Effect of transmission switching and short circuit on the transient stability at interconnected power system: A case study of 150 kV Mahakam East Kalimantan electrical power system

Mahakam system is an electric transmission line managed by PT. PLN AP2B (State Electricity Company Area of Load Control Center) East Kalimantan. In this research, a test study with transient stability method is given three phases, two-phase and one phase to ground and switching transformer and maneuver line using software Digsilent Power Factory. The frequency and voltage probes are performed by looking at the reference bus graph response and rotor angle observation by looking at the response of the reference generator graph. In a three-phase phase trip, two-phase and one phase to ground frequency oscillation occurs between 0.6% - 0.9%, drop voltage between 0.01 pu to 0.926 pu and a rotor angle change of no more than 120. The case study of switching by manipulating the line from GI Senipah to GI New Balikpapan takes a reasonable oscillation of voltage and frequency for 0.5 seconds. From three case studies of short circuit and one switching, all voltage and frequency oscillations are still below 2% and the rotor angle is not more than 1800 and the time is not more than 10 seconds. However, in the case study of switching transformer 2 the system frequency shift is changed to 12% then a trip occurs on CB2 so that the system can oscillate and start stable at 49.84 Hz frequency according to the standard used as the reference is IEEE Std.c37.1987, SEMI F 42, 47 and ESDM Regulation No. 18 of 2016 on Kalimantan’s electricity system.