地下電纜線路 電纜及附屬器材 電纜遮蔽接地系統 電纜接續匣 電纜終端匣 電纜被覆保護裝置 氣冷式間接水冷卻 差動電驛保護 長期老化試驗 部分放電試驗 監控系統 Underground transmission line Cable and accessories Grounding system of cable metallic shield Cable joint Cable termination Protective device Indirect cooling system of air conditioner Differential protection relay Long term field test or prequalification test Partial discharge measurement Monitoring system