特種電力電纜使用特性
1、接地故障允許時間
為了便于選擇電纜，將運行的系統分為三類
A 類：任一相導體與接地導體接觸時，能在1分鐘內與系統分離；
B 類：每次接地故障持續時間不超過1小時，每年累計不超過125小時；
C 類：包括不屬于A類、B類的系統。
Using properties
Earth fault permissible duration
The operating systems are divided into three categories available for selecting cable.
Category A: When any phase is earthed, the cable can be departed from the system within 1 minute.
Category B：The earth fault duration each time does not exceed one hour, the accumulated time shall not exceed 125 hours each year.
Category C: Excluded categories from A and B.
三相系統用電纜的額定電壓表 Rated voltage of cable for three-phase system
系統電壓Um/kV The maximum voltage vales for the system (Um/kV) | U0/kV |
A 類 Category A B 類 Category B | C 類 Category C |
7.2 | 3.6 | 6.0 |
12.0 | 6.0 | 8.7 |
17.5 | 8.7 | 12.0 |
24.0 | 12.0 | 18.0 |
36.0 | 18.0 |
|
2、額定溫度
電纜長期使用時，其線芯工作溫度不超過90℃。5秒鐘短路溫度不超過250℃。
The maximum rated temperature
The maximum operating temperature of cores shall not exceed 90℃ when the cable is used for long period. The temperature of cores shall not exceed 250℃ at short circuit for 5 seconds.
3、安裝要求 Installation requirement
電纜敷設時不受落差限制，敷設時環境溫度不低于0℃，電纜允許彎曲半徑不小于電纜的直徑10倍。對通交流的單芯電纜，要求采用非鎧裝或采用鋼絲鎧裝，同時不允許敷設在磁性管道中。
The installation of cables is not limited by the difference of level along the route. The ambient temperature should not be below 0℃ during installation. The permissible bending radius for cable shall not be less than 10 times of the cable diameter. The single cable shall be without amour or with steel wire amour when it is electrified with alternating current and shall not be laid in magnetic ducts.
