A NEW METHOD TO IDENTIFY INRUSH CURRENT BASED ON SAMPLED VALUES
HU Yu feng, CHEN De shu (HuaZhong University of Science and Technology, Wuhan 430074,China)
Aimed at the disadvantages of second harmonic restraint and dead angle restraint, a new method is presented in this paper to distinguish inrush current. The new theory is based on sampled values and can disable the relay by phases. The dynamic tests show that the new theory can preferably solve some problems of traditional restraint methods, such as operated slowly when the fault transformer is switched in without loads, affected by harmonic easily and can not identify the symmetrical inrush current. At the same time, the new method owns good reliability.