700kVA Oil Immersed Transformer
The 700kVA Oil Immersed Transformer is a high-performance three-phase distribution transformer optimized for dependable medium-voltage power conversion in 50/60Hz AC grids, featuring primary ratings of 11kV or 33kV and secondary at 0.4kV/0.415kV/0.433kV. It adopts a fully hermetically sealed corrugated tank construction for automatic volume compensation, delivering outstanding resistance to humidity ingress, corrosion. Incorporating low-loss grain-oriented silicon steel core (S11/S13 series compliant) for minimized no-load losses (typically 950-1300W), high-conductivity copper windings, and premium-grade mineral insulating oil (IEC 60296 certified, dielectric >55kV/2.5mm).
- Primary Voltage Ratings 34.5-19.92/13.8-7.957, 24.94, 26.25, 33 or others
- Secondary Voltage Ratings 480/277V, 400/230V, 380/220V or customized
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Oil immersed distribution transformer
- BIL 30/95kV
- Standards IEEE, ANSI, NEMA, IEC, CE
- Application industrial plants, residential communities
- Power Rating 700kVA
- Certificate UL, CESI, IEEE
- Cooling Method ONAN, ONAN/ONAF, KNAN, KNAN/KNAF
- Oil Mineral Oil or FR3
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
700kVA Oil Immersed Transformer
Technical Specifications
Accessories
| Rated Power | 700kVA | |
| Rating Primary Voltage | 2.4 - 34.5kV | |
| Secondary Voltage | 480/277V 400/230V 380/220V Customized |
|
| Frequency | 50/60Hz | |
| Vector Group | Dyn11, Yyn0, Dyn5 | |
| Winding Material | Aluminum/Copper | |
| Efficiency | As IEEE, Doe 2016, CAS Std or Customized | |
| Impedance Voltage | Nominal 2% or Customized 1.1 - 5.75% | |
| Altitude | ≤1,000m or Customized | |
| Color | ANSI 70 Light gray/Munsell 7GY3.29/1.5 or customized, etc | |
| Tank material | Mild Steel, 304 Stainless Steel | |
| Insulating Oil Weight | 900 kg | |
| Total Weight | 3100 kg | |
| Outline Dimensions（L×W×H）in. | 1950 × 1060 × 1900（mm) | |
| HV Bushing |
| LV Bushing |
| Tap changer |
| Oil level gauge |
| Oil temperature indicator |
| Pressure relief device |
| Pressure vacuum gauge |
| Lifting hook for complete transformer |
| Name plate |
| Radiators |
| Oil upper filtering valve |
| Oil drain valve with 3/8" sampler |
Customization Optional
700kVA Oil Immersed Transformer
The 700kVA oil immersed transformer provides extensive tailoring to address unique voltage specifications, efficiency goals, environmental exposures, and deployment needs. Primary voltages cover 11kV or 33kV (with flexible options including 6.6kV/10kV/20kV/22kV), secondary voltages at 0.4kV, 0.415kV, 0.433kV, or project-defined low-voltage setups. Off-circuit tap changers deliver ±2×2.5% or ±5% fine-tuning for consistent output, while on-load tap changers (OLTC) support automated voltage management under varying demands. Core choices include conventional grain-oriented silicon steel for reliable low losses or amorphous metal cores to cut no-load losses by 60-70%, maximizing energy efficiency. Winding configurations feature premium copper for top-tier conductivity and thermal performance or aluminum for optimized cost without sacrificing durability.
Further enhancements encompass cooling system upgrades (additional fins or forced air for high-temperature environments up to +50°C), insulating oils (standard mineral or eco-friendly natural esters compliant with IEC 61099 for fire safety and sustainability), and tank modifications with hermetic sealing, superior anti-corrosion treatments (C3/C5 marine-grade), seismic-resistant designs, or increased IP ratings for coastal or contaminated areas. Integrated accessories cover oil level monitors, winding temperature probes, IoT-enabled remote monitoring systems, gas-actuated relays, and conservator additions for specific preferences. Impedance values (4.5-6%), vector groups (Dyn11, Yyn0, etc.), BIL insulation classes (75kV for 11kV, 170kV for 33kV), frequency adaptations (50/60Hz), acoustic dampening options, and alignment with IEC 60076, GB1094, or local efficiency standards are all adjustable. Our dedicated specialists work in partnership to craft bespoke configurations ideal for utility distribution feeders, commercial facilities, manufacturing plants, or solar farm connections, focusing on superior efficiency, extended durability, reduced ownership expenses, and flawless compatibility with existing infrastructure.
