Hussain Shareef | Universiti Kebangsaan Malaysia (original) (raw)

Papers by Hussain Shareef

This paper presents a new DVR design and a control mechanism to minimize active power injection a... more This paper presents a new DVR design and a control mechanism to minimize active power injection and forced the load voltage to be in phase with grid voltage during the sag, swell and short outage for the non linear load. The control technique incorporates a short time delay and mitigates the harmonic distortion during the charging of the energy storage capacitor. The new design is based on two continuous vector control. It extracts the fundamental components of the measured voltage and current using a 12 switch inverter connected in parallel to improve the time response. The proposed control method is tested on an 11 kV distribution system. Photovoltaic source with a boost converter is included to support the DC source during voltage sag. It shows that the proposed method improve the in-phase compensation technique, minimum active power and response for nonlinear loads. Nomenclature V th Source voltage I L Load current V L Load voltage Z th Thevenin equivalent system impedance V 1 Faulted supply voltage vector Angle of DVR Angle of Z th Angle of V th Angle of load power factor P in Supply input power P out Load power a,b,c Three phase source voltage K p

Power System Stabilizers (PSSs) are the most well-known and efficient devices to damp the power s... more Power System Stabilizers (PSSs) are the most well-known and efficient devices to damp the power system oscillations caused by interruptions. This paper introduces a novel algorithm to determine the PSS parameters, using the multi-objective optimization approach called particle swarm optimization with the passive congregation (PSOPC). The tuning of the PSS parameters is usually formulated as the objective function with constraints, including the damping ratio and damping factor. Maximization of the damping factor and the damping ratio of power system modes are taken as the goals or two objective functions, when designing the PSS parameters. The optimization procedure handles the problem-specific constraints using a penalty function. This could enhance the diversity of the swarm and lead to a better outcome. The two-area multi-machine power system, under a wide range of system configurations and operation conditions is investigated, to illustrate the performance of the proposed approach. In this paper, the performance of the proposed PSOPC is compared to the Standard Particle Swarm Optimization (SPSO) and Genetic Algorithm (GA) in terms of parameter accuracy and computational time. The results verify that, the PSOPC is a much better optimization technique, in terms of accuracy and convergence, compared to PSO and GA. Furthermore, nonlinear simulation and eigenvalue analysis based results also confirm the efficiency of the proposed technique.

In this paper, a hybrid optimization technique is presented to solve the well-known problem of t... more In this paper, a hybrid optimization technique is presented to solve the well-known problem of tuning power system stabilizers' (PSSs) parameters. The hybrid technique is derived from particle swarm optimization (PSO) by adding the passive congregation model. The tuning of the PSS parameters is formulated as the multi-objective function with constraints including the damping ratio and damping factor. Maximizations of the damping factor and the damping ratio of power system modes are taken as the goals or two objective functions, when designing the PSS parameters. The New England 16-unit 68-bus standard power system, under various system configurations and operation conditions, is employed to illustrate the performance of the proposed method. The results are very encouraging and suggest that the proposed PSO with passive Congregation (PSOPC) algorithm is very efficient in damping low frequency oscillations and improving the stability of power system.

Capacitors are used to provide reactive power compensation in distribution networks and are widel... more Capacitors are used to provide reactive power compensation in distribution networks and are widely used to reduce power loss, improve voltage profile and increase system capacity. The benefits of reactive power compensation depend greatly on the placement and size of the added capacitors. Presently, the capacitor placement problem is widely solved by using evolutionary programming methods. In this paper, an improved harmony search (IHS) algorithm is applied to solve the optimal capacitor placement problem. The performance of the proposed IHS algorithm is validated on the 9-bus distribution system. The obtained capacitor placement results using the IHS algorithm are compared with the particle swarm optimization and the traditional harmony search algorithm.

