The Dyn11 vector group (Delta primary, Star secondary with neutral) is the universal standard for modern three-phase distribution networks, offering several critical advantages over the older Yyn0 configuration:

1) High Tolerance for Unbalanced Loads: In commercial and residential buildings, single-phase loads (lighting, appliances) are rarely perfectly balanced across the three phases. The Delta (D) primary winding allows zero-sequence currents to circulate within the closed loop, preventing them from distorting the primary voltage. This ensures the transformer delivers highly stable voltage even when loads are severely imbalanced.

2) Harmonics Suppression: Modern grids are filled with non-linear loads (LEDs, computers, EV chargers) that generate 3rd harmonic currents. The Dyn11 delta winding traps and suppresses these 3rd harmonics, preventing them from polluting the high-voltage grid and reducing overheating in the transformer core.

3) Enhanced Safety & Grounding: The Star (y) secondary provides a solid neutral point, enabling standard 3-phase 4-wire (or 5-wire TN-S) distribution. This ensures safe 220V single-phase tapping and robust ground-fault protection for end-users.

This 3 phase dry type transformer does not need oil for cooling, so it is widely used in indoor places such as commercial buildings, hospitals and subway stations. It features low fire risk and simple maintenance, which makes the dry type transformer suitable for areas with high environmental safety requirements. It can work stably under moderate humidity and avoid leakage hazards brought by oil-immersed transformers.

Our three phase dry type transformer adopts high-quality cast resin insulation material, most models reach Class F or Class H insulation. It can withstand higher operating temperature and has strong resistance to moisture and dust. The solid insulation structure reduces partial discharge, extending the service life and lowering the failure rate during long-term continuous operation.

The resin encapsulated structure of the three phase dry type transformer provides good protection against dampness. But long-term extreme humid and corrosive gas environment will still affect its performance. We suggest installing dehumidification devices in the cabinet and keeping good ventilation to guarantee stable long-time operation of the transformer.

The three phase dry type transformer has no flammable insulating oil, greatly reducing fire and explosion risks. It produces less noise during operation and requires minimal routine maintenance. It also occupies relatively small installation space and can be placed close to the load side to cut power transmission loss for power distribution projects.