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Ahmed Alsammak

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Received the BSc, MSc, and PhD degrees in electrical engineering (Power and Machine) from University of Mosul, Mosul-Iraq in 1997, 1999 and 2007, respectively. He worked on design and implementation in numerous engineering projects. Currently, he works as an assistant professor in EE Department- College of Engineering- University of Mosul. He has more than 27 publications, and his interests include electrical power systems and machines, power system stability, modelling, simulation, fuzzy controller, nonlinear circuit, and system theory as related to electrical power and machine systems.

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K.N.Toosi University of Technology

A Hasib Chowdhury

Bangladesh University of Engineering & Technology

Maulana Azad National Institute of Technology

José Francisco Pessanha

UERJ - Universidade do Estado do Rio de Janeiro / Rio de Janeiro State University

West Bengal University Of Technology

Electronics Research Institute

Malik Sameeullah

National Institute Of Technology Kurukshetra

Victor Orejuela

Universidad Politécnica Salesiana

Fabio Andrés Pavas Martínez

Universidad Nacional de Colombia

University of East London

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Papers by Ahmed Alsammak

Optimization of Power Quality Using the Unified Power Quality Conditioner (UPQC) with Unbalanced Loads

Al-Rafidain Engineering Journal (AREJ)

The power quality (PQ) is a major issue for both electrical utilities and their customers. The no... more The power quality (PQ) is a major issue for both electrical utilities and their customers. The nonlinear loads cause PQ problems like current harmonics, voltage harmonics, frequency deviation, voltage sag and voltage swell. A unified power quality conditioner (UPQC) is utilized in this research to minimize these PQ problems. The UPQC is made up of two active power filters (APFs), one of which is connected to the line in series and the other in parallel. The Unit Vector Template Generation (UVTG) approach is used to control the series APF, whereas the Synchronous Reference Frame (SRF) technique is used to control the shunt APF. The compensating properties of a series-shunt APFs when the loads become imbalanced have been explored. The system performance has been tested under conditions current harmonics, voltage harmonics, voltage sag, and voltage swell. The voltage harmonics are identified and reparation in a series APF using the UVTG technique, whereas the harmonics and unbalanced currents are identified and reparation in a shunt APF using the SRF method. An IEEE-519-compliant THD (Total Harmonic Distortion) of less than 5% is achieved by UPQC in simulations with unbalanced loads. The findings indicate that harmonic currents and supply voltage fluctuations were lessened by UPQC.

Direct Detection of Voltage Collapse in Electrical Power System

Tikrit Journal of Engineering Sciences

Voltage stability is indeed a dynamic problem. Dynamic analysis is important forbetter understand... more Voltage stability is indeed a dynamic problem. Dynamic analysis is important forbetter understanding of voltage instability process. In this work an analysis for voltagestability from bifurcation and voltage collapse point of view based on a centermanifold voltage collapse model. A static and dynamic load models were used toexplain voltage collapse. The basic equations of simple power system and load areused to demonstrate voltage collapse dynamics and bifurcation theory. Theseequations are also developed in a manner, which is suitable for the Matlab-Simulinkapplication. Detection of voltage collapse before it reaches the critical collapse pointwas obtained in simulation results.

Speed Control of Asymmetrical Six Phase Induction Motor based Fuzzy Logic Controller

Ac electric drives for both synchronous and induction take great interests by researchers and ind... more Ac electric drives for both synchronous and induction take great interests by researchers and industrialist especially last type due to there is effortlessness for speed regulation, ruggedness, and high power to weight ratio etc…three phase drives was the conventional types that covered wide range of industrial and transmitting application .but with rising power demand and development in power electronics device and control schemes conventional induction motor drives could not be able to overcome all requirements in different fields , that's leads to think to create an other types of drivers having more than three phase (five, six ,seven and nine etc.) .six phase induction motor drive become one of these type used for many application instead of three phase type rising systems dependability, efficiency and flexibility in control process. [1]

Direct Detection of Voltage Collapse

Tikrit Journal of Engineering Science, 2011

Voltage stability is indeed a dynamic problem. Dynamic analysis is important for better understa... more Voltage stability is indeed a dynamic problem. Dynamic analysis is important for better understanding of voltage instability process. In this work an analysis for voltage stability from bifurcation and voltage collapse point of view based on a center manifold voltage collapse model. A static and dynamic load models were used to explain voltage collapse. The basic equations of simple power system and load are used to demonstrate voltage collapse dynamics and bifurcation theory. These equations are also developed in a manner, which is suitable for the Matlab-Simulink application. Detection of voltage collapse before it reaches the critical collapse point was obtained in simulation results.

