800~31500kva 35kv Oil-Immersed Power Transformer

35kV class three phase oil immersed distribution transformers comply with the standard of ANSI C57.12.00,IEC60076, GB1097(Power transformer) and GB/ T6451(Technical parameter and requirements for three phase oil immersed power transformer), both no-load loss and on-load loss are much lower, good quality C.R.G.O.core type, high-quality oxygen-free copper coil, good appearance, safe operation, widely used over the country.

TRANSFORMER PRODUCTION TECHNOLOGY

• TRANSFORMER WINDINGS

For the low and high voltage coils, either copper or aluminum can be used as conductor material according to the standards or customer requirements. Winding are separated as LV Windings and HV Windings.

Conductor types according to voltage level and load losses:

-On LV coil: Foil (sheet) or paper insulated rectangular sectioned

-On HV coil: Enamel insulated round or paper insulated rectangular sectioned conductors are used.

The windings are made of resin coated DDP and special Kraft paper resistant to high shock and electrical withstand. The structure of this specially formed layer insulation increases the impulse voltage properties. The layer insulation also helps in achieving another important goal: to produce a rigid coil without space.

• VENTILATION

Transformers are naturally cooled with ONAN ventilation. According to customer requirements, transformers with ONAF ventilation can be also manufactured.

• TRANSFORMER CORE

The core transformers are made of cold rolled grain oriented silicon steel (CRGO).

The steels are choosen according to no-load loss value M5, MOH, HI-BI quality class and 0,30-0,23 mm thickness range.

Cores are cut fast and without burr by modern transformer lamination cut machine. The cores are aligned according to the project data with step-lap method to reduce losses and noise.

• ACTIVE PARTS

Active part is formed by the placement of the coils to core legs and alignment of the upper core. Yoke clamps and wedges are placed to compress the coils. Cover, terminal and tap changer installations are done to make it ready for first pre-tests. The alignment of the insulations on the cover, accessories and other equipments are done according to the customer requirements

• TANK AND PAINT

Tanks are in 2 types: with radiator and corrugated walls. Tank base and top covers are made of mild steel. Corrugated walls of front and side surfaces o the tank also forms the cooling surfaces.

Front and side surfaces are made of steel sheet in tank with radiator,

Tanks are sealed with welding. Tanks are cleaned with special chemicals and dry before painting. Corrosion resistant and hardly adhesive undercoat paint is applied as two layers. After undercoating the tanks are subjected to drying process. After drying process, topcoat paint is applied on the undercoating according to the customer's dye thickness requests. The tanks wait in the drying Owens. RAL 7033 color code is used as to coating paint (or with different colors as per customer requests). Inner surface of the tank is coated with special varnish.

• DRYING AND FILLING

Low Frequency Technology for Drying and Filling Oil immersed type distribution transformer, the insulation materials have to be dried before oil filling. This drying process affects the quality of the transformer directly. Pearl Electric chose Vacuum Drying Technology for drying and filling under vacuum environment. Humidity is reduced to minimum in the oil and in the active part of the tank by this process.

TECHNICAL DATASHEET FOR POWER TRANSFORMER