Coordination Of Devices Research Articles

Dual-functional conjugated polymers based on trifluoren-2-yl-amine for RGB organic light-emitting diodes

A series of blue-light-emitting conjugated polymers that possess high-lying HOMO energy levels were synthesized by introducing trifluoren-2-yl-amine (TFA) as a building block. The emission color could be effectively tuned in the region of deep-blue and light-blue by introducing various substituents onto the TFA as the pendants. Deep-blue light emission was achieved for the device based on P4FNCz as an emitting layer without using any hole-transport layer (HTL), giving a maximum current efficiency (CE) of 2.44 cd A−1, corresponding to an external quantum efficiency of 3.00%, with Commission Internationale de L'Eclairage (CIE) coordinates of (0.16, 0.12). Thanks to the improved hole injection and transport ability, red- and green-light-emitting devices based on P4FNCz as an HTL were also successfully fabricated, giving a maximum CE of 7 and 25 cd A−1 with CIE coordinates of (0.64, 0.34) and (0.29, 0.64), respectively, which are comparable to those of the devices based on a general HTL of 4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB). The CIE coordinates of the RGB devices are very close to those of the National Television System Committee (NTSC) and High Definition Television (HDTV) standard colors. The RGB devices achieved by tuning the carrier recombination zone with different electron-transport layers will facilitate the development of the polymer-based full-color flat-panel displays in an alternative process.

FAULT LOCATION SCHEME IN DISTRIBUTION SYSTEMS WITH DISTRIBUTED GENERATORS USING NEURAL NETWORKS

Nowadays using DG (distributed generation) in vast variety of cases has been more considerable due to its beneficial advantages, but interconnecting DG to radial distribution systems has some impact on the coordination of protection devices. The main point in the protection scheme is the diagnosis of fault locations, so producing a new method to identify fault location with high accuracy is necessary. This paper presents a novel approach to fault location identification with DG in distributed systems by the means of neural networks. According to this method using a distributed system as intentional islanding in necessary conditions is possible and reduces the ENS (Energy Not Supplied) of the net. Using separate NNs (neural networks) for each island (zone) will increase the accuracy of this method. Implementation results of this scheme on actual distributed systems has been simulated and reported.

Effect of protection device coordination on voltage sag characteristics of distribution networks

In this paper, ATP (a powerful software for simulation of power system transients) is used to assess the performance of a test distribution network in faulty conditions. This study includes the modeling of a distribution network considering the random nature of faults. Fault parameters are produced using a Monte Carlo procedure and initiated before network simulation. To investigate the voltage sag characteristics of the network in faulty conditions, four strategies are introduced for coordination of protective devices. Simulation results are employed to study the network behavior under these protection strategies for fault durations of 200 ms, 600 ms and 1 s. The results are analyzed and compared with ITIC curves where fuses and reclosers are used as protection devices. Simulation results show that protection device coordination has a significant effect on voltage sag characteristics of distribution systems.

Application of pseudorandom signals for underwater distance measurement on a shelf

In this paper, the results of experiments conducted on the Sea of Japan shelf are applied and discussed. The aim of these experiments was to study regularities in the formation of impulse characteristics for wave conductors under variable hydrological conditions. It has been shown that, in order to determine the distance and coordinates of underwater devices precisely when working on a shelf, one should identify the first and last impulses in impulse characteristics for the wave conductor, measure their arrival times, and multiply them to calculate the values of effective sonic velocity along the propagation routes of these impulses.

Alocação otimizada de dispositivos de controle e proteção em redes de distribuição

A Alocação e/ou realocação otimizada de dispositivos de controle e proteção em redes de distribuição de energia elétrica melhora a qualidade do serviço de fornecimento de energia e os índices de confiabilidade do sistema. Neste trabalho apresenta-se um modelo de programação não linear binário (PNLB) para o problema de alocação e/ou realocação de chaves seccionadoras e dispositivos de proteção em alimentadores radiais aéreos de distribuição. As restrições consideradas no modelo refletem limitações técnicas e econômicas, tais como problemas de coordenação de dispositivos de proteção em série, número de equipamentos disponíveis, importância do alimentador sob análise, topologia do circuito, qualidade do fornecimento de energia e limitações físicas do sistema. Para solução desse problema propõe-se um algoritmo de Busca Tabu Reativo (RTS). São apresentados os resultados obtidos através de testes realizados com a implementação computacional da metodologia proposta, utilizando-se um alimentador de distribuição radial real com 134 barras.

