in this paper. Research was conducted using HOMER software to assess the potential of wind energy along the South China Sea coastline. This study indicates the best sites to set up offshore wind farms in Malaysia while costs associated for wind energy generation are calculated. Two model of the wind turbines Vestas V-47 and V-80 are taken for economic feasibility analyses. Investment, operation and maintenance costs have been evaluated for offshore wind energy. Feed-in tariff policy effects energy price and wind farms profitability were analyzed.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6129028

At Drexel University, instrumentation and measurement of the Reconfigurable Distribution Automation and Control Laboratory include hardware and software instruments which together form an automated measurement and control system. This system contains special features that were included to enable meter placement and network reconfiguration studies. This paper presents an outline of the measurement and control system for the general laboratory and then focuses on the capabilities purposely added for the meter placement and network reconfiguration studies.

Flexible models for aggregated residential loads are needed to analyze the impact of demand response policies and programs on the minimum comfort setting required by end-users. This impact has to be directly deduced from the probability profiles of thermal and electrical performance variables.

Linear Programming (LP) is a widely used tool for solving many linear/non-linear power-system optimization problems such as transmission planning, constrainedsecurity dispatch, optimal power flow, emergency control, etc. Variants of simplex-based methodologies are generally used to solve the underlying LP problems. In this paper an implementation of the newly developed Dual Affine (DA) algorithm (a variant of Karmarkar's interior point method) is described in detail and some computational results are presented. This algorithm is particularly suitable for problems with a large number of constraints, and is applicable to linear and nonlinear optimization problems. In contrast with the simplex method, the number of iterations required by the DA algorithm to solve large-scale problems is relatively small, generally between 20 -60, irrespective of problem size; this feature makes the DA method very fast in practical applications. The DA algorithm has been implemented considering the sparsity of the constraint matrix. The normal equation that is required t o be solved in every iteration is solved using a preconditioned conjugate gradient method.

A generalized macroscopic representation of electrical steels used in transformer manufacturing industry is developed. The proposed representation is specifically formulated for integration in the finite element method. Usage of the specific technique enables the accurate evaluation of electromagnetic field distribution of transformer cores under heavily saturated conditions. Advantages over conventional techniques include numerical stability, numerical accuracy, and reduction of iterations of the Newton–Raphson method.

 We describe new analytical techniques to help mitigate the disruptions to electric power grids caused by terrorist attacks. New bilevel mathematical models and algorithms identify critical system components (e.g., transmission lines, generators, transformers) by creating maximally disruptive attack plans for terrorists assumed to have limited offensive resources. We report results for standard reliability test networks to show that the techniques identify critical components with modest computational effort.

The article discusses the problem of the determination of savings on active energy as a result of a reactive power compensation. Statutory guidance on the required energy audit to obtain white certificates in the European Union was followed. The paper presents a detailed analytical method and an estimation method taking into account the impact on the line, the transformer and the generator. The effect of the reactive power compensation on the environment in accordance with relevant laws was estimated. Discussed method is particularly helpful in the calculations for simple network topology generator-network-receiver. The analysis was performed using the energy equivalent of reactive power. The effect of the reactive power compensation on the security of the power system has been omitted. The presented simplified method for determining the transmission loss is particularly useful in economic operations. It is useful when the electricity audit covers many connection points, and it is impossible the implementation of accurate calculations.

In this paper, a novel evolutionary algorithm-based approach to optimal design of multimachine power-system stabilizers (PSSs) is proposed. The proposed approach employs a particle-swarm-optimization (PSO) technique to search for optimal settings of PSS parameters. Two eigenvalue-based objective functions to enhance system damping of electromechanical modes are considered. The robustness of the proposed approach to the initial guess is demonstrated. The performance of the proposed PSO-based PSS (PSOPSS) under different disturbances, loading conditions, and system configurations is tested and examined for different multimachine power systems. Eigenvalue analysis and nonlinear simulation results show the effectiveness of the proposed PSOPSSs to damp out the local and interarea modes of oscillations and work effectively over a wide range of loading conditions and system configurations. In addition, the potential and superiority of the proposed approach over the conventional approaches is demonstrated.

This paper presents a particle swarm optimization (PSO) as a tool for loss reduction study. This issue can be formulated as a nonlinear optimization problem. The proposed application consists of using a developed optimal power flow based on loss minimization function by expanding the original PSO. The study is carried out in two steps. First, by using the tangent vector technique, the critical area of the power system is identified under the point of view of voltage instability. Second, once this area is identified, the PSO technique calculates the amount of shunt reactive power compensation that takes place in each bus. The proposed approach has been examined and tested with promising numerical results using the IEEE 118-bus system.