Performance Improvement for Distance Relay Based Fuzzy Logic for All Prospective Faults

1Assistance Professor, Dept. of Electrical Engineering, University of Mosul, Mosul-Iraq. 2Assista... more 1Assistance Professor, Dept. of Electrical Engineering, University of Mosul, Mosul-Iraq. 2Assistance Lecturer, Dept. of Electrical Engineering, University of Mosul, Mosul-Iraq. ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract:The advanced application of fuzzy logic was introduced recently in protection of power system transmission lines. In this paper, a three-phase distance relay was designed by using an adaptive neuro-fuzzy inference system algorithm (ANFIS) that produced a fuzzy logic system (FS), which used to protect the overhead transmission lines where these lines are exposed to the faults continuously being built in outdoor and accompanied with the fault a high electrical current to large values lead to the destruction of electrical equipment in the power system. The paper had studied of adding a load to the end of the line as (over load) and also adding a load in the center o...

Voltage Sag, Voltage Swell and Harmonics Reduction Using Unified Power Quality Conditioner (UPQC) Under Nonlinear Loads

Iraqi Journal for Electrical and Electronic Engineering, 2021

In light of the widespread usage of power electronics devices, power quality (PQ) has become an i... more In light of the widespread usage of power electronics devices, power quality (PQ) has become an increasingly essential factor. Due to nonlinear characteristics, the power electronic devices produce harmonics and consume lag current from the utility. The UPQC is a device that compensates for harmonics and reactive power while also reducing problems related to voltage and current. In this work, a three-phase, three-wire UPQC is suggested to reduce voltage-sag, voltage-swell, voltage and current harmonics. The UPQC is composed of shunt and series Active Power Filters (APFs) that are controlled utilizing the Unit Vector Template Generation (UVTG) technique. Under nonlinear loads, the suggested UPQC system can be improved PQ at the point of common coupling (PCC) in power distribution networks. The simulation results show that UPQC reduces the effect of supply voltage changes and harmonic currents on the power line under nonlinear loads, where the Total Harmonic Distortion (THD) of load v...

A Survey Paper on Six Phase Induction Motor Drive

Al-Rafidain Engineering Journal (AREJ), 2020

This paper introduces different topics about six phase induction motor drives. It describes a dif... more This paper introduces different topics about six phase induction motor drives. It describes a different methods used for analyzing and representing induction motor model, by using (d-q-o) modelling and (x-y-o) some papers discussed motor model and its characteristics, controlling speed of motor and efficiency improvement. some techniques of control strategy such as (direct torque control, field oriented control, indirect field oriented control and sliding mode control etc. will be present to improve motor operation.as well this paper will present some techniques for voltage generation used to drive motors, some methods are implemented for this purpose depending upon quasi voltage generation, pulse width modulation, and space vector pulse width modulations etc are also discussed.

Modelling and simulation of self-excited induction generator driven by a wind turbine

Eastern-European Journal of Enterprise Technologies, 2020

The excellent specifications of the isolated squirrel cage self-excited induction generator (SEIG... more The excellent specifications of the isolated squirrel cage self-excited induction generator (SEIG) make it the first choice for use with renewable energy sources. However, poor voltage and frequency regulation (under load and speed perturbations) are the main problems with isolated SEIGs. Wide dependence on the SEIG requires prior knowledge of its behaviour with regard to variations in the input of mechanical power and output of electrical power to develop a control system that is capable of maintaining the voltage and frequency at rated values, as far as possible, with any change in the input or output power of the SEIG. In this paper, a mathematical model of a wind energy conversion system (WECS) based on a squirrel cage SEIG with a generalized impedance control (GIC) was built using the Matlab/ Simulink environment in a d-q stationary reference frame. A fuzzy logic controller (FLC) was used to control the parameters of the GIC. The training of the FLC was conducted by a neural network through Matlab's Neuro-Fuzzy designer. The results of this paper showed that the trained FLC succeeded in controlling the real and reactive power flow between the SEIG and the GIC system, in which the maximum variation for both magnitude and frequency of the generated voltage with any load or wind speed perturbation will not exceed (0.2 %) for the frequency and (3 %) for the voltage magnitude in both directions. The SEIG model was validated by comparing the results obtained with those of wellknown studies with the same rating and operating conditions

A Literature Review on the Unified Power Flow Controller UPFC

International Journal of Computer Applications, 2018

Power electronic controllers for a flexible ac transmission system (FACTS) can offer a greater co... more Power electronic controllers for a flexible ac transmission system (FACTS) can offer a greater control of power flow, secure loading and damping of power system oscillations. A unified power flow controller (UPFC) is a one of FACTS elements that can provide VAR compensation, line impedance control and phase angle shifting. The UPFC consist of two fully controlled inverters, series inverter is connected in series with the transmission line by series transformer, whereas parallel inverter is connected in parallel with the transmission line by parallel transformer. The real and reactive power flow in the transmission line can be controlled by changing the magnitude and phase angle of the injected voltage produced by the series inverter. The basic function of the parallel inverter is to supply the real power demanded by series inverter through the common dc link. The parallel inverter can also generate or absorb controllable reactive power. This paper offers and discusses most papers that used a UPFC to improving the active and reactive power flow of the power systems.

