On the morning of December 12, 2021, transformer No. 5 at the Wanlong primary substation in Taipei caught fire and exploded. Burning insulating oil and a bus trip cut power to 305,418 households across Taipei and New Taipei; the fault even propagated to a transmission tower on the same line. Traffic signals failed, water supply was disrupted, and the social impact was enormous.
What deserves the industry’s deepest reflection is the lead-up. The transformer had an emergency 36-hour shutdown on November 24; after returning to service, its insulating oil was sent for testing seven times in ten days — versus the normal once a year. The asset was clearly abnormal and operators were on high alert, yet the failure still wasn’t intercepted before insulation breakdown.
As transformer insulation degrades toward short-circuit breakdown, measurable PD activity usually accompanies the process. Dissolved gas analysis (DGA) tells you “insulation may have a problem”; PD monitoring answers “how active is the discharge, and how fast is it degrading?” Together, they buy the critical decision time between “knowing something is wrong” and “acting in time” — the irreplaceable value of online monitoring for aging substation assets.
Wintech Electric’s online transformer PD monitoring complements DGA, helping utilities turn early warning signs into timely action.
