Mehrdad Tarafdar Hagh

• Professor
• Professor (Full) at University of Tabriz

Multi‐level inverters (MLIs) have a wide range of applications that try to minimize power electronics such as switches, diodes, and DC sources. Switched‐capacitor inverters are offered with reduced sources that reduce the number of sources and switches. This paper presents a switched capacitor‐based MLI with fewer components for grid‐connected appl...

This paper is a comprehensive reference for researchers interested in flexible AC alternating current transmission systems (FACTS) technologies. This study investigates modified UPFC models. Besides UPFC, an overview of DPFC will be presented, and the critical differences between these advanced power flow control technologies will be discussed. In...

The growing significance of network resilience underscores the importance of research in integrating Renewable Energy Resources (RESs) and battery energy storage Systems (BESS) with electrical networks. This paper presents a real-time simulation for systematically integrating renewable energy sources (RESs) and battery energy storage systems (BESS)...

This paper presents an optimal framework for demand response aggregators in wholesale electricity markets. Demand response aggregators provide customers with flexible contracts in the proposed model. These contracts allow for hourly load reductions through load curtailment, load shifting, onsite generation utilization, and energy storage systems. T...

Multilevel inverters are known as essential converters in renewable sources. First, in this paper, a new submodule is presented, and based on it, a new sub-multilevel inverter is presented. The proposed sub-multilevel inverter consists of several unidirectional and bidirectional switches and DC voltage sources. Then, the generalized topology, devel...

In this study, to solve total harmonic distortion (THD) and voltage stress on switches, challenges have been made by presenting a new multi‐level inverter (MLI). The proposed topology can operate with both symmetric and asymmetric sources. The proposed topology in symmetric and asymmetric mode with 18 switches can produce 17 and 49 voltage levels,...

In this paper, a new topology is introduced for capacitor-based multi-level inverters. The proposed topology is based on combination of two Cross-Square-Switched T-Type inverters. This structure can be generalized in two modular and cascaded modes. In the cascaded mode, higher voltage levels are produced with low power switches. The main features o...

The interconnection between different energy networks considerably improves their technical and economical aspects; however, it increases the complexity of decisions. This paper optimizes the short-term planning of a hybrid multi-microgrid integrated with an all-in-one vehicle station composed of charging facilities, battery swapping slots, parking...

The optimal operation of power systems is one of the most critical issues for operators. Optimizing the operation of power systems while accommodating the increasing penetration of RES, owing to the intermittent and variable nature of these resources, stands as one of the most critical challenges for power systems. Numerous primary challenges, incl...

Application of micro-grids (MGs) as a solution for future energy systems are significantly increasing in recent years. On the other hand, more stringent requirements are added to grid codes (GCs) of low-voltage distribution networks. Accordingly, this paper proposes a low-voltage ride-through (LVRT) control scheme for four-wire multi-source MGs. Th...

One of the main challenges in the security of energy supply in modern power systems is the frequency deviation. Appearance of an imbalance between the demand and supply of electrical energy is the main reason for any change in the frequency level of the grid. Thus, the Load Frequency Control (LFC) operation is usually performed automatically to res...

In multi energy microgrids with renewable energy sources, the significance of consideration of the gas supply network and efficient interaction between various energy carriers has been developed. Also, one of the most consequential matters linked with the operation of microgrids is affording the resiliency of the microgrid in inconstant conditions...

New technologies for wind energy systems have received great attention globally in recent years. These technologies are trying to reduce the drawbacks of conventional wind systems. This paper introduces a novel concept for wind systems to improve efficiency, reduce costs, and reduce environmental damage. The proposed system is considered from two v...

This paper proposes a coordinated control strategy to enhance the low/high‐voltage ride‐through (L/HVRT) capability of grid‐tied micro‐grids (MGs). The novel control scheme, which is based on grid‐following concepts, contains two layers for each power source of MG. The former, known as the primary layer, has reverse‐droop and non‐linear robust slid...

Generally, in contingency analysis, N-1 events are studied. However, simultaneous failure of more than one device is more dangerous and might result in cascading failures. Due to cyber-attacks and malicious motivations, attacking several components of the system is more probable. Various methods have been proposed for contingency screening, which a...

This paper has proposed a hybrid framework to accurately predict and forecast the State of Health (SOH) of Lithium-ion batteries for Electric Vehicles (EV) using noisy data. Due to significant environmental and sustainability benefits, the EVs are getting popular worldwide. The EVs are getting fully powered from Lithium-ion batteries instead of fos...