Fuzzy Logic based Power Factor Control of Synchronous Machine

International Journal of Computer Applications, 2018

In this paper, a fuzzy logic technique is used to control the power factor (PF) that compensate t... more In this paper, a fuzzy logic technique is used to control the power factor (PF) that compensate the reactive power of the load by controlling the excitation system of synchronous machine. This fuzzy logic controller can give a fast response compensation to meet the required load reactive power and hence keeping the load bus at constant set point PF value. The V curve of PF is treated in a way to get the flexibility and the limitation the over or under values, as well as time delay could therefore be eliminated with such a control configuration. The results show that fuzzy based power factor controller using synchronous machine is reliable, sensitive, faster and more efficient compare with the other methods such as capacitor groups.

Optimal Power Flow Solution with Maximum Voltage Stability

AL-Rafdain Engineering Journal (AREJ), 2011

This paper presents an Optimal Power Flow (OPF) formulation that is based on multi-objective opti... more This paper presents an Optimal Power Flow (OPF) formulation that is based on multi-objective optimization methodology, which can minimize both of operating costs and losses and it would at same time result in maximizing the distance to voltage collapse. A "Maximum Distance to Voltage Collapse" algorithm, which incorporates constraints on the current operating condition, is firstly presented, while OPF formulations which incorporate voltage stability criteria is secondly presented. The algorithm built on Matlab-Simulink is tested on an IEEE 6-bus test system using a standard power flow model, where the effect of maximum loading point limits is demonstrated.

Bifurcation and Voltage C ollapse in the Electrical Power Systems

AL-Rafdain Engineering Journal (AREJ), 2005

Voltage stability is indeed a dynamic problem. Dynamic analysis is important for a better underst... more Voltage stability is indeed a dynamic problem. Dynamic analysis is important for a better understanding of voltage instability process. In this work an analysis of voltage stability from bifurcation and voltage collapse point of view based on a center manifold voltage collapse model. A static and dynamic load models were used to explain voltage collapse. The basic equations of a simple power system and load used to demonstrate voltage collapse dynamics and bifurcation theory. These equations are also developed in a manner, which is suitable for the Matlab-Simulink application. As a result detection of voltage collapse before it reach the critical collapse point was obtained as original point.

Reactive Power Compensation using Fuzzy Gain Scheduling Controlled STATCOM for Grid Connected PV System

Asian Journal of Research in Social Sciences and Humanities, 2016

Integration of a grid-connected renewable energy system is expected to meet the energy demand of ... more Integration of a grid-connected renewable energy system is expected to meet the energy demand of the grid and reduce the carbon emission thereby global warming. This paper presents a grid-connected photovoltaic (PV) system combined with STATic synchronous COMpensator (STATCOM) that uses Fuzzy Gain Scheduling controller, to improve the grid quality of the power system by reactive power injection from STATCOM to compensate the voltage oscillation and to improve the voltage stability. This paper compares the proposed STATCOM with Fuzzy Gain Scheduling (FGS) controller for the dynamic state voltage oscillation of the PV system with the conventional PI controller for voltage compensation. On testing the proposed system through simulation using MATLAB/Simulink, the proposed model was found to be effective in mitigating voltage sags and swells with improved voltage regulation and power factor.

Power quality improvement using fuzzy logic controller for five-level shunt active power filter under distorted voltage conditions

Frontiers in Energy, 2013

In this paper, a five-level inverter is used as a shunt active power filter (APF), taking advanta... more In this paper, a five-level inverter is used as a shunt active power filter (APF), taking advantages of the multilevel inverter such as low harmonic distortion and reduced switching losses. It is used to compensate reactive power and eliminate harmonics drawn from a thyristor rectifier feeding an inductive load (RL) under distorted voltage conditions. The APF control strategy is based on the use of self-tuning filters (STF) for reference current generation and a fuzzy logic current controller. The use of STF instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the α-β axis without phase locked loop (PLL). The MATLAB fuzzy logic toolbox is used for implementing the fuzzy logic control algorithm. The obtained results show that the proposed shunt APF controller has produced a sinusoidal supply current with low harmonic distortion and in phase with the line voltage.

A New Transient Stability Analysis with Automatic Voltage Regulators, Turbine-Speed Governors, and Saturation Effect via Trapezoidal Method

In this paper, step-by-step Trapezoidal method is applied to a power system to solve the differen... more In this paper, step-by-step Trapezoidal method is applied to a power system to solve the differential equations those relate the actions of the transient stability, in which generators are installed with automatic voltage regulator (AVR), turbine-speed governor (TSG), and the effect of the saturation is also included. The results compare the individual and combined effects of those controllers. Saturation is modeled by two parts, i.e. excitation and generator saturation. The action of the inertia constant on the swing curve is shown in results. List of Symbols Vt = Terminal voltage. Ei&#39; = internal voltage(Ef). X&#39; d = Direct-axis transient reactance. X&#39; ds = Direct-axis transient reactance with saturation effect. X P = Potier reactance. δ = generator rotor angle. V t = generator terminal voltage. Pm = mechanical power. Pe = electrical power. Qe = Reactive power. ω = Speed. K A , KE = Regulator and exciter gain. T A , TE = Regulator and exciter time constant.