Packing and Shipping
700kVA Oil Immersed Transformer
Ensuring the safe transit of the 700kVA oil immersed transformer demands rigorous safeguards to protect core stability, winding integrity, and insulating oil purity from mechanical impacts, climatic fluctuations, and logistical hazards. Pre-shipment inspections cover tank pressure/leak integrity (positive pressure verification), bushing/terminal securement, oil quality sampling (dielectric >55kV/2.5mm, low moisture/acidity), and protective device functionality. Most units depart oil-filled under controlled nitrogen overpressure (0.02-0.05MPa) to exclude air and moisture; for transport weight limitations, oil is partially or completely removed into sealed, certified drums, accompanied by vacuum processing equipment and equivalent high-purity oil supplies for site re-filling according to IEC protocols.
Component-level protection includes radiators individually crated with vibration-isolating padding, high-voltage bushings in reinforced, shock-absorbent cases, and auxiliary controls sealed with humidity absorbers. The transformer body is anchored to heavy-duty ISPM-15 compliant wooden crates or steel platforms incorporating precise blocking, side restraints, and impact-dampening systems engineered for 4-5g transport accelerations. Full packaging layers feature durable weather barriers, volatile corrosion inhibitors, environmental indicators for humidity/temperature, and electronic shock/tilt monitors to record handling conditions.
Ocean transportation, prevalent for global exports, utilizes flat-rack or open-top containers secured per IMO lashing guidelines, with salt-resistant coverings and protective enclosures; overland/rail movements employ specialized low-loader trailers with weight-balanced supports and accessible lift points. Export documentation encompasses commercial invoices, detailed packing lists, certificates of origin and conformity, routine test protocols, engineering drawings (dimensional/lifting), oil material safety data sheets, installation/handling instructions, and HS code classifications (8504.21 for distribution transformers ≤650kVA, or adjusted per rating).
We deliver integrated logistics services from origin to destination, including FOB/CIF/door-to-door arrangements, customs brokerage, cargo insurance, and premium add-ons such as independent inspections, professional rigging at arrival, on-site oil reclamation/degassing, erection supervision, and commissioning support. This end-to-end approach eliminates transit vulnerabilities, upholds factory-fresh performance, satisfies international compliance, and guarantees efficient, damage-free arrival for clients in distribution, commercial, and industrial sectors worldwide.
Component-level protection includes radiators individually crated with vibration-isolating padding, high-voltage bushings in reinforced, shock-absorbent cases, and auxiliary controls sealed with humidity absorbers. The transformer body is anchored to heavy-duty ISPM-15 compliant wooden crates or steel platforms incorporating precise blocking, side restraints, and impact-dampening systems engineered for 4-5g transport accelerations. Full packaging layers feature durable weather barriers, volatile corrosion inhibitors, environmental indicators for humidity/temperature, and electronic shock/tilt monitors to record handling conditions.
Ocean transportation, prevalent for global exports, utilizes flat-rack or open-top containers secured per IMO lashing guidelines, with salt-resistant coverings and protective enclosures; overland/rail movements employ specialized low-loader trailers with weight-balanced supports and accessible lift points. Export documentation encompasses commercial invoices, detailed packing lists, certificates of origin and conformity, routine test protocols, engineering drawings (dimensional/lifting), oil material safety data sheets, installation/handling instructions, and HS code classifications (8504.21 for distribution transformers ≤650kVA, or adjusted per rating).
We deliver integrated logistics services from origin to destination, including FOB/CIF/door-to-door arrangements, customs brokerage, cargo insurance, and premium add-ons such as independent inspections, professional rigging at arrival, on-site oil reclamation/degassing, erection supervision, and commissioning support. This end-to-end approach eliminates transit vulnerabilities, upholds factory-fresh performance, satisfies international compliance, and guarantees efficient, damage-free arrival for clients in distribution, commercial, and industrial sectors worldwide.
32
32 years of industry experience
Manufacturer Test
700kVA Oil Immersed Transformer
Progress Test
Progress testing for the 700kVA oil immersed transformer initiates with grain-oriented silicon steel sheet evaluation for uniform thickness insulation coating magnetic permeability and precise edge preparation through Epstein frame analysis to achieve minimal core losses then core stacking progress verifies optimized step-lap miter joints uniform clamping torque electromagnetic symmetry and effective vibration damping. Winding fabrication progress monitors conductor purity enamel insulation layering automated tension consistency turn counting accuracy and inter-layer dielectric withstand verification after winding completion. Core-coil assembly progress confirms critical radial axial clearances pressboard spacer placement end-turn insulation integrity and robust compression structures resistant to short-circuit forces. Tank manufacturing progress inspects multi-pass weld seam quality hydrostatic pressure resistance surface grit-blasting epoxy primer topcoat DFT compliance and long-term corrosion protection pre-assembly progress checks bushing radiator valve precise alignment accessory mounting and preliminary vacuum pressure cycle tests to uncover early defects ensuring seamless advancement to comprehensive qualification.