Distributed generations (DGs) have been increasingly connected on the distribution networks that ... more Distributed generations (DGs) have been increasingly connected on the distribution networks that will have the unfavorable impact on the traditional protection methods because the distribution system is no longer radial in nature and is not supplied by a single main power source. This paper presents a new automated protection method using radial basis function neural network (RBFNN) for a distribution system with DG units. In the proposed method, the fault type is determined first by normalizing the fault currents of the main source. For implementing fault location considering various types of faults, two staged RBFNNs have been developed. The first RBFNN is used for determining the fault distance from each power source and the second RBFNN is used for identifying the faulty line. To isolate the fault, another RBFNN has been developed for determining which circuit breakers (CBs) that must be open or close. Several case studies have been made to verify the accuracy of the method to specify the fault location and protection of the system in distribution networks with DGs. The predicted results showed that the proposed RBFNN based protection method can accurately determine the location of faults and isolate the faulted line in the test power system.

Lighting accounts for roughly one-fifth of all global electricity consumption, yet the major shar... more Lighting accounts for roughly one-fifth of all global electricity consumption, yet the major share of this energy is emitted not as light but as radiated heat from inefficient bulbs. Compact fluorescent Lights (CFLs) were the initial substitute for incandescent bulbs, but certain characteristics of CFLs, light emitting diodes (LEDs) will be used dramatically in the next few years because of its low energy consumption and long life. This paper presents a survey of literature on the light (LEDs) as energy efficient light bulbs due to their high efficiency. The literature shows an increasing interest in this subject for the last decade, where the enhancement of LED lighting systems using various controllers has been widely investigated. Several technical issues related to thermal properties and LED array configurations have been highlighted. Moreover, some of the developments in LED driver technology have been summarized.

This paper proposes a novel optimization technique for simultaneous coordinated designing of powe... more This paper proposes a novel optimization technique for simultaneous coordinated designing of power system stabilizer (PSS) and static VAR compensator (SVC) as a damping controller in the multi-machine power system. PSO and chaos theory is hybridized to form a chaotic PSO (CPSO), which reasonably combines the population-based evolutionary searching ability of PSO and chaotic searching behavior. The coordinated design problem of PSS and SVC controllers over a wide range of loading conditions are formulated as a multi-objective optimization problem which is the aggregation of the two objectives related to the damping ratio and damping factor. The proposed damping controllers are tested on a weakly connected power system. The effectiveness of the proposed controllers is demonstrated through the eigenvalue analysis and nonlinear time-domain simulation. The results of these studies show that the proposed coordinated controllers have an excellent capability in damping power system interarea oscillations and enhance greatly the dynamic stability of the power system. Moreover, it is superior to both the manually coordinated stabilizers of the PSS and the SVC damping controller.

Power consumers are always expecting quality and continuous electric supply from utilities in ord... more Power consumers are always expecting quality and continuous electric supply from utilities in order to prevent financial losses. Therefore, utilities have to provide high quality and reliableelectric power supply. For this purpose, an accurate and fast fault diagnosis in distribution systems should be provided to reduce the customer average interruption duration index. This paper presents an intelligent technique for fast and accurate fault diagnosis of power distribution systems. The fault diagnosis functions include correct fault type classification, precise fault location, accurate identification of faulty protection devices and current operation status of protection devices in a distribution system. To determine fault types and fault points, the proposed intelligent technique uses post-fault three-phase root-mean-square currents to train the Sugeno-type parallel-series adaptive neuro-fuzzy inference system (ANFIS). Meanwhile, the current operating status of protection devices are presented as binary ones or zeros by ANFIS prediction using fault point geometrical coordinates. The simulation results show that the technique has an average maximum percentage error of 0.02% for predicting the type of faults and 2.8% in determining the fault points. Average maximum errors of 0.053 and 0.182 were obtained for operating status of main and back up protection devices, respectively. The proposed technique is validated through simulations using the PSS-ADEPT commercial software package. The results showed thatthe Sugeno-type ANFIS approach provides fast and precise fault diagnosis that can be implemented in a distribution network.