A New Model of Representation of Magnetisation Curve

The transformer magnetisation curves are important to power systems under transient operations. C... more The transformer magnetisation curves are important to power systems under transient operations. Conventional methods to determine these characteristics required several analyses. This paper presents simplified model in exponential form to fit the transformer magnetisation curve. The MATLAB computer program is used to determine the constants of the suggested fitting function. The results are compared with that obtained by other results in the literature and showed that the suggested model has good improvement in determining the true linear, knee, and saturation characteristics with a relatively high accuracy.

Modeling & Simulation of Synchronous Machine Controlled By PID Control for The Reactive Power Compensation

This paper present a suitable model set up for the analysis of the synchronous machine. The model... more This paper present a suitable model set up for the analysis of the synchronous machine. The model is then test with some cases such as sudden change in load, field voltage as well as loading or no loading condition. The basic equations of the motor are also developed in a manner, suitable for the Matlab-Simulink application. The computer and practical results were represented and compared. Good agreement between these results has been observed. This proves the validity of the simulation method used in this work. A PID controller for firing angle (alpha) was added to this model to control six-pulse rectifier circuit, which gives variable DC field voltage and this voltage changes as the output of the PID controller changes depending on the set point (reference power factor). The parameters of the PID controller was selected to give high performance for the reactive power control. LIST OF SYMBOLS va,vb and vc = Thee phase terminal voltages (volt). ia,ib and ic = Thee phase terminal current (amper). α= Firing angle (degree). Vf= DC field voltage (volt). If= DC field current (amper). Rf= Resistance of field circuit (ohm). Lff= Self of rotor inductance (henry). La,Lb and Lc= Stator self inductance (static)/ phase (henry). Lab,Lbc and Lca= Mutual inductance between stator Phases (henry). Laf,Lbf and Lcf= mutual inductances between stator phases and rotor (henry). Ls= Part of phase inductance harmonic because of salience (henry). λa, λb and λc= Instantaneous linkage flux for stator phases (Wb). λf = Instantaneous linkage flux for rotor (Wb). [V]= Voltage matrix (volt). [R]= Resistance matrix (ohm). [i]= Current matrix (amper). [λ]=Linkage flux matrix (Wb). [L]= Inductance matrix (henry). Te= Electrical torque (N.m). TL= Mechanical torque (N.m). ωs= Synchronous speed (rpm). ωr= Rotor speed (rpm). θ= Displacement angle for rotor refers to stator phase (a) (rad). Vf =DC field voltge (volt). PL&amp;QL = Real and reactive power load demand respectively (watt, var). Pm&amp;Qm = Real and reactive power of the Synchronous motor respectively (watt, var). Pt&amp;Qt = total Real and reactive power for the Synchronous motor and load demand respectively (watt, var). K p = Proportional gain for the PID control. K I = Integral gain for the PID control. K d = derivative gain for the PID control. Kcr= critical value gain for the PID control which give sustained oscillations output of system.

Adaptive Neuro-Fuzzy Inference System (ANFIS) Real Time Based Power Factor Control By Synchronous Machine

13_Transient Stability Improvement _IJEIT1412201707_03.pdf

— Transient stability is the ability of power system to maintain synchronism when subjected to a ... more — Transient stability is the ability of power system to maintain synchronism when subjected to a severe disturbance such as three phase fault on transmission line or large increase in load or loss of large load as a result of a separation in one of the transmission lines in the system. The energy storage systems represented by Static Var Compensator (SVC) and Solar Photo-voltaic Generator (PVG) are used to improve the transient stability of the power system. It regulates voltage at its terminal by controlling the amount of reactive power injected into or absorbed from power system. In this paper, the ability of energy storage systems to improve the transient stability has been studied. The multi-machine system was studied and IEEE 3-machine 9 bus system is taken as case study. The simulation is carried out using PSAT software. At the beginning the system has been simulated under three phase fault and then under sudden changes in load levels as a result of separation occurs in one of the transmission lines and without energy storage systems. Then energy storage system is installed in the system and its ability to enhance the transient stability has been investigated.

