overhead line的用法和樣例：
例句
- Combinations of both overhead and under-ground HVDC line segments frequently occur.
高壓直流架空線路和地下線路分段的組合也常採用。 - It is difficult to obtain the dynamic models of converters, overlong overhead HVDC lines and passive filters in audio frequency.
然而，由於運行工況及氣候的影響，難以求取換流器及長距離高壓架空線路在音頻帶內的動態數學模型。
