Multiparameter-Based Fuzzy Logic Health Index Assessment for Oil-Immersed Power Transformers

Table 2

Transformer standard parameter limits [1, 26].

Category	Parameter	Condition
		Normal	Caution	Alarm	Failure
DGAF
	Dissolved gases
	H2 (ppm)	0–100	101–700	701–1800	>1800
	CH4 (ppm)	0–120	121–400	401–1000	>1000
	C2H2 (ppm)	0–1	2–7	7–35	>35
	C2H4 (ppm)	0–50	51–100	101–200	>200
	C2H6 (ppm)	0–65	66–100	101–150	>150
	CO (ppm)	0–350	351–700	701–1400	>1400
	CO2 (ppm)	0–2500	2501–4000	4001–10000	>10000
OQF
	Oil quality
	BDV (kV)	100–50	49–40	39–30	<30
	IFT (mN/m)	50–30	30–23	23–18	<18
	Moisture (ppm)	0–15	16–20	21–25	>25
	Acidity (mg KOH/g)	0–0.05	0.051–0.1	0.11–0.2	>0.2
	DDF	0-0.1	0.1–0.5	0.5–1	>1
	Colour	0–1.5	1.5–2	2–2.5	>2.5
FF
	Furans
	Furans (ppm)	0–0.1	0.1–1	1–10	>10