This paper proposes a new method to trace the transmission loss in deregulated power system by in... more This paper proposes a new method to trace the transmission loss in deregulated power system by incorporating the Genetic Algorithm (GA) and Least Squares Support Vector Machine (LS-SVM). The idea is to use GA to find the optimal values of hyper-parameters of LS-SVM and adopts a supervised learning approach to train the LS-SVM model. The proportional sharing method (PSM) is proposed to trace the transmission loss at each transmission line which is then utilized as a teacher in the proposed hybrid technique called GA-SVM method. Based on load profile as inputs and PSM output for transmission loss allocation, the GA-SVM model is expected to learn which generators are responsible for transmission losses. In this paper, 4-bus system and IEEE 14-bus system are used to show the effectiveness of the proposed method.

The connection of distributed generators (DGs) to distribution networks greatly influences the p... more The connection of distributed generators (DGs) to distribution networks greatly influences the performance and stability of such networks. Though DGs have significant economic and environmental benefits, increased penetration of DGs will impose significant technical barriers for the efficient and effective operation of bulk power systems. Increased fault current contribution and load flow changes are the major two impacts on utility systems, and these will affect existing protective relaying, especially overcurrent relays. To ensure safe and selective protection relay coordination, the impact of DGs should be taken into account when planning DG interconnection. This paper presents an introduction of distributed generators and an overview of the effects of DGs on system protection relay coordination, particularly in cases where DGs are added to a distribution feeder.

This paper presents the application of the improved harmony search (IHS) algorithm for determinin... more This paper presents the application of the improved harmony search (IHS) algorithm for determining the optimal location and sizing of static Var compensator (SVC) to improve the voltage profile and reduce system power losses. A multi-criterion objective function comprising of both operational objectives and investment costs is considered. The results on the 57-bust test system showed that the IHS algorithm give lower power loss and better voltage improvement compared to the particle swarm optimization method in solving the SVC placement and sizing problem. Streszczenie. Artykuł przedstawia zastosowanie algorytmu IHS (Improved harmony search) do określania optymalnej lokalizacji kompensatora mocy biernej. Rezultaty testów wykazały że algorytm zapenia mniejsze straty mocy oraz zniekształcenia w porównaniu do innych metod optymalizacji. (Optymalizacja lokalizacji kompensatora mocy biernej z wykorzystaniem algorytmu IHS) Introduction Flexible AC transmission system (FACTS) can provide benefits in increasing system transmission capacity and power flow control flexibility and rapidity [1]. FACTS devices are power electronic converters that have the capability of controlling various electrical parameters in transmission circuits, facilities, both in steady state power flow and dynamic stability control. These devices include thyristor controlled series compensator, static Var compensator (SVC), unified power flow controller, static compensator (STATCOM), etc [2]. The most widely used shunt FACTS devices within power networks is the SVC due to its low cost and good performance in system enhancement. It is a shunt-connected static Var generator or absorber whose output is adjusted to exchange capacitive or inductive current so as to provide voltage support and when installed in a proper location, it can also reduce power losses. Many methods and approaches have been reported in the literature to determine the optimal location of SVC in the power system using different techniques such as genetic algorithm (GA), simulated annealing (SA), artificial immune system (AIS) and particle swarm optimization (PSO) [3, 4]. A solution algorithm based on SA is used to determine the location, types and sizes of Var sources and their settings at different loading conditions [5]. The purchase cost, the installation cost and the total cost of energy loss over the life of the Var sources, are minimized considering operational constraints [5]. In [6], GA is applied to determine the best location of only one SVC within a power system in which the objective function is defined for reducing power loss, voltage deviation and cost. An AIS technique is used to minimize the total loss and improve the voltage in a power system [7] by determining the correct placement of SVC. The well known PSO is explored in [8] to obtain optimal locations of SVCs in the IEEE 30 bus system. This paper presents a relatively new optimization technique known as the improved harmony search (IHS) algorithm for finding optimal placement and sizing of SVC in power systems. The harmony search algorithm is a meta-heuristic optimization method that is inspired by musicians in improvising their instrument pitches to find better harmony [8]. It has several advantages in which it does not require initial value settings for the decision variables and it can handle both discrete and continuous variables. Harmony search algorithm has been successfully applied to solve optimal placement of FACTS devices to improve power system security [9]. In this paper, the IHS algorithm is applied to determine the optimal placement of five SVCs for voltage profile improvement and power loss reduction in a 57-bus test system. The obtained results using the IHS algorithm are then compared with the PSO optimization method for validation.

