Affiliations: College of Information and Communication Engineering, Dalian Nationalities University, Dalian, Liaoning, China
Correspondence:
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Corresponding author: Zhongfu Liu, College of Information and Communication Engineering Dalian Nationalities University, Dalian, Liaoning, China. Tel.: +86 15566824093; E-mail:lzhongfu@dlnu.edu.cn
Abstract: In the running of mine motor, it is extremely vulnerable
to overcurrent faults such as short-phase failure or short circuit, so the
study in overcurrent protection for asynchronous motor is of great
significance. The characteristics of overcurrent failure for mine
asynchronous motor are analyzed, a mathematical model of overcurrent fault
is established and the overcurrent protection principle is analyzed in this
paper. Due to the malfunction defect of traditional symmetrical
short-circuit protection in the starting of large motor, a new protection
scheme is proposed, which is to adopt the phase-sensitive protection based
on power factor detection and short-circuit fault detection scheme based on
wavelet transform Mallat algorithm. Meanwhile, a method of asymmetrical
fault protection based on negative-sequence current detection is proposed in
the paper. In addition, overcurrent protection technology is applied to the
overcurrent protection of mine squirrel cage asynchronous motor, of which
the effectiveness and the practicality have been verified.
