Sistem Tenaga Listrik yaitu sekumpulan pembangkit dan Gardu Induk yang terhubung oleh jaringan distribusi. Tujuan dari sistem distribusi adalah memindahkan daya listrik dari pusat pembangkit ke pusat beban secara aman, effisien, handal dan ekonomis. perubahan profil tegangan dan kemampuan operasi saluran distribusi PT. PLN (persero) Sebatik dengan analisis kontingensi saluran N-1 dengan pola operasi satu generator dilepaskan secara bergantian dan saluran menggunakan software ETAP powerstations 19.0.1 yaitu melepas dengan sengaja sebuah saluran distribusi dari sistem untuk mengevaluasi sistem tersebut. Ketika terjadi kontingensi diasumsikan terjadi sebuah gangguan, sehingga berdampak terhadap perubahan nilai tegangan bus dan overload pada saluran. Selanjutan, Pada Analisa kontingensi dilakukan melalui dua pola yaitu: kontingensi generator dan kontingensi saluran. Pada kontingensi generator didapatkan hasil sebagai berikut: pada saat Pembangkit Mitsubishi 1, Mitsubishi 2, dan Mitsubishi 3 dilepas maka terjadi overload sebesar 154% - 377%, dan pada saat MAN 8 dilepas tidak ada generator yang mengalami overload. Sedangkan pada kondisi kontingensi saluran didapatkan hasil sebagai berikut: pada saat kabel 28 (feeder 1) dilepas terjadi kehilangan daya beban 575,2 kW dan daya generator 592,8 kW, kabel 169 (feeder 2) dilepas terjadi kehilangan daya 297,8 kW dan kehilangan daya generator 306,8 kW, kabel 107 (feeder 3) dilepas terjadi kehilangan daya beban 351 kW dan kehilangan daya generator 337 kW, kabel 143 (feeder 4) dilepas terjadi kehilangan daya beban 263,4 kW dan kehilangan daya generator 260,2 kW, dan kabel 187(feeder 5) dilepas terjadi kehilangan daya beban 117,3kW dan kehilangan daya generator 112,9 kW. hasil simulasi berupa rugi-rugi daya dan jatuh tegangan pada setiap bus masih masuk dalam batas toleransi.

Kata Kunci— Sistem Distribusi, Kontingensi Saluran N-1, Undervoltage, Overload.

Electric Power System is a set of generator and substations connected by a distribution network. The purpose of the distributions system is to move electrical power from the generating center to the load center safely, efficiently, reliably, and economically. Changes in the voltage profile and operating capabilities of the PT PLN (Persero) Sebatik distribution line with N-1 line contingency analysis with the oprerating pattern of one generator released alternately and the line using ETAP powerstations 19.0.1 softwear, which deliberately removes a distribution line from the system to evaluate the system. When a contingency is assumed to occur, adisturbance occurs, resulting in changes in bus voltage values and overloads on the line. Furthermore, contingency analysis was cerried out through two patterns including generator contingency and line contingency. In the generator contingency, the following results were obtained: when Mitsubisih1, Mitsubisih2, and Mitsubisih 3, generators were released, there was an overload of 154% - 377%, and whan MAN 8 was released, there were no generators that experienced overload. Meanwhile, the contingency conditions of the channel obatinen the following results: When cable 28 (feeder 1) was removed there was a loss of 575.2 kW load power and 592.8 kW generator power, cabel 169 (feeder 2) was removed there was a loss of 297.8 kW power and a loss of 306.8 kW generator power, cabel 107 (feeder 3) was removed there was a loss of 351 kW power and a loss of 337 kW generator power, cabel 143 (feeder 4) was removed there was a loss of 263.4 kW power and a loss of 260.2 kW generator power, cabel 187 (feeder 5) was removed there was a loss of 117.3 kW power and a loss of 112.9 kW generator power. Simulation results in the from of power losses and voltage drops on each bus were still within the tolerance limit. Keywords—Distribution System, N-1 Line Contingency, Undervoltage, Overload.