I. Product Overview

The 110 kV oil‑immersed transformer is a high‑voltage oil‑immersed power transformer (maximum system voltage Um=126 kV). It is designed and manufactured in accordance with standards including GB1094, GB/T6451 and IEC60076. Adopting transformer oil as insulation and cooling medium, it serves as the core power transformation equipment for China’s regional power grids and urban distribution networks. The product range covers two‑winding, three‑winding and autotransformers. It is mainly applied for step‑down power transmission and step‑up transformation in power plants and new‑energy stations to realize electric energy transmission and voltage conversion.

II. Basic Structural Composition

Active Part: Core made of high‑magnetism cold‑rolled grain‑oriented silicon steel sheets with full‑mitred joints; oxygen‑free copper windings (transposed conductors), together with formed insulation parts and lead fastening structure, featuring excellent short‑circuit resistance.

Tank and Cooling System: Sealed steel‑plate welded tank. Common cooling modes: ONAN (Oil Natural Air Natural), ONAF (Oil Natural Air Forced), OFAF (Oil Forced Air Forced). ONAN/ONAF are widely adopted for medium‑and‑small‑capacity units; OFAF is selected for large‑capacity units.

Insulating Medium: Mineral insulating oil. Environment‑friendly ester insulating oil is optional on demand, functioning for insulation, heat dissipation and arc extinction.

Auxiliary Fittings: High‑voltage and low‑voltage bushings, on‑load / off‑circuit tap‑changers, oil conservator, gas relay, pressure relief valve, oil level indicator, temperature‑measuring elements, cooling fans. Optional accessories include on‑line monitoring devices for oil chromatography and partial discharge.

III. Main Product Features

Low Loss and High Energy Efficiency: Optimized design of core and windings reduces no‑load loss and load loss, complying with power energy‑efficiency requirements and cutting long‑term operating electricity costs.

High Operational Reliability: Adopts vacuum drying and vacuum oil‑filling processes with strict control over internal partial discharge for stable insulation, suitable for long‑term non‑stop operation.

Superior Short‑circuit Resistance: Reinforced winding ends verified by short‑circuit mechanical simulation to withstand short‑circuit surges from power grids.

Fully‑sealed Anti‑leakage Structure: Fully‑sealed structure with corrugated tank or capsule‑type oil conservator reduces moisture ingress and oxidation of oil, lowering maintenance workload.

Low‑noise Design: Vibration‑damped core and sound‑insulated tank structure meet noise control requirements for urban substations.

Intelligent Expansion: On‑line monitoring devices can be installed for connection to smart substation systems to support condition‑based maintenance.

IV. Typical Application Scenarios

‑ Urban 110 kV public substations and county‑level regional substations ‑ Main transformers for step‑up stations of wind farms and photovoltaic power stations ‑ Self‑owned substations of large‑scale industrial enterprises such as chemical, mining and metallurgical plants ‑ Power supply substations for critical loads including rail transit and data centers ‑ Renovation and capacity‑expansion projects of urban‑rural power grids

V. Explanation of Common Model Designations (Examples)

‑ SZ22‑50000/110: Three‑phase, Energy‑efficiency Class 22, 50 MVA capacity, 110 kV high‑voltage, two‑winding oil‑immersed on‑load tap‑changing transformer ‑ SFP‑63000/110: Three‑phase, forced‑air‑cooled, two‑winding transformer with 63 MVA capacity ‑ SSP‑90000/110: Three‑phase, forced‑air‑cooled, three‑winding transformer

Common connection group: YNd11; Voltage regulation modes: off‑circuit tap changing, on‑load tap changing.