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This study describes the derivation of an analytical model and simulation for the unified series-shunt compensator (USSC) for investigating power quality in power distribution system. The USSC simulation comprises of two 12-pulse inverters which were connected in series and in shunt with the system. A generalized sinusoidal pulse width modulation (SPWM) switching technique was developed in the proposed controller for fast control action of the USSC. Simulations were carried out using the PSCAD/EMTDC electromagnetic transient programs to examine the performance of the USSC model. Simulation results from the proposed model demonstrated the performance of the USSC and its effectiveness for voltage sag compensation, flicker reduction, voltage unbalance mitigation, power flow control and harmonics elimination. Key words: Unified series-shunt compensator; modeling; simulation; power quality mitigation, INTRODUCTION Power quality issues have been attracting the attention of researches for decade. The increased concern has lead to measuring power quality variations, studying the characteristics of power disturbances and [...]

In this research, a new method based on Singular Value Decomposition (SVD) is proposed to solve the problem of optimal placement of meters for static estimation of harmonic sources in a power system. Also, the Binary Genetic Algorithm (BGA) is used to solve the problem of optimization. IEEE 14-bus test system is provided to validate the measurement placement algorithm. It has been observed that the quality of estimation is improved and the Number of Observable Variable (NOV) is increased. Moreover, the BGA-based meter placement strategy yields the same solution as obtained from the complete enumeration technique but in shorter time. Key words: Harmonic state estimation (HSE), singular value decomposition, optimal meter placement, binary Genetic algorithm (BGA), INTRODUCTION Harmonic distortion has experienced a continuous increase in power systems owing to the growing use of nonlinear loads. Many studies have shown that harmonics may cause serious effects on [...]

The usage of parallel converters is ever increasing. However, the voltage and current harmonics, zero-sequence and negative- sequence components of voltage and current and reactive power present in parallel converters give an alarming signal to power system and power electronic engineers. This research discusses performance of three-phase shunt active power filter (APF) system using three different control techniques namely synchronous detection algorithm (SDM), instantaneous active and reactive (p-q) theory and instantaneous direct and quadrature (d-q) current method for the control of zero and negative sequence components, reactive power and harmonics. The novelty of this research lies in the successful application of SDM based APF and (d-q) current method APF for the control of reactive power, harmonics and negative and zero sequence currents resulted by the use of parallel three-phase converters. MATLAB 6.1 toolbox is used to model the systems. Key words: parallel converters, zero-sequence, negative sequence, SDM, p-q theory, d-q method, INTRODUCTION The usage of parallel converters is increasing due to high reliability, high power, distributed power, high performance and enabling technology for emerging applications (1). However the presence of zero-sequence [...]

Active power filters have been widely used for harmonic elimination. The performance of a conventional three-phase shunt Active Power Filter (APF) using Synchronous Detection Method (SDM) has been compared with Nonlinear Autoregressive-Moving Average (NARMA)-L2 based APF. The novelty of this study lies in the application of NARMA-L2 control to generate the amplitude of the reference supply current required by the APF circuit and the successful implementation of the APF system for harmonic elimination. The entire system has been modeled using MATLAB 6.1 toolbox. Simulation results demonstrate the applicability of NARMA-L2 controller for the control of APF. Key words: APF, NARMA-L2, VSI, harmonics, THD, SDM, power quality, INTRODUCTION Power Quality (PQ) is an important measure of an electrical power system. The term PQ means to maintain purely sinusoidal current wave form in phase with a purely sinusoidal [...]

Power quality is an important measure of the performance of an electrical power system. This paper discusses the topology, control strategies using artificial intelligent based controllers and the performance of a unified power quality conditioner for power quality improvement. UPQC is an integration of shunt and series compensation to limit the harmonic contamination within 5 %, the limit imposed by IEEE-519 standard. The novelty of this paper lies in the application of neural network control algorithms such as model reference control and Nonlinear Autoregressive-Moving Average (NARMA)-L2 control to generate switching signals for the series compensator of the UPQC system. The entire system has been modeled using MATLAB 7.0 toolbox. Simulation results demonstrate the applicability of MRC and NARMA-L2 controllers for the control of UPQC. Key words: APF, MRC, NARMA-L2, VSI, DVR, INTRODUCTION The better controllability, higher efficiency, higher current carrying capability, and fast switching characteristics of static power converters are promoting major changes in controlling the power flow of transmission and [...]

A program for handling and improving the transient stability of the Iraqi Super Grid electrical network was developed. The idea was demonstrated by applying it to the outages of the main generating units. The methodology was built upon a state of increasing power transfer through the healthy portion of network during disturbances. There were three parts concerned; the first part was the developing of the load flow program using fast decoupled method and the transient stability program using Modified Euler's method in the step by step solution, the second part was the engagement between the two programs, the third part was the application of the new program on the Iraqi supper grid network (400 kV). Keywords: Power flow, transient stability, Modified Euler's method, Iraqi supper grid network, INTRODUCTION Due to increased power transactions between various power systems and due to continuing postponement of transmission reinforcements, power systems are being operated closer to their lower secure limits. This [...]

Abstract: An important consideration when evaluating the impact of harmonics is their effect on power system component and loads. Transformers are major components in power systems. The increased losses due [...]

Abstract: This paper describes results of an investigation of the variation of power loss, building factor, flux leakage and flux distribution in 3-phase model transformer cores assembled from various type [...]