Project: Southern Transmission System (STS) or Intermountain Power Project
Service: Condition Assessment
Client: Los Angeles Department of Water and Power (LADWP)
Southern Transmission System (STS) comprises of HVdc converter stations at Intermountain and Adelanto and a ±500 kV 490 mile HVdc line. The original 1600 MW STS system was commissioned in 1986 and was later uprated to 1920 MW in 1989. The converter station is currently rated at 2,400 MW after an upgrade that took place in the Fall of 2010, which included the addition, replacement and modification of various ac/dc equipment, as well as replacement of the original control, protection, and monitoring system. The converter stations are based on the line commutated converter technology (LCC).
The purpose of this work was to identify the most cost effective way to ensure the function and reliability of the Southern Transmission System for 40 years starting in 2025. This would be accomplished by determining the remaining life expectancy of the major equipment starting from the year 2025, and recommending either a complete system replacement or replacement of specific parts of the Southern Transmission System.