Pengaruh harmonik terhadap rele arus lebih pada sistem distribusi tenaga listrik

ZULKARNAINI, Ir. Tumiran, M.Eng.,Ph.D

2007 | Tesis | S2 Teknik Elektro

Proteksi Rele arus lebih (Over Current Reley) elektromekanik tipe induksi dengan karakteristik inverse didesain operasi pada arus sinusoidal. Operasi rele arus lebih dengan adanya arus harmonik tidak dapat diandalkan. Maka pengujian dihubungkan dengan Total Hormonic Distorsion (THD) arus, frekuensi, amplitudo dan pergeseran fase dari bentuk gelombang yang dibangkitkan oleh beban non linear pada sistem distribusi. Arus harmonik dimodelkan dengan melalui impedansi sistem dalam distribusi tenaga listrik. Amplitudo arus harmonik yang terjadi dalam sistem distribusi, mengakibatkan penundaan waktu bekerjanya rele. Operasi rele arus lebih elektromekanik tipe induksi disk dengan karakteristik inverse waktu bekerjanya tergantung kepada THD arus. Berdasarkan hasil penelitian pada jaringan distribusi, maka waktu yang paling lama ter dapat pada THD arus sudah mencapai 96.2 % dan untuk arus Irms 122 A konstant maka waktu kerja rele dari 1.51 detik naik menjadi 2.51 detik. Selanjutnya naiknya THD arus maka arus root mean square (rms) juga naik dan arus fundamental semakin turun, karena rele bekerja berdasarkan arus fundamental maka rele bekerja semakin lama. Ini bisa menyebabkan kerusakan pada peralatan jaringan distribusi.

The electromechanical over current protection relays are designed to operate with sinusoidal current. The test were conducted such that the current Total Harmonic Distort ion (THD), frequency, amplitude and phase shift of individual harmonics could be controlled by employing a waveform load harmonic in distribution system . The relation between the harmonics currents was modeled through the power system impedances within residential distribution systems. It was found that for harmonic voltage and current amplitude , as they occur in distribution system, time delay operation of over current relays show a marked deterioration in their performance. Electromechanical inverse time over current relay protection in system distribution the experiment result ,the current and the operating time of the inverse time over current relay increase proportionally to the total harmonic distortion (THD)value of the non sinusoidal current. The experiment result on distribution system, long time relay operation when , THD current 96.2 % value and the root mean square current (Irms) = 122 Ampere, time operation from was 1.51 second increase to 2.51 second and operating time relay delayed. Because the THDi and root mean square current increase as well as fundamental current lessen. It is dangerous in distribution system equipment

Kata Kunci : Sistem Distribusi Tenaga Listrik,Rele Arus Lebih,Harmonik,Harmonic, Over current relays , Distribution system