Research Articles
Power systems
Hassan Abniki; Mostafa Hajati Samsi; Behrooz Taheri; Seyed Amir Hosseini
Abstract
Power transmission lines are vital components of today's power systems. These power lines transmit the electricity produced in power plants in high volume and with very low losses to distant areas so that it can be reached to consumer through distribution networks. In fact, these lines are the intermediary ...
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Power transmission lines are vital components of today's power systems. These power lines transmit the electricity produced in power plants in high volume and with very low losses to distant areas so that it can be reached to consumer through distribution networks. In fact, these lines are the intermediary between major energy producers and distribution networks. Accordingly, these transmission lines are of a great importance and must be protected appropriately with a suitable protection system. Distance relays are widely used to protect these lines due to their convenient coordination characteristics and simplicity. High impedance fault (HIF) can be a critical challenge for distance relays due to their low current amplitude and similarity to conventional events in power systems such as capacitive bank switching. For this reason, in this paper a new approach is presented based on the instantaneous frequency variations obtained from the current RMS in order to detect the high impedance fault. This method detects high impedance faults via calculating a Detection index (DI) and considering a threshold value. The proposed method has been tested using DIgSILENT and MATLAB software in an IEEE standard 39-bus network. The presented results evidently demonstrate that the proposed method is suitable for detecting HIF and Low impedance fault (LIF). In addition, this method has a proper performance during capacitor bank switching and can well distinguish between HIF and capacitive bank switching. Moreover, the presented method is resistant to noise and also is capable to detect the faulty phase.
Research Articles
Power systems
Mahnaz Rezaei; Mohammad Tolou Askari; Meysam Amirahmadi; Vahid Ghods
Abstract
Since the presence of an energy hub (EH) leads to change the expansion planning problem of electrical power system. Therefore, in this study, the nature of optimal generation and transmission expansion planning in the presence of EH is studied. Also, the effect of applying the proposed hub with and without ...
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Since the presence of an energy hub (EH) leads to change the expansion planning problem of electrical power system. Therefore, in this study, the nature of optimal generation and transmission expansion planning in the presence of EH is studied. Also, the effect of applying the proposed hub with and without considering energy storages (ESs) as well as the short and long-term corrective actions to reduce the losses and costs are investigated. In addition, demand response and line transmission switching are considered as effective approaches to improve resilience in the proposed dynamic multi-level model. This nonlinear problem is solved sequentially considering the random approach and using differential evolution algorithm (DEA) and the symphony orchestra search algorithm (SOSA). In this paper, the proposed objective functions are studied in five-level and the results show the efficiency of this model in solving the planning problem. The findings show that the proposed planning model decreased capital costs of transmission switches as much as 26%, the capital cost of the transmission as much as 2.29%, the congestion cost as much as 1.8%, The capital cost of generation units as much as 3.75%, the payment capacity paid to generation units as much as 1.8%. Also, the expected profit of the generation units has increased as much as 3.75%. To show the competence of the proposed algorithms, the 400-kV test system with 52 buses in Iran is simulated in MATLAB environment.
Research Articles
Industrial Electronics
Morteza Ghaseminezhad; Morteza Jadidoleslam
Abstract
The use of permanent magnets in the structure of electric machines, in addition to simplifying design and construction by reducing losses, leads to increased efficiency in the motor. However, the magnetic material can be damaged by failure caused by faults such as short circuits in the electronic driver ...
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The use of permanent magnets in the structure of electric machines, in addition to simplifying design and construction by reducing losses, leads to increased efficiency in the motor. However, the magnetic material can be damaged by failure caused by faults such as short circuits in the electronic driver of the motor. Magnets containing samarium and neodymium are completely brittle and easy to crack. These elements are also very vulnerable due to their crystalline structure and grain texture. Magnet defect fault is one of the most common faults in permanent magnet machines. In this paper, a permanent magnet synchronous motor (PMSM) with a magnet defect fault is simulated using the finite element method. Moreover, Prony's method is modified by the matrix pencil method for the estimation of the component created in the stator current. The frequency spectrum of magnetic flux density and stator current in both faulty and healthy modes are extracted and fault detection is done through a modified Prony's method.
Research Articles
Industrial Electronics
Nasim Bagheri; Hasan Alipour; Leila Mohammadian; Jamal Beiza; Mohsen Ebadpour
Abstract
This paper proposes an integrated bidirectional multiport DC-DC converter for battery charging of plug-in electric vehicles, which is able to integrate the photovoltaic (PV) system, traction batteries, and the AC grid. The presented converter is more reliable than the conventional topologies because ...
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This paper proposes an integrated bidirectional multiport DC-DC converter for battery charging of plug-in electric vehicles, which is able to integrate the photovoltaic (PV) system, traction batteries, and the AC grid. The presented converter is more reliable than the conventional topologies because both PV panels and the grid can simultaneously or separately deliver power to the high voltage batteries. In addition, the topology is bidirectional can transfer power from batteries to the AC grid by employing half-bridge CLLC converter with fewer switches. Moreover, a unified controller along with optimum maximum power point tracking (MPPT) algorithm is utilized for control of the converter. The converter topology, control system, and operating scenarios are analyzed by using state space modeling. To evaluate the whole system performance, MATLAB/Simulink software is used to test the converter’s operation during different conditions. The simulation results depict that the proposed converter is not only able to control the batteries charge and discharge according to the state of the charge, but also maintain the DC-link voltage of the grid side to be in constant level.