12_Voltage stability margin improving_IJEIT1412201707_04.pdf

—This paper present a method to improving voltage stability margin depending on power transmissio... more —This paper present a method to improving voltage stability margin depending on power transmission paths. Weak buses and lines are determined by using voltage stability indices, some comparison between these indices are made to determined weakest buses, the voltage stability margin is illustrate using the P-V curves and Q-V curves. After defined the weak buses and the degree of stress in each path depending on the indices values, voltage stability marginimprove by two methods. The first one adding a parallel line in the systemwhiles the second one by adding a device to supply only active power, reactive power and complex power. The results on IEEE 30 buses sample system shows extending and improving in the margin of voltage stability. Index Terms—Voltage stability margin, Voltage collapse, voltage stability indices, Matlab-Simulink, P-V curves and Q-V curves.

Optimization of Power Quality Using the Unified Power Quality Conditioner (UPQC) with Unbalanced Loads

Al-Rafidain Engineering Journal (AREJ)

The power quality (PQ) is a major issue for both electrical utilities and their customers. The no... more The power quality (PQ) is a major issue for both electrical utilities and their customers. The nonlinear loads cause PQ problems like current harmonics, voltage harmonics, frequency deviation, voltage sag and voltage swell. A unified power quality conditioner (UPQC) is utilized in this research to minimize these PQ problems. The UPQC is made up of two active power filters (APFs), one of which is connected to the line in series and the other in parallel. The Unit Vector Template Generation (UVTG) approach is used to control the series APF, whereas the Synchronous Reference Frame (SRF) technique is used to control the shunt APF. The compensating properties of a series-shunt APFs when the loads become imbalanced have been explored. The system performance has been tested under conditions current harmonics, voltage harmonics, voltage sag, and voltage swell. The voltage harmonics are identified and reparation in a series APF using the UVTG technique, whereas the harmonics and unbalanced currents are identified and reparation in a shunt APF using the SRF method. An IEEE-519-compliant THD (Total Harmonic Distortion) of less than 5% is achieved by UPQC in simulations with unbalanced loads. The findings indicate that harmonic currents and supply voltage fluctuations were lessened by UPQC.

Direct Detection of Voltage Collapse in Electrical Power System

Tikrit Journal of Engineering Sciences

Voltage stability is indeed a dynamic problem. Dynamic analysis is important forbetter understand... more Voltage stability is indeed a dynamic problem. Dynamic analysis is important forbetter understanding of voltage instability process. In this work an analysis for voltagestability from bifurcation and voltage collapse point of view based on a centermanifold voltage collapse model. A static and dynamic load models were used toexplain voltage collapse. The basic equations of simple power system and load areused to demonstrate voltage collapse dynamics and bifurcation theory. Theseequations are also developed in a manner, which is suitable for the Matlab-Simulinkapplication. Detection of voltage collapse before it reaches the critical collapse pointwas obtained in simulation results.

Speed Control of Asymmetrical Six Phase Induction Motor based Fuzzy Logic Controller

Ac electric drives for both synchronous and induction take great interests by researchers and ind... more Ac electric drives for both synchronous and induction take great interests by researchers and industrialist especially last type due to there is effortlessness for speed regulation, ruggedness, and high power to weight ratio etc…three phase drives was the conventional types that covered wide range of industrial and transmitting application .but with rising power demand and development in power electronics device and control schemes conventional induction motor drives could not be able to overcome all requirements in different fields , that's leads to think to create an other types of drivers having more than three phase (five, six ,seven and nine etc.) .six phase induction motor drive become one of these type used for many application instead of three phase type rising systems dependability, efficiency and flexibility in control process. [1]

Direct Detection of Voltage Collapse

Tikrit Journal of Engineering Science, 2011

Voltage stability is indeed a dynamic problem. Dynamic analysis is important for better understa... more Voltage stability is indeed a dynamic problem. Dynamic analysis is important for better understanding of voltage instability process. In this work an analysis for voltage stability from bifurcation and voltage collapse point of view based on a center manifold voltage collapse model. A static and dynamic load models were used to explain voltage collapse. The basic equations of simple power system and load are used to demonstrate voltage collapse dynamics and bifurcation theory. These equations are also developed in a manner, which is suitable for the Matlab-Simulink application. Detection of voltage collapse before it reaches the critical collapse point was obtained in simulation results.

Performance Improvement for Distance Relay Based Fuzzy Logic for All Prospective Faults

1Assistance Professor, Dept. of Electrical Engineering, University of Mosul, Mosul-Iraq. 2Assista... more 1Assistance Professor, Dept. of Electrical Engineering, University of Mosul, Mosul-Iraq. 2Assistance Lecturer, Dept. of Electrical Engineering, University of Mosul, Mosul-Iraq. ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract:The advanced application of fuzzy logic was introduced recently in protection of power system transmission lines. In this paper, a three-phase distance relay was designed by using an adaptive neuro-fuzzy inference system algorithm (ANFIS) that produced a fuzzy logic system (FS), which used to protect the overhead transmission lines where these lines are exposed to the faults continuously being built in outdoor and accompanied with the fault a high electrical current to large values lead to the destruction of electrical equipment in the power system. The paper had studied of adding a load to the end of the line as (over load) and also adding a load in the center o...

