When DGA Tells the Story… Listen.
Recent LTC DGA results pointed toward abnormal activity inside this transformer’s OLTC compartment. Elevated gassing patterns, combined with field diagnostics, led us to a planned outage and inspection. What we found confirmed the concern: significant contact wear and reversing switch coking.
This is a good reminder that Load Tap Changer DGA trends often provide early warning of contact degradation and localized heating before catastrophic failure occurs. Reversing switch coking and worn contacts increase gases, resistance and heat, ultimately accelerating deterioration if left unchecked.
Pictured: an LTC changeout in progress to restore reliability and avoid a much larger failure event.
The lessons:
Manually run the the LTC through neutral periodically to help minimize coking on the reversing switch.
Test your LTC’s oil at least twice a year and don’t ignore LTC gas trends. When DGA starts talking, it’s usually telling you something important.