Voltage sag performance of a distribution system and its improvement

Abstract

The voltage sag performance of a distribution system has been investigated. A Monte Carlo procedure has been used to construct the sag density table and estimate the number of unacceptable sags per annum at a sensitive load bus. The sub transmission lines and distribution feeders that largely contribute to the unacceptable sags have been identified. It has been shown that proper protective relay coordination and adequate maintenance of the critical lines and feeders result in significant improvement of the voltage sag performance of the distribution system. Index Terms--voltage sags, power quality, Monte Carlo method.

Voltage quality assessment considering low voltage ride‐through requirement for wind turbines

“…Generally, voltage sag performance compared with a voltage tolerance expressed in a rectangular curve can be assessed using a voltage sag density table. The sag density table reports ESFs with voltage magnitude and duration within a certain range [12, 13]. An ESF exceeding a given voltage tolerance can be estimated by overlap between a sag density table and the rectangular tolerance curve.…”

“…This method is inefficient for real large power systems. Other methods based on Monte Carlo simulation have also been proposed [12, 13]. Monte Carlo simulation is a powerful and flexible tool for stochastic problems.…”

“…Essentially, these methods cannot evaluate voltage sag performance reflecting various sag duration limits. Some assessment methods have taken into account sag duration as well as magnitude [12, 13]. However, the methods are only valid for a specific protection system and provide sag performance in a table form with fixed ranges of sag magnitude and duration.…”

An Evaluation Method for Bus and Grid Structure Based on Voltage Sags/Swells Using Voltage Ellipse Parameters

“…A lot of research work has been carried out by many scholars on the evaluation of voltage sags and swells [3]- [8]. In [9]- [10], voltage magnitude is used to evaluate voltage sags/swells.…”

Half Cycle Discrete Transformation for Voltage Sag Improvement in an Islanded Microgrid using Dynamic Voltage Restorer

“…Voltage sag d-q transformation technique provides excellent performance with detection time of 1 ms with pure sinusoidal voltage, may not provide the required performance in an islanded microgrid which has lot of harmonics/ distortion [12]. The drawback is overcome using low pass filter implemented with d-q transformation, yet it may not detect the single phase voltage sag of 0.3p.u.…”