General
Application
Environmental
Standards
Oil filled distribution transformer with conservator is engineered for stable, efficient voltage transformation under varying load and ambient conditions. The external conservator maintains oil expansion margin, reduces oxidation, and stabilizes dielectric strength. Low-loss core design, robust windings, and optimized cooling keep temperature rise controlled, extending insulation life, minimizing maintenance interventions, and lowering total cost of ownership for long-term grid operation.
Oil-filled distribution transformers with conservator are deployed at utility substations, industrial plants, renewable interconnections, and commercial campuses to step down medium-voltage feeders. The conservator design tolerates wide ambient and load swings, maintaining oil margin and dielectric strength. This improves reliability, extends insulation life, and supports safe, continuous operation of LV switchgear, motor control centers, and building distribution networks over decades.
Application:outdoor installation.
Ambient temperature: -50°C to +40°C
Relative humidity: ≤90% (at 25°C); ambient air RH <93%.
Altitude: ≤1000m above sea level.
Max wind speed: ≤35 m/s.
Seismic withstand: Horizontal ≤0.3 g; Vertical ≤0.15 g.
Special conditions: Custom-built solutions available for project-specific requirements.
Ambient temperature: -50°C to +40°C
Relative humidity: ≤90% (at 25°C); ambient air RH <93%.
Altitude: ≤1000m above sea level.
Max wind speed: ≤35 m/s.
Seismic withstand: Horizontal ≤0.3 g; Vertical ≤0.15 g.
Special conditions: Custom-built solutions available for project-specific requirements.
ANSI/IEEE C57.12.00 — General Requirements and Safety Specifications
ANSI/IEEE C57.12.90 — Standard Test Methods
DOE 10 CFR Part 431 — Energy Conservation Standards
EN 50464-1 (series) — Requirements for Oil-Immersed Distribution Transformers
EN 50464-1 (series) — Requirements for Oil-Immersed Distribution Transformers
EN 61181 (based on IEC) — Dissolved Gas Analysis (DGA) in Factory Tests on Mineral Oil-Impregnated Electrical Equipment
ANSI/IEEE C57.12.90 — Standard Test Methods
DOE 10 CFR Part 431 — Energy Conservation Standards
EN 50464-1 (series) — Requirements for Oil-Immersed Distribution Transformers
EN 50464-1 (series) — Requirements for Oil-Immersed Distribution Transformers
EN 61181 (based on IEC) — Dissolved Gas Analysis (DGA) in Factory Tests on Mineral Oil-Impregnated Electrical Equipment
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Transformer Features
Flexible customization covers voltage ratio, capacity, winding material, bushing type, cooling structure, accessories, paint system, and protection devices.
Flexible Design - Well-matched to a Range of Applications.
The transformer can be engineered for IEC, IEEE, or local utility standards, supporting reliable integration into different medium-voltage distribution applications.
Space Saving – Effective, Flexible Layout
With optimized conservator placement and compact tank design, these transformers minimize footprint while ensuring efficient heat dissipation in congested substation environments.
Laborsaving – Reduction of Manpower
Pre-tested and pre-assembled units with sealed oil preservation systems simplify installation, significantly reducing onsite labor requirements and commissioning time.
Energy Saving – Reduced Operating Costs
Premium grain-oriented silicon steel cores minimize no-load losses (≤0.3 W/kg), meeting IEC 60076-20 Tier 2 efficiency standards to deliver long-term operating cost savings.
High Reliability – Long-term, Trouble-free Operation
Designed with robust tank construction, corrosion-resistant coatings, and vacuum-processed insulation for reliable performance under extreme environmental and load conditions.
Safe Design – Ensures Operator’s Safety
Multiple safety features including Buchholz relays, pressure relief devices, and flame-retardant materials ensure compliance with IEC, EN, and GOST safety standards.
Minimal Maintenance – Reduced Maintenance Costs
Our hermetically sealed conservator with silica gel breathers requires only decadal oil analysis, cutting maintenance costs by 20-25% versus conventional units.
Why Choose Kerun Intelec
Choose us for precision-engineered transformers—superior efficiency, global certifications, 24/7 support, and tailored solutions. Trusted durability, energy-saving innovation, ensuring optimal performance and longevity worldwide.
Fast Lead Times
Our made-to-order production timelines are highly competitive and as low as 8 weeks from order to delivery.
Design Conformance
We maintain rigorous oversight to ensure every transformer adheres precisely to your exact specifications.
