110kV 12500kVA Three-Phase Oil Immersed Distribution Transformer with 11kV Output
1. Product Overview
The 110kV 12500kVA Three-Phase Oil Immersed Distribution Transformer with 11kV Output is a high-capacity, medium-to-high voltage grade power distribution equipment widely deployed in municipal power grids, industrial transmission systems and new energy power collection projects. As a standard 110kV step-down distribution transformer, it features a rated capacity of 12500kVA, designed to convert 110kV high-voltage overhead and cable transmission power into stable 11kV three-phase medium-voltage output, perfectly matching the voltage grading demands of secondary distribution networks and large industrial load terminals.
Manufactured strictly in accordance with IEC 60076, IEEE industrial standards and international energy efficiency specifications, this oil immersed distribution transformer adopts high-permeability grain-oriented silicon steel core and high-purity copper winding structure. The optimized electromagnetic layout effectively suppresses magnetic flux leakage, reduces no-load loss and load loss, achieving ultra-low power consumption and high energy conversion efficiency. Adopting mature oil-natural air cooling (ONAN) as standard with optional ONAF forced air cooling, the equipment supports long-term continuous full-load and variable-load operation. With a classic Dyn11 vector group design, it delivers balanced three-phase voltage output, strong anti-unbalanced load capability and low partial discharge performance below 100pC, ensuring stable and safe operation in complex grid environments.
Different from small-capacity distribution transformers, this 110kV high-voltage 12500kVA transformer adopts a fully sealed corrugated tank structure, which isolates internal insulating oil from external air and moisture to prevent oil aging and insulation dampness. Every unit undergoes rigorous factory tests including short-circuit impact test, temperature rise test and high-voltage withstand test, making it a reliable mainstream solution for modern urban grid upgrading, industrial park power distribution and large-scale power transformation projects.
2. Core Uses
The primary core purpose of this 110kV to 11kV three-phase oil immersed transformer is to implement hierarchical voltage conversion and safe power distribution in high-voltage power transmission and distribution systems. It acts as a critical step-down hub equipment to convert 110kV long-distance transmission high voltage into usable 11kV medium voltage, providing qualified power sources for downstream 11kV distribution networks, industrial power distribution rooms and high-power electrical equipment.
In actual grid operation, this high-efficiency 12500kVA power transformer undertakes key functions such as regional grid load balancing, voltage stabilization, power quality optimization and fault isolation. It can effectively buffer voltage fluctuation and line surge interference caused by grid load changes and new energy grid connection, stabilize terminal 11kV output voltage, and avoid power supply instability and equipment damage. The excellent short-circuit withstand capability can resist instantaneous grid faults, prevent fault range expansion, and greatly improve the overall safety and reliability of regional power distribution systems.
In addition, the low-loss design of this energy-saving oil immersed distribution transformer significantly reduces power transmission loss during long-term operation, lowers operational energy consumption and grid operating costs for power enterprises and industrial users. It also supports flexible voltage regulation through off-load tap adjustment, adapting to different grid voltage deviations and ensuring continuous and stable power supply for regional loads.
3. Typical Application Scenarios
3.1 Urban and Regional Power Grid Substations
This 110kV 12500kVA 11kV output transformer is the core equipment for urban district substations, county-level power grid hubs and urban power grid reconstruction and expansion projects. It undertakes the step-down distribution task of 110kV main grid power, provides stable 11kV medium-voltage power for urban residential communities, commercial buildings and municipal public facilities, and supports peak load regulation and daily stable power supply of urban power grids.
3.2 Large Industrial Park Power Distribution
It is widely used in centralized power supply of comprehensive industrial parks, chemical industrial zones, metallurgical bases and mining industrial clusters. Large industrial areas have concentrated high-power loads and require continuous and stable medium-voltage power support. The 12500kVA large rated capacity fully meets the simultaneous operation demand of multiple industrial equipment, and the stable 11kV output perfectly matches the power supply standard of industrial medium-voltage distribution systems.
3.3 New Energy Power Station Grid Connection
Suitable for centralized power collection and grid connection of large-scale photovoltaic bases, onshore wind farms and energy storage power stations. New energy power generation has inherent intermittency and volatility. This high-stability three-phase oil immersed transformer can stabilize fluctuating power quality, complete 110kV high-voltage matching and 11kV medium-voltage conversion, realize safe grid connection and centralized power transmission of new energy power, and improve the utilization rate of new energy power generation.
3.4 Key Infrastructure Engineering Projects
The transformer provides supporting power transformation for large transportation hubs, port terminals, data center clusters and urban comprehensive energy projects. These key infrastructure scenarios have zero tolerance for power supply interruption and high requirements for power quality. The equipment’s low failure rate, strong overload resistance and stable voltage output can ensure 24-hour uninterrupted high-quality power supply, guaranteeing the safe operation of key national infrastructure.
3.5 Rural and Remote Regional Grid Upgrading
It is applied to power grid upgrading in remote industrial clusters and suburban expansion areas. It effectively solves the problems of insufficient power capacity, aging equipment and unstable voltage in the original regional power grid, improves the power supply carrying capacity and coverage of medium-voltage distribution networks, and provides reliable power guarantee for regional industrial development and resident power consumption upgrading.