Inverters as one of the most important elements of power systems have been profoundly developed in recent decades and their performance has attracted researches in control and structure point of view. In this paper, a new structure based on low power switch count is proposed for multilevel converter is feeding. The proposed structure is presented f...

Recently, the application of multi-energy infrastructure has been widespread since the emergence of new technologies in this field. Accordingly, modeling and providing energy supply for consumers at an acceptable level of security is vital. It is also important for sustainable development in all directions to develop and support resources and infra...

In recent decades, the penetration of inverter-interfaced distributed generators (IIDGs) in power systems has increased significantly due to the environmental and economic benefits. The increasing participation of IIDGs and the developments of power electronic technologies have raised the possibility of controlling the power injected by IIDGs for r...

This study, as the leading one, proposes power-based distribution locational marginal pricing (PDLMP) to determine the active and reactive powers tariffs in distribution systems with high penetration of distributed energy resources (DERs). The main merit of the proposed approach alludes to its power-based characteristics within which the price sign...

This article investigates a clustering‐based approach to simultaneously seek the optimal allocation of wind farm (WF) and shunt capacitor (SC) in distribution systems. The stochastic nature of wind turbines leads the allocation problem to become more intricate nowadays. Hence, the application of probabilistic methods for this stochastic analysis is...

A new structure for doubly fed induction generator (DFIG) wind farms with coordinated power control under grid fault conditions are proposed in this paper. The proposed structure uses one grid side converter (GSC) and one energy storage system (ESS) for the entire wind farm unlike conventional structures, which have one GSC for each of the DFIGs. A...

Utilizing renewable generators can solve many critical problems of electrical energy systems such as the finitude of fossil fuels. However, due to the major role of fuel-based generators to supply the load demand in the current networks and investment costs of renewable generators, some issues such as energy losses and greenhouse gasses emission st...

This article proposes a method based on data clustering for the optimal placement and sizing of wind farms (WFs) in radial distribution systems considering the wind uncertainty and the wake effect. The stochastic output of wind turbines makes the optimization problem more challenging. Using the probabilistic methods for such analyses proves efficie...

In this paper, a frequency-reactive power channel (FRCh) is proposed for improving the performance of conventional frequency control system in an islanded MicroGrid (MG). Using this channel, it will be possible to take advantage of reactive power management for frequency control, in addition to the conventional methods of using active power. In ord...

This paper presents an Exchange Market Algorithm (stocktickerEMA) method for solving the Economic Emission Dispatch (EED) problem including wind farms in the power systems. The stocktickerEMA algorithm is a powerful and useful method for finding the optimal value of an optimization problem with high accuracy. In recent years, because of the emissio...

This study proposes a new frequency control of islanded and storage independent wind‐powered microgrid based on coordinated robust dynamic droop power sharing. The islanded microgrid includes wind turbine as undispatchable distributed generation (DG) and fuel cell as dispatchable DG. In the first layer of control, the reverse and direct droop contr...

In this paper, a new fault tolerant dc-ac converter-fed induction motor drive is proposed to maintain motor as close as possible to its desired normal operation under open- and short-circuit switch failures. The operational principles for fault detection and isolation schemes are provided. Two control strategies including predictive control and vol...

One of the ways to manage and provide flexibility in power systems is demand response (DR). A large number of end-users as DR sources must be aggregated by an intermediate entity called DR aggregator. This paper proposes an approach based on game theory to obtain the best bidding strategy of DR aggregators in electricity market. In the presented sc...

Optimal placement and sizing of shunt capacitors are important issues to improve voltage profile and reduce power losses in distribution networks. In this regard, dealing with stochastic nature of wind farms (WFs), the issue becomes more complex in wind‐integrated radial distribution networks. This study aims at optimal siting and sizing of shunt c...

This study investigates the impact of incentive-based demand response on the optimal economic sizing of hybrid power systems for a remote area in South Australia. The hybrid power systems are modelled as AC-coupled system with various power generation and energy storage systems including diesel generators, solar photovoltaics, wind turbines, batter...

High impedance grounding systems offer great service continuity by limitation of fault currents during single line to ground faults. Recently, a new power electronic based grounding system has been presented, in which an adjustable current was injected into the neutral point. This active grounding system operates as a high impedance grounding syste...