Comprehensive Warranty
We stand behind the longevity and reliability of our products with a robust warranty that covers both materials and workmanship.
Competitive Pricing
We deliver exceptional value so you receive top-tier, reliable, high-quality products without the premium price tag
Exceptional Quality
We implement strict quality control measures at every stage of production to ensure our products meet or exceed industry standards.
Dedicated Support
Our support team is always at your service.Offering expert guidance from initial inquiry through post-installation support.
Standard Feature
HV&LV&Neutral bushings
Tap changer
Oil level gauge
Oil Thermometer indicator
Pressure relief device
Gas relay
Oil sample valve
Oil drain valve
Transformer breather
Earthing terminals
Lifting lugs
Rating plate
Optional Features
DIN/EN/ANSI bushings
Off Circuit/On-load Tap changer
Copper/aluminum windings
Dial type thermometer with two contacts
DGPT2 / RIS / DMCR control device
Pressure – vacuum gauge
Pressure relief valve with contacts
Winding Temperature Indicator
LV/HV Cable boxes / Common cable box
Protection CT
Bidirectional rollers
Design Drawings
Detailed oil-filled conservator distribution transformer drawings provide clear dimensions, interface data, and layouts, simplifying engineering coordination and installation.
10kV-400kVA-Distribution-Transformer-drawing
20kV-4000kVA-Distribution-Transformer-drawing
34.5kV-3800kVA-Distribution-Transformer-drawing
Accessories Include
Active Part
Main Tank
Tank Cover
Conservator Tank
Sealing Gaskets
Tank Cover
Radiators
HV Bushings
LV Bushings
Neutral Bushing
Tap Changer
Gas Relay
Pressure Relief Valve
Surge Arrester
Oil Temperature Indicator
Oil Filling Valve / Plug
Oil Drain Valve
Oil Sampling Valve
Oil Level Gauge
Magnetic Oil Level Indicator
Dehydrating Breather
Transformer Oil
Grounding Device
Lifting Lugs
Wheel
Cable Box
Nameplate
About Construction
Configurable accessories such as bushings, tap changers, monitoring devices and protection hardware enhance safety, observability, maintenance efficiency and long-term grounding reliability performance.
01
Tanks
02
Core
03
Coils
04
Transformer Active Part
05
Conservator
06
Corrugated radiator
Tanks
The tank of our oil filled distribution transformer with conservator is fabricated from low carbon steel plate, robot-welded for leak-tight seams and mechanical rigidity. Shot-blasting and electrostatic coating provide durable, reliable long-term corrosion protection for harsh outdoor service. Custom options include wall thickness, footprint, lifting and jacking details, radiators, conservator supports, and coating systems matched to the specific site environment.
Robotic welding ensures consistent seam quality and leak tightness.
Electrostatic coating system tailored for coastal or industrial atmospheres.
Core
The core of the oil filled distribution transformer with conservator can be specified in grain-oriented silicon steel or amorphous alloy, processed on a fully automatic transverse cutting line and automated stacking machine to maintain tight tolerances. Custom grades, lamination thickness, and step-lap patterns reduce no-load losses, lower noise, control magnetizing current, and improve efficiency under varying load and temperature conditions.
Fully automatic transverse cutting line ensures precise lamination dimensions.
Automated stacking machine maintains consistent step-lap overlap and alignment.
Coils
Coils in the oil filled distribution transformer with conservator are engineered around copper or aluminium HV/LV windings, with LV also available in Cu or Al foil for high-current, low-stress operation. Insulation systems can be tailored using DMD, Nomex® or Weidmann materials to achieve the required thermal class, dielectric margins, and short-circuit strength for each project and reliable long-term field performance.
HV/LV Winding materials:Cu/Al wire.LV also available in Cu/Al foil.
Insulation materials: optional DMD, Nomex®, or Weidmann.
Transformer Active Part
The active part of the oil filled distribution transformer with conservator integrates a low-loss, low-noise core, precision copper or aluminum coils, and rigid clamping frames that control magnetic forces and vibration. Optimized oil ducts and cooling paths limit hotspot temperatures and losses, while high mechanical strength and impact resistance improve short-circuit withstand and long-term reliability under demanding grid conditions worldwide.
Rigid clamping frames minimize vibration, noise and mechanical deformation.
Modular active part concept simplifies future refurbishment or power uprating.