4. Core Product Features
4.1 Ultra-Low Loss & High Energy Efficiency
Adopting high-grade low-loss silicon steel core and precision copper winding process, this 110kV distribution transformer minimizes no-load current and operating loss, with overall energy efficiency exceeding mainstream industry standards. The optimized magnetic circuit structure eliminates magnetic flux leakage in full load ranges, maintaining efficient energy conversion whether under light load, medium load or full load. Long-term operation effectively reduces grid transmission loss and user electricity costs, delivering remarkable energy-saving and economic benefits for power grid and industrial projects.
4.2 Superior Structural Stability & Strong Short-Circuit Resistance
The internal coil adopts integral vacuum pressure impregnation and overall fastening technology, with high mechanical strength and structural rigidity. It can withstand instantaneous severe short-circuit impact and frequent load surges in 110kV high-voltage grids, effectively preventing coil displacement, deformation and insulation cracking. The integrally welded steel oil tank features high pressure resistance and structural stability, avoiding mechanical deformation during long-term operation and greatly improving equipment operational safety.
4.3 Low Noise & Low Partial Discharge, Eco-Friendly Operation
Through precision core stacking optimization and professional vibration damping structure design, the operating noise is controlled below 60dB, fully meeting urban environmental protection noise standards and suitable for urban suburban substation layout. The product strictly controls internal partial discharge value below 100pC, avoiding long-term partial discharge erosion leading to insulation aging. It features low noise, low radiation and zero pollution, conforming to green power grid construction requirements.
4.4 Fully Sealed Structure & Excellent Environmental Adaptability
Adopting fully sealed corrugated oil tank design, the equipment completely isolates internal insulating oil from external air and moisture, preventing oil oxidation, deterioration and insulation dampness. The whole machine undergoes shot blasting rust removal and multi-layer anti-corrosion electrostatic spraying, with excellent waterproof, moisture-proof, dust-proof and salt-fog resistance. It can operate stably in extreme environments such as high temperature, severe cold, high humidity and coastal salt fog, adapting to long-term unattended outdoor substation operation with a service life of over 30 years.
4.5 Flexible Cooling & Stable Voltage Regulation Performance
The standard configuration adopts reliable ONAN natural oil cooling system with stable heat dissipation effect and no noise interference. ONAF forced air cooling can be customized for high-load and high-temperature environments to enhance continuous operating capacity. Equipped with off-load tap changer, the transformer can adjust output voltage within a standard range to adapt to grid voltage deviation, ensuring constant and balanced 11kV three-phase output voltage and strong adaptability to variable load working conditions.
4.6 Low Maintenance & High Cost Performance
The fully sealed maintenance-free design eliminates frequent oil replenishment and internal cleaning work, greatly reducing daily operation and maintenance labor costs and later equipment investment. The compact and standardized structural design saves substation installation space, with simple on-site installation and commissioning procedures. With low failure rate and long service life, it delivers high comprehensive cost performance for large-scale power transformation and distribution projects.
5. Frequently Asked Questions (FAQ)
Q1: What is the optimal operating load range for the 110kV 12500kVA 11kV three-phase oil immersed transformer?
A: This 12500kVA high-capacity distribution transformer achieves the best balance of efficiency and service life when operating at 70% to 85% of its rated capacity for long-term continuous use. It supports 110% short-term overload operation within 2 hours to cope with instantaneous peak power consumption of industrial equipment and grid load surges. Continuous full-load or overloaded operation is not recommended, as it will cause sustained overheating, accelerate insulation aging, increase operating loss and raise equipment failure risks, affecting long-term stable grid power supply.
Q2: Can this 110kV to 11kV oil immersed transformer adapt to coastal high salt-fog and humid outdoor environments?
A: Yes, this fully sealed three-phase oil immersed distribution transformer is fully applicable to coastal, high-humidity and salt-fog intensive outdoor working environments. The fully enclosed oil tank structure completely protects internal windings and insulating oil from external moisture and corrosive gas erosion. The multi-layer anti-corrosion weather-resistant coating effectively resists ultraviolet aging, rainwater corrosion and salt-fog oxidation. Compared with ordinary open-type transformers, it has stronger environmental stability and can maintain long-term trouble-free operation in harsh coastal industrial and suburban substations.
Q3: What are the essential routine maintenance and annual inspection items for this 110kV 12500kVA power transformer?
A: Daily routine maintenance mainly includes visual inspection for tank oil leakage, abnormal operating noise and excessive temperature rise, real-time monitoring of oil level and oil color, and regular inspection of wiring terminals and grounding system firmness. Annual professional inspection requires testing insulation resistance, winding resistance and voltage transformation ratio to verify electrical performance stability. It is recommended to conduct insulating oil filtration and quality analysis every 3 to 5 years, and replace aging insulating oil regularly according to operating environment. Standardized maintenance can effectively eliminate hidden faults and ensure the equipment’s 30-year stable service life.