Voltage Sag, Voltage Swell and Harmonics Reduction Using Unified Power Quality Conditioner (UPQC) Under Nonlinear Loads

Iraqi Journal for Electrical and Electronic Engineering, 2021

In light of the widespread usage of power electronics devices, power quality (PQ) has become an i... more In light of the widespread usage of power electronics devices, power quality (PQ) has become an increasingly essential factor. Due to nonlinear characteristics, the power electronic devices produce harmonics and consume lag current from the utility. The UPQC is a device that compensates for harmonics and reactive power while also reducing problems related to voltage and current. In this work, a three-phase, three-wire UPQC is suggested to reduce voltage-sag, voltage-swell, voltage and current harmonics. The UPQC is composed of shunt and series Active Power Filters (APFs) that are controlled utilizing the Unit Vector Template Generation (UVTG) technique. Under nonlinear loads, the suggested UPQC system can be improved PQ at the point of common coupling (PCC) in power distribution networks. The simulation results show that UPQC reduces the effect of supply voltage changes and harmonic currents on the power line under nonlinear loads, where the Total Harmonic Distortion (THD) of load v...

A Survey Paper on Six Phase Induction Motor Drive

Al-Rafidain Engineering Journal (AREJ), 2020

This paper introduces different topics about six phase induction motor drives. It describes a dif... more This paper introduces different topics about six phase induction motor drives. It describes a different methods used for analyzing and representing induction motor model, by using (d-q-o) modelling and (x-y-o) some papers discussed motor model and its characteristics, controlling speed of motor and efficiency improvement. some techniques of control strategy such as (direct torque control, field oriented control, indirect field oriented control and sliding mode control etc. will be present to improve motor operation.as well this paper will present some techniques for voltage generation used to drive motors, some methods are implemented for this purpose depending upon quasi voltage generation, pulse width modulation, and space vector pulse width modulations etc are also discussed.

Modelling and simulation of self-excited induction generator driven by a wind turbine

Eastern-European Journal of Enterprise Technologies, 2020

The excellent specifications of the isolated squirrel cage self-excited induction generator (SEIG... more The excellent specifications of the isolated squirrel cage self-excited induction generator (SEIG) make it the first choice for use with renewable energy sources. However, poor voltage and frequency regulation (under load and speed perturbations) are the main problems with isolated SEIGs. Wide dependence on the SEIG requires prior knowledge of its behaviour with regard to variations in the input of mechanical power and output of electrical power to develop a control system that is capable of maintaining the voltage and frequency at rated values, as far as possible, with any change in the input or output power of the SEIG. In this paper, a mathematical model of a wind energy conversion system (WECS) based on a squirrel cage SEIG with a generalized impedance control (GIC) was built using the Matlab/ Simulink environment in a d-q stationary reference frame. A fuzzy logic controller (FLC) was used to control the parameters of the GIC. The training of the FLC was conducted by a neural network through Matlab's Neuro-Fuzzy designer. The results of this paper showed that the trained FLC succeeded in controlling the real and reactive power flow between the SEIG and the GIC system, in which the maximum variation for both magnitude and frequency of the generated voltage with any load or wind speed perturbation will not exceed (0.2 %) for the frequency and (3 %) for the voltage magnitude in both directions. The SEIG model was validated by comparing the results obtained with those of wellknown studies with the same rating and operating conditions

A Literature Review on the Unified Power Flow Controller UPFC

International Journal of Computer Applications, 2018

Power electronic controllers for a flexible ac transmission system (FACTS) can offer a greater co... more Power electronic controllers for a flexible ac transmission system (FACTS) can offer a greater control of power flow, secure loading and damping of power system oscillations. A unified power flow controller (UPFC) is a one of FACTS elements that can provide VAR compensation, line impedance control and phase angle shifting. The UPFC consist of two fully controlled inverters, series inverter is connected in series with the transmission line by series transformer, whereas parallel inverter is connected in parallel with the transmission line by parallel transformer. The real and reactive power flow in the transmission line can be controlled by changing the magnitude and phase angle of the injected voltage produced by the series inverter. The basic function of the parallel inverter is to supply the real power demanded by series inverter through the common dc link. The parallel inverter can also generate or absorb controllable reactive power. This paper offers and discusses most papers that used a UPFC to improving the active and reactive power flow of the power systems.

Fuzzy Logic based Power Factor Control of Synchronous Machine

International Journal of Computer Applications, 2018

In this paper, a fuzzy logic technique is used to control the power factor (PF) that compensate t... more In this paper, a fuzzy logic technique is used to control the power factor (PF) that compensate the reactive power of the load by controlling the excitation system of synchronous machine. This fuzzy logic controller can give a fast response compensation to meet the required load reactive power and hence keeping the load bus at constant set point PF value. The V curve of PF is treated in a way to get the flexibility and the limitation the over or under values, as well as time delay could therefore be eliminated with such a control configuration. The results show that fuzzy based power factor controller using synchronous machine is reliable, sensitive, faster and more efficient compare with the other methods such as capacitor groups.