This paper proposes an adaptive neurofuzzy interface system (ANFIS) approach to identify the rea... more This paper proposes an adaptive neurofuzzy interface system (ANFIS) approach to
identify the real power transfer between generators. Based on solved load flow
results, it first uses modified nodal equation method (MNE) to determine real
power contribution from each generator to loads. Then the results of MNE method
and load flow information are utilized to train the designed ANFIS. It also
incorporated an enhanced feature extraction method called principle component
analysis (PCA) to reduce the input features to the ANFIS. The 25-bus equivalent
system of south Malaysia is utilized as a test system to illustrate the
effectiveness of the ANFIS output compared to that of the MNE method. The ANFIS
output provides promising results in terms of accuracy and computation time.
Furthermore, it can be concluded that the ANFIS with enhanced feature extraction
method reduces the time taken to train the ANFIS without affecting the accuracy
of the results.

Voltage sags have emerged as one of the most serious power quality problems, particularly for se... more Voltage sags have emerged as one of the most serious power quality problems, particularly for sensitive loads. This paper presents the results of a study on the effects of voltage sags on selected equipmentsin the context of the local Malaysian power distribution system. Extensive tests were performed on three categories of equipment sensitive to voltage sags namely, personal computers (PCs), fluorescent lamps (FLs) and ac contactors. For a predefined malfunction criterion, sag depth and duration were varied to construct individual voltage immunity curves for each test sample. The effect of point on wave of sag initiation on contactors was also studied. The predefined malfunction criterion for PCs, FLs and ac contactors are standard reboot, zero luminance and contact disengagement condition, respectively. For each category of equipment, a generic voltage tolerance curve was developed in order to compare with the common industry standards such as the SEMI F47. Test results show that the PCs used in the local distribution have relatively high tolerance level while lamps and contactors show similar voltage immunity levels that were reported in earlier studies.

This paper presents an overview of solutions proposed in the literature for the overcurrent rela... more This paper presents an overview of solutions proposed in the literature for the overcurrent relay coordination problem in the presence of distributed generators (DGs). Furthermore, several protection issues are identified to study the requirements for protection in the presence of DGs, and possible innovative solutions for resolving the operational conflicts between distribution networks and DGs are also discussed.

This paper presents a new dynamic voltage restorer (DVR) design and a control mechanism to improv... more This paper presents a new dynamic voltage restorer (DVR) design and a control mechanism to improve the DVR performance compared to the conventional DVRs. The new design is based on two continuous-vector control. It extracts the fundamental components of the measured voltage and current using 12 switches 6-pulses inverter, unlike the DVRs that uses 6 pulses, 12 pulses and 24 pulses, to improve the response and reduced the harmonic distortion. The proposed control method is tested on an 11 kV distribution system. Photovoltaic source with a boost converter is also included to support the DC source during voltage sag. It shows that the proposed method improve the in-phase compensation technique and improved the time response for nonlinear loads. PSCAD/ EMTDC simulation verifies the validity of the proposed technique.

