Mechanism Analysis And Experimental Study Of Voltage Sag On Typical Sensitive Equipment

This paper mainly research on the mechanism analysis and test on typical sensitive equipment. First of all, to understand voltage sag deeply, based on a large amount of test data, the method of extracting voltage sag characteristics is analyzed. In addition to sag magnitude, sag duration, extraction has also carried on the point-on-wave of sag initiation, phase-angle jump and damped oscillation, which made the foundation for the following study on voltage sag test.On basis of cognition of voltage sag, mathematical and simulation model of AC contactor and switch-mode power supply (SMPS) are established by PSCAD. Then the mechanism analysis of different voltage sag characteristic index on typical sensitive equipments are studied based on the PSCAD models. The effects of voltage sag with point-on-wave of sag initiation, phase-angle jump, frequency fluctuation, harmonics, multiple sags, continuous sags and damped oscillation on the AC contactor are analyzed in detail. Then two measures for improving the tolerant ability on voltage sag of AC contactor are given by the simulation. And the effects of the sag magnitude, duration, point-on-wave of sag initiation and the phase-angle jump on the SMPS are analyzed in detail.Based on the mechanism analysis, the test of the sag influence on typical sensitive equipment is taken in this paper. First of all, a program is made for test. Then according to the program, the sag characteristics including voltage sag magnitude, duration, phase-angle jump, point-on-wave of sag initiation, multiple sags, continuous sags, damped oscillation and other index as harmonics and frequency fluctuation are tested for studying their influence on AC contactor and on SMPS. After the test, the distribution regularity of sensitive equipment tolerance curves is formed through analyzing the test data on record, which verified the correctness of mechanism analysis. The tolerance curves of AC contactor and SMPS under different characteristics are extracted, and the effect of voltage sags on AC-DC contactor is researched with test. The research results and useful conclusions in this paper could provide necessary basis for equipment manufacturers users, and power companies to take measures to restrain disturbance of voltage sag on the AC contactor and SMPS.