Design Tests
All transformers will be tested after finishing the production, test items as follows:
♦ Insulation Power Factor
♦ Ratio, Polarity, and Phase Relation
♦ Winding Resistance
♦ Impulse Tests
♦ On load Loss Test
♦ No Load Loss Test
♦ Leak Test
♦ DC Insulation Resistance Test
♦ Transformer Turns Ratio/TTR (All Tap Voltages)
♦ Impedance Voltage & Load Loss (Rated Voltage)
♦ Polarity, 1-Ph / Phase Relation, 3-Ph (Rated Voltage)
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
♦ Dielectric Withstand (Hipot)
Transformer Factory Acceptance Test
Load loss short-circuit impedance efficiency tests for the 700kVA oil immersed transformer short secondary apply reduced primary voltage compute copper losses impedance percentage (~4.5-6%) total losses at 75°C for regulation overload predictions. Oil routine testing verifies dielectric strength (>55kV/2.5mm) water content (<30ppm) acidity initial DGA profile absent fault indicators. Temperature rise indicators confirm gauge accuracy alarm thresholds. Functional verification includes pressure relief device activation gas relay tripping tap changer full-range operation and acoustic power level (<58dB). Mechanical integrity checks encompass tank overpressure endurance leak-free seals bushing coordination wiring continuity. Comprehensive FAT documentation with traceable calibration certificates optional client third-party witnessing certifies IEC 60076 GB/T6451 full compliance routine type test fulfillment prior to release authorization.
Routine Test - Leak Test
Purpose of Testing
The purpose of water leakage test is to check whether there is leakage in the equipment or system, to ensure that it has good sealing and safety during use. The integrity of the equipment can be verified by simulating the pressure or load conditions in the working environment.
Testing Equipment
Leakage current tester (e.g. Fluke, Hioki, Megger, etc.)
Voltage source (usually 500V, 1 KV or 2.5 KV, customized according to test requirements)
Temperature and humidity meter
Ground electrode
Voltage source (usually 500V, 1 KV or 2.5 KV, customized according to test requirements)
Temperature and humidity meter
Ground electrode
Pre-Test Preparation
Ensure that the test environment conditions are suitable for leak testing. Test between 20°C and 30°C. Relative humidity should be less than 75% to avoid moisture affecting the test equipment and results.
Test Progress
Connect the Test Instrument:
Properly connect the test equipment (such as a leak detector) to the pipe, container or sealing structure of the device under test.
Apply Test Voltage:
Apply the appropriate test pressure (e.g. 10 bar, 15 bar, etc.) depending on the equipment's operating pressure or test standard.
Properly connect the test equipment (such as a leak detector) to the pipe, container or sealing structure of the device under test.
Apply Test Voltage:
Apply the appropriate test pressure (e.g. 10 bar, 15 bar, etc.) depending on the equipment's operating pressure or test standard.
Measure and Record
Start the test and record the following parameters:
Applied test pressure
Leakage (can be monitored by flow meter or other equipment)
Time record (to ensure that the test time meets the standard requirements)
Initial pressure and final pressure (if any changes)
Applied test pressure
Leakage (can be monitored by flow meter or other equipment)
Time record (to ensure that the test time meets the standard requirements)
Initial pressure and final pressure (if any changes)
Check for leaks
Check for leaks on equipment surfaces and joints by using a foam detector, gas leak detector, or other suitable method.
Repeat Testing (if necessary)
If the test finds leakage or there is any doubt, repeat the test as necessary to verify the sealing of different locations or different equipment parts.
Evaluation Criteria (Reference)
No leakage (excellent): No leakage during the test, the equipment is completely sealed.
Minor leakage (good): Very small leakage is allowed, and it is necessary to judge whether it is qualified according to industry standards.
Minor leakage (good): Very small leakage is allowed, and it is necessary to judge whether it is qualified according to industry standards.
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
It is suitable for various combined scenarios such as power supply for medium-sized commercial complexes, power distribution in industrial plants, substations in residential communities, critical loads in hospitals and schools, grid connection of medium-sized photovoltaic power stations, power consumption in agricultural processing plants, and power distribution in office parks, providing 700kVA of efficient and reliable voltage conversion and energy-saving distribution.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
Product Packaging
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What is a Transformer?A transformer is an electrical device used to change the voltage of alternating current (AC). It works on the principle of electromagnetic induction, converting high-voltage current into low-voltage current or low-voltage current into high-voltage current. Transformers are widely used in power transmission, distribution systems, and various electronic devices.
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What are the main uses of a transformer?The main use of a transformer is voltage conversion. Transformers are used in power transmission systems to help transfer electricity from power plants to consumers. In addition, transformers are also used in electronic devices such as chargers, televisions, power adapters, etc., to adjust the voltage to meet the requirements of different devices.
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Do you have UL listed?Yes, our transformer has UL listed. We have exported to America many pad mounted transformer,substation transformer and HV.
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