Effect of Point of Sag Initiation on Performance of Induction Machine

International Journal of Research and Scientific Innovation (IJRSI) | Volume VI, Issue XI, November 2019 | ISSN 2321–2705

Effect of Point of Sag Initiation on Performance of Induction Machine

Shobhit Gupta*, Ajay Srivastava and Harendra Singh Rawat

^1,2,3Department of Electrical Engineering, College of Technology, G. B. Pant University of Agriculture & Technology, Pantnagar, U.S. Nagar, Uttarakhand, 263145, India
*Corresponding author

Abstract: In this paper a simulation based study has been made to analyze the effect of voltage sags on the performance of the induction motor. Voltage sag can be characterized on the basis of magnitude, duration and point of sag initiation on the wave. In this paper the effect of voltage sag has been studied on the basis of various sag magnitude and different initial point on wave. The effect on the induction motor has been observed in terms of current & torque peaks and speed loss. Initially the effect of intensity of symmetrical voltage sag with different starting point has been observed on the induction motor and then effect of unsymmetrical voltage sag has been studied. The simulation work has been done in MATLAB-SIMULINK.

Key words: voltage sag, sag magnitude, initial point on wave.

I. INTRODUCTION

There are various power quality issues that can affect the induction motor performance in many ways. Voltage sag is one of them. In recent time a great emphasize has been given on the issues related to voltage sag because of power requirement of sensitive equipment and increased voltage-frequency pollution [1]. According to IEEE standards 1159-1995, voltage sag is defined as a decrease in rms voltage down to 90% to 10% of nominal voltage for a time greater than 0.5 cycles of the power frequency but less than or equal to one minute.” Voltage sag may be symmetrical or asymmetrical, depending upon the type of fault [2]. In symmetrical voltage sag the magnitude of the individual phase voltages are equal and their phasor are displaced at 1200 from each other. The main reason of a symmetrical voltage sags are three phase fault or starting of a large induction motor. The single line to ground faults, line to line fault or two lines to ground fault results in unsymmetrical voltage sags in the system.
The voltage sag may cause the current and torque peaks and speed loss in the induction motor. All these changes can be observed just after the time of sag initiation and recovery instant.

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