Optimal Placement of Dc Bias Blocking Devices with Multiple Constraints Based on Quantum Genetic Algorithm

In order to maximize the utilization ratio of equipment, from the perspective of the effects of direct current on the AC system, combined with DC current distribution calculation and AC power flow calculation model, this article takes multiple constraints like bus voltage, generator power and transformer reactive power loss into consideration for modeling the layout optimization problem of the blocking devices, so as to minimize the number of blocking devices in the network. In this paper, the quantum genetic algorithm is used to solve optimal placement problem of the blocking devices, which is a large-scale 0-1 integer programming. With IEEE 118 nodes standard power system as an example, for the condition of different into-ground DC currents, solution for optimal placement of the blocking devices is calculated. When the into-ground current is 3000A, it's necessary to equip blocking device for 8 out of 154 sets of transformers. When the into-ground current rises to 9000A, 20 sets of transformers need to be equipped with blocking device. With the increase of the into-ground current, the increasing speed of the number of required blocking device increases gradually, while increasing speed of the total neutral point currents of the system gradually slows down.