SCB11~18 Split-phase Dry-type Transformer for Photovoltaic Power Generation Projects of 35kV and Below

Structural Design of Dry-Type Transformers for Solar Photovoltaic Power Generation

Dry-type transformers for solar photovoltaic applications can be classified into 10kV class and 35kV class products. For 10kV class products, with a moderate voltage rating that makes the insulation structure relatively easy to handle, our company designs them in accordance with the traditional double-winding, two-split structure. The two sets of low-voltage coils are axially split, and the two sets of high-voltage coils are axially arranged. During the casting process, the two sets of coils are cast into a single integrated coil, and electrically, the two sets of coils are connected in parallel and led out as a single unit.

For 35kV class products, given the higher voltage rating, our company adopts a special structural treatment for the low-voltage coils in the design to ensure excellent electrical performance of the coils—such as partial discharge level and lightning impulse withstand capability (our company has currently applied for a patent for the relevant structure). With the structural treatment of the low-voltage coils as designed by our company, the high-voltage coil can be fabricated as a single coil, which reduces the number of turns of the high-voltage coil. Consequently, the number of segments and layers of the high-voltage coil are both reduced accordingly, resulting in a more uniform electric field distribution inside the coil.