Iman Sadeghkhani

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Islamic Azad University of Najafabad | IAUN · Department of Electrical Engineering

One of the major challenges in protection of the inverter-interfaced islanded microgrids is their limited fault current level. This degrades the performance of traditional overcurrent protection schemes. This paper proposes a fault detection strategy based on monitoring the transient response of the inverter current waveform using a transient monit...

With high penetration of distributed energy resources (DER), fault management strategy is of great importance for the distribution network operation. The objective of this paper is to propose a current and voltage limiting strategy to enhance fault ride-through (FRT) capability of inverter-based islanded microgrids (MGs) in which the effects of inv...

An important requirement for interconnecting distributed generation is anti-islanding protection. This paper uses the capabilities of two methods, application region (AR) and power imbalance AR, to efficiently adjust frequency-based relays. The proposed method gives a proper simple and nonexpensive solution to the synchronous distributed generation...

In this paper, a one-cycle control (OCC)-based approach for wind turbines equipped with doubly fed induction generators (DFIGs) is presented. The OCC is used to control back-to-back converter which includes generator-side converter and grid-side converter. The former is used for regulating generator speed, and the latter is used for controlling rea...

Developing a reliable protection system is crucial to facilitate the integration of renewable energy sources (RESs) into modern power grids, paving the way for reaching net-zero carbon emissions. The bidirectional power flow and limited fault current contribution of inverter interfaced RES units make designing an efficient protection system for inv...

Although the development of electric vehicle (EV) technology offers opportunities for reducing CO2 emissions through the electrification of transportation, the integration of EVs into distribution systems poses a significant challenge to the reliable operation of existing protection systems. As the penetration level of EVs continues to rise, the fa...

The protection of high-voltage direct current (HVDC) grids is a crucial aspect in ensuring the reliable and efficient operation of modern electrical energy transmission systems. The high amplitude and rate of change of fault current as well as the presence of multiple paths for fault current contribution of voltage-sourced converters make the prote...

The increasing trend of energy generation and management systems towards decentralized structures such as using renewable energy resources makes it necessary to use digital and smart platforms for exchanging information and even conducting financial transactions in a decentralized manner, known as the peer‐to‐peer model. The decentralized transacti...

Increasing the penetration level of distributed generation (DG) units requires overcoming the technical challenges associated with their integration into the distribution systems, especially protection problems. Change in the current profile of the distribution system due to the presence of DG units disrupts the operation of the conventional fuse s...

Integrating the self‐healing capability realizes the automated protection of smart distribution systems. This article presents a fault location scheme for low voltage (LV) distribution systems based on the information collected from the smart meters. First, a fault condition is detected and classified by processing the current signal at the seconda...

The heavy traffic and modern trains increase the load current of the railway electrical transportation system. This current may be comparable to the current due to a distant fault. As a consequence, differentiating these two conditions poses a serious challenge to the conventional current amplitude-based protection system of the direct current trac...

With growing concerns over environmental degradation and climate change, the shipping industry is under increasing pressure to reduce its environmental impact. This has led to the development of green port initiatives in the field of maritime transport and logistics, which aim to promote sustainable practices and reduce the environmental footprint...

The reliable performance of the shipboard power system (SPS) is essential for the safe and efficient operation of marine vessels. SPSs are subject to various types of electrical faults that can cause equipment failure, system downtime, and even catastrophic events. One effective way to provide redundancy and fault tolerance in the event of a fault...

Electricity generation is one of the major concerns of today’s world due to increasing dependence on this energy. Continuity in power supply and service to network consumers may be disrupted by various disturbances; thus, the power grid requires a reliable and fast protection system. The protection of distribution networks is conventionally perform...

Lack of an effective protection scheme is a major barrier to increased integration of renewable energy sources. Despite the system instability and personnel safety concerns due to unintentional islanding, detection of this abnormal condition has not been adequately addressed in the DC microgrids. To overcome the large non-detection zone (NDZ) and p...

📣 مراکز تحقیقاتی ریزشبکه‌های هوشمند و پردازش دیجیتال و بینایی ماشین با همکاری باشگاه پژوهشگران جوان و نخبگان دانشگاه آزاد اسلامی واحد نجف آباد برگزار می‌کنند: 💠 ششمین کنفرانس ملی مهندسی برق و سیستم‌های هوشمند 🔰 محورهای کنفرانس: 🔶 مهندسی برق قدرت 🔷 مهندسی برق کنترل 🔶 مهندسی برق الکترونیک 🔷 مهندسی برق مخابرات 🔶 مهندسی پزشکی بیوالکتریک 🔷 مهندسی کامپ...

