voltage grade的用法和樣例：
例句
- Adoption of higher voltage class makes more rigor request for allowable value of switching overvoltage of the transmission lines.
電網電壓等級的提高對輸電線路操作過電壓允許值提出了更加嚴格的要求。 - With the transmission line voltage class escalating, ultra-high speed protection becomes the hot spot in the current researches.
隨著輸電線路電壓等級的不斷升高，基於行波原理的故障測距和超高速線路保護已經成為目前研究的熱點。
