S Series Oil immersed Transformer

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  • S Series Oil immersed Transformer
  • S Series Oil immersed Transformer

S Series Oil immersed Transformer

S Series Oil Immersed Transformer is designed for medium voltage power distribution systems, providing reliable voltage conversion, stable operation, and long service life for utility networks, industrial facilities, infrastructure projects, and renewable energy applications.

As a key product within Oil Immersed Transformers, the S Series adopts cold rolled grain-oriented silicon steel core, copper or aluminum windings, insulating oil, and fully sealed corrugated oil tank technology. The product covers S9, S11, S13, S20, and S22 energy efficiency series to meet different distribution requirements.

The transformer adopts vacuum drying, vacuum oil filling, and sealing inspection processes to improve insulation reliability and operating stability. It supports ONAN natural cooling and optional ONAF forced air cooling, with optional monitoring accessories including oil temperature, oil level, pressure, gas relay protection, and remote monitoring systems.

As an Oil Immersed Distribution Transformer, the S Series can be customized according to project requirements, including capacity, voltage level, frequency, winding material, voltage regulation, cooling method, protection accessories, and environmental adaptation.

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  • Product Details
  • FAQ
Product Type
S Series Oil Immersed Transformer
Rated Capacity
30 kVA–6300 kVA
Voltage Level
6 kV–35 kV
Core Material
Cold Rolled Grain-Oriented Silicon Steel
Winding Conductor
Copper or Aluminum
Cooling Method
ONAN; ONAF Optional
Frequency
50 Hz / 60 Hz
Voltage Regulation
Off-circuit Tap Changer; OLTC Optional
Tank Structure
Fully Sealed Corrugated Oil Tank
Energy Efficiency Series
S9 / S11 / S13 / S20 / S22
Special Environment
High Temperature, High Altitude, Salt Fog, Humidity, Dust, Corrosion Protection
Monitoring Options
Oil Temperature, Oil Level, Pressure, Gas Relay, Remote Monitoring
Design Standards
IEC 60076, GB/T 1094, ANSI/IEEE or Customer Specifications

1. What is an Oil Immersed Distribution Transformer used for?
An Oil Immersed Distribution Transformer is used in medium voltage power distribution systems to convert voltage levels and provide reliable electricity supply.
The S Series is commonly applied in utility networks, industrial facilities, infrastructure projects, and renewable energy systems.

2. What is the difference between Oil Immersed Transformers and Dry Type Transformers?
Oil Immersed Transformers use insulating oil for insulation and heat dissipation, making them suitable for outdoor distribution networks, utilities, and industrial applications.
Dry Type Transformers do not contain insulating oil and are commonly selected for indoor applications with higher fire safety requirements.
The selection depends on installation environment, safety requirements, maintenance conditions, and lifecycle cost.

3. How should S9, S11, S13, S20, and S22 transformers be selected?
Different series represent different design platforms and energy efficiency levels.
Selection should consider:
Applicable standards
Guaranteed no-load loss
Load loss
Operating hours
Load characteristics
Project efficiency requirements

4. What are the differences between ONAN and ONAF cooling?
ONAN uses natural oil circulation and natural air cooling.
ONAF adds forced air cooling through fans to improve heat dissipation capability.
The suitable cooling method depends on transformer capacity, thermal design, ambient temperature, and operating conditions.

5. Can Jiangsu Xinxin Electric provide customized Oil Immersed Distribution Transformers?
Yes.
As an Oil Immersed Distribution Transformer Manufacturer, Jiangsu Xinxin Electric provides OEM and ODM solutions including:
Electrical parameter customization
Structural design
Accessory configuration
Environmental adaptation
Branding and technical documentation

  • Product Features

Energy Efficient Core Design
The Oil Immersed Transformer uses cold rolled grain-oriented silicon steel core with optimized magnetic circuit design and 45° mitered joints.
The low-loss core structure helps reduce no-load loss, no-load current, and operating noise, improving energy efficiency for long-term power distribution operation.
The transformer can be configured according to different energy efficiency requirements, with performance evaluated based on guaranteed loss values and project operating conditions.

Reliable Winding and Short-Circuit Performance
Copper or aluminum winding solutions are available according to project requirements.
The winding structure is designed according to current density, temperature rise, impedance, and short-circuit mechanical strength requirements to ensure reliable operation under different load conditions.