The term wide area measurement system (WAMS) implies a system including new digital metering devices (e.g., phasor measurement unit) together with communication system which is designed for monitoring, operating, and controlling power systems. Generally, a WAMS process includes three main functions: data acquisition, data transmitting, and data processing performed by measurement devices, communication systems, and energy management systems, respectively. While these three functions are seriously interdependent, most researches carried out on this topic investigate these functions independently. In this paper, meters placement and their required communication infrastructure for state estimation program are co-optimized simultaneously. To perform this, these two planning issues are jointly formulated in a single genetic algorithm (GA) problem. Then, three IEEE test networks without any conventional measurements and communications are used to investigate the advantages of considering dependability of optimization of these two sections. The results confirm that the proposed method is advantageous over the techniques optimizing each section independently. The results indicate that while the total number of measurement devices for system observability may increase (and therefore, the observability is improved), the total cost for the plan is reduced. Index Terms-Communication link placement, meter placement, power system communication infrastructure, state estimation, wide area measurement system. I. INTRODUCTION W IDE AREA measurement system (WAMS) is a term introduced to the power system literature, recently. This term implicitly implies a system including new digital metering devices (e.g., phasor measurement unit) together with communication system which is designed to monitor, operate and control power systems in wide geographic area [1]. In general, a WAMS process includes three different interconnected functions [2]: data acquisition, data transmitting, and data processing. Measurement devices and communication systems together with energy management systems perform these functions.

In this paper a robust three-dimensional (3D) finite element (FE) anisotropy model is introduced based on a particular scalar potential formulation. The specific 3D FE model is suitable for the accurate evaluation of the peak flux density distribution and no load loss of one-phase and three-phase wound core distribution transformers. The accuracy of the proposed 3D FE anisotropy model is validated by local flux density and no load loss measurements.

In recent years, sustainable and clean renewable energy resources are widely used instead of fossil fuel energy resources in electrical energy generation systems. Especially, wind and solar energy conversion systems are utilized together in stand-alone systems. In this study, reliability analysis of a hybrid system installed in Davutpasa Campus of Yildiz Technical University is investigated. The system includes a wind turbine, PV panels, a hybrid charge regulator, a MPPT charge controller, an inverter, battery group and loads. Reliability indexes are calculated for analyzed system. The obtained results are examined and presented in this paper.

This paper presents the design of different topologies of active power filters to compensate reactive power and harmonics in the medium voltage level of a distribution power system. One pure active filter and two hybrid topologies, are implemented. A pure active compensation is obtained with a Shunt Active Power Filter (SAPF). The shunt combination of SAPF and passive filter, form one of the hybrid topologies implemented, named Shunt Hybrid Active Power Filter (SHAPF). The other hybrid topology, called Hybrid Shunt Active Power Filter (HSAPF), connects the active filter in series with two shunt passive filters. Simulation for different load demands and distortions are performed. Finally a comparative evaluation of the different filters is carried out.

Vector fitting (VF) is a popular iterative rational approximation technique for sampled data in the frequency domain. VF is nowadays widely investigated and used in the Power Systems and Microwave Engineering communities. The VF methodology is recognized as an elegant version of the Sanathanan-Koerner iteration with a well-chosen basis.

In this paper a new reference generation technique to in Hybrid Renewable Energy (solar photovoltaic (PV), Wind energy and Fuel cell) power to the grid is proposed. The power electronics converters are widely use to mitigate the current harmonics, reactive power compensation, improve the load power factor and to regulate the load voltage. This converter requires a dc link voltage support that can be provided by any of the renewable source of energy like solar, wind etc. which act as a voltage source and also inject the active power generated by the source. It is shown in this paper that the Hybrid active power filter is used to compensate the reactive power, reduce harmonies in the source current and also injects the active power from the Hybrid Renewable energy source into the grid. The varying nature of power due to change in solar radiation and temperature of injected power, wind speed variations can be accounted for with the online computation of the reference power available. The simulation studies are carried out for single-phase application using power system simulator MATLAB. Thus we get the better power factor and good voltage or power stability when the non-linear loads are applied to the system. Major thing in this paper is to compensating the Reactive power in the transmission lines for 24 hrs by using a Hybrid Renewable Energy sources in the case of emergency we can also use a Fuel cell.

A Flywheel Energy Storage System (FESS) is associated to Wind Turbine (WT) to increase its penetration rate into the grid and to improve its contribution to the ancillary services. In this paper, the authors investigated a FESS associated to PMSM-wind turbine connected to the grid via a three-phase PWM inverter. The FESS is controlled by a FOC (Flux Oriented Control) strategy cascaded with an external power loop for the supervision of the power reference value. A Direct Power Control (DPC) strategy is proposed to control the grid-connected converter due to its high transient capability and its constant switching behavior.

Francis Fukuyama discussed the different perspectives of known thinkers regarding the inner and outer self in the third chapter. He discussed how Augustinian friar Martin Luther King sees humans as sinful in nature and that the inner self is made of layers that can only be recognized through private introspection. While according to French philosopher Jean-Jacques Rousseau, man is not sinful in nature and that the discovery of the state is responsible for man's unhappiness.

