Banyak nya trip yang terjadi akibat gangguan hubung singkat antar fasa pada sisi 22 kV Gardu Induk Payo Selincah sehingga diperlukan keselektifitas dari sistem proteksi yang beupa rele diferensial dan rele arus lebih, guna menimalisir adanya trip akibat gangguan tersebut. Metode yang digunakan adalah metode kuantitatif dengan melakukan perhitungan matematis dan penggunaan software ETAP Power Station 19.01.0. Acuan standar dalam setting rele differensial dan rele arus lebih pada bay transformator daya Gardu Induk Payo Selincah ini yakni berdasar pada Surat Keputusan Direksi PT. PLN (Persero) No. 0520-3.K/DIR/2014. Sehingga didapatkan perhitungan arus diferensial pada perhitungan didapatkan senilai 0,08 A dengan arus setting differensial senilai 0,37 A. Pada perhitungan rele arus lebih didapatkan nilai arus setting primer 150 kV senilai 277,12 A, arus setting primer 22 kV senilai 1731, 04 A, dengan TMS sisi 150 kV yaitu 0,31 dan TMS sisi 22 kV yaitu 0,26. Dalam simulasi dengan menggunakan ETAP, kinerja dari rele diferensial dan rele arus lebih sudah benar dan sesuai dengan syarat dari sistem proteksi.

Many trips occur due to short-circuit interference between phases on the 22 kV side of the Payo Selincah Substation so that selectivity is needed from the protection system which is a differential rele and overcurrent rele, in order to minimize trips due to the disturbance. The method used is a quantitative method by performing mathematical calculations and using ETAP Power Station 19.01.0 software. The standard reference in setting differential rele and overcurrent rele in the power transformer bay of Payo Selincah Substation is based on the Decree of the Board of Directors of PT. PLN (Persero) No. 0520-3.K/DIR/2014. So that the calculation of differential current in the calculation is obtained at 0.08 A with a differential setting current of 0.37 A. In the calculation of the overcurrent rele, the primary setting current value of 150 kV is valued at 277.12 A, the primary setting current is 22 kV is valued at 1731.04 A, with a side TMS of 150 kV of 0.31 and a TMS of 22 kV side of 0.26. In simulations using ETAP, the performance of the differential relay and overcurrent relay is correct and in accordance with the requirements of the protection system.