Power quality issues have been a source of major concern in recent years due to extensive use of power electronic devices and non-linear loads in electrical power system. In power systems the common disturbances are voltage sags and swells, usually associated with power system faults. Therefore the effective detection of voltage sags and swells event is an important issue for both voltage sag a...

This study presents optimal placement of voltage sag monitors based on new Sag Occurrence Index (SOI) which ensures observability even in case of monitor failure or line outages. Multiple solutions for optimal placement of voltage sag monitors for voltage sag detection have been obtained by genetic algorithm approach such that observability of the whole system is guaranteed. A new Sag Occurrenc...

Voltage sag is the major power quality problem and receives wide attention. Although wavelet analysis works well for detecting voltage sag features, the existence of noise can reduce the advantages of wavelet method or even make it ineffective. To solve the problem, the paper uses multi-scale wavelet information by multiplying the results of several scales, and then searches the local maxima fr...

Abstract: Voltage sag is considered to be the most serious problem of power quality. It is caused by faults in the power system or by the starting of large induction motors. Voltage sag causes about 80% of the power quality problems in power systems. One of the main reasons for voltage sag is short circuit fault, which can be compensated for by a distribution static compensator (DSTATCOM) as an...

Today, with attention to increase in sensitive electrical equipments application in distribution networks and their susceptibility to the power quality deficiencies, the protection necessity of sensitive loads against undesirable effects of these disturbances are in focus. So, in this paper voltage sag deficiency and Dynamic Voltage Restorer (DVR) would be introduced as the most prevalent power...

Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs). By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to...

Power quality monitors (PQM) are required to be installed in a power supply network in order to assess power quality (PQ) disturbances such as voltage sags. However, with few PQMs installation, it is difficult to pinpoint the exact location of voltage sag. This paper proposes a new method for identifying the voltage sag source location by using the artificial neural network (ANN). Radial basis ...

Suitable voltage sag objectives are not yet found in any standard document. One of the reasons for the lack of objectives is the difficulty of defining suitable site sag indices. In this paper present sag characterisation methods are reviewed and discussed. The University of Wollongong sag index is summarized which shows a better way of characterizing voltage sags. A new method is then given fo...

AbstractThe dynamic voltage restorer (DVR) is a series connected device for mitigating voltage sag/This paper presents with feed forward pre-sag/swell voltage control method to regulate the output voltage of pulse width modulated (PWM) voltage source converter (VSC). The proposed controller maintains a constant load voltage under the multiple balanced/unbalanced dynamic PQ disturbances. The pro...

This paper concentrates on the control of hybrid fuelcell (FC)/energystorage distributed generation (DG) systems under voltage sag in distribution systems. The proposed control strategy makes hybrid DG system work properly when a voltage disturbance occurs in distribution system, and it stays connected to the main grid. This controller determines the supercapacitor power that should be generate...