The impact of initial conditions on the initiation of fundamental frequency ferroresonance is investigated. The investigation is carried out by simulating the behaviour of the mathematical model of ferroresonant circuit realized in the laboratory. The initiation of fundamental frequency ferroresonance is investigated by varying the values of phase angle and amplitude of voltage source in order ...

Thyristors are now widely used in many power electronics and motors drives applications. This is due to their several advantages such as relatively small size, low losses, market availability, and low cost. In this paper, a stator voltage control of three-phase induction motor by using thyristors is analyzed and simulated in details. The stator voltage has been controlled by phase angle control...

A digital moisture measuring instrument based on phase angle measuring technique with porous silicon (PSi) or porous alumina (PA) as capacitive moisture sensor is proposed. The proposed technique can measure digitally the phase angle change of capacitive impedance of porous silicon or porous alumina sensor due to change in moisture concentration in terms of clock pulses. Analysis shows that the...

According to the physical process of discharge development of insulator that is struck by lightning, the lightning flashover model for quadruple-circuit transmission line with dual voltage 220kV/110kV in same tower is established basing on EMTP. The actual evaluation index of lightning protection performance is adopted with the consideration of influence of system voltage. The characteristics o...

We demonstrate a controllable viewing angle liquid crystal display (LCD) using an inserted blue-phase liquid crystal (BPLC) cell. The BPLC layer functions as a tunable positive C-film or a negative C-film, depending on whether the employed LC has a positive or negative dielectric anisotropy. Therefore, the viewing angle of the LCD panel can be controlled continuously by the applied voltage of t...

In future grid codes wind farms will have to fulfill demanding fault ride through requirements. Among several grid faults the voltage swell is a critical event. Wind farms with doubly-fed induction generators will not be able to fulfill the new grid code requirements without additional fault mitigation equipment. In this publication the applicability of the Dynamic Voltage Restorer and the Stat...

Nowadays the control of stator voltage at a constant frequency is one of the traditional and low expense methods in order to control the speed of induction motors near its nominal speed. The torque of induction motor is a nonlinear function of the firing angle, phase angle and speed. In this paper the speed control of induction motor regarding various load torque and under different conditions ...

This paper deals with a medium-voltage distribution network. The feeders in the open-loop arrangement are changed to the closed-loop arrangement with the aim to improve reliability of the power supply. The paper focuses on the analysis of transient and steady-state operation in the closed-loop that is established by connecting feeders supplied from two different transformers located in the same...

one of the main goals of interpretation of gravity data is to detect location and edges of the anomalies. edge detection of gravity anomalies is carried out by different methods. terracing of the data is one of the approaches that help the interpreter to achieve appropriate results of edge detection. this goal becomes a complex task when the gravity anomalies have smooth borders due to gradual ...