Assessing transient response of DFIG based wind turbines during voltage dips regarding main flux saturation and rotor deep-bar effect

With increasing wind power penetration, transient responses of doubly-fed-induction-generator (DFIG) based wind turbines gain attentive focus. Accurate prediction of transient performance of DFIG under grid faults is required with increasing wind power penetration. Taking into account the main flux saturation and deep-bar effect, this paper concentrates on transient responses and stability of the DFIG system under symmetrical grid faults. Their roles played in the enhancement of system transient stability are clarified. The analyses proposed contribute greatly to proper selection, design and coordination of protection devices and control strategies as well as stability studies.

Optimized Allocation of Control and Protective Devices in Electric Distribution Systems

Optimized allocation and/or reallocation of control and protective devices in distribution networks allow for better operation and improved system reliability indices. Control devices (used to reconfigure the feeders) are allocated in distribution networks to obtain an optimal operation strategy in order to facilitate power supply restoration in case of a contingency. Protective devices (used to isolate faults) are allocated in distribution systems to improve the reliability and continuity of power supply. Protective devices significantly reduce the impacts of faults in terms of customer outages and the time needed for fault location and system restoration. This work presents a mixed-integer non-linear programming model for the sectionalizing switches and protective devices allocation and/or reallocation problem. The constraints considered for the problem reflect technical and economical limitations, such as in-series protective devices coordination, number of available equipment, importance of the analyzed feeder, circuit topology, quality of power supply, and physical limitations of the system. A dedicated reactive tabu search algorithm is proposed for solving this problem. Results and optimized strategies for allocating or reallocating protection devices and switches considering a real-life network restoration are presented.

Fabrication of White Organic Light-Emitting Diodes Using Two Complementary Color Methods

White organic light-emitting diodes (WOLEDs) were fabricated using two complementary color methods with two emissive layer structure such as NPB (500 Å)/DPVBi (65 Å)/MADN:DCM2-0.5% (170 Å)/Bphen (300 Å)/Liq (20 Å)/Al (1000 Å). A deep blue and orange emissions were obtained from DPVBi layer and MADN host doped with a red fluorescent DCM2 dopant each. White emission was achieved through controlling hole-electron recombination by optimization of emissive layers thicknesses and DCM2 concentrations. Optimized WOLED device shows emission efficiency of 5.04 cd/A, current density of 2.64 mA/cm2 and luminance of 938 cd/m2 at 6 V with CIEx,y color coordinate of (0.338, 0.330). These results indicate that DPVBi layer effects on hole blocking and the exciton generation due to difference of energy level in highest occupied molecular orbital. The CIEx,y coordinates of device was slightly changed change from (0.338, 0.330) at 6 V to (0.341, 0.333) at 12 V, which is almost independent on driving voltages.

A publish-subscribe architecture and component-based programming model for medical device interoperability

Medical devices historically have been monolithic units --- developed, validated, and approved by regulatory authorities as standalone entities. Modern medical devices increasingly incorporate connectivity mechanisms that offer the potential to stream device data into electronic health records, integrate information from multiple devices into single customizable displays, and coordinate the actions of groups of cooperating devices to realize "closed loop" scenarios and automate clinical workflows. In this paper, we describe a publish-subscribe architecture for medical device integration based on the Java Messaging Service. We provide a overview of a model-based development environment that we have built for rapidly programming device coordination scenarios. We assess the extent to which this framework is capable of supporting and complementing the Integrated Clinical Environment that has been proposed by the Medical Device Plug and Play Interoperability Project The implementation of this framework is freely available and open source. One of the primary goals of the framework is to provide researchers in acadaemia, industry, and government with an open test bed for exploring development, quality assurance, and regulatory issues related to medical device interoperability.

