A new method to balance currents of the generator

In modern power systems, most generators use negative sequence current relays to detect the negative sequence current and, if necessary, alarm or trip the generators to protect them from the damage of it. However, tripping major generation facilities may create social, security, and economic problems. This paper presents a feasible method for negative sequence current reduction at the generator terminal through a special function single-phase active power filter (APF), which can be connected to system either at Y₀ or Δ side of the transformer between the generator and the transmission lines. The control algorithm and digital simulation results of this method are also presented in this paper.