The invention relates to a safe energy-saving and electric-energy-quality-improvement method for low-voltage electric power distribution network and electric power distribution equipment, i.e. a three-phase load unbalanced limitation method and a voltage-regulation type three-phase load unbalanced limiter. The invention installs the voltage-regulation type three-phase load unbalanced limiter a little larger than the load capacitance of a branch line at a load important node of the low-voltage electric power distribution network. The three-phase load unbalanced limiter forms a new three-phase power supply system with a load at the node part and generates a new ground neutral line N', and thus, the zero sequence current path is limited below the node. The voltage-regulation type three-phase load unbalanced limiter consists of a self coupling three-phase load unbalanced device or an insulation type three-phase load unbalanced device and a voltage-reduction switch. The invention limits the zero sequence current causing the unbalance of the low-voltage system below the circuit node, so the circuit above the node can realize the balance with the inter-phase load of the electric power distribution transformer, considerable consumption of the part can be eliminated, the damage caused by three-phase unbalance can be eliminated, and the safety level of the low-voltage electric distribution network can be improved.