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In power distribution fault data, the percentage of faults with different causes could be very different and varies from region to region. This data imbalance issue seriously affects the performance evaluation of fault diagnosis algorithms. Due to the limitations of conventional accuracy (ACC) and geometric mean (G-mean) measures, this paper discusses the application of Receiver Operating Characteristic...
A smart grid is capable of integrating a broad array of generation resources and enables the participation of demand side resources in reliable system operation. To cost effectively realize this flexibility, the associated devices and systems need to connect and interact simply and reliably. Interoperability is the important ingredient to make this happen. Because the electric system transcends organizational...
In this paper we report on the preliminary results of a collaborative investigation effort between researchers in North America and Europe aiming to baseline the electromechanical modes and mode shapes of the Nordic system from synchronized phasor measurement data. We provide an overview on the Danish power grid and its interconnections, and describe the features of an experimental phasor measurement...
The field of distribution system analysis has made significant advances in the past ten years. It is now standard practice when performing a power flow simulation to use an algorithm that is capable of unbalanced per-phase analysis. Recent work has also focused on examining the need for time-series simulations instead of examining a single time period, i.e., peak loading. One area that still requires...
This paper describes an adaptive filtering to reduce noise in the analog input circuits of microprocessor-based protection relay (digital relay) systems. Considering that digital relays tend to have multiple functions, it is important to raise signal to noise ratios (SNR) in analog input circuits to a level that will satisfy the requirements of these functions. We have realized a noise reduction method...
A number of characteristics of power system is hidden in the operating point space, including the stability aspect. This paper presents a data-structure analysis of the operating point space scheme for power system transient stability assessment (TSA) with the adoption of RELIEF, which is an attribute estimation method capable of evaluating the ability of attributes to discriminate in different classes...
We propose here a cost-effective, realistic method for testing the continuity of the grounding grid and for identifying its weak points or discontinuities. The proposed method involves injecting an ac current of ~200 A frequency not 60 Hz or 60 Hz harmonic into a grounding grid. The purpose of the frequency setting is to be able to distinguish the magnetic field produced by the injected current when...
Since the hourly spot market price is available one day ahead, the price could be transferred to the consumers and they may have some motivations to install an energy storage system in order to save their energy costs. This paper presents an optimal operation strategy for a battery energy storage system (BESS) in relation to the real-time electricity price in order to achieve the maximum profits of...
Modern day power systems in the restructured environment have grown to a level of complexity that the use of automation has become imperative for secure operation and control. The volume of significant events that occur in a multi-area interconnected power system has become enormous to an extent that system operators need intelligent systems to support them in decision making. This paper presents...
A method of tracking a power system's electromechanical mode shape and coherence over time is presented. It uses an algorithm of weighted-updates to efficiently compute an existing spectral estimation algorithm. The advantage of this over other mode shape estimators is that it overcomes the assumption that the system being estimated is stationary. The relationship between spectral densities and mode...
Modern power grids with their physical current-carrying components and the embedded computer, communication and control networks are fast emerging as one of the largest and most complex cyber-physical systems. The addition of more sensing, communication, variable power sources and storage under the renewable energy thrust and smart grid initiative will add even higher orders of dimensionality and...
This paper presents some comparisons between the trends in electricity infrastructure growth in the United States and Brazil, and attempts to identify commonalities and differences on grid modernization efforts in these two countries using the Smart Grid Initiative as a template.
This paper presents the idea and initial results of building decision trees (DTs) for detecting and identifying various transient dynamic events using the characteristic ellipsoid method. In this paper, the objective is to determine fault types, fault locations and clearance times in the system using DTs based on ellipsoids surrounding system transient responses in the system operating parameter space...
This paper presents the practical experience of the Brazilian System Operator with the online dynamic security assessment. More specifically, it describes the adopted models, analytical methods and functions, performance, EMS integration, user interface and implementation issues. Examples of situations in which the online security assessment was very useful are also shown.
This paper presents a feedback linearization based controller design methodology for a unified power flow controller (UPFC) to achieve rapid reference signal tracking in the internal level. Feedback linearization control (FBLC) is a nonlinear technique based on differential geometry theory and overcomes the drawback of traditional PI control linearzing at one specific operating condition. FBLC is...
Negotiation of secure bilateral transactions has become an important issue for better operation, planning and management of competitive electricity markets. In this paper, secure bilateral transactions have been determined with minimum deviations in economic generation schedule and real power losses for hybrid electricity markets. The generation pattern and real and reactive power loss has been obtained...
This paper reviews the hybridization techniques and system configurations for hybrid alternative energy systems. The topic is extended to the control and energy management of microgrids, the cornerstones of smart grids. A framework of distributed, hierarchical control for microgrids is also discussed in the paper.
The instrument transformer is the necessary equipment which connects the primary power system and PMU. Therefore, the measurement accuracy of PMU is directly affected by the transfer accuracy and the transient response of instrument transformer. In this paper, the dynamic signal models are abstracted from the phenomena of practical power systems. Under such kinds of dynamic signal models, the impact...
To ensure that the future students / researchers are equipped for operate the new Smart Grid, the diversification of the Power Engineering Education is required. Fundamentals of Smart grid Technology such as Communications, Wide area Measurements, Systems Theory and Control, renewable energy penetration, cyber-security and standards requirements must be included. An overview of the Smart Grid Fundamentals...
Harmonics is a growing concern to both electric utilities and their customers. Nonlinear loads in large-scale industries are important causes for the harmonic currents and voltage distortion. In modern steel manufacturing facilities, Arc furnaces and rolling mill loads are the two major nonlinear loads. They generate significant harmonic currents that flow through the plant and utility power system...
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