Conservator
The conservator on the oil filled distribution transformer is a round, low carbon steel vessel manufactured with the same welded, blasted and electrostatically coated process as the main tank. It absorbs oil expansion, stabilizes internal pressure and limits moisture ingress, increasing dielectric margin, supporting temporary overloads and helping extend insulation life with configurable volume, supports and monitoring accessories.
Electrostatic coating aligned with tank system for uniform protection.
Supports temporary overloads by maintaining adequate oil headroom and margin.
Corrugated radiator
Corrugated radiators on the oil filled distribution transformer with conservator are manufactured from cold-rolled steel panels, pressed for rigidity and robot welded to ensure consistent, leak-tight seams and high mechanical strength. Optimized fin geometry improves natural oil circulation and cooling performance, while heights, fin spacing and connection details are fully customizable and coated to match the tank’s corrosion-resistant paint system.
Robot-welded seams improve leak tightness and dimensional consistency.
Radiator banks sectionalized to simplify isolation, maintenance and replacement.
About Accessories
Accessories can be customized according to transformer rating, installation environment, protection scheme, and utility operation requirements.
01
HV/LV Bushings
02
Tap Changer
03
Oil Level Indicator
04
Oil Thermometer indicator
05
Winding Temperature Indicator
06
Gas relay
07
Pressure relief device
08
Transformer breather
09
Oil sample Device
10
Terminal box
11
Earthing terminals
12
Lifting lugs
13
Nameplate
14
Wheel
HV/LV Bushings
Porcelain bushings for distribution transformers with Conservator cover flexible 6–36 kV ratings, DIN, EN or ANSI interfaces, and creepage distances matched to environmental requirements. High-strength internal insulation, configurable conductive angles, and clamping-plate or clamp-foot mounting ensure secure terminations, strong impact resistance and durable sealing, supporting long-term transformer reliability and reducing unplanned grid outages.
Voltage range: HV bushings available from 6–36 kV.
Type options: DIN, EN, or ANSI configurations available.
Tap changer
Tap changers for the oil filled distribution transformer with conservator can be specified as off-circuit or on-load designs, using high-conductivity copper contacts with silver or tin plating to minimize resistance and erosion. Tap range, step size and neutral position are engineered around system grid voltage variation, supporting precise regulation, reduced flicker and easier coordination with upstream and downstream protection settings.
Off-circuit or on-load tap changer options for flexible regulation.
Alternative tin-plated contacts support cost-sensitive, medium-duty applications reliably.
Oil level indicator
Oil level indicators on oil filled distribution transformers with conservator use corrosion-resistant housings, glass or polycarbonate windows and float-driven mechanisms to provide clear, stable readings of oil height. Optional low and high alarm contacts, customized scales and flexible mounting interfaces support early leak detection, safe loading margins and straightforward maintenance throughout service life.
Glass or polycarbonate windows provide clear, long-lasting visual indication.
Clear MIN and MAX markings support quick, unambiguous condition checks.
Oil Thermometer indicator
Thermometer indicators on oil filled distribution transformers with conservator use a stainless-steel case and brass sensing element to deliver accurate, repeatable top-oil temperature readings. A hermetically sealed body with shock-resistant glass withstands vibration, moisture and contamination, maintaining long-term calibration. Custom dial sizes, temperature ranges and alarm or trip contacts support safe loading decisions, coordinated protection settings and informed lifecycle management.
Clear dials with bold markings support quick, unambiguous visual checks.
Optional alarm contacts signal low oil conditions to SCADA.
Winding Temperature Indicator
The winding temperature indicator on oil filled distribution transformers with conservator with cable box simulates winding hot-spot temperature using a top-oil sensor and current-proportional heater. It drives alarm, trip, and cooling stages, reducing insulation ageing and unexpected outages. Options include multiple switch contacts, remote SCADA outputs, customized dial ranges, and dual scales, supporting flexible protection coordination and condition-based loading decisions during its life.
Provides continuous temperature indication for quick, on-site condition assessment.
Adjustable set points for tailored protection thresholds.
Gas relay
Gas relays on oil filled distribution transformers with conservator use aluminum alloy housings and corrosion-resistant internals to reliably detect gas accumulation and oil flow surges from internal faults. Options include Buchholz and sudden pressure types, with configurable flange patterns, contact schemes and protective coatings to match network protection philosophy, environmental conditions and ongoing maintenance practices.
Two-stage alarm and trip contacts enable graded protection responses.
Both standard Buchholz and rapid-response pressure relay types available
Pressure relief device
Pressure relief device on oil filled distribution transformers with conservator provides instantaneous overpressure protection through quick-reset diaphragm operation. It features an integrated visual indicator for local fault identification with optional electrical contacts for remote signaling. Available in single or multi-stage versions, customization includes pressure settings, connection sizes, and protective coatings.
