[1] State Polytech Ujung Pandang, Dept Elect Engn, Makassar, Indonesia
[2] Yogyakarta State Univ, Dept Elect Engn Educ, Yogyakarta, Indonesia
[3] State Polytech Ujung Pandang, Dept Chem Engn, Makassar, Indonesia
[4] PT Pembangkit Jawa Bali, Surabaya, Indonesia