A regional utility needed revenue metering at multiple tap points on a rural feeder network. With spans over open farmland and no station buildings, every unit had to be pole-mounted, weatherproof and accurate in widely varying load conditions.
The challenge
Tap points sat up to 40 km from the nearest service centre, so failures meant long outages and expensive truck rolls. The utility asked for units that would survive ten years outdoors with zero maintenance and hold 0.5S accuracy while load swung between 5% and 120% of rating.
Our solution
We supplied outdoor current transformers with 0.5S metering cores and 10P10 protection cores, cast in epoxy with umbrella skirts for the local pollution level, plus metering boxes with stainless-steel enclosures and sealable meter compartments. Dual-ratio secondaries let the utility re-rate each tap without opening the enclosure.
Products supplied
Outdoor current transformers in 20/5 and 50/5 dual-ratio versions, three-phase pole-mounted metering boxes with V/V connected CTs and VTs, and hot-dip galvanised mounting frames and crossarms.
Outcome
Over two seasons of operation the utility reported no weather-related failures and meter readings within the 0.5S band at every tap point. The dual-ratio design has already absorbed two load increases without a single site visit.