Pacific DC Intertie - Components

Components

The Pacific Intertie consists of:

• The Celilo Converter Station which converts three phase 60 Hz AC at 235 to 525 kV to ±500 kV DC at 45°35′39″N 121°6′51″W / 45.59417°N 121.11417°W / 45.59417; -121.11417 (Celilo Converter Station - Pacific DC Intertie (north end))Coordinates: 45°35′39″N 121°6′51″W / 45.59417°N 121.11417°W / 45.59417; -121.11417 (Celilo Converter Station - Pacific DC Intertie (north end)).
• The grounding system at Celilo consists of 1,067 cast iron anodes buried in a two foot trench of petroleum coke, which behaves as an electrode, arranged in a ring of 3,255 m (2.02 mi) circumference at Rice Flats (near Rice, Oregon), which is 10.6 km (6.6 mi) SSE of Celilo. It is connected to the converter station by two aerial 644 mm2 steel-reinforced aluminum (ACSR) cables, which end at at a strainer situated at 45°29′51″N 121°03′53″W / 45.4975865°N 121.0646206°W / 45.4975865; -121.0646206 (End of electrode line).
• A 1,362-kilometre (846 mi) overhead transmission line consisting of two uninsulated conductors each 1,171 mm2 in cross sectional area, containing a steel wire core for strength.
• The Sylmar Converter Station (34°18′39″N 118°29′21″W / 34.31083°N 118.48917°W / 34.31083; -118.48917 (Sylmar Converter Station - Pacific DC Intertie (south end))) which converts DC to AC (a process also called inverting) and phase-synchronized with the L.A. power grid.
• The Sylmar grounding system is a line of 24 silicon-iron alloy electrodes submerged in the Pacific Ocean at Will Rogers State Beach suspended in concrete enclosures about one meter above the ocean floor. The grounding array, which is 48 km (30 mi) from the converter station and is connected by a pair of 644 mm2 aluminum conductors, which are in the sections north of Kenter Canyon Terminal Tower at 34°04′04.99″N 118°29′18.5″W / 34.0680528°N 118.488472°W / 34.0680528; -118.488472 (Southern California Edison Malibu Substation, Pacific DC Intertie - End of overhead electrode line) installed instead of the ground conductors on the pylons. It runs from Kenter Canyon Terminal Tower, via DWP Receiving Station U, Southern California Edison Northridge Substation and Rinaldi Electrical Substation to Sylmar Converter Station. On the section between Northridge substation and Rinaldi Street substation one of the two ground conductors of 2 parallel running 220 kV powerlines is used as electrode line conductor.
• The combined wires have a capacity of 2 gigawatts in bipolar mode and 1.55 gigawatts with earth (ground) return.