protective gap保护放电器,保险隙protectiveadj.保护的；防卫的protective relay testing继电保护测试protective tariff system保护关税制度, 保护关税税则protective contact grease保护性接触油脂protective coastal forest海岸防护林protective relay test set保护继电器测试仪Protective medical system保护性医疗制度protective control system保护控制系统protective concrete layer保护混凝土层protective source housing辐射源防护罩protective reactance coil保护电抗器保护扼力