Optimal Power Flow Solution with Maximum Voltage Stability

AL-Rafdain Engineering Journal (AREJ), 2011

This paper presents an Optimal Power Flow (OPF) formulation that is based on multi-objective opti... more This paper presents an Optimal Power Flow (OPF) formulation that is based on multi-objective optimization methodology, which can minimize both of operating costs and losses and it would at same time result in maximizing the distance to voltage collapse. A "Maximum Distance to Voltage Collapse" algorithm, which incorporates constraints on the current operating condition, is firstly presented, while OPF formulations which incorporate voltage stability criteria is secondly presented. The algorithm built on Matlab-Simulink is tested on an IEEE 6-bus test system using a standard power flow model, where the effect of maximum loading point limits is demonstrated.

Bifurcation and Voltage C ollapse in the Electrical Power Systems

AL-Rafdain Engineering Journal (AREJ), 2005

Voltage stability is indeed a dynamic problem. Dynamic analysis is important for a better underst... more Voltage stability is indeed a dynamic problem. Dynamic analysis is important for a better understanding of voltage instability process. In this work an analysis of voltage stability from bifurcation and voltage collapse point of view based on a center manifold voltage collapse model. A static and dynamic load models were used to explain voltage collapse. The basic equations of a simple power system and load used to demonstrate voltage collapse dynamics and bifurcation theory. These equations are also developed in a manner, which is suitable for the Matlab-Simulink application. As a result detection of voltage collapse before it reach the critical collapse point was obtained as original point.

Reactive Power Compensation using Fuzzy Gain Scheduling Controlled STATCOM for Grid Connected PV System

Asian Journal of Research in Social Sciences and Humanities, 2016

Integration of a grid-connected renewable energy system is expected to meet the energy demand of ... more Integration of a grid-connected renewable energy system is expected to meet the energy demand of the grid and reduce the carbon emission thereby global warming. This paper presents a grid-connected photovoltaic (PV) system combined with STATic synchronous COMpensator (STATCOM) that uses Fuzzy Gain Scheduling controller, to improve the grid quality of the power system by reactive power injection from STATCOM to compensate the voltage oscillation and to improve the voltage stability. This paper compares the proposed STATCOM with Fuzzy Gain Scheduling (FGS) controller for the dynamic state voltage oscillation of the PV system with the conventional PI controller for voltage compensation. On testing the proposed system through simulation using MATLAB/Simulink, the proposed model was found to be effective in mitigating voltage sags and swells with improved voltage regulation and power factor.

Power quality improvement using fuzzy logic controller for five-level shunt active power filter under distorted voltage conditions

Frontiers in Energy, 2013

In this paper, a five-level inverter is used as a shunt active power filter (APF), taking advanta... more In this paper, a five-level inverter is used as a shunt active power filter (APF), taking advantages of the multilevel inverter such as low harmonic distortion and reduced switching losses. It is used to compensate reactive power and eliminate harmonics drawn from a thyristor rectifier feeding an inductive load (RL) under distorted voltage conditions. The APF control strategy is based on the use of self-tuning filters (STF) for reference current generation and a fuzzy logic current controller. The use of STF instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the α-β axis without phase locked loop (PLL). The MATLAB fuzzy logic toolbox is used for implementing the fuzzy logic control algorithm. The obtained results show that the proposed shunt APF controller has produced a sinusoidal supply current with low harmonic distortion and in phase with the line voltage.

A New Transient Stability Analysis with Automatic Voltage Regulators, Turbine-Speed Governors, and Saturation Effect via Trapezoidal Method

In this paper, step-by-step Trapezoidal method is applied to a power system to solve the differen... more In this paper, step-by-step Trapezoidal method is applied to a power system to solve the differential equations those relate the actions of the transient stability, in which generators are installed with automatic voltage regulator (AVR), turbine-speed governor (TSG), and the effect of the saturation is also included. The results compare the individual and combined effects of those controllers. Saturation is modeled by two parts, i.e. excitation and generator saturation. The action of the inertia constant on the swing curve is shown in results. List of Symbols Vt = Terminal voltage. Ei&#39; = internal voltage(Ef). X&#39; d = Direct-axis transient reactance. X&#39; ds = Direct-axis transient reactance with saturation effect. X P = Potier reactance. δ = generator rotor angle. V t = generator terminal voltage. Pm = mechanical power. Pe = electrical power. Qe = Reactive power. ω = Speed. K A , KE = Regulator and exciter gain. T A , TE = Regulator and exciter time constant.