With the increasing penetration of distributed generations, preserving the protection system coordination is of great importance for the distribution network operation. This paper presents a supplementary protection strategy for the multi-agent system (MAS)-based hierarchical protection scheme (HPS). The primary level of MAS-based HPS clears the fa...

Despite various advantages of integrating distributed generation (DG) units into distribution networks such as power loss reduction and voltage profile improvement, they may disrupt the performance of the conventional protection system due to bidirectional power flow and change of short-circuit power. With the development of multi-agent systems (MA...

Low voltage DC (LVDC) microgrids facilitate the integration of renewable energy systems and modern loads. However, they suffer from the lack of a sensitive, selective, reliable, and fast protection strategy. The low fault current of high-resistance faults makes fault detection and faulty zone identification challenging tasks for protection engineer...

Photovoltaic (PV) systems have been gaining popularity among distribution network engineers. The integration of these small-scale sources has a variety of benefits for the distribution network. One of the most important is the power loss reduction. However, a high penetration level of PV systems may disrupt the protection coordination of convention...

Photovoltaic (PV) systems have been gaining great attention during the last decade. One of the main faults in PV arrays is partial shading, affecting its electrical parameters. Failure to detect this fault may result in optimal generated power reduction and hot spotting leading to damage to cell encapsulant and second breakdown. This paper develops...

The limited and bidirectional fault current of inverter interfaced islanded microgrids make the fault detection and faulty feeder identification the major challenges for conventional overcurrent based protection systems. To address the first challenge, this letter proposes a fault detection strategy based on the modified short-time correlation tran...

The high-surety power supply (HSPS) systems are gaining great attention to enhance the reliability of uninterruptable power supplies (UPSs). A high-resistance fault along an HSPS feeder results in a low fault current, making the conventional HSPS protection strategy ineffective. To address this problem, this paper develops a directional fault prote...

Low voltage DC microgrids have been gaining great attention for the integration of renewable energy source and energy storage units, and electronic loads. DC microgrids are commonly controlled using the hierarchical control strategy (HCS) to provide flexible operation in both grid-connected and islanded modes. The HCS relies on proportional-integra...

Aims & Scope: DC microgrids have attracted significant attention over the last decade in both academia and industry. The DC microgrid has demonstrated superiority over the ac microgrid with respect to reliability, efficiency, control complexity, integration of renewable energy sources, and connection of DC loads. Despite these numerous advantages,...

Preface (The book was written in Persian): Regarding the development of renewable energies in the recent decade around the world and international commitments for the reduction of greenhouse gases and following the Iran government programs for developing this industry in the country, various renewable energy-based plants have been developed during...

A high-impedance fault (HIF) is mostly associated with the arcing phenomenon and its main features are low current, randomness, nonlinearity, and asymmetry. The low fault current of an HIF is a major challenge for overcurrent-based protection system of distribution networks. Power loss, potential fire hazard, and electric shock are consequences of...

The lack of an effective protection system may jeopardize resilience offered by low voltage DC (LVDC) microgrids. This paper presents a protection strategy for ring-bus LVDC microgrids, which employs intelligent electronic devices and solid-state circuit breakers (SSCBs). This scheme is developed based on monitoring the modified squared poverty gap...

The low fault current of high-impedance faults (HIFs) is one of the main challenges for the protection of distribution networks. The inability of conventional overcurrent relays in detecting these faults results in electric arc continuity that it causes the fire hazard and electric shock and poses a serious threat to human life and network equipmen...

Development of an efficient protection strategy is one of the main barriers in paving the way for the implementation of inverter-based microgrids. The limited fault current of voltage-sourced converter (VSC) units as the sole fault feeding sources in the islanded mode of operation makes the fault detection difficult for conventional overcurrent-bas...

The high penetration level of photovoltaic (PV) units increases their injected fault current that it may results in fuse-recloser miscoordination in distribution networks. The conventional coordination techniques are based on shifting the fast operation curve of the recloser below the characteristic curve of the fuse for fuse saving in the case of...

One the main challenges for the conventional protection system of a photovoltaic (PV) array is the occurrence of light fault conditions including low location mismatch fault, fault with high fault path resistance, and fault under low solar irradiance because their fault current increment is not enough for triggering the current-based protective dev...

