智能变电站一体化监控系统中网络平均负荷率：（)

A.正常时(任意30min内)≤30%，电力系统故障时(10s内)≤50%

B.正常时(任意30min内)≤10%，电力系统故障时(10s内)≤30%

C.正常时(任意30min内)≤20%，电力系统故障时(10s内)≤40%

D.正常时(任意30min内)≤30%，电力系统故障时(10s内)≤40%