Fully Sealed Corrugated Oil Tank
The fully sealed corrugated oil tank integrates heat dissipation and oil volume compensation functions.
The sealed structure reduces direct contact between insulating oil and external air, helping slow oil oxidation and reduce maintenance requirements.
Vacuum drying and vacuum oil filling processes improve insulation performance and long-term operating reliability.

Flexible Cooling and Monitoring Configuration
The S Series Oil Immersed Transformer supports ONAN natural cooling for standard applications.
For higher heat dissipation requirements, ONAF forced air cooling can be configured according to project conditions.

Optional accessories include:
Oil temperature indicators
Oil level indicators
Pressure relief devices
Gas relay protection
Temperature monitoring systems
Remote communication interfaces
Adaptation for Different Environments

The Oil Immersed Distribution Transformer can be designed for various operating environments, including:
High temperature areas
High altitude installations
Coastal salt fog environments
Humid conditions
Dusty industrial locations
Corrosive environments
Customized solutions may include enhanced sealing, insulation coordination, cooling optimization, and corrosion protection.

  • Application Fields
Application Area
Typical Applications
Industries Served
Power Distribution Networks
Urban distribution networks, rural grid upgrades, utility substations, energy-saving distribution projects
Utilities, power distribution companies, EPC contractors
Industrial Facilities
Manufacturing plants, mining projects, petrochemical facilities, steel plants, industrial parks
Industrial companies, EPC contractors, electrical system integrators
Renewable Energy Projects
Solar power plants, wind power projects, energy storage systems, auxiliary power supply systems
Renewable energy developers, system integrators, EPC companies
Infrastructure Projects
Airports, ports, rail transit, municipal facilities, public infrastructure
Infrastructure contractors, engineering companies
Commercial Power Systems
Commercial buildings, business parks, building distribution systems
Building contractors, electrical contractors, property developers

  • OEM·ODM

Jiangsu Xinxin Electric provides OEM, ODM, and customized Oil Immersed Transformer solutions for utilities, EPC contractors, distributors, and equipment manufacturers.
Customized solutions are developed according to technical specifications, drawings, environmental conditions, and project requirements.

Customization Module Available Options
Electrical Design: Capacity, voltage, frequency, vector group, impedance, tap range, loss requirements, temperature rise
Structural Design: Tank dimensions, terminal arrangement, cable connection, base structure, lifting points
Environmental Adaptation: High temperature, high altitude, salt fog, humidity, dust, corrosion protection
Regulation & Protection: OLTC, off-circuit tap changer, temperature monitoring, oil level monitoring, pressure protection
System Integration: Switchgear, ring main units, protection systems, SCADA and monitoring interfaces
Branding & Documents: OEM nameplate, labels, manuals, drawings, packaging marks, technical documents

  • Why Choose Us

Complete Transformer Product Capability
Jiangsu Xinxin Electric provides transformer solutions including:
Oil Immersed Transformers
Oil Immersed Distribution Transformers
Dry Type Transformers
Amorphous Alloy Transformers
Box Type Substations
This allows EPC contractors, distributors, and system integrators to coordinate different power distribution requirements with one supplier.

Engineering Customization Capability
The company supports project-specific design covering:
Electrical parameters
Mechanical structure
Cooling methods
Protection accessories
Environmental adaptation
Technical documentation
All solutions are reviewed according to approved specifications and project requirements.

Quality Control and Project Support
Manufacturing follows controlled procedures including:
Technical review
Material inspection
Core and winding process control
Vacuum drying and oil filling
Assembly inspection
Electrical testing

Jiangsu Xinxin Electric can provide:
Technical data sheets
Drawings
Test reports
Nameplates
Operation manuals
Export documentation according to IEC, GB, ANSI/IEEE, or customer-specific requirements.