Arc Flash and Coordination Study Conflict in an Older Industrial Plant

Once arc flash hazard analysis became a requirement for many industrial power system studies, the reduction of arc flash hazards has become an important concern. Inevitably, the factors that lead to reductions in arc flash hazards do not always lead to an improvement in other areas, i.e., in particular, protective device coordination. This paper will examine several particular cases where an arc flash hazard analysis of an older industrial plant yielded several cases of buses where the hazard level was ldquoextreme dangerrdquo above category 4. By changing protective device settings and, if necessary, the devices themselves, the hazard level can be reduced. Methods to maintain coordination, if possible, are discussed.

Software for Automatic Coordination of Protection Devices in Distribution System

Among the several components of distribution systems, protection devices present a fundamental importance, since they aim at keeping the physical integrity not only of the system equipment, but also of the electricians team and the population in general. The existing tools today in the market that carry out the making of protection studies basically draw curves, and need direct user's interference for the protection devices adjustment and coordination analyses of selectivity, being susceptible to the user's mistakes and not always considering the best technical and economical application. In Brazil, the correct application of the protection devices demand a high amount of time, being extremely laborious due to the great number of devices (around 200 devices), besides the very dynamic behavior of distribution networks and the need for constant system expansion. This paper presents a computational tool developed with the objective of automatically determining the adjustments of all protection devices in the distribution networks to obtain the best technical application, optimizing its performance and making easier protection studies.

Procedures for fault location and isolation to solve protection selectivity problems in MV distribution networks with dispersed generation

Present planning and operation criteria used for MV passive radial distribution networks are, in general, not suitable to cope with the presence of a significant distributed generation (DG) capacity. In fact, many technical problems are still to be solved in order to increase DG penetration and to provide, at the same time, high service quality levels to customers. In this context, the present paper illustrates the results of the first part of a research project, conducted in collaboration with ENEL Distribuzione S.p.A. (Italy), which analyses possible solutions for various protection issues arising in distribution networks in presence of DG. The paper deals, in particular, with the problem of incorrect operation of traditional protection schemes for multi-phase and phase-to-ground faults in MV networks, and proposes a protection philosophy based on innovative technical solutions to solve the problem of lack of protective devices coordination in presence of DG to improve service continuity.

Computer-assisted stereotactic neurosurgery with framework neurosurgery navigation

Objective To evaluate mechanical registration in a stereotactic system with framework neurosurgery navigation, setting scalp markers as the mutual frame of reference. Materials and methods The system can automatically convert the coordinates of the stereotactic device and CT or MRI images, and realize computer-assisted neurosurgery by the stereotactic system (framework neurosurgery navigation). We set targets in the skull; seven patients were operated on by open-skull stereotactic neurosurgery for clinical trials. Three cases were operated on by this method; the other four cases were treated by this method and the ASA620S operation plan system at the same time as a comparison. Results The targets were accurately located in seven patients. Four patients underwent the two different localization methods; the probe directed equally accurately (vector error: 3.96 ± 1.90 vs. 3.26 ± 1.22, P = 0.06 > 0.05, paired t-test). All surgical procedures were successful. Conclusions Framework neurosurgery navigation has equal localization accuracy compared with the traditional stereotactic device. Framework neurosurgery navigation does not require installation of a stereotactic framework before imaging or narcotic intubation; this differs from the traditional stereotactic technique. It can alleviate patient suffering, shorten preparation time, benefit anesthesia, and aid patient positioning during surgery.

Fabrication of a white organic light-emitting device with single liq:rubrence luminescent layer

A kind of white OLED with single luminescent layer was designed, in which rubrene was doped in Liq. The structure of the devices is ITO/PVK:TPD/Liq: Rubrene/Alq3/Al. The brightness of the devices comes to 3120 cd/m2(at a driving voltage of 25 V), the CIE coordinates of the typical devices is (0.308,0.347), and the coordinates is very close to the white equi-energy point. The emitting and luminescent characteristics of the devices were discussed.

