Showing 3 results for Voltage Sag
M. Aliakbar-Golkar, Y. Raisee-Gahrooyi,
Volume 4, Issue 4 (12-2008)
Abstract
This paper compares fault position and Monte Carlo methods as the most
common methods in stochastic assessment of voltage sags. To compare their abilities,
symmetrical and unsymmetrical faults with different probability distribution of fault
positions along the lines are applied in a test system. The voltage sag magnitude in different
nodes of test system is calculated. The problem with these two methods is that they require
unknown number of iteration in Monte Carlo Method and number of fault position to
converge to an acceptable solution. This paper proposes a method based on characteristic
behavior of Monte Carlo simulations for determination required number of iteration in
Monte Carlo method.
H. Fallah Khoshkar, A. Doroudi, M. Mohebbi,
Volume 10, Issue 4 (12-2014)
Abstract
This paper studies the effects of symmetrical voltage sags on the operational characteristics of a Permanent Magnet Synchronous Motor (PMSM) by Finite Element Method (FEM). Voltage sags may cause high torque pulsations which can damage the shaft or equipment connected to the motor. By recognizing the critical voltage sags, sags that produce hazardous torque variations could be prevented. Simulations results will be provided and the critical voltage sags are recognized. A simple theoretical analysis will also be presented to obtain a qualitative understanding of the phenomena occurring in PMSM during symmetrical voltage sags
E. Babaei, M. R. Farzinnia,
Volume 12, Issue 1 (3-2016)
Abstract
In this paper, a new topology for Interline Dynamic Voltage Restorer (IDVR) is proposed. This topology contains two direct three-phase converters which have been connected together by a common fictitious dc-link. According to the kind of the disturbances, both of the converters can be employed as a rectifier or inverter. The converters receive the required compensation energy from the gird through the direct link which is provided by the dual-proposed switches. Due to the lack of the huge storage elements, the practical prototype of the proposed topology is more economical in comparison with the traditional structure. Moreover, compensating for long time duration is possible due to the unlimited eternal energy which is provided from the grids. The low volume, cost and weight are the additional features of the proposed topology in comparison with traditional types. This topology is capable to compensate both of the balanced and unbalanced disturbances. Furthermore, restoring the deep sags and power outages will be possible with the support from the other grid. Unlike the conventional topologies, the capability of compensation is independent from the power flow and the power factor of each grid. The performance of the proposed IDVR topology is validated by computer simulation with PSCAD/EMTDC software.
