Optimizing the Capacity of 150 kV Transmission Lines Through the Addition of Shunt Capacitors: Case Study at PT. PLN (Persero) West Sumatra Subsystem

This study evaluates the impact of shunt capacitor installations on the voltage stability in the electrical network of the West Sumatra subsystem, focusing on the Pauh Limo, PIP, and Simpang Haru substations. Although the Simpang Haru Substation was initially identified as the optimal location for enhancing voltage regulation, practical considerations, such as land availability and cost, led to its installation at the Pauh Limo Substation. The required shunt capacitor capacities to maintain a nominal voltage of 150 kV during peak loads were calculated as 155.57 MVAr for Pauh Limo, 82 MVAr for PIP, and 78.15 MVAr for Simpang Haru. However, PT PLN implemented a uniform capacity of 25 MVAr across these substations. Despite this deviation from the calculated requirements, the installations effectively maintained the voltage within standard limits, with post-installation voltages at 144.3 kV, 144.9 kV, and 143.9 kV for the respective substations. This study demonstrates the necessity of balancing theoretical ideals with practical constraints in electrical engineering, highlighting that while optimal solutions are desired, real-world limitations often guide implementation strategies.