A Power Quality Improvement Study in Central Java Indonesia

This paper proposes possible solutions to mitigate voltage sag problem in Kaliwungu Industrial Center, Central Java, Indonesia. In the last three years, there were 17 voltage sag occurrences which violate the ITIC curve. In Central Java area, Kaliwungu in particular, suffers from unbalanced deep voltage sags due to application of Y-Y connected transformers from the upstream 500 kV backbone to the 380 V low voltage distribution. Thus, voltage sag due to unbalanced fault elsewhere in the Central Jawa grid will directly pass to the consumer appliances in Kaliwungu Industrial Center. Several relatively low-cost solutions have been proposed to mitigate this situation. The proposed solutions are to modify the transformer winding connections and the grounding system in the substation that feeds directly the area. Simulated results show the effectiveness of the proposed solution.