1节点固定为平衡节点，其他节点为pq节点，程序可以计算网络损耗，支路功率，输电效率，平衡节点功率，潮流分布。-One node is fixed at a balanced node, other node to node pq, the program can calculate the network loss, the slip power, the transmission efficiency of node power balance, the trend of the distri