Negative sequence protection in comprehensive protection of LV flameproof motor
Chen Ying-song · Dianli zidonghua shebei · 2007
Based on the analysis of main fault types of LV(Low Voltage) flameproof motor,the negative sequence protection principle is proposed for its asymmetric short circuit fault and open phase fault.The design of negative sequence protection is mainly introduced with seriously unbalanced power supply voltage fault,open phase fault and two-phase short circuit fault.The strain sequence arithmetic is used to deduce sequence components from instantaneous samples.Negative sequence currents generated in asymmetric short circuit fault and open phase fault are simulated by experiments and the measured experimental results coincide with the requested values,which proves the correctness of protection scheme.The application of negative sequence protection in LV flameproof motor comprehensive protection reduces equipment cost and improves its reliability.