200 kVA Oil-Immersed Distribution Transformer

200 kVA Oil-Immersed Distribution Transformer is specified for 200 kVA oil-immersed distribution service. It uses ONAN cooling. Engineering details address maintenance-Free Operation Strategy, construction, application context, and electrical data for project selection.

Maintenance-Free Operation Strategy

For this 200 kVA rating, maintenance-free operation strategy affects how the transformer is selected, protected, and operated in the field.

• Is designed to minimize Operational Expenditure (OPEX) for facility managers and grid operators.
• Unlike traditional transformers that require regular oil sampling and breather maintenance, this rating adopts a fully enclosed architecture.
• By eliminating the oil conservator and using a flexible corrugated tank, we have engineered a robust hermetically sealed oil filled transformer.
• The tank and active-part design completely isolates the internal insulation oil from the ambient atmosphere.
• The primary benefit is the prevention of oxidation and moisture absorption-the two leading causes of insulation degradation-thereby extending the service life without the need for periodic oil purification.

Elastic Tank Technology

The elastic tank technology details below highlight design choices that matter during continuous distribution service.

• The core innovation in this 200 kVA model lies in its tank mechanics.
• As the transformer operates and temperature rises, the insulating oil expands.
• In a standard unit, this would require a breather; however, the design utilizes elastic corrugated fins.
• Thermal Expansion: The corrugated sheets act as a "lung," expanding and contracting to accommodate oil volume changes (typically ranging from -25°C to +40°C ambient).
• Pressure Management: The tank is structurally reinforced to withstand internal pressure variations (tested to 0.25 bar overpressure) without permanent deformation, ensuring the seal integrity remains compromised over decades of use.

Internal Assembly & Reliability

These internal assembly and reliability points connect the electrical rating with grid conditions, downstream equipment, and maintenance expectations.

• While the exterior focuses on sealing, the interior is built for mechanical rigidity.
• The 200 kVA core uses Cold Rolled Grain Oriented (CRGO) silicon steel, mitered and stacked to reduce magnetostriction (noise).
• Crucially, for a hermetically sealed oil filled transformer, the internal connections must be robust.
• The design uses a specialized clamping structure for the active part to prevent movement during transport or short-circuit events.
• Since the tank is sealed, we also integrate a pressure relief valve (PRV) as a standard safety feature to release excess pressure in the unlikely event of an internal fault.

Target Applications

Application guidance links the transformer rating with the substations, industrial loads, and site conditions where it is normally used.

• This sealed design is particularly suited for environments where maintenance is difficult or costly: 1.
• Polluted Environments: Industrial zones with high dust or chemical vapors (since no air enters the tank).
• Compact Substations: The absence of a conservator tank reduces the vertical height, fitting easily into prefabricated compact substations.
• Remote Infrastructure: Telecom towers or pumping stations where regular maintenance crews cannot easily visit.
• 200 kVA hermetically sealed transformer installed inside a compact prefabricated substation.

Electrical and Mechanical Data

The electrical data summarizes the main values needed for project comparison and project comparison.

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