With recent advances in power-electronics, inverter-based microgrids are gaining great attention. Droop control is one of the main methods to share the real and reactive power among distributed energy resources (DERs) in an islanded microgrids. Due to different characteristics of microgrid feeders, reactive power sharing is not fully accurate and c...

With the high penetration of photovoltaic (PV) systems, fault detection scheme is of great importance for the distribution network operation. The low fault current makes the detection of low-irradiance, low-mismatch, and high-impedance faults a challenging task, especially for PV systems with active maximum power point tracking algorithm and equipp...

Despite the growing deployment of photovoltaic (PV) systems, they are still facing challenges in developing the proper control and protection schemes. One of the main protection challenges of PV arrays is their low fault currents under low-irradiance, low-mismatch, and high-impedance faults. In addition to these conditions, the operation of maximum...

The mismatched feeder impedance of the voltage-sourced converter (VSC) units may result in reactive power sharing error in the islanded microgrids. This paper presents a reactive power sharing strategy for single-phase inverter-based microgrids that eliminates the circulating currents and reduces the coupling between real and reactive powers. The p...

Owning to economical and environmental concerns, the photovoltaic (PV) technology has been significantly developed over the past few years. To ensure the safe operation of PV systems, it is necessary to develop effective fault detection techniques. Low fault current of high impedance, low mismatch, and low irradiance faults may lead to they remain...

The installation of photovoltaic (PV) systems is gaining great attention due to the matured PV technology and the lowered price of PV modules. With an increasing penetration of PV systems, the selectivity of distribution network protection may be affected which results in undesirable de-energization of loads, damage of network equipment, and reduct...

The ability of riding through the grid disturbances can increase the integration of microgrids into the distribution system. Consequently, a grid-connected microgrid should provide ancillary services such as low voltage ride-through (LVRT) capability and reactive power support to sustain the power system operations during abnormal grid conditions....

Interconnection standards prevent islanding operation of distributed generations (DGs) to keep the safety and avoid the equipment failure. To meet this requirement for synchronous DGs (SDGs), the frequency-based relays are commonly used in the active distribution networks. This paper shows that in some conditions, a voltage relay has better islandi...

One of the most important concerns during Induction Motor (IM) starting is high starting current. This current can be 5 to 8 or more times the rated current. This phenomenon affects not only winding insulation but also power quality issues. The paper deals with a method of reducing the starting current. A Voltage-Sourced Converter (VSC) is connecte...

In recent years, the penetration of distributed energy resources (DER) as a solution for alleviating the economical, technical, and environmental concerns has increased. The main advantages of the electronically coupled DER units, commonly interfaced using a droop-controlled voltage-sourced converter (VSC), are their flexibility in providing contro...

Although distributed generation (DG) installation in distribution systems can technically and economically be beneficial, it may cause issues, one of which is islanding condition. According to the standard, each DG unit must be equipped with an anti-islanding protection system to be disconnected within appropriate time after the islanding occurrenc...

One of the most important issues in power system restoration (PSR) is switching overvoltage caused by power equipment energization. This phenomenon may damage some equipment and delay power system restoration. This paper proposes an intelligent estimator which can be used to evaluate and control switching overvoltages. Transformer, shunt reactor, a...

Induction motors (IMs) are widely used in industry including it be an electrical or not. However during starting period, their starting currents are so large that can damage equipment. Therefore, this current should be estimated accurately to prevent hazards caused by it. In this paper, the artificial neural network (ANN) as an intelligent tool is...

One of the most important concerns in electrical systems is to deliver energy to the consumers with high power quality (PQ). Because of great importance of voltage sag among all PQ events, this paper presents evaluation of voltage sags caused by induction motors (IMs) starting. Malfunctioning or failure of sensitive loads is main effect of this phe...

In this paper an intelligent approach is introduced to study switching overvoltages during transmission lines energization. In most countries, the main step in the process of power system restoration, following a complete/partial blackout, is energization of primary restorative transmission lines. An artificial neural network (ANN) has been used to...

In this work, voltage evaluation after power components energization such as transmission line, transformer and shunt reactor is analyzed using artificial neural network (ANN)-based approach. Throughout the initial phase of system restoration, unexpected overvoltage may happen due to nonlinear interaction between the unloaded transformer and the tr...

