摘要：In the rapid development of the world as it is today, the electricity has a very important role in supporting people activities. PT PLN (Persero), which in this case as Government State Owned Company that directly manage the provision of electrical energy is required to be ready to face the development of electricity demand in Indonesia. In distribution system of electricity, problems often occure because of the length of line distribution system which cause voltage drop, technical losses, power losses, etc. One of them happened to PT PLN (Persero) Rayon Muaralabuh. Where the distance between the main substation (GI Solok) with the first connecting substation is ±110 KMS. This distance cause 9.62 % voltage drop during peak load. This nominal of voltage drop happens for just the first connecting substation that will be the source of division for all working areas of PT PLN (Persero) Rayon Muaralabuh. This factor encourages PT PLN (Persero) West Sumatra Area Solok to agree if Independent Power Plant (IPP) takes part in generating electricity, which will be distribute to PT. PLN (Persero) West Sumatera Area Solok Rayon Muaralabuh through interconnection system. The simulation of power flow using Etap 12.6.0 is used to analyze the stability of 20 kV system voltage at PT PLN (Persero) Rayon Muaralabuh before and after interconnection. Based on the result of simulation and Etap calculation, the highest voltage drop before interconnection by IPP is on Feeder express LubukGadang which is 13,71 %. After the interconnection by IPP, the voltage drop on that feeder becomes 4,326%, and the highest voltage drop is 4,855 %. Therefore, the voltage drop after the interconnection by the IPP already meets the standards allowed by SPLN No. 72 of 1987 which is maximum 5 % voltage drop. The precentage of technical losses in PT PLN (Persero) Rayon Muaralabuh before interconnection is 13,074 %, and after interconnection is decreased to 8,306 %.