Nigeria is suffering from the worst energy crisis in its history, resulting in its rural communities being subjected
to massive power outages, daily. Energy promotes economic well-being and makes social life worthwhile such
that youths are less disposed to violent crimes. This study investigated the consequences of power outages on the
social-economic life of rural households in the Niger Delta region of Nigeria. Primary data were collected
through a semi-structured questionnaire circulated among unemployed youth, students, housewives, businessmen
and professionals in the area. The study focused on the relationship between power outage and its impact on the
everyday life of the people. This study adopted a descriptive research design using 1000 randomly selected
members of 44 rural households in the areas mostly affected by incessant power outages. It was found that
stunted economic growth, reduced leisure time as well as heightened criminality and insecurity are some of the
major results of rampant power outages among rural households in the Niger Delta. It is concluded that power
outages have severe negative impact on the social and economic lives of the people. The findings from this
research would help improve the outlook of rural communities in Nigeria and other developing countries.

Decoupling techniques are extensively used in Power System State Estimation (PSSE). The most popular decou¬ pled algorithm is based on decoupling the gain matrix G. After decoupling, two diagonal submatrices Gn and G22 form two matrix equations with only half dimension. Hence, computing time and storage locations are reduced.

One of the major goals of the automotive industry is to improve vehicular fuel efficiency and performance with much lesser percentages of harmful tailpipe emissions. One of the major technologies includes fuel cell vehicles (FCV). Various advantages of fuel cells including reliability, simplicity, quietness of operation, and low pollution have made them an attractive potential candidate for providing automotive power. This paper aims at discussing the basic possible topologies of fuel cell vehicles and the major issues that need to be overcome in order to make them practically viable. In addition, critical comparative factors between the FCV option and its closest competitor, the hybrid electric vehicles (HEV) option, are presented. Finally, this paper provides a summary of various fuel cell demonstration vehicles wherein various social and cost related issues are addressed.

At the point of common coupling (PCC), the summation of two harmonic voltage vectors at same frequency is only certain if their amplitudes and phase angles are well known. Therefore, there are many cases where the phase angle difference between harmonic voltage vectors is unknown. In practice, for example, in calculating the steady state rating of the a.c. passive harmonic filter, arithmetic summation method is often used in determining maximal harmonic level. This summation law is very conservative as it may result in high cost of equipment ratings. Actually, a compromise should be made in taking into account the equipment safety and the risk of overrating as well as excessive costs. Based on uniform distribution of difference in phase angles, the paper provides an algorithm to calculate the probability upon which the magnitude of summation vector of two harmonic voltages may exceed a given value. On the basis of the probability and the given harmonic value, harmonic summation can be assessed. This may also result in a recommendation of another harmonic summation method for the standard IEC/TR 61000-3-6.

This paper contributes a Markov chain Monte Carlo (MCMC) method for the direct generation of synthetic time series of wind power output. It is shown that obtaining a stochastic model directly in the wind power domain leads to reduced number of states and to lower order of the Markov chain at equal power data resolution. The estimation quality of the stochastic model is positively influenced since in the power domain, a lower number of independent parameters is estimated from a given amount of recorded data. The simulation results prove that this method offers excellent fit for both the probability density function and the autocorrelation function of the generated wind power time series. The method is a first step toward simple stochastic black-box models for wind generation.

Capacitor banks are applied in power systems to provide reactive power. The reactive power results in lower current in lines upstream of the bank improving system voltage and power factor and reducing line losses. Capacitor banks can be configured as ...

This paper aims at demonstrating the potential benefits of using electrical vehicles (EVs) as Distributed Energy Resources (DERs) in smart distribution system. It discusses the options of grid-to-vehicle (G2V) and vehicle-to-building (V2B) operating modes that might be used to support the power grid through demand side management (DSM) program. The V2B mode is particularly promising since it provides an option to use the energy stored in a battery in Electric Vehicles (EVs) to support the local load in the power grid during severe system loading and outages, hence alleviating the demand on the grid and its reliability requirements. The implementation and benefits of using EVs as DERs for demand-side management are discussed and demonstrated with test cases and numerical results.

A renewable energy system RES with cooperation of diesel driven autonomous doubly fed induction generator is presented in the paper. The analysis takes into consideration the power system, where the main power source is a variable speed diesel engine, which operates in full range of power consumption. The RES source is used for diesel engine fuel reduction. The paper presents power distribution between the two sources during supply of isolated load. Reduction of fuel consumption by the use of variable speed operation of diesel engine is also discussed. The issue of energy storage ESt cooperation with RES-Diesel power generation system is evaluated. Simulation results of described system are obtained using PSIM simulation software and they are presented in the paper.