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Based on the Preisach theory in hysteresis, this paper presents a novel transformer core model. Unlike existing mathematical-based hysteresis models, the proposed model is based on a physically correct hysteresis model and can precisely represent the actual behaviors of magnetic materials. In addition, the experimental results of a ferroresonance test of a Voltage Transformer (VT) are presented. The accuracies of the proposed model and the EMTP hysteretic model in duplicating the experimental results are investigated. This paper concludes that in studying ferroresonance phenomenon, the hysteresis of the transformer core must be accurately represented. Furthermore, the proposed model presents more accurate results, compared with the EMTP hysteresis model. 

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Integration of distributed generation (DG) into distribution networks causes some protection challenges, which can be solved by appropriate coordination of directional overcurrent relays. The optimal coordination of directional overcurrent relays is an important task to fulfill the protection requirements of the network. This paper presents an optimal coordination method for directional overcurrent relays in the presence of synchronous DGs. The optimization problem is solved by using Harmony Search algorithm to obtain optimal protection settings. Then, the transient stability of synchronous DGs is studied by modeling DGs excitation system according to the clearance time of the network faults. Instantaneous setting of the relays is used in case of the generators instability. The simulation results on an MV network using DIgSILENT Power Factory show that the transient stability of synchronous DGs plays an important role in the coordination of overcurrent relays. The results validate the effectiveness of the proposed method for coordination of overcurrent relays when considering the transient stability of synchronous DGs.

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One of the main problems of field effect diode (FED) is the increasing of its turn-off current as the channel length decreases. Thus, in this paper, a new structure is presented which decreases the injection of extra carriers to the channel and also increases the control of the gate over the channel by reducing the portion of channel shared with the source and drain regions and without the need for reservoirs. Using this technique and without the need for the reservoirs, the source and drain regions increase in size compared to the S-FED structure, and turn-on current is enhanced. Therefore, by comparing the proposed structure with S-FED, it is demonstrated that the important parameters such as Ion, Ion / Ioff ratio, Gate Delay, and EDP have been improved, and this structure can be a proper alternative to conventional structures

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Today, video conferencing is one of the most sought after features of the Internet. The purpose of routing algorithms in online video conferencing is to increase the number of requests accepted according to Quality of Service (QoS) satisfaction. Most research in this field focuses solely on bandwidth, and relatively few studies consider both bandwidth and delay constraints. In this paper, we propose a new routing algorithm in the context of MPLS networks with fuzzy rules approach that considers both bandwidth limitation and end-to-end delay (bandwidth-delay) for path searches. The fuzzy system is a fuzzy weighted prediction model for filtering high resource requests. A combination of traditional routing and MPLS improves the mobility mechanism, scalability and overall network performance. We name the proposed algorithm as Fuzzy Bandwidth and Delay Routing Algorithm (FBDRA). The FBDRA is attempting to delay requests with high bandwidth and maximum end-to-end delay. We will use Matlab R2017a to simulate many different scenarios and measure criteria such as the number of requests received, average route length, and load balancing. In addition, we compare the performance of FBDRA compared to some of the previous related work such as MHA, WSP, MIRA, BCRA, MIRAD, BGDG, BGLC, SAMCRA and MDMF. The simulation results show that the FBDRA provides the best performance for video conferencing.

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This paper investigates the problem of image steganography. The existing algorithms provide low performance due to disregarding the structure and properties of images. Furthermore, most of these schemes are lossy. Considering the shortcomings of the previous algorithms, we propose an effective algorithm, namely Lossless and High Capacity Image Steganography (LHCIS), which embeds the secret image into the cover image losslessly. The proposed scheme comprises secret image compression and embedding the compressed image into the cover image using the LSB algorithm. The compression procedure includes two phases. The first phase constructs the corresponding difference image to the given secret image. The mentioned image represents the variations of the adjacent pixels of the secret one. Each pixel of this image is derived by subtracting its corresponding pixel in the secret image from the adjacent one. The difference image is encoded to reduce its storage space in the second phase. The compression ratio is high due to the small values of the pixels of the difference image. According to the performed simulations, LHCIS increases the embedding capacity by 40%. Furthermore, it improves the PSNR of the stego image by 2.16 in comparison to the previous algorithms.

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Recently, environmental, economic and reliability oriented motivations facilitate cellular operation of smart power systems in the light of microgrid paradigm. Obviously, due to low inertia stack, high variety of generation units with various technical characteristics and different islanded and grid-connected operational modes, make the protection and control structures become new challenges. On the other hand, by integration of advanced metering and communication infrastructures in the microgrids, differential protection as the most reliable relaying logic, play a vital role in the protection structure of the microgrids. Owing to nature of occurring faults in the microgrids, high resistance faults have created a major problem in applying differential protection and directional fault. In this paper is used a new method for quick and accurate detection of fault in DC micro-grid, so that it detected internal fault from external fault, the performance of this new algorithm is also shown for increasing the fault resistance and compared with the conventional differential protection. The basis of new method is to use the Fault Component Current of the two sides of the study line and plot them on the  plan to identify the type of fault. In this paper simulation of internal and external fault in EMTP-ATP for different values of fault resistance is done and the implementation of the new algorithm and conventional differential protection is done in MATLAB. The simulation results indicate the accuracy and high speed of the operation of the new expressed method.
 

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Luby Transform (LT) codes are the first realization of a class of fading codes, which we call pervasive fading codes. The properties of such codes are well defined when using large data files, but they do not perform well when used for short messages. In this paper, a new encoder and decoder, specifically an efficient LT encoder using the Robust Soliton Distribution (RSD) as a new right-degree distribution and a new left-hand distribution tested in the Binary Erasure Channel (BEC) is introduced. The left-degree distribution of an LT code is intended as a Poisson distribution for general protection. Left-degree shaping creates better performance than LT code, which is compared to high-performance designs in other papers. In information blocks with length k = 256 and bit error rate 10^-8, the realized coding rate of this model is 0.58, which is 25% more than the developed BP design of Mr. Jamshidi and his colleagues. Experimental results show that this new codec leads to improvements in all system features. As such, it is a step towards designing and building better code for the BEC channel.

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High-voltage transmission lines (HVTLs) are one of the important parts of power systems exposed to different types of fault. As most of the faults that occur in HVTLs are single line to ground (SLG) and transient type, the operating speed of the single-pole auto-reclosing (SPAR) will play an important role in the stability of power systems. In this paper, an ultra-fast protection strategy is proposed based on the cumulative sum (CUSUM) algorithm to improve the performance of the SPAR. In the proposed protection scheme, first, the terminal voltage of one side of the HVTL is sampled. Then by employing the CUSUM algorithm for the sampled voltage and applying the corresponding settings, the reclosing moment of the faulty phase is determined. The results of extensive simulations in the EMTP-RV software environment on a 400 kV test power system show that the proposed protection scheme has been very accurate in identifying the moment of successful reclosing. The ultra-fast performance and low computational complexity of the proposed method along with its robustness to noise make it useful for practical applications.