Ruibian (Jiangsu) Electric Power Co., Ltd. is one of the leading manufacturers and suppliers of 66kv oil-immersed transformer in China. With abundant experience, our factory offer high quality products made in China with competitive price. Welcome to contact us for pricelist.
Materials and Special Design
Conductor Material
Adopts semi-hard copper wires or high-strength transposed conductors, which greatly enhance the equipment's capability to withstand electromagnetic force generated by short-circuit faults.
Insulation Structure
The main insulation applies the mature thin-barrel and small oil-gap structure, while reinforced oil-paper composite insulation is adopted for longitudinal insulation. The equipment reserves sufficient margin for power frequency withstand voltage and lightning impulse withstand voltage to adapt to complex grid conditions.
Tap Changer
Equipped with vacuum on-load tap changers adopting mature MR or ABB technologies, with a service switching cycle of no less than 300,000 times. It supports remote automatic voltage regulation without shutting down the equipment.
Bushing Structure
Fitted with professional 66kV capacitive bushings with high-temperature vulcanized silicone rubber (HTV) outer sleeves. The creepage distance reaches more than 1250mm, fully meeting the operation requirements of Class IV polluted areas with excellent pollution and aging resistance.
Core Advantages
Excellent Grid Compatibility: The 66kV voltage level bridges upper and lower power grid tiers. Transformers of this grade simplify power transformation procedures and effectively reduce power transmission loss in regional grid operation.
Compact Footprint: Compared with 110kV transformers of the same capacity, 66kV models feature a more compact overall structure. They are highly applicable to urban underground substations and scenarios with limited installation space.
Superior Short-Circuit Dynamic Stability: The transformer body adopts an integral pressure plate structure with epoxy glass fiber board for full support. The maximum dynamic displacement of windings is controlled within 2mm under short-circuit electromagnetic force, ensuring outstanding deformation resistance.
Reliable Low-Temperature Startup: An optional cold-start kit equipped with heating strips and automatic oil temperature control systems is available. It ensures stable startup and operation in extreme low-temperature environments of -40℃, perfectly adapting to alpine regions such as Inner Mongolia and Heilongjiang.
Low Full-Life Cycle Cost: Designed with high energy efficiency and long-life insulation materials, the equipment requires no major overhaul within a 20-year service cycle. It minimizes daily maintenance workload and delivers superior economic benefits throughout the whole operation period.
Application Scenarios
It covers a wide range of high-voltage power supply scenarios, including 66kV hub substations and terminal substations for regional power grids; power supply systems for large industrial and mining enterprises such as petrochemical refineries, large coal mines and non-ferrous metal smelters; 66kV traction substations for electrified railways; auxiliary power transformation equipment including station transformers and standby transformers for thermal power and nuclear power plants.
Packaging and Transportation
66kV transformers are generally transported with dry nitrogen sealing. The internal tank pressure is maintained at 0.01 to 0.03MPa during transit. After on-site delivery, nitrogen evacuation and vacuum oil filling must be carried out in accordance with standard procedures. A typical 20MVA/66kV transformer has overall transportation dimensions of 6.5m × 3.2m × 4.5m, which belongs to over-limit equipment and requires official over-limit transportation permits. If immediate installation is unavailable after delivery, the equipment shall be stored in a dry and ventilated indoor environment. The nitrogen protection pressure needs weekly inspection, and nitrogen supplementation is required once the pressure drops below 0.005MPa.
FAQ
Q1: Is partial discharge testing mandatory for 66kV transformers?
A: Yes. For all transformers of 66kV and above, partial discharge measurement is a mandatory factory test, with the standard partial discharge value limited within 100pC. Meanwhile, on-site partial discharge inspection is also required during project handover and acceptance to verify qualified insulation performance.
Q2: What is the routine maintenance cycle for on-load tap changers?
A: Maintenance shall be conducted once either after 50,000 switching operations or 5 years of continuous operation, whichever comes first. The maintenance contents include core inspection of tap changers, contact wear detection and insulating oil replacement.
Q3: Why is hot oil circulation necessary before transformer commissioning?
A: Hot oil circulation treatment can thoroughly remove trace moisture inside the transformer body and insulating components, so as to improve overall insulation strength and operational stability. Standard specifications require a circulation duration of no less than 48 hours and an oil flow rate of no less than 5m³/h to guarantee qualified treatment results.
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