Knowledge

During the test, I saw a large spark and the relay tripped. Was it a flashover or a breakdown - and how do I tell the difference? Distinguishing flash

What is the basis for selecting the test voltage for an AC Hipot test? Test voltage is determined by the equipment's rated insulation level (Um, B

What exactly does the AC Hipot test verify, and why is it "destructive" yet indispensable? The AC Hipot test applies an AC voltage significa

Q: I hear about the "Duval Triangle" a lot in DGA interpretation. How does it work? A: The Duval Triangle (by Michel Duval, IREQ, now IEEE C

Q: Should I install an on-line DGA monitor, or continue sending oil samples to the lab? A: Each method has a distinct role. The choice depends on tran

Q: How should transformer oil be sampled for DGA, and what are the most common sampling mistakes? A: DGA results are only as reliable as the sampling

I have a DGA report with concentrations of seven gases. How do I turn these numbers into a diagnosis? A: Three internationally recognized ratio method

What are the seven key gases in DGA, and what failure modes do they correspond to? DGA monitors seven key gases dissolved in transformer oil. Each gas

How is PD detected and measured in the field and during factory testing? There are four established PD detection methods: Recommended combination: &bu

What is partial discharge, and how does it lead to transformer failure? Partial discharge (PD) is a localized electrical breakdown that does not compl

How is the tanδ test applied to bushings, and what physical quantity are we measuring? For a capacitive bushing (OIP or RIP), the tanδ tes

My SFRA traces are not repeatable. What could be going wrong? Poor SFRA repeatability is almost always caused by measurement setup issues rather than