A New Model of Representation of Magnetisation Curve

The transformer magnetisation curves are important to power systems under transient operations. C... more The transformer magnetisation curves are important to power systems under transient operations. Conventional methods to determine these characteristics required several analyses. This paper presents simplified model in exponential form to fit the transformer magnetisation curve. The MATLAB computer program is used to determine the constants of the suggested fitting function. The results are compared with that obtained by other results in the literature and showed that the suggested model has good improvement in determining the true linear, knee, and saturation characteristics with a relatively high accuracy.

Modeling & Simulation of Synchronous Machine Controlled By PID Control for The Reactive Power Compensation

This paper present a suitable model set up for the analysis of the synchronous machine. The model... more This paper present a suitable model set up for the analysis of the synchronous machine. The model is then test with some cases such as sudden change in load, field voltage as well as loading or no loading condition. The basic equations of the motor are also developed in a manner, suitable for the Matlab-Simulink application. The computer and practical results were represented and compared. Good agreement between these results has been observed. This proves the validity of the simulation method used in this work. A PID controller for firing angle (alpha) was added to this model to control six-pulse rectifier circuit, which gives variable DC field voltage and this voltage changes as the output of the PID controller changes depending on the set point (reference power factor). The parameters of the PID controller was selected to give high performance for the reactive power control. LIST OF SYMBOLS va,vb and vc = Thee phase terminal voltages (volt). ia,ib and ic = Thee phase terminal current (amper). α= Firing angle (degree). Vf= DC field voltage (volt). If= DC field current (amper). Rf= Resistance of field circuit (ohm). Lff= Self of rotor inductance (henry). La,Lb and Lc= Stator self inductance (static)/ phase (henry). Lab,Lbc and Lca= Mutual inductance between stator Phases (henry). Laf,Lbf and Lcf= mutual inductances between stator phases and rotor (henry). Ls= Part of phase inductance harmonic because of salience (henry). λa, λb and λc= Instantaneous linkage flux for stator phases (Wb). λf = Instantaneous linkage flux for rotor (Wb). [V]= Voltage matrix (volt). [R]= Resistance matrix (ohm). [i]= Current matrix (amper). [λ]=Linkage flux matrix (Wb). [L]= Inductance matrix (henry). Te= Electrical torque (N.m). TL= Mechanical torque (N.m). ωs= Synchronous speed (rpm). ωr= Rotor speed (rpm). θ= Displacement angle for rotor refers to stator phase (a) (rad). Vf =DC field voltge (volt). PL&amp;QL = Real and reactive power load demand respectively (watt, var). Pm&amp;Qm = Real and reactive power of the Synchronous motor respectively (watt, var). Pt&amp;Qt = total Real and reactive power for the Synchronous motor and load demand respectively (watt, var). K p = Proportional gain for the PID control. K I = Integral gain for the PID control. K d = derivative gain for the PID control. Kcr= critical value gain for the PID control which give sustained oscillations output of system.

Adaptive Neuro-Fuzzy Inference System (ANFIS) Real Time Based Power Factor Control By Synchronous Machine

13_Transient Stability Improvement _IJEIT1412201707_03.pdf

— Transient stability is the ability of power system to maintain synchronism when subjected to a ... more — Transient stability is the ability of power system to maintain synchronism when subjected to a severe disturbance such as three phase fault on transmission line or large increase in load or loss of large load as a result of a separation in one of the transmission lines in the system. The energy storage systems represented by Static Var Compensator (SVC) and Solar Photo-voltaic Generator (PVG) are used to improve the transient stability of the power system. It regulates voltage at its terminal by controlling the amount of reactive power injected into or absorbed from power system. In this paper, the ability of energy storage systems to improve the transient stability has been studied. The multi-machine system was studied and IEEE 3-machine 9 bus system is taken as case study. The simulation is carried out using PSAT software. At the beginning the system has been simulated under three phase fault and then under sudden changes in load levels as a result of separation occurs in one of the transmission lines and without energy storage systems. Then energy storage system is installed in the system and its ability to enhance the transient stability has been investigated.

12_Voltage stability margin improving_IJEIT1412201707_04.pdf

—This paper present a method to improving voltage stability margin depending on power transmissio... more —This paper present a method to improving voltage stability margin depending on power transmission paths. Weak buses and lines are determined by using voltage stability indices, some comparison between these indices are made to determined weakest buses, the voltage stability margin is illustrate using the P-V curves and Q-V curves. After defined the weak buses and the degree of stress in each path depending on the indices values, voltage stability marginimprove by two methods. The first one adding a parallel line in the systemwhiles the second one by adding a device to supply only active power, reactive power and complex power. The results on IEEE 30 buses sample system shows extending and improving in the margin of voltage stability. Index Terms—Voltage stability margin, Voltage collapse, voltage stability indices, Matlab-Simulink, P-V curves and Q-V curves.