Research Articles
Control
Ramezan Havangi; Maryam Moradi
Abstract
An ideal traction and braking system not only ensures ride comfort and transportation safety but also attracts significant cost benefits through reduction of damaging processes in wheel-rail and optimum on-time operation. In order to overcome the problem of the wheel slip/slide at the wheel-rail contact ...
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An ideal traction and braking system not only ensures ride comfort and transportation safety but also attracts significant cost benefits through reduction of damaging processes in wheel-rail and optimum on-time operation. In order to overcome the problem of the wheel slip/slide at the wheel-rail contact surface, detection of adhesion and its changes has high importance and scientifically challenging, because adhesion is influenced by different factors. However, critical information this detection provides is applicable not only in the control of trains to avoid undesirable wear of the wheels/track but also the safety compromise of rail operations. The adhesion level between the wheel and rail cannot be measured directly but the friction on the rail surface can be measured using measurement techniques. Estimation of wheel-rail adhesion conditions during railway operations can characterize the braking and traction control system. This paper presents the particle swarm optimization (PSO) based Extended Kalman Filter (EKF) to estimate adhesion force. The main limitation in applying EKF to estimate states and parameters is that its optimality is critically dependent on the proper choice of the state and measurement noise covariance matrices. In order to overcome the mentioned difficulty, a new approach based on the use of the tuned EKF is proposed to estimate induction motor (as a main part of the train moving system) parameters. This approach consists of two steps: In the first step the covariance matrices are optimized by PSO and then, their values will be introduced in the estimation loop. .
Research Articles
Industrial Electronics
Rohollah Abdollahi; Alireza Reisi
Abstract
The 12-pulse diode rectifier (12-PDR) fails to comply with the limits of total harmonic distortion (THD) of supply current to be less than 5% specified in the IEEE Standard 519. Passive harmonic suppression circuits (PHSCs) have been observed to be a viable and cost-effective solution to improve the ...
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The 12-pulse diode rectifier (12-PDR) fails to comply with the limits of total harmonic distortion (THD) of supply current to be less than 5% specified in the IEEE Standard 519. Passive harmonic suppression circuits (PHSCs) have been observed to be a viable and cost-effective solution to improve the THD of AC-mains current at a reduced cost. PHSCs increase the number of rectification pulses without leading to significant changes in the installations and yield harmonic reduction in both AC and DC sides. This paper presents a comparative analysis of two novel PHSCs connected at the DC-bus of 12-PDR. One is PHSC-I based on four tapped reactors (FTRs) and four auxiliary diodes; the other is PHSC-II, with two tapped reactors (TTRs) and two auxiliary diodes. The operation modes and optimal parameters of both PHSCs are analyzed with similar inputs (AC side) and outputs (DC side). Both 12-PDR are connected to the same AC source as input, and both PHSCs supplied similar DC loads at their outputs, thus leading to an accurate and fair comparison between the two PHSCs. The results show that the input current THD of a 12-PDR with PHSC-II is lower than that of a PHSC-I and lower than existing passive harmonic suppression circuits. In addition, PHSC-II leads to lower connection losses, current stress, and cost than PHSC-I, so in industrial applications that require low input current THD, low connection losses/current stress, and low cost, PHSC-II is highly recommended.
Research Articles
Communication
Fatemeh Kazemi
Abstract
In this paper, a dual-polarized antenna fed by CPW is presented. The proposed includes a conductor on the radiator and has defected ground, so it has been achieved as an omnidirectional antenna which makes it a low loss, and a simple antenna which is appropriate for a wireless communication ...
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In this paper, a dual-polarized antenna fed by CPW is presented. The proposed includes a conductor on the radiator and has defected ground, so it has been achieved as an omnidirectional antenna which makes it a low loss, and a simple antenna which is appropriate for a wireless communication system. By imposing the different circumstances of U-shape elements on the ground, the features of antennas have been improved. The scattering characteristic of the antenna are less than -20 dB with high impedance matching at 2.2GHz, 4.8GHz, and 6.6GHz. Also, the antenna covers 400 MHz bandwidth from 2 GHz to 2.4 GHz, 500 MHz bandwidth from 4.6 GHz to 5.1 GHz, and 1.3 GHz bandwidth from 5.7 GHz to 7 GHz, respectively. In addition, the maximum gain of the antenna is almost 10 dB. The simple and compact antenna with an overall size of 25x20mm2 is designed on an FR-4 substrate with 0.8 mm thickness. On the one hand, the structure is fabricated and tested. The results of the antenna have shown that the measured results agree with the simulated results; The performance of the antenna with CPW-fed, consisting of compact size, circular polarization, and suitable gain at resonance frequencies, make it a suitable choice for the communication system and the portable device.
