DC transmission line的用法和樣例：
例句
- The converter units generate harmonics which flow in the AC and DC lines.
換流器單元產生的諧波會流過交流和直流線路。 - But high-voltage lines are already approaching the million-volt limit on insulators and the operating limits of semiconductor devices that control DC lines.
不過，高壓線路的絕緣體已經逐漸接近百萬伏特的限制，而控制直流線路的半導體裝置，也即將達到運作極限。
