Composite reliability evaluation of existing 500 kV Jawa Bali power system

Power system reliability must be considered in the site planning and operation of electric power system. Referring to “Rencana Usaha Penyediaan Tenaga Listrik PLN 2016-2025” document, the annual growth of Jawa Bali System is 8.4%. The growth of the load will increase the power flow in the 500 kV Jawa Bali System in which affects the index value of composite reliability. This study calculates reliability index value at the hierarchy level II that is EENS in 500 kV Jawa Bali System that describes energy that is not served for one year (MWh/year). The simulation results show that the EENS value of 500 kV Jawa Bali System in 2015 is 18,281.23 MWh/year. The transmission release will affect the EENS value of the composite system. The largest EENS value occurred when scenario 6, the Ungaran-Mandirancan transmission is removed with a 2% load decreament in region 1 and 2 which was 1,238,817.20 MWh/year. While the smallest EENS value occurred when scenario 3, the Kediri-Pedan transmission is removed was 17,870.76 MWh/year. In order to anticipate the growth of the load will be an addition of plants, substation (GITET) and transmission lines to reduce the value of EENS. The smaller value of EENS represent a more reliable system. The EENS value for 2016 is 17,171.62 MWh/year, while EENS 2017 is 13,432.09 MWh/year and EENS 2018 is 11,637.7 MWh/year.