特种电力电缆使用特性
1、接地故障允许时间
为了便于选择电缆，将运行的系统分为三类
A 类：任一相导体与接地导体接触时，能在1分钟内与系统分离；
B 类：每次接地故障持续时间不超过1小时，每年累计不超过125小时；
C 类：包括不属于A类、B类的系统。
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.
三相系统用电缆的额定电压表 Rated voltage of cable for three-phase system
系统电压Um/kV The maximum voltage vales for the system (Um/kV) | U0/kV | |
A 类 Category A B 类 Category B | C 类 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、额定温度
电缆长期使用时，其线芯工作温度不超过90℃。5秒钟短路温度不超过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、安装要求 Installation requirement
电缆敷设时不受落差限制，敷设时环境温度不低于0℃，电缆允许弯曲半径不小于电缆的直径10倍。对通交流的单芯电缆，要求采用非铠装或采用钢丝铠装，同时不允许敷设在磁性管道中。
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.
