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This paper proposes and demonstrates a novel wide dynamic range rectifier. The proposed rectifier consists of two rectifying circuits in parallel, an asymmetrical output impedance power divider for RF input signal, and a DC combiner. The asymmetric power divider sequentially distributes the RF signal to the rectifier for high input power from the rectifier for low input power without switch devices,...
In this paper, the relationship between real and reactive power sharing in islanded microgrid considering the complex impedance effect is analyzed. It is determined that traditional droop control has drawbacks in achieving accurate power sharing caused by the mismatched feeder line effect. In order to enhance the power sharing accuracy, an adaptive droop control using virtual impedance for islanded...
This paper proposes and demonstrates a novel wide dynamic range rectifier. The proposed rectifier consists of two rectifying circuits in parallel, an asymmetrical output impedance power divider for RF input signal, and a DC combiner. The asymmetric power divider sequentially distributes the RF signal to the rectifier for high input power from the rectifier for low input power without switch devices,...
Supercapacitor is a new type of energy storage element, and its performance is easily influenced by temperature. In order to have more precise energy storage characteristic research of supercapacitor, a modified porous circuit equivalent model is proposed on the basis of porous circuit equivalent model in electric double layer supercapacitor. The simulation results show that modified porous circuit...
Because the fault characteristics are not obvious and the detection is difficult, the high impedance fault is always the difficulty of the distribution network fault identification. According to the actual situation of power grid, the current signal at each measurement point in the line is selected to be a measured one, and the corresponding complex sequence current and zero sequence current are obtained...
Operation of two-coil inductive power transfer (IPX) system is affected by bifurcation phenomenon. In this paper, bifurcation in dependency on resonance frequency is examined. At first, voltage equations are analyzed, and impedance and transfer function derived. In next step, condition for resonance frequency is stated, which is followed by bifurcation analysis. Resulting bifurcation map is analytically...
Updating current swell for each feeder is one of stage of fault localization considering impedance based method. Estimation formula was adopted based on impedance line and load value. This paper investigate the impact of single and paralel impedance load to the accuracy of current swell estimation in the each feeder. Three Phase to ground fault (LLLGF) was simulated using the PSCAD simulation program...
For Medium Voltage DC (MVDC) power systems, we greatly extend the coverage of local-information-based fault protection (LIFP), an approach defined for independent distributed management of short-circuit line-to-line faults that does not rely on any high-speed ship-wide communications, to arc faults under varying load conditions. The method for LIFP was previously developed for systems where all loads...
This paper introduces the realization and calibration of complex impedance standard which is a kind of active simulation impedance. As a new calibration equipment for digital bridge, complex impedance standard can simulate any amplitude or angle of complex impedance by generating voltage and current to calibrate digital bridge in the whole complex plane, which can make up for deficiency in the calibration...
Operation of two-coil inductive power transfer (IPX) is affected by the bifurcation phenomenon. So far, its dependence on primary and secondary quality factors was examined. However, similar dependencies exist for coupling coefficient and resonance frequency. In this paper, these dependencies and their mutual relationships are examined. This analysis is based on the normalized impedance approach and...
Inverters in voltage control mode including droop control and virtual synchronous generator (VSG) are promising for interconnecting the renewable energy to the grid, which are both emulating the frequency and voltage regulating functions of synchronous generators through droop method. However, improper transient impact current and reactive power output are observed for inverters in voltage control...
In this paper, the evaluation of the concept of impedance differential scheme for long transmission line protection is presented. Using the voltages and currents of both line ends, the differential impedance is calculated. Capacitive charging current which constitutes the main drawback of current differential protection is eliminated in presented protection method. What is more, the advantage of presented...
Mho elements constitute the main component of transmission line protection in North America and many countries overseas. Distance elements based on incremental quantities and derived from the same base equations as mho elements emerged about two decades ago as a way to improve the speed of distance elements. This paper compares the intrinsic protective properties of mho and incremental distance elements,...
This paper reports on flexible, transparent, conductive films, which consist of poly-(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) spun onto indium-tin-oxide (ITO) substrates for potential applications in biomedical optoelectronic devices. The properties of the combined films are characterized using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron...
This paper deals with studying the behavior of a photovoltaic (PV) array in faulty conditions. In this context, the authors propose a new approach offering a good evaluation of the PV array performances under progressive faults. The approach implemented in Matlab/Simulink, is based on the analysis of anomalies shown in current-voltage (I-V) and power-voltage (P-V) characteristics, which are obtained...
A new approach of the iterative method WCIP (Wave Concept Iterative Process) using the technique of the auxiliary sources considers a pixel or a unit cell in a periodic structure as an electrical circuit instead of a sub-domain representing metal or dielectric in the classical iterative method. The intersection of this new approach with the old is on the application of the iterative process in waves...
This paper proposes an accurate fault location method for underground power cable in power distribution systems. The cable is modelled using PSCAD EMTP simulation tool. The cable core as well as sheath and various grounding modes were considered in the cable modelling. The algorithm uses voltage and current measurements recorded at the terminal where the fault locator is placed. The simulation studies...
This paper introduces a fault localization algorithm for 66/132 kV electric power sub-transmission lines. The fault locator utilizes voltage and current phasors from Disturbance Fault Recorders (DFR) at sending end terminal of the transmission line. The proposed method has been proved for accuracy under different system as well as fault conditions using EMTP/PSCAD simulations. Further, the algorithm...
Most of the existing overhead transmission lines are operated in parallel configuration. These transmission lines are protected by the distance protection scheme with the help of distance relays. The impedances measured by the distance relay are affected by the mutual coupling between the lines and the fault resistances. In this paper, the impact of mutual impedance between parallel transmission lines...
In this paper, a modelling method of a 25 kV-50 Hz railway line, in a frequency range from 0 to 5 kHz, is presented. A model is proposed to quantity current and voltage harmonics generated by traction converters in different points of the network. An equivalent circuit, taking into account the skin effect for time-domain simulations, is also proposed. A new model, based on state space representation...
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