This paper presents a new solution to the problem of transmission cost allocation to its users. The proposed technique utilizes modified Z-bus theory, equivalent current injection and impedance of the generators and loads, and is developed by the equal-sharing as well as the orthogonal projection principle. The procedure is performed in three steps...

Existence of distributed generators (DGs) makes it possible to split distribution systems into multi-microgrids (MGs) in emergency conditions. In this study, after optimal allocation of distributed generation sources with a multi-objective function, the test system is optimally sub-divided into some self-adequate MGs with the least not supplied act...

Doubly-fed induction generator (DFIG) based wind turbine generators (WTG) needs to be connected back to integrated power grid after tripping due to disturbances and emergencies in power grids. Re-connection can cause switching transients which may affect overall grid stability. This situation can be avoided if proper synchronization can be ensured...

Virtualization in the data center network is used to overcome the resistance of Internet ossification. Node mapping in virtual network embedding (VNE) process is more important than link mapping because each node mapping has a lot of choices with high probability. Historical data always have valuable information which displays how to be mapped virt...

Network virtualization provides the substruction of various heterogeneous Virtual Networks (VNs)on a single physical infrastructure which is called Virtual Network Embedding (VNE)and is known as an Np-hard problem. The VNE includes two sub-problem; virtual node mapping and virtual link mapping. Related works do not consider network topology and ene...

This paper proposes a new method to allocate the transmission fixed costs among the network participants in a pool-based electricity market. The allocation process relies on the circuit laws, utilizes the modified impedance matrix and is performed in two individual steps for the generators and loads. To determine the partial branch power flows due...

Fault current limiters (FCLs) can play an important role to provide protection of power systems against high fault current levels. This paper proposes a new three-phase structure of saturable-core FCL based on the common core for all three phases. Due to the existence of flux linkage between all three phases, the resulting electromagnetic fluxes ne...

Deregulation and competition appearance in electric power systems and fundamental changes in control and operation structures of such systems require a strong tool for handling such issues. Game theory approach, which is defined as an analytical concept for dealing with the decision-making process in a variety of sciences, is vastly employed in pow...

This paper presents a comprehensive review of fault ride through (FRT) in the grid code of 38 selected countries with an emphasis on renewable energy (REN) sources–related rules. Grid codes are the rules legislated usually by the transmission system operators (TSOs) to determine the grid integration requirements of electrical power generators. Each...

This paper presents a new islanding detection method for synchronous Distributed Generation (DG). The proposed method is developed based on the combination of rate of change of exciter voltage (RCEV) and open-close circuit breaker (OCCB) at DG connection point. Whenever the RCEV parameter is not sufficient enough to detect islanding condition effic...

Partial shading is one of the main causes in reducing the output power of photovoltaic (PV) systems. This paper proposes a circuit to recover the energy of shaded PV modules during partial shading condition (PSC). The proposed circuit, which is a combination of a buck–boost converter and the switched-capacitor (BBSC) circuits, equalizes the voltage...

Uncertainty management is a challenging task in decision making of the operators of the power systems. Prediction of the system state is vital for operation of a system with stochastic behavior especially in a power system with significant amount of renewable energies such as wind power. Predictable power systems are in more interest of operators,...

In conventional fossil-fuel power systems, the economic environmental dispatch (EED) problem is a major problem that optimally determines the output power of generating units in a way that cost of total production and emission level be minimized simultaneously, and at the same time all the constraints of units and system are satisfied properly. To...

Due to the high price of fossil fuels, the increased carbon footprint in conventional generation units and the intermittent functionality of renewable units, alternative sources must contribute to the load frequency control (LFC) of the power system. To tackle the challenge, dealing with controllable loads, the ongoing study aims at efficient LFC i...

In this paper, a new fault tolerant DC-AC converter-fed induction motor drive is proposed to maintain motor as close as possible to its desired normal operation under open- and short-circuit switch failures. The operational principles for fault detection and isolation schemes, are provided. Two control strategies including predictive control and vo...

This paper presents a new dynamic model and control approach for static synchronous series compen-sator (SSSC) to participate effectively in automatic generation control (AGC) of an interconnected dereg-ulated power system. In doing so, a new mathematical formulation is extracted to present the participation of the SSSC in the tie-line power flow e...

