Product Introduction
Overview
• Distribution transformers with conservator tanks use oil-immersed windings and a separate expansion reservoir to manage thermal volume changes, maintain stable oil level, and preserve dielectric strength. The design supports reliable voltage transformation, controlled impedance, and adequate cooling margins while accommodating routine inspection and protection devices, helping engineers balance performance, maintainability, safety, and long-term asset reliability across standard distribution voltages worldwide.
Application
• Conservator-type distribution transformers are applied in primary and secondary substations, industrial plants, and utility feeders where step-down transformation, flexible tap ranges, and predictable thermal behavior are required. They support overhead or underground networks, rooftop or ground-mounted installations, and retrofit upgrades, helping asset owners standardize ratings, coordinate protection, and maintain continuity of service safely under varied loading patterns and environmental conditions.
Technical
• Voltage Level: ≤36kV
• Rated Power: ≤Power capacities from 10 kVA to 100,000 kVA
• Frequency: 50/60 Hz
• Insulation Grade: up to 170 kV
• Maximum Ambient Temperature: 55°C
• Altitude: ≤5000m
• Cooling Types: ONAN/ONAF/OFWF
• Winding Material: Copper/Aluminum
• Voltage Regulation: Off Circuit
• Insulating Medium: Natural/Synthetic Ester / Mineral Oil
• Rated Power: ≤Power capacities from 10 kVA to 100,000 kVA
• Frequency: 50/60 Hz
• Insulation Grade: up to 170 kV
• Maximum Ambient Temperature: 55°C
• Altitude: ≤5000m
• Cooling Types: ONAN/ONAF/OFWF
• Winding Material: Copper/Aluminum
• Voltage Regulation: Off Circuit
• Insulating Medium: Natural/Synthetic Ester / Mineral Oil
Advantages
• Key advantages of distribution transformers with conservator tanks include controlled oil expansion, reduced risk of main-tank overpressure, and improved oil quality through breather systems. Stable dielectric conditions enhance insulation life and reliability. Provision for Buchholz relays and clear oil-level indication simplifies condition monitoring, helping reduce unplanned outages, optimize maintenance intervals, and support consistent lifecycle performance further in demanding distribution networks.
Feature
• Have the low maintenance expenses
• Are suitable for large capacity (kva) requirements
• Have excellent ventilation capabilities and position of cooling radiator fins can be designed to suit the air flow direction of installation site thus allowing transformer to be installed on ground or area where ventilation is not optimum
• Allow the installation of extra cooling fans at the radiator fins
• Has higher durability and longer product usage lifetime compared to other oil type transformers
• Are able to perform at full kva (100% rating)
• Have lower operating noise levels compared to other standard transformers of the same kva rating
• Have low partial discharge resulting in longer operation lifetime
• Can be designed and manufactured to any special requirements
• Are suitable for large capacity (kva) requirements
• Have excellent ventilation capabilities and position of cooling radiator fins can be designed to suit the air flow direction of installation site thus allowing transformer to be installed on ground or area where ventilation is not optimum
• Allow the installation of extra cooling fans at the radiator fins
• Has higher durability and longer product usage lifetime compared to other oil type transformers
• Are able to perform at full kva (100% rating)
• Have lower operating noise levels compared to other standard transformers of the same kva rating
• Have low partial discharge resulting in longer operation lifetime
• Can be designed and manufactured to any special requirements
Technical Comparison Table
| Feature | Hermetically Sealed Transformer | Conservator Type Transformer |
| Air Exposure | Completely sealed (hermetic) | Breathes air via silica gel breather |
| Oil Expansion System | Internal bellows or corrugation | External conservator tank |
| Maintenance Requirement | Very low | Moderate to high |
| Moisture Protection | Excellent | Dependent on breather condition |
| Best Application Environment | Harsh, humid, enclosed | Outdoor, accessible substations |
| Initial Cost | Higher | Lower |
| Cooling Type | ONAN / ONAF | ONAN / ONAF |