Configurable set pressures tailored to transformer rating and fault duties.
Versatile selection including single-stage and multi-stage pressure release versions
Transformer breather
Transformer breathers on oil filled distribution transformers with conservator dry inhaled air before it reaches the oil, using silica gel or long-life desiccant cartridges to limit moisture ingress and preserve dielectric strength. Single or multi-chamber designs, clear inspection tubes, stainless-steel or coated bodies, and refillable or replaceable elements can be configured to match site humidity, maintenance intervals and mounting interfaces.
Single- or multi-chamber designs sized for different transformer capacities.
Sizing based on oil volume and breathing rate optimizes performance.
Oil Sample Device
The oil sampling device on oil filled distribution transformers with conservator provides a point for extracting representative liquid samples during operation and outages. Positioned at a convenient height and clearly identified, it supports dissolved-gas, moisture, acidity and dielectric-strength diagnostics. Rugged, corrosion-resistant construction, sealed connections and optional lockable cover protect personnel, prevent contamination, and help maintain insulation performance and asset reliability.
Tight sealing prevents moisture ingress and particulate contamination.
Enables convenient in-service oil sampling without planned outages.
Terminal box
Terminal boxes on oil filled distribution transformers with conservator house LV power and control wiring in sealed sheet-steel or stainless enclosures with gasketed covers and cable glands. IP-rated designs, segregated CT and relay sections, configurable terminal layouts, earthing bars and optional anti-condensation heaters can be tailored to local wiring standards, inspection practices and access requirements for long, reliable service in demanding environments.
IP55 protection rating ensuring complete dust and water ingress prevention
Multiple cable entry options including top, bottom, and side entry configurations
Earthing terminals
Earthing terminals on oil filled distribution transformers with conservator are designed to give a defined, low-impedance fault path between tank, core earthing and site grid. Heavy-duty copper or tinned-steel pads with galvanized hardware withstand high fault currents. Single, dual or multiple terminals, accessible locations and clear markings can be configured to match local grounding codes and maintenance practices.
Available in both single-point and multi-point grounding configurations for different applications
Uniform electro-tin plating providing superior corrosion resistance in harsh environments
Lifting lugs
Lifting lugs on oil filled distribution transformers with conservator are welded to reinforced tank zones and verified for the full oil-filled mass with appropriate safety margins. Configurable hole size, geometry and quantity support single-, two- or four-point lifting. Clear identification, shackle clearance and coordinated jacking pad locations help reduce rigging risk and simplify safe handling and installation.
Reinforced lifting lugs are welded into structurally strengthened tank zones.
Hole size and geometry customized to suit shackle and hook dimensions.
Nameplate
Rating plates on oil filled distribution transformers with conservator use stainless steel or anodized aluminum, with engraved or laser-etched characters that remain legible in outdoor service. Electrical ratings, impedance, losses, vector group, cooling and standard references are grouped in a single reference point. Custom layouts, languages and asset IDs support fast identification, field maintenance planning, compliance checks and technical documentation.
Key ratings, impedance and losses consolidated for quick on-site reference.
Consistent plate design across models simplifies training and field operations.
Wheel
Wheels on oil filled distribution transformers with conservator use high-load steel wheelsets with sealed bearings to support full operating weight and controlled movement. Rail and flat-floor versions are available, with removable bogies, defined jacking points, and locking or blocking options. Diameter, track gauge and surface treatment can be specified to match on-site handling methods and long-term maintenance practices.
High-load wheelsets support full transformer weight during movement.
Rail-compatible wheel profiles guide safe, controlled movement along tracks.
About Oil-Filled
High-grade mineral insulating oil delivers stable dielectric strength, efficient cooling, extended insulation life and long-term reliable transformer performance
Mineral Oil
Low Transformer Cost
Preventative maintenance
Good Dielectric Performance
Potentialhigher installation cost
Low Maintenance Cost
Vaults required for indoor installations per NEC® due to low fire
Good heat dissipation
<30% biodegradability
Good cold climate performance
Silicone Fluid
Low heat release
Non-biodegradable
Reduced smoke
Not suitable for use with internal Bay-O-Net fuses
Low flame
Transformer cost
Self extinguishing
Disposal cost
Good dielectric performance
Viton gaskets required
Low toxicity
Retrofil applications
Moderate viscosity
High transformer cost
High stability
High moisture absorption
Envirotemp FR3
High fire point—360 °C
Transformer cost (lower than silicone fluid)
High flash point—330 °C
Pour point (–15 °C to –25 °C) transformer energized with full load with top oil temperature at –50 °C with no problems—no crystals formed at –68°C
Compatible with mineral oil
Allows transformers to be designed to operate at 10°C higher average winding rise (75°C) without reducing normal transformer insulation life
Excellent dielectric performance
Excellent switching medium
Greater than 99% biodegradable
Excellent cold weather performance
Greater tolerance to moisture, dramatically extending insulation life
About Testing
Each transformer is tested to verify electrical performance, insulation strength, winding condition, losses, and safe operation before delivery.
