Abstract
Air-Core Reactors are employed in shunt configurations to maintain the line voltage within limits.The reactors consume VARs under lightly loaded conditions, countering the shunt capacitance of
transmission lines. Turn-to-Turn faults are commonly observed in the high-side of the reactor wind-
ings, and are attributed to the degradation of insulation caused by transients from switching or surge
conditions. The fault behavior in these air-core reactors is often observed, but not fully understood.
This document is presented as a summary of work developing methods to evaluate the behavior of
air-core reactors due to inter-turn shorts. Modeling tools developed for the analysis of turn-to-turn
faults, and examples of use are provided, with examples of faults in reactors similar to those used in
high-voltage shunt applications.