Compensation for the negative-sequence currents of electric railway based on SVC

Abstract

As a classic unbalanced load, the traction engines of the electric railways result in negative-sequence currents(NSC) in power systems, which cannot be ignored in most cases. SVC is considered as an effective method to reduce or even eliminate NSC, as well as some other power quality problems, such as reactive power compensation. Calculation formulae of NSC of two kinds of transformers are formed firstly in this paper. Then the mechanism of NSC compensation by SVC is discussed. Simulations by PSCAD of the system are followed. The results show that SVC is efficient to compensate NSC.