25 Transformer Oil is a high-performance mineral insulating oil designed for oil-immersed transformers below 500KV, ideal for areas with minimum temperatures not lower than -10℃.

It excels in electrical insulation and heat dissipation, keeping transformers running stably under normal working conditions.

Made of high-quality low-sulfur base oil, it meets the latest industrial standards and is a reliable choice for power transmission and distribution equipment in industrial and commercial fields.

Technical requirements

Item			Quality Index					Test Method
Lowest Cold Start Temperature (LCSET)			0℃	-10℃	-20℃	-30℃	-40℃
Functional Characteristics	Pour Point / ℃ ≤		-10	-20	-30	-40	-50	GB/T 3535
	Kinematic Viscosity / (mm²/s) 40℃ ≤ 0℃ ≤ -10℃ ≤ -20℃ ≤ -30℃ ≤ -40℃ ≤		12 1800 - - - -	12 - 1800 - - -	12 - - 1800 - -	12 - - - 1800 -	12 - - - - 2500	GB/T 265 NB/SH/T 0837
	Water Content / (mg/kg) ≤		30/40					GB/T 7600
	Breakdown Voltage (meet one of the following requirements) / KV Untreated Oil ≥ Treated Oil ≥		30 70					GB/T 507
	Density (20℃) / (kg/m³) ≤		895					GB/T 1884 and GB/T 1885
	Dielectric Dissipation Factor (90℃) ≤		0.005					GB/T 5654
Refining / Stability Characteristics	Appearance		Clear and transparent, no sediment or suspended matter					Visual Inspection
	Acid Value (as KOH) / (mg/g)		≤ 0.01					NB/SH/T 0836
	Water-Soluble Acid or Alkali		None					GB/T 259
	Interfacial Tension / (mN/m)		≥ 40					GB/T 6541
	Total Sulfur Content (mass fraction) / %		No general requirement					SH/T 0689
	Corrosiveness		Non-corrosive					SH/T 0804
	Antioxidant Additive Content* (mass fraction) / % Oil without antioxidant additive (U) Oil with trace antioxidant additive (T) Oil with antioxidant additive (I)		Not detectable ≤ 0.08 0.08～0.40					SH/T 0802
	2-Furfural Content / (mg/kg)		≤ 0.1					NB/SH/T 0812
Operational Characteristics	Oxidation Stability (120℃)		1.2					NB/SH/T 0811
	Test Time: 164h for oil without antioxidant additive (U) 332h for oil with antioxidant additive (I) 500h for oil with antioxidant additive (I)	Total Acid Value (as KOH) / (mg/g)
		Sludge (mass fraction) / % ≤	0.8
		Dielectric Dissipation Factor (90℃) ≤	0.500					GB/T 5654
	Gas Evolution Rate / (mm³/min)		No general requirement					NB/SH/T 0810
Health, Safety and Environmental (HSE) Characteristics	Flash Point (Closed Cup) / ℃ ≥		135					GB/T 261
	Polycyclic Aromatic Hydrocarbon (PCA) Content (mass fraction) / % ≤		3					NB/SH/T 0838
	Polychlorinated Biphenyl (PCB) Content (mass fraction) / (mg/kg)		Not detectable					SH/T 0803

Key Features

• Excellent dielectric strength, with a breakdown voltage of over 30KV, effectively preventing insulation breakdown.
• Good low-temperature fluidity, pour point below -20℃, ensuring normal circulation in cold weather.
• Strong oxidation stability, reducing oil sludge generation and extending oil change intervals.
• Non-corrosive to transformer metal parts and compatible with sealing materials, avoiding equipment damage.

Craft & Technology

We select premium naphthenic base oil and adopt a fully enclosed production process. The oil goes through multi-stage refining including distillation, hydrotreatment and solvent extraction to remove impurities like sulfur and water. We add high-efficiency antioxidants and anti-foaming agents, and conduct strict degassing and dehydration treatment. Each batch of product undergoes testing for viscosity, flash point, and dielectric properties to ensure that all specifications meet relevant standards.

Packaging & Transportation

We offer various packaging sizes, including 1L, 10L, 18L, and 200L, to meet different purchasing needs. All packaging is tightly sealed and labeled with clear product model, production date, and batch number information. During transportation, avoid strong impacts and direct sunlight, and keep the product away from flammable and corrosive materials. The product can be transported by sea and land, and handled by professional personnel to ensure the packaging remains intact.

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