PROJECT TITLE :

Test and analysis on sensitivity of low-voltage releases to voltage sags

ABSTRACT:

This study discusses the sensitivity (i.e. ride-through performance) of low-voltage releases to voltage sags on the basis of extensive tests, and presents 2 sensitivity models to assess the tripping characteristics of low-voltage releases, which haven't been studied before. First, working principle of low-voltage unleash and existing standards are reviewed. Second, a detailed take a look at theme is proposed and 10 kinds of low-voltage releases have been tested. Check results show that magnitude, duration and point-on-wave angle of voltage sag jointly determine the sensitivity of low-voltage releases. After extraordinarily processing take a look at results and applying the curve fitting theory, the functions representing the connection between magnitude and period at totally different point-on-wave angles are formed, that symbolise an in depth sensitivity model of low-voltage unharness. Moreover, the opposite less complicated and additional practical sensitivity model is proposed by introducing rectangular envelope lines of voltage tolerance curves at completely different purpose-on-wave angle.