中村 零

An oil distribution transformer is a step down transformer used in distribution networks that relies on insulating oil for cooling and dielectric insulation. It is designed for continuous service near end users, often pole mounted or pad mounted, and optimized for efficiency at typical load profiles. It can be sealed or conservator type, usually with ONAN cooling, and built to utility standards for protection, losses, and reliability.

Good insulating oil has high dielectric strength, low moisture content, low acidity, stable viscosity, good thermal conductivity, high flash point, oxidation resistance, and chemical compatibility with solid insulation. These properties ensure reliable insulation and cooling performance.

The BDV test measures the breakdown voltage of transformer oil, indicating its dielectric strength. It shows the oil’s ability to withstand electrical stress without failure. Low BDV values usually indicate contamination by moisture, particles, or aging by-products.

Dissolved gas analysis is essential because it detects early signs of internal electrical and thermal faults by identifying specific gas patterns. Gases such as hydrogen, acetylene, methane, and ethylene indicate partial discharge, arcing, or overheating. DGA enables predictive maintenance, reducing the risk of catastrophic transformer failure.

A 1500 kVA oil filled transformer is commonly used for large commercial buildings, hospitals, shopping centers, industrial facilities, and utility distribution nodes where medium voltage is stepped down to low voltage for plant loads. It can also serve renewable energy balance of plant systems and data center support loads depending on voltage class. Oil filled construction supports higher power density and outdoor installation. Exact application depends on primary voltage, secondary voltage, impedance, cooling class, and utility interconnection requirements.

Oil power transformers use liquid insulation and cooling, which supports higher voltage classes, higher MVA ratings, and better thermal management. Dry-type transformers use solid insulation with air cooling, which reduces spill concerns and can be suitable for indoor facilities. Oil units require containment, oil testing, and leak management, while dry-type units require ventilation control and are limited at very high voltages. Grid level transmission applications overwhelmingly use oil units, while dry-type is common for buildings, hospitals, and indoor industrial distribution.

Oil power transformers use liquid insulation and cooling, allowing higher voltage class, higher MVA capacity, and more compact insulation structures. Dry-type designs use solid insulation and air cooling, which reduces spill risk but limits power density and makes very high voltage designs impractical. Oil units require tanks, bushings, conservators, and containment systems, while dry-type units require ventilation management and may have higher audible noise in some cases. Grid design typically uses oil units for transmission and large substations.

Industrial oil purifiers are used to clean hydraulic, gear, or turbine oils from water, particles, and oxidation products. Fluidex systems serve metalworking, plastic, paper, and energy industries – improving oil cleanliness, reducing wear, and prolonging system uptime.