The ongoing study aims to establish a direct probabilistic load flow (PLF) for the analysis of wind integrated radial distribution systems. Because of the stochastic output power of wind farms, it is very important to find a method which can reduce the calculation burden significantly, without having compromising the accuracy of results. In the pro...

Purpose This paper aims to propose a new transformer-less inverter structure to reduce the common-mode leakage current in grid-connected photovoltaic (PV) systems. Design/methodology/approach The proposed circuit structure is the same as the conventional full-bridge inverter with three additional power switches in a triangular structure. These thr...

Optimal transmission switching (OTS) has been introduced as a persuasive approach for cost minimization and the improvement of power system flexibility by utilizing lines existence condition. Ordinary OTS based on optimal power flow equations as used in the previous studies may expose system security in some cases. This paper proposes a novel seque...

In this paper, a new non-isolated free ripple input current bidirectional dc-dc converter with capability of zero voltage switching (ZVS) is proposed. The free ripple input current condition at low voltage side is achieved by using third winding of a coupled inductor and a capacitor for the whole range of duty cycles. In the proposed structure, the...

This study investigates a grid-tiedphotovoltaic (PV) system with active power injection, reactive power compensation and harmonic current elimination capability. The equivalent electric model presented in the literature is used to implement the PV system. In non-linear loads, low-frequency synchronous reference frame (SRF) methods cannot eliminate...

In this paper, a new transformer-less inverter structure is proposed to reduce the common mode leakage current in grid-connected photovoltaic systems. The proposed circuit structure is the same as the conventional full bridge inverter with three additional power switches in a triangular structure. These three power switches are between the bridge a...

In this study, a clustering scheme based on the particle swarm optimisation (PSO) algorithm is used for probabilistic load flow calculation in the presence of wind generations. In this method, input random variables are first clustered in several groups according to their similarity and then a representative is assigned to each group by the PSO alg...

One of the most important optimization problems in operation planning of power systems is unit commitment (UC). Consideration of transmission lines and operation constraints in UC problem leads to a more general problem known as Security Constrained Unit Commitment (SCUC). The SCUC can be formulated as a very large scale mixed-integer problem in pr...

This study compares fractional order phase lead‐lag controller, fractional order proportional‐integral‐derivative (FOPID), and tilt‐integral‐derivative controllers as thyristor controlled series capacitor (TCSC)‐based damping controller to improve load frequency control (LFC) performance in a restructured power system. To prepare an efficient ancil...

In this paper, fractional order proportional-integral-derivative (FOPID) and tilted-integral-derivative (TID) controllers are applied in the design of load frequency controller (LFC). Tuneable parameters are adjusted via an improved particle swarm optimization algorithm which is powered by chaotic parameter and crossover operator to find a globally...

Nowadays, most double fed induction generators (DFIGs) based wind turbines are equipped with rotor crowbar connected in parallel with the rotor side converter (RSC). The parallel rotor side crowbar (PRSC) is used to protect the RSC and DC link capacitor by dissipating the rotor energy during grid fault condition. In this paper, two types of crowbar...

Doubly-fed induction generator (DFIG)-based wind turbines utilise small-scale voltage sourced converters with a limited overcurrent withstand capability, which makes the DFIG-based wind turbines very vulnerable to grid faults. Often, modern DFIG systems employ a crowbar protection at the rotor circuit to protect the rotor side converter (RSC) durin...

This chapter titled, “Low Voltage Ride Through of Wind Energy Systems” focuses on the importance of low voltage ride through (LVRT) of wind turbines. The investigation of some selected grid codes has revealed that LVRT has different requirements in different grid codes. The results of the investigation have found that higher penetration of wind ene...

The fuzzy logic (FL) comes as a vital and viable solution method in various engineering fields which mutates the optimal point in many engineering issues. This study presents a fuzzy-logic approach to promote the controller performance. The power system is one of the fundamental, complicated and principle systems in the world, doing so there has be...

This paper presents a dynamic reverse droop power-sharing scheme to control frequency of micro grids based on neural networks. Micro grid is included undispatchable distributed generation (DG) such as wind turbine and dispatchable voltage source converter DG which is considered as auxiliary generation. Power sharing control strategies of distribute...

Arrival of the concept of smart grids and electricity market introduces the demand-side management (DMS) which leads to controllable loads. Furthermore, by the rapid penetration of renewable energy sources, such as photovoltaic (PV) and wind generation systems, operating as distributed generation systems (DGs), many issues about utilization of thes...