Reduksi Harmonisa pada Sistem Distribusi 3 Fasa 4 Kawat Menggunakan Four Branch Star Filter dan Passive Single-Tuned Filter (Studi Kasus pada Transformator Distribusi 20 Kv/400 V)

Abstract

Non-linear load in the electric power system of three four-wire phases generates positive/negative order current harmonics and zero order harmonics. These harmonics bring about the increase in resonant, voltage distortion, over heating, increase in energy loss, failure and early aging in electric equipment, and so on. Based on the measurement in a distribution transformator owned by PT. PLN (Persero) of North Sumatera Regional Medan with unbalanced load, it was found that there was the phenomena of harmonics with Individual Harmonic Distortion (IHDi) of Order-3 and order-5 current which was not in line with IEEE 519-1992 standard. The reduction of harmonics was done by using Four Branch Star (FBS) Filter and Passive Single-Tuned Filter. MATLAB/Simulink was used for the result of simulation to design filter parameter. The result of simulation showed that FBS Filter and Passive Single-Tuned Filter could decrease IHDi order-3 and order-5 in each phase and was neutral according to IEEE 519-1992 standard. The decrease in IHDi was followed by the decrease in phase current and neutral current.

Beban-beban non-linier pada sistem tenaga listrik tiga fasa empat kawat membangkitkan harmonisa arus urutan positif/negatif maupun harmonisa urutan nol. Harmonisa ini menyebabkan kenaikan resonansi, distorsi tegangan, pemanasan lebih, bertambahnya rugi-rugi, kegagalan dan penuaan dini pada peralatan listrik, dan sebagainya. Berdasarkan pengukuran pada suatu transformator distribusi milik PT. PLN (Persero) Wilayah Sumatera Utara Area Medan dengan beban yang tidak seimbang ditemukan adanya gejala harmonisa dengan Individual Harmonisa Distortion (IHDi) arus orde-3 dan orde-5 yang tidak sesuai Standar IEEE 519-1992. Pengurangan harmonisa dilakukan menggunakan Four Branch Star (FBS) Filter dan Passive Single-Tuned Filter. Simulasi data menggunakan MATLAB/Simulink untuk merancang parameter filter. Hasil simulasi menunjukkan FBS Filter dan Passive Single-Tuned Filterdapat menurunkan IHDiorde-3 dan orde-5 pada tiap fasa dan netral sesuai dengan Standar IEEE 519-1992. Penurunan IHDi diikuti oleh penurunan arus fasa maupun arus netral.