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About Xinxin Electric

Xinxin Electric operates a 30,000 m2 manufacturing facility and specializes in transformers and prefabricated substations. With a commitment to quality and integrity, we provide equipment and technical support for power projects worldwide.
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  • 2026/08.25 Exhibitions

    Jiangsu XinXin Electric Co., Ltd. Shines at the 2025 Indonesia International Power Exhibition—Showcasing China's Smart Manufacturing Power and Supporting Indonesia's Green Energy Transition

    From September 17 to 20, 2025, Mr. Zhan Chungen, Chairman of Jiangsu XinXin Electric Co., Ltd., along with Sales General Manager Mr. Wang Hua and their team, attended the "Electric & Power Indonesia 2025," the International Exhibition on Power Generation, Renewable Energy, and Electrical Equipment held in Jakarta, Indonesia. This year’s event focused on upgrading Southeast Asia’s power infrastructure and advancing renewable energy development. This exhibition highlights our company's latest Energy‑efficient transformer series These products include the S14‑M, S20‑M, and S22‑M series oil‑immersed power transformers, as well as the SCB14 and SCB18 series dry‑type transformers, among others. XinXin Electric's transformer products feature High protection level and excellent thermal design, capable of adapting to Indonesia's hot and humid environmental conditions. Several Indonesian power industry experts made a special trip to the XinXin Electric booth to engage in in‑depth technical exchanges and discuss potential collaborations. This year's exhibition holds significant strategic importance for XinXin Electric in expanding into the Southeast Asian market. Indonesia, as the largest economy in Southeast Asia, is actively promoting a transformation of its energy structure. Chairman Zhan Chungen stated during the exhibition: " Southeast Asia is a key component of our globalization strategy. "We will contribute China's strength to Indonesia's power development, leveraging advanced technology and reliable product quality." Xinxin Electric also plans to leverage this exhibition to connect with power equipment importers, distributors, and agents from Indonesia and Southeast Asia, discussing new business opportunities in this rapidly growing industry. Leveraging this exhibition, XinXin Electric has further expanded its brand presence in the Southeast Asian market, laying a solid foundation for deeper penetration into the local market in the future.
  • 2026/08.25 Company News

    Deepening School‑Enterprise Cooperation to Cultivate Industrial Talents — Jiangsu XinXin Electric Co., Ltd. Receives Visiting Leaders from Nanjing University

    Jiangsu XinXin Electric Co., Ltd. (hereinafter referred to as "XinXin Electric") has always attached great importance to industry‑university‑research collaborative innovation, as well as the recruitment and cultivation of high‑quality talents. On June 12, the company was honored to receive a delegation from Nanjing University, led by Professor Zhu Songqing, Member of the Standing Committee and Vice‑President of the University Party Committee. Both sides held fruitful exchanges on deepening school‑enterprise cooperation and advancing the integration of production and education. During the on‑site exchange, Mr. Zhan Chungen, Executive Director of XinXin Electric, gave the delegation led by Vice‑President Zhu Songqing a detailed introduction to the company’s development history, core business layout, advanced production processes, and technological strengths in the R&D and manufacturing of new‑energy electrical equipment. Mr. Zhan highlighted the company’s urgent demand for and long‑term planning of university talents. He expressed sincere expectations for further in‑depth and extensive substantive cooperation with Nanjing University in key areas, including close school‑enterprise integration, joint construction of high‑level internship and training bases, and joint incubation of innovation and entrepreneurship projects. Mr. Zhan stated that XinXin Electric’s development relies on innovation and talent support. Universities serve as an important source of talent and innovation, promising broad prospects for bilateral cooperation. After the briefing, Vice‑President Zhu Songqing spoke highly of XinXin Electric’s industry standing and achievements. He introduced Nanjing University’s disciplinary features, industry‑university‑research cooperation foundation, as well as student employment and entrepreneurship work. Vice‑President Zhu noted that the university will give full play to its disciplinary advantages and industry influence, integrate scientific research and talent resources with industrial resources, and align them with XinXin Electric’s technical strengths to jointly build a high‑level platform for talent training and innovative practice. He emphasized that this initiative aims to implement the integrated development strategy of education, science & technology and talent, so as to boost the sound development of the local economy and society. Vice‑President Zhu’s positive response has boosted XinXin Electric’s confidence in future cooperation. This high‑level exchange marks an important step for XinXin Electric to deepen its strategic partnership with universities. The company firmly believes that close cooperation with Nanjing University will effectively expand talent recruitment channels, optimize its talent structure, accelerate the transformation of scientific and technological achievements, and enhance its core competitiveness. It will also contribute “XinXin” strength to local industrial upgrading and economic growth. XinXin Electric will keep seizing opportunities and looks forward to conducting pragmatic multi‑dimensional and in‑depth cooperation with universities, jointly opening a new chapter for win‑win school‑enterprise collaboration.
  • 2026/08.25 Industry News

