A comparative analysis of the advantages and disadvantages of the YNyn0 and Dyn11 wiring methods is presented below.

The advantages and disadvantages of the Dyn11

In particular, the Dyn11 wiring method offers several notable advantages. First and foremost, it can provide a high-quality output voltage, which is essential for ensuring the stable operation of the power system. Secondly, the neutral point remains stable with Dyn11 wiring, even when the three-phase load is unbalanced. This reduces voltage fluctuations, ensuring a more reliable power supply. Furthermore, the Dyn11 wiring method offers enhanced lightning protection capabilities. This is due to the fact that lightning current can flow in the closed loop of the high-voltage winding, thereby reducing the impact of lightning on the transformer. However, it should be noted that Dyn11 wiring does present a potential issue in terms of non-full-phase operation. This can be effectively addressed through the installation of an undervoltage protection device on the low-voltage main switch.

The advantages and disadvantages of the YNyn0

In contrast, the YNyn0 wiring method also has its own distinctive advantages in certain instances. As an illustration, in the event that the fuse of a single phase on the high-voltage side is blown, the voltage of that phase will be zero, while the voltages of the other two phases remain unchanged. This limits the scope of the power outage to less than one-third, which has minimal impact on the lighting load of a single-phase power supply. However, for power loads powered by three-phase power, it is typically necessary to implement phase loss protection measures to prevent damage to equipment due to phase loss operations. It is important to note that the zero sequence impedance of the transformer in the YNyn0 wiring mode is relatively high, which can impede the removal of low-voltage single-phase grounding short-circuit faults.

How to choose Dyn11 or YNyn0？

In conclusion, the selection of a transformer wiring method should be based on a cost-benefit analysis of specific needs and system conditions. The Dyn11 wiring method offers advantages in output voltage quality, neutral point stability, and lightning protection performance. Conversely, the YNyn0 wiring method can reduce the scope of power outages in certain fault situations. However, it should be noted that the zero sequence impedance of the transformer in the YNyn0 wiring mode is large, which may not be conducive to the removal of low-voltage single-phase grounding short-circuit faults.