Structural Design of Dry-Type Transformers for Solar Photovoltaic Power Generation
Dry-type transformers for solar photovoltaic power generation are available in 10 kV and 35 kV voltage classes.
10 kV Transformer Structure
Because the 10 kV voltage level is moderate, the insulation structure is relatively easy to arrange.
The transformer adopts a conventional double-winding and double-split structure. The two low-voltage windings are divided axially, while the two high-voltage coils are also arranged in the axial direction.
During casting, the two groups of coils are formed as one complete coil assembly. Electrically, the two coil groups are connected in parallel and led out through a common terminal.
35 kV Transformer Structure
Because the 35 kV voltage level is higher, the coil structure must provide reliable electrical performance, including low partial discharge and good lightning impulse resistance.
For this reason, the low-voltage winding adopts a specially designed structure. The company has applied for a patent covering the related design.
Based on this low-voltage coil structure, the high-voltage winding can be designed as a circular coil. This reduces the required number of turns in the high-voltage winding.
The number of sections and layers in the high-voltage coil is also reduced. The coils are connected in parallel and led out through a common terminal.
By reducing the number of sections and layers, the electric field inside the high-voltage coil becomes more evenly distributed.
