Transmission Line

We propose an equivalent circuit representation of the photogenerated charge separation and propagation in dye sensitized polycrystalline semiconductor in contact with a redox electrolyte. The suggested equivalent circuit for this type of photocell is based on an electrical transmission-line, and uses distributed photodiode model for the semiconductor-redox electrolyte interface. It was found that for small signal conditions, diodes can be replaced by equivalent elements, each consisting of a resistor and a capacitor connected in series. The equivalent circuit also provides for Beer-Lambert characteristics of light absorption. The simulation of the transmission line equivalent circuit, subjected to short pulse illumination, allows us to reproduce the experimentally found difference between the photocurrent responses of the photocell to illumination from the electrolyte side, and its response to illumination through the semitransparent back electrode, to which the polycrystalline sem...

A new crosstalk model between two twisted pairs when a mismatch of the wire pairs extremities exist, is proposed. The crosstalk model allows to predict the PSD at the near-end and far-end of the victim line if the PSD of the disturber is known. The model takes any mismatch into account which exists when a line is not terminated with its characteristic impedance. Using the same unbalance assumptions as other authors used with success in the past, analytical expressions are given to calculate the crosstalk.

A simple non-quasi-static small-signal equivalent circuit model is derived for the ideal MOSFET wave equation under the gradual channel approximation. This equivalent circuit represents each Y-parameter by its DC small-signal value shunted by a (trans) capacitor in series with a charging (trans) resistor. A large-signal model for the intrinsic MOSFET is derived by first implementing this RC topology in the

SUMMARY Nowadays, the installed power capacity of Itaipu Power Plant is 14.000 MW, with a energy production around 90.000 GWh per year. This amount of energy makes the plant responsible for the supplying about 23% of Brazil and 90% of Paraguay electricity markets. Another parameter gives an idea of the dimension of the involved systems: only 6% of the energy

Electrical Engineering Department, Technical University of Cluj-Napoca Bartiu Street 26-28, 400027 Cluj-Napoca, Romania E-mail Adina.Racasan@et.utcluj.ro ... Abstract - One of the major goals in designing of the integrated EMI filters is to improve their high-frequency ...

This paper describes the dynamic behaviour of a doubly-fed induction machine, operating with wind turbine. The rotor circuit of the machine consists only of a generator-side converter working under abnormal condition at stator side (fault condition and voltage drop take place in transmission lines of the grid system). The induction machine model is based on the stationary reference frame and the control-unit model is based on the line-voltage oriented reference frame. The generator-side controller provides good decoupling between active and reactive power. A powerful MATLAB/SIMULINK was used for the simulation of the wind energy conversion system of a 4 kW wind generator. The simulation results of the generator side converter show that the speed, torque and the ϕ sin (power factor) can be regulated independently to match the reference signals. The effects of assumed abnormal condition in the grid system are discussed with regard to stator current and rotor current of the induction m...

The series and shunt inductivity introduced by the probe and shorting pin respectively in a single-feed shorted rectangular microstrip antenna has been evaluated theoretically using transmission line method. The proposed structure provides compact dual band operation using single feed mechanism. The input impedance, VSWR, and return loss are calculated theoretically. It is found that the ratio of the resonant frequencies highly depends on the position of shorting pin.

Converting existing AC lines to DC for increasing power transmission has been an interesting topic for scientists, such applications could be managed by conventional converters. Converting AC lines to DC upgrades the power capacity of existing lines up to square root of two. In this paper, a modified converter that would use all three existing AC lines at the same

Abstract:- Flexible AC Transmission (FACTS) devices are installed in the transmission network to divert the power flow, minimize the power losses and to improve the line performance but it has some limitations and drawbacks. Distributed Flexible AC Transmission (D-FACTS) is a improved version of FACTS devices which is used to improve the security and reliability of the network in a cost effective manner. This paper discusses the concept of D-FACTS technology for saving of electrical energy, minimization of losses, reduction of coal consumption and minimization of environmental pollution from thermal power plants. This paper also discusses comparative evaluation of passive and active approaches in design of controllers for transmission line. Analysis also deals with computer simulation for reactances, equivalent voltages required for injection in the transmission line, and number of distributed modules per conductor per kilometre. Computations for saving of coal and associated enviro...

The corrosion of metallic reinforcement is a major threat to aging infrastructure. Prestressed structures such as the bridges built in the early 1950's and 1960's are showing signs of deterioration. The current corrosion detection methods for embedded or encased steel reinforcement suffer from several significant drawbacks. A nondestructive evaluation technique has been developed that is capable of determining the location and severity of corrosion of embedded or encased steel rebar and strands. This technique utilizes time domain reflectometry (TDR). By applying a sensor wire alongside of steel reinforcement (such as a prestressing strand), a transmission line is created. Physical defects of the reinforcement will change the electromagnetic properties of the line. Both analytical models and small-scale laboratory tests have shown that TDR can be effectively utilized to detect, locate and identify the extent of damage in steel reinforcement in this manner. Currently, the TDR...