The aim of deregulation in the electric power industry is to optimize the system welfare, by intr... more The aim of deregulation in the electric power industry is to optimize the system welfare, by introducing competitive environment, mainly among the suppliers. Developing fair and equitable real and reactive power allocation method has been an active topic of research. This book suggests current methodologies to allocate real and reactive power output of individual generators to system loads and flows. Allocation procedures presented can be used independently in deregulated power system. The choice of the chosen algorithm depends on their limitations and suitability. The advantages of various mythologies are demonstrated on commonly used test systems. The new methodologies provide better reliability and minimize the limitations of conventional methods. The presented methods could be used by independent system operators and engineers to resolve some of the difficult real and reactive power pricing and costing issues and to ensure fairness and transparency in the deregulated environment of power system. Furthermore, the ideas developed in the book can be utilized for educational and research purpose such as loss allocation and congestion management in deregulated power systems.

Protective relay maloperation due to overload and power swing is believed to be one of the contr... more Protective relay maloperation due to overload and power swing is believed to be one of the contributing factors in major blackouts in the world. Most of the problems are associated with relays tripping too many healthy lines which are due to inadequate real time diagnostic support for verifying the correctness of relay operation. Therefore, there is a need for real-time monitoring tools equipped with new adaptive
distance protection algorithms to help prevent relay maloperation during voltage collapse and power swings. The objectives of the research are to develop new techniques for preventing undesirable distance relay maloperation during voltage collapse and power swings in transmission grids. The initial work carried out in this research focuses on the development of a mathematical model of the zone 3 distance
relay with adaptive protection features. To prevent distance relay tripping during voltage collapse, a new adaptive algorithm has been developed by using indicators such as the rate of change of voltage (dV/dt) and the voltage stability index (VSI).
Another new adaptive algorithm is also developed to block distance relay false tripping signals during power swings and unblocks the signals if a fault occurs during power swings. The derivative of line reactive power (dQline/dt) as seen by a relay is
used as additional criteria in the proposed blocking scheme. To address the need for fast detection of voltage collapse and a three phase fault at transmission lines, a new scheme is proposed by using under impedance fault detector (UIFD) and support vector machine (SVM). Likewise, an intelligent approach is developed to discriminate a fault, stable swing and unstable swing for correct distance relay operation by using
the the S-transform and the probabilistic neural network (PNN). To illustrate the effectiveness of the proposed techniques, simulations were carried out on the IEEE 39
bus and a practical test system using the PSS/E and MATLAB software. Test results of adaptive setting of zone 3 distance relay show that the combined use of dV/dt and
VSI is proven to effectively block the trip signals during voltage collapse compared to the use of only the dV/dt or dV/dt with the system status indicator (SSI). The results of the algorithm for blocking distance relay tripping signals during power swings
show that the dQline/dt can effectively differentiate a fault, fault clearance and power swing unlike the conventional power swing detector which uses the rate of change of power angle. The performance of SVM in detecting and classifying three phase fault and voltage collapse is better than the PNN, in which the accuracy of the SVM is 99.05%. Test results show that the PNN gives an overall classification accuracy of 97.33% in which it performs better than the multi layer perceptron neural network (MLPNN) in detecting and classifying unstable swing, stable swing, fault, fault clearance and post fault events. Such fast and accurate intelligent detection schemes are useful for preventing distance relay from tripping during voltage collapse and power swing.

In this book, harmonic source localization methods have been developed by considering two method... more In this book, harmonic source localization methods have been developed by considering two methods. The first method consider a single point measurement strategy for locating dominant harmonic source by determining the harmonic contributions of utility and customer at a based on a Norton equivalent circuit for simplifying the system under study, and modelling the customer load with parallel RLC components using the measured harmonic voltage and current at the PCC. While, the second method considers a multiple point measurement strategy for locating multiple harmonic sources in a distribution system using independent component analysis (ICA) and mutual information theory (MI). in this method, ICA is used for reconstructing the magnitude of the injected harmonic current caused by harmonic sources while MI is applied for determining the exact location of harmonic source based on the reconstructed harmonic currents.