Synthesis and Characterization of Novel Red-Light-Emitting Materials with Push-Pull Structure Based on Benzo[1,2,5]thiadiazole Containing Arylamine as an Electron Donor and Cyanide as an Electron Acceptor

New efficient red emitter having short p?-conjugation length and asymmetric bulky structure, 2-(7-diphenylamino-benzo[1,2,5]thiadiazole-4-ylmethylene)-malononitrile, was synthesized and characterized. Using this material as a dopant, we fabricated electroluminescence device with a structure of ITO/DNTPD/NPD/BTZA (5 wt% in Alq3)/Alq3/LiF/Al. The device exhibited a high brightness of 761 cd/m2 at a driving voltage of 4.8 V, and current efficiency is 0.75 cd/A. The Commission International de IEclairage (CIE) coordinates of the EL device were found to be (0.62, 0.37) at 10 mA/cm2.

Neural networks for adaptive control coordination of PSSs and FACTS devices in multimachine power system

The paper develops a new design procedure for online control coordination which leads to adaptive power system stabilisers (PSSs) and/or supplementary damping controllers of flexible ac transmission system (FACTS) devices for enhancing the stability of the electromechanical modes in a multimachine power system. The controller parameters are adaptive to the changes in system operating condition and/or configuration. Central to the design is the use of a neural network synthesised to give in its output layer the optimal controller parameters adaptive to system operating condition and configuration. A novel feature of the neural-adaptive controller is that of representing the system configuration by a reduced nodal impedance matrix which is input to the neural network. Only power network nodes with direct connections to generators and FACTS devices are retained in the reduced nodal impedance matrix. The system operating condition is represented in terms of the measured generator power loadings, which are also input to the neural network. For a representative power system, the neural network is trained and tested for a wide range of credible operating conditions and contingencies. Both eigenvalue calculations and time–domain simulations are used in the testing and verification of the dynamic performance of the neural-adaptive controller.

Automatic coordination of protection devices in distribution system

Among the several components of distribution systems, protection devices present a fundamental importance, since they aim at keeping the physical integrity not only of the system equipment, but also of the electricians’ team and the population in general. The existing tools today in the market that carry out the making of protection studies basically draw curves, and need direct user's interference for the protection devices adjustment and coordination analyses of selectivity, being susceptible to the user's mistakes and not always considering the best technical and economical application. In Brazil, the correct application of the protection devices demand a high amount of time, being extremely laborious due to the great number of devices (around 200 devices), besides the very dynamic behaviour of distribution networks and the need for constant system expansion. This article presents a computational tool developed with the objective of automatically determining the adjustments of all protection devices in the distribution networks to obtain the best technical application, optimizing its performance and making easier protection studies.

Overcurrent Protection in Electrical Distribution Systems Through Probabilistic Approach

This work describes the study of distribution system overcurrent protection through a probabilistic approach. Conventional approaches for overcurrent protection do not consider the probabilistic nature of the main variables involved, such as fault location, fault type and fault impedance for faults involving the ground. In this case, for instance, it is very difficult to assess the impact of situations where full coordination cannot be attained for some reason. The probabilistic approach, on the other hand, allows quantifying the risk of two adjacent protective devices operating in a non-coordinated way. This information is extremely valuable for electrical engineers at design level. In this work, the proposed methodology is illustrated through a few detailed application studies, including various sensitivity analyzes for assessing the influence of model parameters on the coordination of protective devices.

Identification of Fuse and Recloser Operations in a Radial Distribution System

Recloser and fuses are the main overcurrent protective devices on distribution systems. Poor coordination adversely impacts the overall power quality especially from the momentary voltage interruption and voltage sag perspectives. Therefore, the purpose of this paper is to develop a novel approach to detect and identify which protective devices operate to clear a short-circuit condition using power-quality waveform measurement data. The proposed approach is intended to evaluate performance coordination of overcurrent protective devices and help locate faults on the feeder. The effectiveness of the techniques is demonstrated using simulation and real-world data. Results indicate a promising potential for real-world deployment and applications.

Protection scheme for a distribution system with distributed generation using neural networks

Interconnection of distributed generation (DG) to a radial distribution system has some impacts on the coordination of protection devices. In this case, faults are fed by multi-sources; networks and DGs. Existence of multi-sources in fault condition is the main difficulty in the identification and location of faults and therefore distribution system protection. New protection methods should be introduced for isolation of faulted sections. This paper presents a novel approach that can overcome the above problems. A feed forward neural network is used to identify the fault location. The predicted results from the algorithm prove the effectiveness of the proposed procedure for identifying fault location and then protection of the system for a wide range of system conditions.