35Kv 200Kva 300Kva Three Phase Oil Immersed Transformers

1. Product Description

35Kv 200Kva 300Kva Three Phase Oil Immersed Transformers are mainstream medium-capacity three-phase power distribution transformers widely used in 35kV medium-voltage power grid systems and industrial power supply projects. These S11/S13 series low-loss oil-filled transformers adopt mature oil-immersed cooling and fully sealed structural design, serving as core step-down power conversion equipment for industrial and municipal power distribution terminals. Manufactured in strict accordance with IEC 60076 and GB/T 1094 international power industry standards, both 200kVA and 300kVA 35kV three-phase oil immersed transformers undergo rigorous factory tests including insulation performance detection, loss calibration and short-circuit resistance verification to ensure stable and reliable long-term field operation.

Equipped with high-permeability low-loss grain-oriented silicon steel core and high-purity oxygen-free copper three-phase windings, these 35kV medium-voltage distribution transformers effectively reduce no-load magnetic loss and load copper loss, realizing low energy consumption and low temperature rise during continuous full-load operation. Adopting standard Dyn11 vector group connection, the transformers optimize three-phase current and voltage balance, suppress power grid harmonics and zero-sequence current, and solve common power quality problems such as unbalanced three-phase load and voltage fluctuation in industrial power consumption. The fully sealed corrugated oil tank structure isolates internal components from external dust, moisture and corrosive gases, preventing insulating oil aging and insulation degradation. With two conventional mainstream capacities of 200kVA and 300kVA, this series of three-phase oil immersed power transformers can flexibly match medium-load power demand of industrial parks, rural grid upgrades and municipal engineering projects, featuring high cost performance and strong operational stability.

2.  Technical Parameters

3. Core Purpose

The core purpose of 35Kv 200Kva 300Kva Three Phase Oil Immersed Transformers is to provide efficient, stable and safe medium-voltage step-down conversion and three-phase power distribution for 35kV industrial and municipal power grids. As essential medium-capacity power transformation equipment for medium-voltage grid terminals, these oil-filled three-phase transformers convert 35kV high grid voltage into standard 0.4kV low-voltage power or 10.5kV medium-voltage power, solving the voltage level mismatch between overhead transmission lines and terminal industrial and civil power consumption equipment.

In daily power grid operation, these Dyn11 three-phase oil immersed transformers undertake key functions including three-phase load balancing, power quality optimization, grid voltage stabilization and circuit safety isolation. The 200kVA model is suitable for conventional medium-load power distribution scenarios, while the 300kVA model reserves sufficient load margin to cope with peak power surge and future load expansion. Both capacities effectively suppress power grid harmonic interference and zero-sequence current, reduce voltage deviation caused by unbalanced three-phase load, and avoid equipment overheating and burnout. They continuously optimize the operating efficiency of 35kV medium-voltage power grids, reduce long-term energy consumption, and ensure stable and qualified power supply for industrial production, municipal infrastructure and rural centralized power consumption.

4. Application Scenarios

Benefiting from low-loss energy-saving performance, strong overload resistance and excellent outdoor environmental adaptability, 35Kv 200Kva 300Kva Three Phase Oil Immersed Transformers cover most mainstream medium-load three-phase power distribution scenarios of 35kV power grids. They are the preferred equipment for industrial supporting, grid renovation, infrastructure power supply and new energy grid connection projects:

• Small and Medium Industrial Factory Power Supply: Widely applied in machinery processing factories, food processing plants, chemical workshops and light industrial parks. The 200kVA and 300kVA medium-capacity models stably support long-term continuous operation of production lines, mechanical equipment and industrial auxiliary facilities, adapting to daily medium-load industrial power consumption demands.

• 35kV Rural & Urban Power Grid Upgrading: Used for capacity expansion and loss reduction transformation of old urban and rural medium-voltage power grids. Replacing outdated high-loss transformers, these low-energy-consumption oil immersed transformers effectively improve regional power supply capacity, stabilize terminal voltage and reduce grid operation energy consumption.

• Municipal Infrastructure Supporting Power: Suitable for urban water supply and drainage projects, sewage treatment plants, highway service areas and municipal engineering supporting facilities. They provide 24-hour stable three-phase power guarantee for public infrastructure and ensure the normal operation of urban supporting equipment.

• New Energy Station Grid Connection: Matched with small and medium-sized photovoltaic power stations, distributed wind power projects and energy storage systems. These three-phase oil immersed transformers complete stable voltage conversion and power quality regulation for new energy power generation, effectively suppressing grid-connected harmonics and ensuring safe grid access of new energy equipment.

• Mining & Field Engineering Power Distribution: Adaptable for open-pit mining bases, field construction projects and water conservancy engineering sites. With strong anti-interference and overload resistance, they adapt to complex field power consumption environments and provide reliable power support for engineering mechanical equipment.

