"高压输电线路网" can be translated into English as "high-voltage power transmission line network" or "high-voltage power grid for transmission".
"High-voltage power transmission line network" directly emphasizes the network of lines used for high-voltage power transmission.
"High-voltage power grid for transmission" highlights the grid (a more comprehensive system) specifically designed for high-voltage power transmission.
Both expressions are accurate and commonly used in the context of electrical engineering and power systems.