This paper presents an intelligent approach to evaluate switching overvoltages during power equipment energization. Switching action is one of the most important issues in power system restoration schemes. This action may lead to overvoltages that can damage some equipment and delay power system restoration. In this work, transient overvoltages cau...

Overvoltages caused by switching operation of power system equipments might damage some equipment and delay power system restoration. This paper presents a comparison between transmission line (TL) models for overvoltages study and investigates which TL model is most proper for every case study. Both simulation time and accuracy factors of TL model...

This paper proposed an artificial neural network (ANN)-based approach to mitigate harmonic overvoltages during transformer energization. Uncontrolled energization of large power transformers may result in magnetizing inrush current of high amplitude and switching overvoltages. The most effective method for the limitation of the switching overvoltag...

This paper presents an approach to the study of switching overvoltages during power equipment energization. Switching action is one of the most important issues in the power system restoration schemes. This action may lead to overvoltages which can damage some equipment and delay power system restoration. In this work, switching overvoltages caused...

This paper introduces an intelligent-based method using artificial neural network (ANN) to reduce shunt reactor switching overvoltages. In power systems, an overvoltage could be caused by core saturation on the energization of a shunt reactor with residual flux. The most effective method for the limitation of the switching overvoltages is controlle...

The shunt reactors located on both line terminals and substation bus-bars are commonly used on long extra high voltage (EHV) transmission systems for controlling voltage during load variations. In a small power system that appears in an early stage of a black start of a power system, an overvoltage could be caused by core saturation on the energiza...

This paper presents an artificial intelligence application to measure switching overvoltages caused by shunt reactor energization by applying analytical rules. In a small power system that appears in an early stage of a black start of a power system, an overvoltage could be caused by core saturation on the energization of a reactor with residual fl...

In this paper an intelligent-based approach is introduced to evaluate harmonic overvoltages during three-phase transformer energization. In a power system that appears in an early stage of a black start of a power system, an overvoltage could be caused by core saturation on the energization of a three-phase transformer with residual flux. Such an o...

One of the most important issues in power system restoration is overvoltages caused by transformer switching. These overvoltages might damage some equipment and delay power system restoration. This paper presents a radial basis function neural network (RBFNN) to study transformer switching overvoltages. To achieve good generalization capability for...

Transformer switching is one of the important stages during power system restoration. This switching can cause harmonic overvoltages that might damage some equipment and delay power system restoration. Core saturation on the energisation of a transformer with residual flux is a noticeable factor in harmonic overvoltages. This work uses artificial n...

This paper introduces an approach to analyse transient overvoltages during capacitor banks switching based on artificial neural networks (ANN). Three learning algorithms, delta-bar-delta (DBD), extended delta-bar-delta (EDBD) and directed random search (DRS) were used to train the ANNs. The ANN training is based on equivalent parameters of the netw...

During early stage of primary restoration process, unexpected overvoltages may happen due to nonlinear interaction between the unloaded transformer and the transmission system. The most effective method for the limitation of the switching overvoltages is controlled switching since the magnitudes of the produced transients are strongly dependent on...

During early stage of primary restoration process, unexpected overvoltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. Such an overvoltage might damage some equipment and delay power system restoration. Artificial neural network (ANN) is addressed in this work, in order to estimate the tempor...

The quality of electric power has been a constant topic of study, mainly because inherent problems to it can lead to great economic losses, especially in industrial processes. Among the various factors that affect power quality, those related to transients originating from capacitor bank (CB) switching in the primary distribution systems must be hi...

In most countries, the main step in the process of power system restoration, following a complete/partial blackout, is energization of primary restorative transmission lines. Artificial neural network (ANN) is employed for performing a nonlinear input–output mapping in this work, in order to estimate the temporary overvoltages (TOVs) due to transmi...

In a small power system that appears in an early stage of a black start of a power system, an overvoltage could be caused by core saturation on the energization of a three-phase transformer with residual flux. Such an overvoltage might damage some equipment and delay power system restoration. A new approach based on worst case determination is prop...

The energization of power transformers following a complete or partial collapse of the system is an important issue. This paper presents an Artificial Neural Network (ANN)-based approach to estimate the temporary overvoltages (TOVs) due to transformer energization. In proposed methodology, Levenberg-Marquardt second order method is used to train th...

During early stage of primary restoration process, unexpected Overvoltages may happen due to nonlinear interaction between the unloaded transformer and the transmission system. The most effective method for the limitation of the switching overvoltages is controlled switching since the magnitudes of the produced transients are strongly dependent on...