Situated between Courtenay and Parksville, Nile Creek (also known as Sunshine Bay) is one of those places that you’ll miss if you take the inland Highway 19 instead of the “old Island highway”.
Sunshine Bay is home to the British Columbia Transmission Corporation Nile Creek Shore Terminal station, the landing point for the 500 kV submarine electrical transmission cable from Texada Island.
The station serves as the point of transition from underwater/underground cable to overhead transmission lines for two 500 kV transmission circuits. Six underwater cables (three per circuit) arrive at shore buried in the seabed. The cables run underground for about 200m between the shoreline and the station, where they emerge from the ground through concrete pedestals supporting vertical insulator stacks.
The feed conductors exit the top of the vertical insulator stacks and connect to bar and rail systems that lead horizontally under the overhead transmission lines and then connect with the overhead lines.
The underwater cables have inner and outer conductors separated by an oil-impregnated laminate-paper insulator. The inner conductor carries the transmission line current, while the grounded outer conductor serves primarily as a protective jacket. Pressurized oil is supplied to the entire length of cable through a conduit on the cable axis. Resistive heating from increased electrical load can cause the cable temperature to rise and this leads to expansion of the contained oil. When oil expansion occurs the excess oil must be stored so it can be reinserted when the temperature decreases. The excess oil is stored in two large tanks housed in a storage and pump building at the Nile Creek terminal.
And now you know…