    How to Install the Transformer

    1. Construction Prerequisites (1) Drawings shall be reviewed, and detailed operating instructions shall be prepared and approved in accordance with the manufacturer’s technical data. (2) Construction quality for works related to box‑type transformer installation shall comply with current national codes for construction and acceptance of building works. (3) Positions of embedded parts and pre‑buried cable conduits shall satisfy design requirements, and all embedded parts shall be securely fixed. 2. Construction Preparation 2.1 Transformer Foundation Inspection (1) Inspect the construction quality of the transformer foundation and fill in the inspection record sheet. The record shall be signed and confirmed by all relevant parties. Any defects found shall be reported and rectified promptly. (2) Carefully verify the horizontal and longitudinal axis dimensions of the transformer foundation as well as the positions of pre‑buried conduits, and cross‑check against drawing dimensions. Proceed with subsequent work only after all dimensions are confirmed correct. 2.2 Transformer Unpacking Inspection (1) Upon arrival, the transformer shall be unpacked and inspected jointly by representatives of the owner, supervisor and manufacturer. (2) Measure and record the reading of the shock recorder before unloading; the impact value shall be less than 3G. (3) Inspect the transformer exterior for damage and confirm complete paint finish, and keep relevant records. (4) Check internal components of the transformer for displacement, contamination and other abnormalities. 3. Transformer Positioning & Installation (1) Mount the channel‑steel foundation onto embedded parts. Perform levelling and alignment. Weld the channel‑steel foundation firmly to embedded parts. Remove welding slag from welds and apply anti‑corrosive paint. (2) After hoisting the fan unit, hoist the transformer directly onto the foundation, then use jacks for levelling and alignment. (3) Connect the transformer to the foundation following the fixing method (bolted connection or welding) specified by the manufacturer. (4) In case of split delivery, install the enclosure after the transformer is positioned and oriented. (5) Affix nameplates and clean the interior of the transformer cabinet. (6) Implement finished‑product protection prior to commencing subsequent procedures.
  • 2026/08.25 Industry News

    Do Dry‑Type Transformers Need to Be De‑energized?

    Dry‑type transformers are widely applied for local lighting, high‑rise buildings, airports, wharves, CNC machinery and other facilities. Simply put, a dry‑type transformer is a transformer whose core and windings are not immersed in insulating oil. Under what conditions shall a dry‑type transformer be immediately de‑energized? Fire occurs on the dry‑type transformer; the unit must be shut down immediately. Severe damage or discharge phenomena are observed on the transformer bushing. Stop operation immediately and arrange inspection by qualified professionals. Heavy smoke is emitted from the transformer. Abnormal, loud internal noise accompanied by explosion‑like sounds inside the transformer. Immediate shutdown is mandatory to prevent hazardous accidents. Abnormally high and continuously rising temperature under normal load and cooling conditions. When any of the above‑mentioned symptoms appear, the dry‑type transformer must be de‑energized right away. Continuing operation under such faults may cause personal injury as well as permanent damage to the transformer. These issues shall be addressed promptly. Exercise great caution when encountering any of the above‑mentioned conditions to avoid hazards. Yizheng Hongxin Transformer Co., Ltd. specializes in transformers, including dry‑type transformers, power transformers and oil‑immersed transformers. As a transformer manufacturer based in Jiangsu Province, our plant produces dry‑type transformers, power transformers and oil‑immersed transformers. The company is situated in the Economic Development Zone of Yizheng City, Jiangsu Province, within the Yangtze River Delta. It lies at the geographic heart of the Nanjing‑Zhenjiang‑Yangzhou Silver Triangle region. To its west is Nanjing, to its east Yangzhou; it borders the Yangtze River in the south and faces Zhenjiang across the river. Close to the Nantong‑Nanjing Expressway, it enjoys distinctly advantageous geographic conditions. Boasting years of experience in power transformer design and manufacturing, the company is equipped with advanced production facilities and mature manufacturing techniques. We deliver reliable‑quality products and maintain a solid market reputation. We look forward to cooperating with customers for mutual development and shared success!
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