Routine Tests
Type Tests
Special Tests
Winding resistance
Induced AC withstand voltage
Voltage ratio & polarity / phase displacement
Insulation resistance (IR/PI)
No-load loss & no-load current
Oil dielectric tests (BDV, moisture)
Load loss & short-circuit impedance
Tank / radiator leak tightness test
Applied AC withstand voltage
Functional checks
Temperature rise test
Lightning impulse withstand test
Sound level measurement
Short-circuit withstand test
Partial discharge measurement
Capacitance & dissipation factor (tan δ)
Zero-sequence impedance
SFRA (frequency response analysis)
Dielectric response (FDS/PDC)
Stray loss / harmonic loss verification
DGA baseline (oil)
Vacuum / pressure mechanical test (tank)
Coating / corrosion protection tests
Accessories calibration / functional verification
All transformers undergo strict testing based on the latest ieee and iec standards, with detailed reports ensuring traceability. this guarantees each unit meets the highest standards of quality, safety, and performance.
Package & Delivery
Engineered packaging and coordinated logistics protect transformers in transit, simplify site handling, and support safe, on-time delivery worldwide
Wooden / Steel Skid with Sealing Film
For nearby deliveries, we recommend skid plus sealing film when you need economical protection, forklift handling and quick onsite positioning.
Wooden / Steel Frame
We suggest wooden or steel framing when you require protection for protruding parts, highway transport, repeated loading and open-deck shipping.
Wooden Crate
Preferred for export and long routes; closed crates protect from weather, dirt and impact, allow stacking and minimise accessory loss.
Container Shipment
Ideal for high-value or overseas projects; containers improve weather protection, security and standardised lashing, simplifying sea–rail–road multimodal logistics.
Transportation & Delivery
We propose skid, frame, crate or container options based on route, handling and budget, ensuring safe, efficient transformer delivery.
Review key FAQ before purchasing a Distribution Transformer with Conservator, covering lead time, grid standard customization,certified components, factory testing, installation support, and long-term reliable operation.
What Is The Lead Time For A Distribution Transformer with Conservator?
The typical lead time for a Distribution Transformer with Conservator is 4 to 8 weeks, depending on rated capacity, voltage class,
winding material, conservator design, radiator configuration, accessories, factory testing, drawing approval, and transportation requirements.
winding material, conservator design, radiator configuration, accessories, factory testing, drawing approval, and transportation requirements.
Can The Transformer Be Customized For Different Grid Standards?
The transformer can be customized according to IEC, IEEE/ANSI, EN, or local utility standards. Project-required certificates, test reports, CE,KEMA,KERI or related documents, and third-party inspection reports can be provided where applicable.
What Customization Options Are Available For A Distribution Transformer with Conservator?
Customization options include winding material, insulation system, conservator tank, oil level indicator, breather, radiator type,
bushing type, transformer oil, tap changer, protection devices, monitoring accessories, enclosure coating, and anti-corrosion treatment.
bushing type, transformer oil, tap changer, protection devices, monitoring accessories, enclosure coating, and anti-corrosion treatment.
What Tests Are Performed Before Delivery?
Routine tests include winding resistance, voltage ratio, vector group, impedance, load loss, no-load loss, insulation resistance, applied voltage, induced voltage, leak test, and oil tests. Type and special tests can be arranged as required, and third-party witnessed FAT.
Do You Support Installation And Commissioning?
Installation and commissioning support can be provided by documents, remote guidance, video support, or on-site engineers. Support includes
oil level checking, accessory assembly, wiring checks, grounding inspection, protection verification, pre-energization inspection, and commissioning coordination.
oil level checking, accessory assembly, wiring checks, grounding inspection, protection verification, pre-energization inspection, and commissioning coordination.
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Kerun Intelec
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