MOTOR PROTECTION RELAY AND CONTROL METHOD USING THE SAME

摘要

PURPOSE: A motor protection relay and a control method using the same are provided to determine the entry of a negative phase current by comparing a first phase current with a third phase current when a first phase current passes through a zero point. CONSTITUTION: A motor protection relay comprises a measuring unit(120), a comparing unit(130), a determining unit(140) and a storage(150). The measuring unit measures the edge state and a point when a first phase current passes through a zero point. The comparing unit compares a second phase current with a third phase current when the first phase current passes through the zero point. The determining unit determines the entry of the negative phase current based on the comparison result of the comparing unit. The storage stores the determination result of the determining unit as cumulative data.