substation

Etymology

sub- + station

noun

1. A site where electricity supplied by long-distance (high-voltage) transmission lines is transformed and/or regulated for local (low-voltage) distribution.
   Meanwhile, an upgraded power supply at Sundon substation, between Leagrave and Harlington, will be commissioned concurrent with the overhead line connection and will be sufficient to power the initial electrified Corby services. 2019 October, Philip Sherratt, “Midland Main Line upgrade presses on”, in Modern Railways, page 62
2. A satellite police station serving one neighborhood or part of a larger jurisdiction.