A monitor that reports every hour but never raises an alarm adds data, not warning. Choosing the trigger condition is what decides whether condition-based maintenance for transformers pays off.
Reliability-based DGA ranks transformers by what a failure would cost, not by nameplate rating. That ranking decides how many units get continuous gas monitoring, and which gas each is watched for.
Handling faults, not the analyser, produce most misleading DGA results. The gas signatures that identify air ingress, degassing loss and contamination, and the order to rule them out.
A UHF partial discharge sensor most often enters the tank through an oil valve. What a live retrofit requires, where sensors go, and what to specify in the IED.
A transformer dissolved hydrogen sensor can alarm on air ingress, sampling error or sensor drift rather than a real fault. Here is how to rule each cause out.
Online and offline DGA answer different questions: online monitors catch trends and fast faults; offline labs provide independent confirmation. Run both.
An online hydrogen sensor for transformer oil DGA is the lowest-cost first step when upgrading 110 kV substations — retrofit on the valve, no outage, no consumables.
Retrofit online DGA on an energized transformer: closed-loop oil circuit, no oil consumption or flow disturbance, live-install safety, and a 1-3 month trial.
For most of the 20th century, transformer maintenance followed a simple rule: open it up every N years, inspect, replace whatever looks worn, and hope […]
