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This paper highlights the importance of assessing Power Quality (PQ) of microgrids using the recommended indices as stated in IEEE 519 and IEEE 1547 standards. It assesses the microgrid PQ by verifying if converter harmonics at the Point of Common Coupling (PCC) to the grid complies or exceeds the IEEE 519 standard on harmonic limit.
The TLM simulation of the slow-varying envelope of a carrier wave using the principle of dynamic phasors enables the TLM cell size to greatly exceed the normal λ/10 restriction. The TLM equivalent circuit necessary to simulate dynamic phasor propagation is described. Example results showing the performance of the technique for solving fundamental problems such as lossy propagation or the simulation...
Cognitive Radio (CR) dynamically finds the spectrum opportunity i.e. spectrum hole in space-time-frequency and code to do its adaptive transmission without harming the incumbent or the Primary User (PU). TV white spaces (TVWS) are the unused or underutiliised bands in the UHF and VHF part of the band which according to Federal Communication Commission (FCC) can be exploited if the secondary user (SU)...
Operational uncertainties such as variation of power or grid impedance affect the level of conducted emission of power converters in renewable energy systems. This paper utilizes an enhanced Unscented Transform (UT) method based on dimension reduction technique to predict the conducted emissions of multiple Voltage Source Converters (VSCs) in the presence of uncertainties. The accuracy of the predicted...
Various types of power converters including Voltage Source Converters (VSCs) have been known to produce conducted emissions. The net effect of simultaneously operating multiple VSCs is non-linear and this makes the prediction of the emission level more difficult. This paper presents an efficient method that can be used to predict conducted emissions of multiple VSCs in the presence of various uncertainties...
In full field CEM analysis the maximum frequency obtained is commonly imposed by a dispersion (phase accuracy) criterion. Thus very large computational resources are required in order to analyse problems many wavelengths long. In this work we demonstrate an approach through the application of frequency scaling that allows the usable bandwidth for over-moded problems to be extended past the traditionally...
A procedure is described which allows the wideband characterisation of shielded cables in a form suitable for direct implementation within time domain CEM modelling techniques such as TLM or FDTD. The process is based on the solution of an inverse problem.
The more-electric aircraft concept is a fast-developing trend in modern aircraft power systems and will result in an increase in electrical loads fed by power electronic converters. Finalizing the architectural bus paradigm for the next generation of more-electric aircraft involves extensive simulations ensuring power system integrity. Since the possible number of loads in an on-board power system...
This paper presents a dynamic phasor model of the autotransformer rectifier unit (ATRU) for the more-electric aircraft power system study. This model considerably reduces the complexity in modeling of an aircraft power system making it more practical to model the electrical power system for transient and stability analysis. The developed phasor model of the ATRU is based on the development of a non-switching...
In this paper the crosstalk between two parallel coaxial cables is investigated. It is shown that the degree of coupling is strongly effected by the geometry of the system. In many practical situations the geometry of the cable routing is ill-defined so that an exact deterministic solution is not possible or helpful. A simple solution based on the first resonant frequency is proposed which can also...
Using system identification techniques, a wide band model is developed of a typical epoxy laminate material often used as the substrate in printed circuit boards (printed wiring boards). The model is expressed in the frequency-domain using a set of Debye poles. The model is then incorporated in a time-domain electromagnetic simulation code and validated by the consideration of the scattering properties...
The effectiveness of a grounding system is highly dependent on several parameters such as its size, i.e. the length of the ground conductor, the electrical characteristics of the ground conductor and its surrounding soil. A single long horizontal ground conductor being a basic configuration of a grounding system could act as a path for the transient currents to be easily and effectively dissipated...
Time-domain electromagnetic simulations employing unstructured tetrahedral meshes can be sensitive to local mesh characteristics. In particular, the maximum permissible time step for stable operation can be unacceptably small. In this paper, a cell clustering technique is described for the transmission line modeling algorithm that reduces the sensitivity to local mesh characteristics and permits substantial...
This paper presents the small-signal stability analysis of AC-DC power system taking into account dynamics of electromechanical actuator (EMA). A dq modelling method is employed to predict unstable operation caused by possible variations in operating points and/or system parameters. The obtained theoretical results are supported by intensive simulations and verified experimentally.
This study is carried out to determine a suitable excitation source that can be used to model the lightning return stroke on a single long horizontal ground conductor. It is used to determine the fastest results obtained for the transient response of a single long horizontal ground conductor and for computation efficiency purposes. In this study, three various excitation sources are used and been...
This paper proposes a new protection scheme for marine power systems (MPS). The scheme exploits the increased use of power electronic devices to provide a useful complement to traditional protection strategies which can also provide the necessary back up protection during extreme protection failure, without the need for communication channels. The scheme is described for an AC zonal Advanced Power...
The knowledge of the parameter values of a power network is very valuable for power system modelling, simulation, protection and control since it is a fundamental parameter for solving many problems such as minimizing the effect of voltage distortion, active filter control or relay setting. The electrical parameters in a power network are usually unknown or poorly quantified and can not be measured...
In this paper a technique for analysing aircraft frequency wild power systems with constant power loads is developed and demonstrated. Power electronic based loads often behave as constant power loads, especially when feeding machine or actuator drives under current and speed control. The constant power (CP) loads can affect the stability of the power system. The problem is a particular issue in aircraft...
The use of unscented transforms UT for the statistical analysis of nonlinear linear problems is described. The UT methodology is then applied to the analysis of wire coupling within an enclosure which is a typical problem encountered in EMC studies. The UT results are compared with the more traditional Monte Carlo approach. It is demonstrated that UT is a powerful technique that can greatly improve...
This paper presents the effect on radiated power measured at the GTEM output port if the phase between the radiating dipole moments of the EUT is altered in steps from -180 degree to +170 degree. In current practice it is often assumed that the phase difference between dipole moments does not change the power measured at the GTEM output port. The results from this work disprove this assumption. Results...
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