Multi-Object Ant Colony Optimization for Optimal Neutral Blocking Device Configuration

The earth return currents (ERCs) of highvoltage direct current transmissions can lead to DC bias of neutral-grounded transformers. An optimal configuration of neutral blocking devices have been proposed to minimize the risk by using the multiobjective ant colony optimization. The proposed configuration has been applied to an AC system in southern China. The online monitoring measurement data of neutral current shows that the risk of DC bias has been well controlled.