Transmission line ampacity improvements of altalink wind plant overhead tie-lines using weather-based dynamic line rating

Overhead transmission lines (TLs) are conventionally given seasonal ratings based on conservative environmental assumptions. Such an approach often results in the underutilization of the overhead TL capacity as the most conservative environmental conditions occur only for a short period over an year/season. We present computational fluid dynamics (CFD) enhanced weather-based dynamic line rating (DLR) as an enabling smart grid technology that adaptively computes ratings of TLs based on local weather conditions to utilize the additional headroom of line ampacity due to concurrent cooling of existing lines. In particular, a general line ampacity state solver is proposed to utilize measured weather data for computing the real-time thermal rating of the TLs. The performance of the proposed CFD enhanced weather-based DLR is demonstrated from a field study of DLR technology implementation on four TL segments at AltaLink, Canada. The performance is evaluated by comparing the existing static and the proposed dynamic line ratings, and the potential benefits of DLR for enhanced transmission assets utilization are quantified. For the given line segments, the proposed DLR results in real-time ratings above the seasonal static ratings for most of the time (up to 95.1%) with a mean increase of 72% over static rating.