• Commercial & Residential Cluster Power Supply: The 300kVA high-capacity model is ideal for large community clusters and comprehensive commercial zones, while the 200kVA model matches ordinary residential and small commercial areas. Both realize balanced three-phase power distribution and avoid voltage fluctuation caused by concentrated peak power consumption.

5. Product Features

35Kv 200Kva 300Kva Three Phase Oil Immersed Transformers adopt upgraded S13 low-loss design and mature industrial oil-immersed manufacturing technology. Compared with traditional old-spec transformers, this series of medium-capacity three-phase transformers have prominent advantages in energy saving, stability, safety and durability, fully adapting to long-term heavy-load operation of 35kV medium-voltage power grids:

• Ultra-low Energy Loss & High Energy Efficiency: Adopting high-quality low-loss silicon steel core and high-purity oxygen-free copper winding, the transformers greatly reduce no-load magnetic loss and load operating loss. All energy efficiency indicators meet national first-class energy efficiency standards, effectively cutting down long-term grid operation energy consumption and enterprise electricity costs, with remarkable energy-saving and emission-reduction benefits.

• Dyn11 Balanced Three-phase Output: Standard Dyn11 vector group design realizes precise balance of three-phase voltage and current, effectively inhibiting zero-sequence current and power grid harmonics. It can maintain stable voltage output under unbalanced load conditions, significantly improve terminal power quality, and reduce equipment failure rate caused by three-phase power imbalance.

• Fully Sealed Anti-leakage & Anti-aging Structure: Integral welded corrugated oil tank adopts fully sealed design, which completely isolates internal core, windings and insulating oil from external humid air, dust and corrosive substances. It prevents insulating oil aging, moisture ingress and insulation degradation, eliminates common oil leakage faults of traditional transformers, and extends equipment service life.

• Stable ONAN Self-cooling System: Adopting natural oil circulation and natural air heat dissipation mode, the cooling is uniform and efficient. It can quickly discharge internal heat generated by long-term full-load and peak-load operation, avoid equipment overheating failure, and ensure continuous and stable operation under variable load conditions.

• Strong Overload & Short-circuit Resistance: Optimized internal winding reinforcement structure and enhanced insulation design greatly improve short-circuit impact resistance and peak overload tolerance. The 300kVA model has more sufficient load margin, which can cope with sudden load surge and meet future power load expansion demands.

• All-weather Adaptability & Low Maintenance: The whole machine adopts heavy-duty anti-corrosion electrostatic spraying process, resisting ultraviolet aging, rain erosion, frost and snow damage. It can operate stably in harsh outdoor environments all year round. The modular standardized structure simplifies daily inspection and maintenance work, with low failure rate and low long-term operation cost.

6. FAQ (Frequently Asked Questions)

Q1: How to choose between 200kVA and 300kVA 35kV three-phase oil immersed transformers?

The capacity selection mainly depends on actual daily load, peak power demand and future expansion plans. The 200kVA three-phase oil immersed transformer is more suitable for small factories, ordinary residential communities and conventional medium-load municipal projects, with lower no-load loss and higher cost performance for stable daily load operation. The 300kVA model is preferred for scenarios with frequent peak load fluctuations, large power consumption and potential load growth, such as medium-sized industrial parks, comprehensive commercial zones and engineering construction sites. It has stronger overload resistance and load-bearing capacity, avoiding frequent overload operation and equipment tripping. Reasonable capacity matching can balance power supply stability and long-term energy-saving benefits effectively.

Q2: What are the core advantages of 35kV oil immersed transformers compared with low-voltage transformers?

35Kv 200Kva 300Kva Three Phase Oil Immersed Transformers are specially designed for medium-voltage power grid systems, with obvious advantages in transmission efficiency and power supply stability. Compared with conventional 10kV low-voltage transformers, 35kV medium-voltage transformers support longer-distance power transmission, effectively reducing line voltage drop and transmission loss. Equipped with enhanced medium-voltage insulation structure, they have stronger lightning resistance and over-voltage protection ability, adapting to complex outdoor grid environments. In addition, the oil-immersed cooling structure has better heat dissipation performance and higher continuous operation stability, which is more suitable for long-term uninterrupted power supply of industrial and municipal medium-load scenarios.

Q3: What daily maintenance is required for 35kV 200kVA/300kVA three-phase oil immersed transformers?

This series of medium-capacity three-phase oil immersed transformers has low daily maintenance threshold and stable long-term performance. Daily routine work mainly includes visual inspection of oil tank welding seams, sealing points and radiator surfaces to check for oil leakage, deformation and dust accumulation. Operators need to regularly confirm the insulating oil level and oil clarity to ensure they are within the standard range, and clean radiator dust to guarantee unobstructed heat dissipation. It is necessary to periodically test winding insulation resistance and three-phase voltage balance, and fasten high and low voltage wiring terminals. Long-term overload operation should be avoided in daily use. With standardized simple maintenance, the service life of the transformer can steadily exceed 25 years.