How To Identify The Oil Of Oil Filled Distribution Transformers?

S11 oil-immersed distribution transformers are critical hubs connecting distribution boxes and power equipment, with their operational quality directly determining the stability of the entire power distribution system. Oil quality is paramount to their performance—unqualified oil can lead to equipment failures and power outages. Below is a systematic breakdown of oil quality inspection requirements, simple identification methods, and maintenance measures.

Contents hide

1 1. Importance & Mandatory Test Requirements

2 2. Simple Oil Quality Identification Methods (Preliminary Judgment)

3 3. Key Maintenance Measures

4 OUR CERTIFICATE

5 OUR PROJECTS

1. Importance & Mandatory Test Requirements

Core Significance of Oil Quality

The insulation and cooling performance of S11 transformers rely entirely on qualified transformer oil. Poor oil quality reduces insulation reliability, accelerates component aging, and increases the risk of short circuits or breakdowns.

Mandatory Test Regulations

Per 《Preventive Test Regulations for Power Equipment》, S11 oil-immersed distribution transformers must undergo a withstand voltage test 1–3 years after commissioning.
If the transformer oil fails to meet technical requirements (e.g., insufficient insulation strength, excessive impurities), it must be replaced or filtered immediately. This proactive measure prevents potential failures and minimizes losses caused by unplanned power outages.

2. Simple Oil Quality Identification Methods (Preliminary Judgment)

Without professional testing equipment, CHH Power recommends two on-site preliminary identification methods—reliable for rapid initial assessments:

(1) Smell Test (Odor Judgment)

Qualified Oil: No obvious odor, or a faint, gas-like neutral smell (consistent with fresh transformer oil characteristics).
Unqualified (Deteriorated) Oil: Emits abnormal odors (e.g., burnt smell, sour smell, or pungent chemical odor), indicating oxidation, contamination, or internal component overheating.

(2) Visual Inspection (Color & Transparency)

New/Qualified Oil:
- Color: Light yellow (fresh oil); slightly darker after opening (normal oxidation, no deterioration).
- Transparency: Clear and transparent when poured into a glass bottle.
- Fluorescence: Shows a blue-violet fluorescence under light (a key sign of pure, uncontaminated oil).
Unqualified (Deteriorated) Oil:
- Color: Dark brown, black, or cloudy.
- Transparency: Opaque, with visible sediment, suspended particles, or water droplets.
- Fluorescence: Faded or absent (indicates severe contamination or oxidation).

3. Key Maintenance Measures

Preliminary Judgment + Professional Testing: Simple smell/visual inspections are only for initial screening. Final oil quality confirmation requires professional tests (withstand voltage test, simplified oil analysis) to ensure compliance with GB/T 7595 standards.
Timely Oil Treatment: If preliminary inspection or professional testing indicates unqualified oil, replace or filter it immediately—do not continue operation to avoid equipment damage.
Regular Oil Monitoring: Beyond the 1–3 year mandatory test, conduct quarterly visual/smell inspections during routine maintenance to track oil quality changes.