Study on neutral point grounding method with low reactant for main transformers in Xi'an power grid

To get rid of the latent danger induced by the current neutral point grounding way of transforms in Xi'an power grid, an optimal grounding method of 330 kV auto-transformers and 110 kV transforms through a low reactance is proposed. The simulation results reveal that after grounding through low reactance with appropriate value, the single-phase grounding short-circuit current on the 110 kV bus-bar of 330 kV auto-transform decreases clearly, and the over-voltage on neutral point of other 110 kV transforms is significantly reduced to a lower level, which guarantee safe insulation of neutral point and enhance reliability of the power grid.