推荐回答（6个）
先估算电压损失。
380／220V配电线路电压损失的简易计算：
ΔU％=M÷（C×S）
M—总负荷矩（kW•m），如题，假设负荷在末端，
M=250×200（kW•m）；
S—导线截面（mm2），如题S=185；
C—电压损失计算系数，三相四线，铜芯导线，C=70，铝芯导线，C=41.6。
（引自《电工计算应用280例》，P．46）
该题，经计算得配电线路电压损失
ΔU％=（250×200）÷（70×185）=3.9，
线路电压损失没问题。
再核查导线的安全载流量，
查表可得，VV 185四芯电缆，25℃时的安全载流量为341A，
如果所有的负荷不会同时使用，根据设备的需要系数得到的计算负荷不超过170kW，该电缆能安全使用，
如果250kW的设备需同时使用，该电缆的截面不够，建议用VV 240 单芯3根＋120 1根，明敷。
VV 240 单芯25℃时的安全载流量为552A。
（数据引自《输配电速查速算手册》，P．163）
250kw差不多500多个电流,185的电缆虽然稍小了点,但250KW是安装负荷,所以电缆时可以用的.
看你用电的距离，远点就用8平方，近的话8.8够了，都是铜线啊，呵呵，不过现在的奸商多，好多不够流量，买的时候注意哈。主要看线芯大小。
可选1kV VV 单芯 240mm2
可选1kV VV 单芯 300mm2
（铜芯）
185的四芯铜线电缆安全载流量才396A，而楼主的输电功率为250KW，三相有功电流达500A（还不包括无功电流),还有200米的距离，因此太小了，如一定用电缆的话应用3*300+1*120的电缆才安全，用单芯铜电缆可用240平即可，还节约银子
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