小型隔爆电动机过载断相保护技术及其微机算法的研究

Study on overload and open-phase protection technique and microcomputer algorithm for minitype explosion-proof motor

煤矿井下小型隔爆电动机常用的过载、断相保护存在一些缺陷,为了改进其保护方案,对过载保护采用符合电动机发热特性的迭代法进行动态过载保护,以取代常规的静态过载保护;对断相保护引入交流采样及滤序算法提取断相故障信号,以取代常规的分立元件的直流采样算法及滤序方法.试验结果表明,动态过载保护装置可计及电动机的动态过载的热积累,其动作的反时限特性更容易与电动机的过载特性相配合;断相保护采用的全数字化处理方案可使其采样精度更高,实时性及抗干扰能力更强.

Ordinary overload and openphase protections for miniexplosionproof motor in mine have some defectives. In order to improve the protection schemes, for overload protection, dynamic overload protection based on motor's heating characteristic instead of ordinary static overload protection is introduced here; for openphase protection, AC sampling and phasesequencefiltration algorithm instead of DC sampling algorithm is adopted to gain the openphase fault signal. Test results indicate dynamic overload protection consider the heating accumulation of motor's dynamic overload, its antitime characteristic conforms to motor's overload characteristic more easily,and openphase protection can get higher measure precision and better realtime characteristic and antijamming.